Please don't read too much into what I had said. The context of my statement was regarding the surging condition and what the AFR was doing. The INT and BLM values didn't matter in this situation.

As far as the money thing, I can definitely sympathize with you there. On the other hand the engine is going to need enough fuel to feed it. MSD sells an inline pump for about $70-80 US. Can try the 454 TBI with the original regulator and injectors to see how it goes. Once the cal is roughed in you can then make a decision as to how much more (or less) flow is required. At a minimum the vehicle will be driveable and you can get some tuning experience.

RBob.

 

i just found a injector sizing calculator. it fiqures at 13 lb FP a 68 lb inj at 90% DC will support 283 HP for 5.7L. up the FP to 20 lbs and it wiill handle 351 HP. a 90 lb will handle 360 HP at 13 lbs. and a 80 lb at 12 lbs is good for 320 HP. same 80 lb at 16 lbs FP is good for 370 HP. if we back the DC to 80%, 68 lbs inj at 20 lb FP at 7.4 L will handle 242 HP. it is possible that they are a smaller injector. still no answer from chev dealer? i dont have an issue cause i have the 90 lbs and will set at 10-12 lbs FP but if i did not i would have no idea where to set BPW. is there any advantages that we know of using a smaller injector but at higher FP to provide fueling requirements? i read the spray at all times(triangular?) must hit bore of venturi in TB RATHER that miss it and shoot directly into intake plenum? i wonder if GM determined higher FP has advantage in TB applications?

 

i got a response from dealer 26-32 lbs on 1995 454 TB....i will reverse calculate to assume 240 HP at 80 % DC at 7.4 L. sure looks like 68 lbs? will report back !! i think my 85 pump only flows 20 lbs max?

 

assuming 28 lbs FP and 68 lbs injectors at 80% duty and 454 cid will support 251 HP per calc. with the above and a 350 cid the BPW is 122. i say they are 68 lbs as was posted by someone previously when i questioned it.

 

80 lbs inj's at 28 lbs FP at 80% duty will support 285 HP. dont think GM would run FP that high with 80's in TB. above at .45 BSFC. boy sure would like to know for sure.

 

Thanks for digging through the injector sizing issue, Ronny...is that injector sizing calculator in Excel? If so, could you shoot me a copy?

 

corvette/injectorsizing.xls

 

:rockon:

Brace yourselves...the Camaro rides again!!!

I burnt a factory AXKW bin with BPC set @ 134, kept the 305 regulator spring for now, installed the new IAC valve, swapped the green wires (thanks sniper_dsl) and she now purrs like a kitten. I set the idle @ about 750 rpm because it seemed happy there...lower, and it started to die.

I took it for a drive to log some data and it did pretty well...but I can definitely tell it needs some tunin'. The worst problem it had was it almost died when leaving from a stop sign, which I think is due to running too rich @ lower rpms based on the data. Speaking of data, here it is (I converted the tables to html to make them easier to read):

<A HREF="http://www.barneswebdesign.com/20040206_100212_LOG.xls">First data log</A>

<A HREF="http://www.barneswebdesign.com/20040206_101314_LOG.xls">Second data log</A>

<A HREF="http://www.barneswebdesign.com/20040206_102121_BLM.htm">BLM table</A>

<A HREF="http://www.barneswebdesign.com/20040206_102129_INT.htm">INT table</A>

<A HREF="http://www.barneswebdesign.com/20040206_102141_O2.htm">O2 table</A>

<A HREF="http://www.barneswebdesign.com/20040206_102150_KNOCK.htm">KNOCK table</A>

From what I can tell, I'm rich @ lower rpms and lean @ upper rpms based on the BLM data. I was a little scared to open it up too much with the concerns about running lean. I can tell that the BPC increase definitely helped, but I've still got issues.

I know I need to make some VE table adjustments, so let me know if this is correct logic (reference attached VE table from factory AXKW bin): for example, I should decrease the value of 40.63 @ 800 rpm and 40% by (113/128) to 35.87...right? Let me know if I'm way off base or not.

Here's what I'm thinking I should do...install the 454 fuel pressure regulator spring, log some more BLM data, adjust the VE table according to the aforementioned method (unless it's incorrect), log more BLMs, and see how they look. If I'm still lean @ upper rpms, I should look into either a high-pressure fuel pump or larger injectors. Any thoughts?

 

Couple thoughts:

First thing I'd do to the bin is set the initial advance value to whatever you dialed the distributor in at. I think you mentioned 10 degrees. If you don't, this just tacks on 10 degrees to the entire spark curve which isn't nessesarily good. This will probably affect the BLM.

After the timing change you'll want to set the throttle blades.

Raise the Idle speed and Idle speed A/C On in the bin from 600 to 700rpm and 712.5 respectively. Get the engine warmed up and closed loop. Then let it idle. Back off the idle speed screw until the IAC counts climb up from zero to approx 5 counts. If the IAC count is zero the ECM isn't controlling idle speed. Keep in mind you can only back the idle speed screw out. If you turn it in the ECM thinks you're leaving idle. Stop and restart the engine to double check.

I didn't see much idle speed logged. The BLM takes time to stabilize otherwise you could be seeing the effects of various fueling corrections. The 1st log.xls isn't really worth much since the engine isn't up to operating temps.

The 2nd log we have 38-39 mph, 158 coolant, a nice steady TPS, MAP 38 and RPM 2450, with INT 130 and BLM 138. This is a good example of how to log. Lets everything stabilize. Add a percentage to the 2400 X 40 VE table and retest.

I'd sit in the driveway and just run the engine at every RPM in the VE #1 table and get some BLMs.

As far as the injectors, fuel pump etc goes....

The 454 30 psi regulator spring is a must. Even if you get the part throttle BLMs ironed out with the L03 spring it will still be lean at WOT.

You need a fuel pressure guage that you can view while driving. Something that could be taped temporarily to the windsheild.

This will show you when the TBI pump starts giving up. If I had to bet the TBI pump will give you a max of 20psi. The pressure will start to drop as you lean on the throttle. I will also bet that the pump won't last long at elevated pressures. If it does die the booster pump idea may not work as it probably won't like pulling fuel through a dead pump.

In otherwords, get a fuel pressure gauge and install the 454 regulator. If the pump can't make 30 psi you'll need the booster.

 

Thanks, Brent. Sorry about the first log...that's the "I just got my car running right after 7 months and I can't wait to log some data" run. Oh, and I forgot to mention that my VSS is still not converting properly...I was going WAY faster than 40 mph, it's just reading slow. I'm going to get it set accurately this weekend.

I made the following changes to my bin:

Initial spark advance: 10 degrees
Target Idle (A/C Off): 700 rpm
Target Idle (A/C On): 712.5 rpm

I wasn't quite sure what you meant by "Add a percentage to the 2400 X 40 VE table and retest." I have a value of 50.39 at that point in the table...do you mean I should use the BLM data I logged last night to make an adjustment at that certain point in the table prior to collecting more data? IOW, I'm seeing a BLM of 136.9 in my "narrow avg" BLM table, so should I increase the 50.39 by (136.9/128) to 53.89?

I am also going to swap back to my 454 regulator spring before collecting more data. I'll be sure to let it warm up to 160 so that everything is stabilized this time (I'm much calmer now). I'll also pick up a fuel pressure gauge this weekend and see how my factory pump does.

Unfortunately, all of my chip burning equipment is 25 miles from home at my job...but hey, it's free. It just keeps me from making a bin change, seeing how it does, and then quickly making more bin changes. However, I'll probably end up making several trips to work this weekend because I'm eager to get my bin optimized (or at least close).

Thanks for all the help and I'll let you know how it goes.

 

Yeah, that was poorly written. You have the right idea though.
Increase the VE table by the percentage the BLM is adding or subtracting fuel. It won't be extact.

In preparation for running the 454 regulator you probably ought to burn several PROMs to take home with you.

The 454 regultor will make the low RPM/ low MAP areas rich. Quite possibly rodent killing rich.

I'd go into VE #1 and reduce the 800-2400rpm X 20-60map area by 15%, 20%, 25%, 30% and burn a prom for each %.



Almost forgot, set EGR On Temp to 01 to disable the EGR routines. As you will note in the 1st log.xls Raw Coolant Temp decreases as the engine warms up. This is because the coolant temps are inverted. 01 is very hot while 254 is very cold.

You running a 160°F Tstat?

 

Thanks for the clarification. Unfortunately, I've only got my factory EPROM to play with...I purchased three additional EPROMS from Jameco, but they were from a manufacturer that the chip burner at work didn't recognize. I sent them back for credit. SO, it's going to take me even longer to "hone in" on an ideal VE table. I know I need to go ahead and reinstall the 454 regulator spring, but you're right...it's gonna be pig rich @ low rpms without some serious VE table adjustments. I guess I'll start out with a conservative 15% reduction of the VE table values in the range you specified and see what kind of BLMs I get...don't want to lean it out too much and burn my new motor up.

As for EGR disable, I already increased the "EGR On Speed" to 255 mph...but I can definitely modify the "EGR On Temp" as well. However, my hack labels the units as actual degrees (it's currently set @ 70.25 degrees)...not as the raw data. Is that an error? If so, I'll set it @ 01 as you advised...otherwise, it would seem to make sense to max it out, although it will only go up to 151.25 degrees.

Regarding the thermostat...man, I don't remember what I did there. The engine/tranny swap was such a thrash that it's tough to remember everything we did. I'm pretty sure I never removed the old thermostat now that I think about it...but I can't find a receipt for a new thermostat, either. Dude, I may not even have one in there...I'll check it out tomorrow and see what I find. BTW, do you recommend a 160F thermostat, in case I have to buy a new one?

One last question...is the "narrow avg" BLM table the best one to go by for making VE table adjustments?

 

Oh man, why make it so difficult on yourself? Call Astro Marketing and order 5 or so 2732 "pulls"(used). 407-727-8817 I haven't called them in a while but they had good prices.

The Speed variables doesn't seem to turn the EGR off in all cases wereas the Temp variable definitely disables it.

Jprevosts 8746 ECU shows EGR On Temp in Decimal. You want the raw hex to be 01 for the EGR On Temp. Just turn off the calculated values if you can.

I was just curious about the tstat becuase the temp seemed to stabilize at 160 in 2ndlog.xls but you listed a 180 on your website. I run a 180 because the heater doesn't work well with a 160.

I've never used the narrow, wide, avg BLM tables for adjusting VE. I have a different scan tool and just use the logged values.

 

Well, today was both frustrating and rewarding.

Frustrating, in that I couldn't get my Dakota Digital SGI-5A converter to work properly. Thus, you will still see inaccurate speed data in my data log. I'm going to have to give them a call on Monday...it looks like my #2 hi/lo dip switch doesn't work or something.

Rewarding, in that I swapped back to the 454 fuel pressure regulator spring and it made a definite change for the better. I have attached the narrow and wide average BLM tables...as you can see, my upper rpm BLMs are much richer now. Here is the rest of the data:

<A HREF="http://www.barneswebdesign.com/20040208_032559_LOG.xls">Data log</A>

I left my VE table alone initially and drove for about 7 minutes and let it idle in my driveway for about 2 minutes. My "Minimum BLM" is set at 108 in my bin, and I'm pretty much pegging it out at idle. That makes it a little difficult to determine how to specifically change the VE table, but I think I'm just going to cut all the values by 20% between 20-50% VE and 400-2400 rpm. It also looks like I should cut the values between 20-30% from 2800-3200 rpm...strange, my VE table only goes to 3200 rpm. What's up with that? Anyway, I'll see how the BLMs look after I reduce the VE table.

Oh, and I changed GMECM to read in hex and I set the "EGR On Temp" to 01. I'll include it in m next burn.

Regarding the thermostat, I believe I just planned on buying a 180F thermostat and never did. I still haven't checked to see what I've got...I'll get back to you on that one.

And thanks for the info on the EPROMs...I'll give them a call this week and pick up a few.

One last thing...I'm not sure that my coolant temp is accurate in my data log. My coolant was literally boiling by the time I shut down and my gauge was reading about 220F. I wonder if my CTS is in a bad location? I had to mount it toward the back of my Air Gap intake, while the factory location was in the front. Any thoughts?

 

That's because there are two VE tables. The ECM adds them together at all times to give resolution up to 6400rpm. You are currently working on VE #1.

VE #2 is added to VE#1 by RPM. The 1600rpm value in VE#2 is added to every cell in the 1600rpm row in VE #1.
The CTS should be as near the thermostat as possible. Aren't there 2-3 coolant taps in the front of the Airgap?

 

Hey Bulldog! did you ever resolve the lbs that 454 injector is out putting? i checked with GM and got the FP it is recommended at and posted earlier. now the spring in that unit is strong(orange) and as stated will be megga rich. be aware a specialy spring between the vette spring and the 454 is available through topdownsolutions.com and they an advertiser on forum. since you are tuning the orange may be acceptable. that alternative spring is for non tuners or vafpr users. just be aware the option is there. i am removing the injectors in my 95 454 and replacing with 90 lbs as i am tuned for that already but will run aeromotive FPR and start at 10 lbs.

 

Hey Ronny, I never did find anything that actually stated the flow rating for my injectors...however, I think it's pretty safe to assume that they are 68 pph based on the information everyone has provided. I'm going to do as Brent advised and hook up a fuel pressure gauge to see if I'm maxing it out @ WOT...if so, I'll either invest in a Walbro high-pressure fuel pump or larger injectors.

Oh, I think that the 454 spring is going to work just fine...but thanks for asking. You can see from the data log in my previous post that it definitely runs richer now, but I think I can correct that through adjustments in the VE table.

Speaking of adjusting the VE table, I can't seem to get GMECM to "take" my new numbers...anyone know what's up with that? It does change the values, but not to what I changed them to...strange.

Oh, and one more question...should I just leave VE table #2 alone for now? It's just a little confusing because I would expect there to be a big increase in the VE table #2 values (see below) above 3200 rpm since there are no values in that rpm range in table #1...but there isn't.

 

Meaning If you type in 31 it changes to 30.86 or something like that? This is normal. The VE number you read in the editor = Hex decimal (0-255) * 0.390625

In other words if your VE is 39.06 (decimal 100) the next step up would be 39.45 (decimal 101).

yes
That's because at 3600rpm and over, the values in VE2 are added to the 3200 row in VE1.

 

Brent...you are the man. :hail: :yourock:

I haven't been able to stump you on a single thing yet...I can't tell you how much I have appreciated all the help. I've learned more from you and these other DIY-PROM guys in the past month than I have in the past 3 years (Camaro-wise, anyway)...thanks a ton.

 

Well, I had hoped that I would be able to "take it from here" and leave you guys alone for a while, but...........I'm having trouble "tuning".

I have made a couple of attempts at adjusting my VE table so that I'm not running so rich at low rpms, but I seem to be making it run richer somehow! I mean, the BLM data is telling me that I'm getting better, but the white smoke coming out of my tailpipe tells me I'm getting worse. It's also not driving @ low rpms near as well as it did with my factory AXKW VE table. Here's a comparison of my factory and modified VE tables:

<IMG SRC="http://www.barneswebdesign.com/VEtablecomp.jpg">

As you can see, I have significantly reduced the values up through 60 KPa. This has helped my BLMs get closer to the "magic" 128 while I'm driving, as you can see here:

<A HREF="http://www.barneswebdesign.com/BLMcomp.xls">BLM Comparison</A>

When you look at the "Wide Average" table, I have progressively improved my BLMs. However, take a look at the "Wide Latest" tables, which represent my BLMs @ idle right before I shut the engine down. You can see that I go back to pig rich as soon as I stop moving...strange, huh? I was watching the BLM table as I drove and noticed that the BLMs actually looked decent @ lower rpms while I was driving, but they hit rock bottom once I go to idle. I could actually sit there and watch one of the BLMs in the 30 KPa column (must have been @ 800 rpm or so) go from around 120 while driving and plummet to 108 @ idle.

Here is my <A HREF="http://www.barneswebdesign.com/20040213_091408_LOG.xls">data log</A> I made tonight...it's got about 30 minutes of driving data on it. I also made a Pivot Table of BLMs for RPM vs. MAP, for what it's worth.

I am also concerned about the white smoke I'm getting now. I don't believe I was getting any smoke with the factory VE table. Also, when I was running rich before, I got black smoke, not white. Does that mean anything?

Any help is much appreciated...thanks

 

White smoke?! Is it cold enough outside that it could be exhaust condensation?

Is it lots of billowing white smoke? If so, sounds like you are burning coolant. Fuel doesn't make white smoke. When during operation does this smoke occur?

Don't forget, you reduced the timing so that will have an effect on drivibilty. I'd leave that be for now.

BLM's are getting better. Just follow their lead. Take another 25% off the VE1 at 20-40 X 400-1200 and see what happens.

Not having used Winaldl I will say that the "Wide" BLM tables seem confusing. The "Narrow" seem to track the raw datalog better. When in doubt, look at the raw datalog. It'll take some time for you to get comfortable with it.

I did notice when you hit 60mph it looks like Lean Cruise mode turns on. The INT locked at 128 and BLM locked at 125 while the O2 plummets to .044. That will definitely throw off the Narrow and Wide BLM reports.

 

My first thought was that the white smoke WAS just from it being cooler outside (it was about 45 degrees at the time), but it sort of smelled like raw fuel. It mainly does it when I first crank up the car and then it dissipates, so I'm hoping it's just exhaust condensation like you said. I just don't know why it smells like it does. Man, I pray I'm not burning coolant...although my engine does still have about 4 months of warranty on it.

I'll just forge ahead with my VE table adjustments...I know I need to trust the data I'm getting, it just confused me with it running seemingly richer each time I modified the table. It has also started to bog down worse when I try to take off quickly from idle.

Is that Lean Cruise Mode a bad thing, i.e. should I disable it somehow? I just didn't know if running that lean would be damaging to the engine.

I'll post when I get new data next week...thanks for the help!

 

A problem with tuning by BLM is that a BLM cell covers a wide area of the VE table. So for idle look at the idle KPa and idle RPM (from the data log) and adjust that area of the VE table.

If in steady cruise then do the same. If the BLM is 118 and the KPa is 60 with an RPM of 1500, then adjust that VE area accordingly.

It is best to disable lean cruise for tuning, then enable it again when done (if desired).

The bog with a quick take off from idle is lack of AE. It is becoming more apparent as you lower the VE table which is removing excess fuel.

RBob.

 

AE bog i was fighting all fall. as i enrichened it the temps fell and back to square one. i finally gave up 11/15/03 and put in barn. but i am thinking it partly due to design of xram not being a cold weather application.

 

That sounds normal. When an engine is burning coolant, atleast what I've seen, the white smoke is very thin or non existant on startup and then gets gradually worse as the engine heats up. Then its very noticeable, as in white clouds puffing out the exhaust.

 

My hack has the following constants that look like they could be for Lean Cruise Mode:

Highway Mode Spark Advance Speed Threshold
Highway mph threshold

Which one sounds right? They are both currently set @ 52 mph. Do I just set one of these to 255 mph or something?

Regarding acceleration enrichment (AE)...do I just not worry about that for now? I assume the goal is to get the VE table modified properly and THEN look at AE...correct? Once I get there, I'm not sure which tables I'll adjust...I see the following in my hack:

Power Enrichment Added Spark in WOT
WOT Air Fuel Ratio vs. RPM

Is one of these the table I will need to adjust when I get around to messing with AE?

Oh, and Brent...you're making me feel better about the white smoke. However, do you have any idea as to why I can smell more and more raw fuel coming from the exhaust every time I take more fuel out of the VE table?

 

I don't know. Haven't played with Hway mode. My guess would be to raise both to greater than 100 mph.

Just a note on setting things to decimal 00 or 255: others have mentioned that its best not to set values to 0 or 255. Something about it causing code jumps. The advice was to use 01 or 254.

I wouldn't worry about AE yet unless its causing major problems getting the car to pull out. You don't want it to stumble when you are trying to pull out of an intersection.

PE Spark @ WOT and WOT AFR are not really an issue till you are ready to do WOT performance testing.

I'd evaluate the fuel pressure before you do WOT testing.

AE is labeled something like Pump Shot vs TPS differential or Accel Enrichment vs TPS differential.

I'm not sure why the exhaust smells worse. Could be the uncalibrated nose and what you had to eat. Once the BLMs come up off 108 it should get better. My stock TBI truck stinks of fuel on cold start during cold weather and runs 122-128 BLM once hot.

Might not be a bad idea to pull the plugs and make sure they aren't fouling.

 

Well, I have taken another stab at my VE table and will test it out tomorrow night. One thing, though...when I change GMECM to show raw hex, it says that 255 mph = FF, not 01. I went ahead and set it to 254, which correlates to "FE" in hex. Just for kicks, I set it to "01" in hex mode and then changed it to calculated values...that correlated to 1 mph. Of course, I then changed it back.

Regarding AE, good point...I've gotta see what my pressure is looking like before I do any WOT testing. As for the bog, it's not TOO bad...I just have to take it real easy when I take off from a stop.

More to follow...

 

OK...frustration is starting to set in. Here's my latest data log:

<A HREF="http://www.barneswebdesign.com/20040218_100431_LOG.xls">Data log</A>

Regarding the white smoke @ startup...it is definitely getting worse every time I pull more fuel out of the VE table. I don't see how it can be exhaust condensation...it just hangs in the air and it totally wreaks of raw fuel. I have to take a shower every time I even get around the freakin' car while it's running because I wreak of gas fumes. Also, I'm shooting a small amount of water out the exhaust @ startup...I can even see a small puddle of water sitting in the exhaust tip. Does exhaust condensation cause this??? Of course, the white smoke still tapers off once the engine hits 160F.

As for my data log, I seem to be chasing my tail. I get a BLM of 108 @ 30 KPa and 2000 rpm @ idle, but in the 120s when I'm driving down the road. What gives? You can see towards the end of my data log (775-1062) that I hold it at certain rpms at idle (2000, 1600, etc) and you can actually watch the BLMs fall from the 120s down to 108. I don't understand what is causing this.

I'm just going to take a real, hard look at the data log (NOT the narrow or wide BLM tables) and attempt to make more VE table adjustments...I had heard this was difficult...and it is.

 

Would you post your bin file?

This white smoke and stinking exhaust getting worse confuses me. As you decrease the VE table in the 400-1200 x 20-50 range it should be getting leaner at idle. I've had to take the idle VE region down to as low as 5-10 to get the BLM up to the 120s. I'd reduce the idle region another 40% and see what happens.

This just mean the 30kpa cells of VE1 are rich, so reduce the 20-30kpa region of the VE1 table. When you are driving down the road your are at 40-60kpa and the VE is closer to being correct in those areas hence the BLM's are in the 120's.


One thought, you might want to datalog only when you are operating at a steady TPS, RPM and KPA. Make sure to drive at the RPMs listed in the VE table. It'll make the logs much shorter and easier to digest.

 

Wow...I didn't know that I could end up with VE table values that low (5-10). That makes me feel better...I was a little hesitant to take them down to that level, even though the BLMs indicated I should.

Regarding the increasing BLMs, I actually meant that the BLMs were increasing in the same 30 KPa and 2000 rpm cell of the BLM table. However, that was based on what I saw while watching the averaged BLMs live in WinALDL...after looking at the data log some more, I see that was not the case. All of the 108 BLMs occurred at idle...none occurred while driving at speed. My mistake.

I'll try to get better data logs in the future...I actually do try to hit the table rpms while driving, but it doesn't always work out right.

Oh, and here's my <A HREF="http://www.barneswebdesign.com/AXKW-mine-mod5.bin">bin file</A>. Now that I'm thinking a little more clearly, I can probably make some intelligent changes to the VE table based on the data log and get some improvements in my BLMs. Any recommendations are very welcome, though.

Once again, thanks for the help. I would probably have yanked this 350 HO and put my 305 back in by now if it weren't for this board.

 

Please don't use my old ecu file to update your main VE table. It isn't configured correctly and will mess things up! The order in which the table is read it backwards from that of the main spark. Then there's the limit of 3 characters x 5 characters for the labels which also through me off. So logically one would have though that if it's going to display engine speed you would need the 5 characters... but it's wrong wrong wrong!
I don't have my laptop in front of me but I'll e-mail you my new ecu file. I had a post on here a while ago addressing this issue but I don't think it got very far. I don't know if Mangus has the new version or not, hmmm.

 

Jon...dude...I think that explains everything. Hmmm...I "take away" fuel, yet it gets richer...a backwards VE table would make sense.

I will GREATLY appreciate it if you could get me your new ecu file, as well as any tunin' tips since we both have the same engine...thanks!!!

 

Oh no! lol Here I thought you were using www.gmpcm.com and their 61 definition file.

That same backwards VE table bit me when I was using Winbin on a 7747 many moons ago. Makes for quite a mess.

Might as well go back to your stock bin and make all the changes to the constants and start over on the VE1 table.

Here are the changes you made. Looks like no change was made to the 800 X 40-50kpa idle area.....

 

No, I'm using GMECM, which is what you appear to be using (except maybe an older version) based on the appearance of the VE table. What ECU file are you using, because my version of GMECM doesn't let you use a PCM hack file like 61.pcm?

That comparison table looks really weird...none of the changes I made are showing up properly. In addition, all of the changes are positive, which iimplies I was adding fuel and not taking it away. My ECU file must be way off base...here is the comparison table from GMECM using JPrevost's ecu file:

<IMG SRC="http://www.barneswebdesign.com/compare.jpg">

As you can see, it shows all negative changes because I was taking away fuel. Of course, your comparison may be positive because you opened the factory bin first and then compared the modified bin.

I downloaded GMPCM, but I can't seem to get it to compare bin files. Thus, I just opened up my same "mod5" bin file in GMPCM and GMECM to do a manual comparison....they were identical! I assumed that it would look totally different using the correct 61.pcm hack compared to JPrevost's hack...now I'm really confused.

Which goes back to me wondering how you did that comparison, Brent...can you help me out?

 

Ah, now I see. I'm using Tunerpro 3.05 (GMECM) and the 8746 ECU file. You're correct, the GMPCM PCM files won't work with Tunerpro.

Like Jon mentioned above, the VE1 table is incorrectly displayed by the ECU version you have. Thats why the confusion. The reason the comparison I pasted shows positive numbers is just the order in which I loaded the two bins. You did infact remove fuel, just not where you thought.

To correct the VE1 display: (I believe you'll need Ver 3.05 or better to do this)

Open the VE1 table in Tunerpro, press F2 and you will get the window I've attached. Just correct All the various fields to match and save. Then close VE1 and reopen it to see the change.

Once you've made the changes you will be able to duplicate the comparison I did.

 

Thanks for the clear instructions, Brent...now I get it. Basically, the X- and Y-axis needed to be swapped and the rpm needed to be sorted in ascending order. I made the ECU changes and arrived at the same comparison table as you did. I went back to my datalog from 2/7/04, which was before I changed the VE table but after I installed the 454 fuel regulator spring. I used it to make my VE table changes and the comp table is as follows:

<IMG SRC="http://www.barneswebdesign.com/camaro/VEtablecomp2.jpg">

I am hoping that this will work MUCH better than my previous VE table adjustments (ha). I'm also praying that the white smoke problem disappears as well.

One thing still confuses me, though...none of the ECU files I tried had the correct VE table #1 structure. My original JPrevost ecu didn't, obviously, but neither did the 61.pcm file I downloaded from the GMPCM site or the 8746jonprevost61h.ecu I downloaded from the TunerPro site (which I assume is the "corrected" ecu that Jon was referring to...I never heard back from him). So, I just used the 8746jonprevost61h.ecu and used the ECU editor in TunerPro to fix it as you recommended, Brent. Now I'm just hoping that there aren't any other errors in the ecu file that could cause me problems.

Oh, one more area of concern...the EGR On (Temp) setting. I had mentioned before about the fact that a raw hex of "01" correlates to 1 mph in calculated form. Do you still think I should use that setting, or should I just set it as 254 mph in calculated form (raw hex = "FE")?

Lastly, I wanted to mention that I was able to contact Astro Marketing, but only after I figured out that their area code has changed from 407 to 321...their current number is 321-727-8817 for anyone who is interested. I spoke with Sherry and she was really helpful...I ordered four AMD Am2732 PROM pulls for $1.25/each. What a deal! That's going to make it a lot easier on me with doing multiple burns, especially since I'm using company equipment to do it. I think these are 200ns chips...but I read that the speed doens't really matter on a 1228746 ECM...I hope so, anyway.

 

Those changes look like a good starting point. Agreed, however, Murphy's law says..... The other thing to keep in mind is, some constants and tables don't do exactly what they SEEM like they'd do.

Even with the commercial bin editors you might find an error here or there.

EGR on TEMP should be set to HEX 01.
Hway mode should be HEX FE or 254mph.

Thanks for the ph# update on Astro Marketing.

 

Well, the car appears to have responded very well to the new VE table changes. My BLMs incrementally came up in almost all of the areas where I made adjustments. I just did "iteration 2" last night, where I found my BLMs to finally go lean in some cases...looks like I'm getting close to the "magic" 128. Unfortunately, I'm still getting some white smoke @ startup, but not as much as before. I may end up swinging by a dealership to let them check it out just to cover myself before the warranty expires in June.

One thing I noticed about my new Am2732 EPROMs...they burn VERY s-l-o-w-l-y. I went from about a 3 second burn on my factory EPROM to a 3:30 burn on these EPROMs. I guess they just have a slower speed or something.

EDIT - I forgot to mention that the car now seems to have an idle problem, which I'm guessing is due to the A/F ratio changing now that I have reduced the idle fuel. The rpms will idle down to 750, but then they try to drop even lower, followed by a small increase in rpm, back and forth. At one point it was even causing my lights to dim...you can watch the voltmeter swing back and forth (FYI - I'm running March power pulleys, if that makes a difference). Should I just open up the TBI butterflies a little more?

 

OK, I just finished analyzing my BLMs from my datalogs last night and I need some help understanding something. I did three datalogs: one @ idle and two while driving. You can see my average BLMs I calculated in Excel for each data set in the attached picture.

As you can see, I'm getting conflicting information @ 30 Kpa manifold air pressure. I was a little thrown off when I got almost "perfect" 128s from 2500 rpm on up when I was at idle...I didn't think I'd be that close to "ideal". However, when I started driving I collected more 30 KPa data in 2nd gear and got significantly higher BLMs, especially @ 3000 rpm and higher. The idle datalog tells me to leave the VE table alone @ 30 KPa x 2400-3600 rpm, but the driving datalog tells me I should add more fuel.

Any thoughts?

 

A moving vehicle will have different airflow pattern into the intake and around the engine. The engine loading is also different with differences in chamber temperature as the engine load/speed is changed vs sitting at idle.

Tune the best you can to the moving vehicle data. If not running manifold heat and air intake heat (thermovac on aircleaner) this will have an effect on AFR.

RBob.

 

A while back, before the IAC was working, when the RPMs were surging around 1500-2000rpms, Rbob idendentified a lean problem. Seems to me this is the same thing. You could raise the idle speed, but this would only cover up the cause.

I'd try adding a bit of fuel at 400rpm X 40-50kpa. If that doesn't work then add a bit of fuel at 800rpm X 50kpa. You'll just have to try some different things. It may not like to idle at BLM 128. IMHO if its 122 or so thats ok.

That said, one thing that will help is to set all the idle timing values to the same thing. This way the timing isn't fluctuating as it's trying to idle.

I'd open Main Spark vs RPM vs Load and set 400-800rpm X 30-55KPA to 35.16.

 

TY. THIS IS HELPFUL TO ME AS I SURGE ONCE A WHILE AND I LEARNED THIS TRICK JUST PAST 2 WEEKS. WHY THE ODD SA 35.16 ??? WHY NOT 35.00 ??

 

My factory spark table has values of 35.16 for 40-50 KPa @ 800 rpm, so he may just be recommending that I match it to them. Thanks for the tip, by the way...I'll try it out on my next burn.

 

After some further thought I believe there is another reason for the idle surge.

You mentioned march underdrives, and a swinging voltmeter at idle. So I took another look at the last log you posted.
If you go to rows 882-890 you'll see where the IAC opens 3 counts when the Voltage drops to 12.6 and the engine speeds up a bit. This happens a couple times.

I suspect that the voltage stall saver is kicking in and causing the idle fluctuation.

If I'm correct, lowering the Batt Volts stall saver will cure the idle fluctuation.

 

I have been WAY busy lately, so my chip burnin' got put on hold...but I plan to hit it again this week. I'll post once I've made the spark table change and let you know how it worked...thanks

 

Well, I still haven't tried a new bin...but I HAVE been driving the car daily to work for the last week and I now have some new concerns. However, first things first:

Brent - My stall saver is currently set to 12.4V...how much do you think I should decrease it? Also, should I go ahead and adjust my spark table as you mentioned anyway?

Back to the issue I discovered this week...I get 14 mpg.

I was obviously expecting a decrease in mileage, but was encouraged by JPrevost's comments about getting 21-23 mpg with his 350 HO/TBI combo. I believe I pretty much have my Dakota Digital speed converter box calibrated properly...it may be reading like 1 mph slow or something. So maybe I'm getting 15 mpg...still pretty bad.

This especially concerns me because I have trimmed so much fuel out of the VE table that I am totally BABYING the throttle as I shift through the gears in an attempt to keep the engine from coughing and sputtering (presumably from lack of fuel). However, I do sometimes have to rev the throttle in 1st gear to keep it from dying, which doesn't help the gas consumption.

Another thought I had was the fact that the car idles @ about 2000 rpm when the engine is cold. After several minutes, it finally falls back down to 750 rpm...but I imagine it sucked down quite a bit of fuel in the interim.

I am also concerned about my coolant temperature. I had to do some "stop and go" driving the other day and I was totally boiling the coolant with the temp gauge reading 220F. Oddly enough, I have even heard the coolant boiling briefly after engine shutdown with the temp gauge reading 160F. I am pretty sure I have a bad CTS because my datalogs usually have about a 20F deviation from what my temp gauge says...but now I'm wondering if my temp gauge is even reading correctly. It'd be horrible to burn this engine up and not even know it!

Anyone have any thoughts here? I'm planning on bringing the chip burning equipment home this weekend so that I can do a full court press on my "issues". I am also planning to finally hook up a fuel pressure gauge and determine whether I need a bigger fuel pump or bigger injectors...this "bog" problem is driving me nuts.

EDIT: I forgot to mention I have a brand new fan switch, but I haven't verified that it works. My overheating problem could very well be the result of the fan not coming on when it should. I'll do some testing to see if it comes on properly. Also, I still need to move my CTS back toward the front of the intake.

 

Idle Spark Advance (35.16) - Yes, that is the first change I would make to try and cure the idle fluctuation. Even if it doesn't cure the surge it can only help.

Batt Stall Saver - Try taking it down to 12.0 and see what happens. Might be helpful to connect your DVOM so you can watch the battery voltage as its surging. I only mention this because the datalogging isn't fast enough to report really quick events.

If those changes don't work then maybe try working the VE cells mentioned before.

The mileage will increase when you start dialing in the spark advance. As far as the cold warmup goes, that's something I'd worry about after the main VE and Timing tables are tuned.

Regarding the stumble - It might be a good time to add some AE. I'd go into Pump Shot vs Diff TPS and add 15% to the 3.1 - 12.5 cells. Save that bin and make two more with 25% and 35% increases over the stock values. Take all three on a drive and see which one works best.

Thoughts on Coolant temps - First thing is to get the CTS back to the stock location. If it still reports lower temps then the gauge you'll want to figure out which one is failing. In my experience the ECM reported temp is usually "close" to the gauge temp. If you've got a stock fan switch you might want to consider the ZZ4 fbody conversion fan switch which turns on at 205F instaed of the factory 238F. Its GM #3053190 or ACdelco #D1874D. You'll want a 180F thermostat also if you use the ZZ4 fan switch. The fan should run when you ground the fan switch lead with the igntion on. Turning on the AC should also run the fan.

You might have a bad radiator cap if its boiling at lower temps. It shouldn't boil until around 250F with a 16psi cap and proper antifreeze mix.

Almost forgot, what version of WINALDL are you using? MrDude posted a datalog recently from his 91 RS and all the bit flags seemed to line up which makes me wonder why yours don't.

 

Well, I had a busy weekend working on the car, but haven't had time to take a breath until now...geez. Anyway, I made a little headway, but not much.

I pulled out my CTS and the brass plug on the front of the intake (where I want to mount the CTS) and traveled down to my friendly Advance Auto Parts store. I needed a reducing bushing to mount the CTS, but they didn't have one. They also did not have what I thought was a "common" in-line fuel pressure gauge...now I'm gonna have to order it from Summit...once I figure out how the heck to tie it into my fuel lines. I'm going to have to totally replace my factory hard lines because they're rubbing against my intake and it's just a matter of time before a hole gets worn in them.

I also removed my thermostat and was surprised to discover that it was rated at 195F! That's really strange, considering the car seems to run at 160F while driving down the road. I went ahead and bought a 180F thermostat and dropped it in...my temp gauge now reads about 140F when driving. Of course, the fluid is often still boiling when I shut the engine off. Like you said, it may be my radiator cap...it often boils below 200F...which I thought was impossible (isn't boiling 212F?). I now remember that I had trouble with the car overheating even before I swapped the motor...goes back to me screwing up the fan switch when I installed my headers. I replaced it (twice), but it has never seemed to work right since.

THANK YOU for the pump shot info...I'm hoping that will address my severe "bog" problem. I still haven't tried a new burn...hopefully this weekend. Do you think there is any risk in modifying the AE since I haven't been able to verify whether I'm "maxing-out" my factory fuel pump pressure?

On a side note, is it a problem to tie my air vent controller line into the MAP sensor vacuum line? I noticed last week that my A/C would only blow out the defrost vents...did a search on thirdgen and discovered that I had not hooked up the vacuum line going to the air vent controller. I just wasn't sure if it would somehow give bad MAP sensor readings or something.

 

give some thought to using aeroquip "push fit" hose and appropriate "push fitting. good product. the reducer to sensor i obtained from hypertech. i have 180 therm and it runs below that regularly especially if cooler temps