thewizzard

Hey All:

So I'm at my wits end. Just built 355 w/ vortec heads, performer vortec intake, Ultimate TBI moded TB, prominator. I'd done a previous tune with a much bigger cam, but swirl port heads... And had it in a very driveable/useable state where I drove it daily for couple of years, so I'm not entirely new to this... but....

Used an ARHT bin to break in the engine (flat tappet RV cam), didn't quite make 20 minutes on account of #5 header pipe getting a little red... But broken in none the less.

FP is ~28 psi, bpw set to 95, vortec spark table transposed into the 747 prom.

I know I have acel pump issues, on account of it stumbling at tip in, I've remedied this temporarily to the point where it doesnt completely die when you hit the throttle... but this is the least of my worries.

I CANT GET IT TO STAY IDLING!!! I've given C/L idle RPM about 800-850... Runs very smooth up past 1200RPM... extremely smooth actually! But below that, it runs like a bag of cr*p!! My BLM's are all between 120-135... so I know I'm not running too lean/reach (after tweaking the VE table a little bit, and at least in the 30-60kpa/400-2000RPM range)... sometimes it will idle "decently" for a couple of minutes before changing something (????) and wanting to stall out (have to feather the throttle to keep it going). Also it stall immediately after letting of the throttle... Also every now and then when trying to idle, it'll jump up to 1300RPM or so... then when coming off of this rpm, immediately die...

It's not throwing any codes either...

HELP???

Six_Shooter

iTrader: (2)

I had what sounds like almost the exact same symptoms using a '7747 ECM.

The difference was though I was running a custom made MPFI intake on a 365 (smaller sibling to a 409).

I was able to get it to idle around 1200 RPM, but not in gear (TH400), and would always want to stall coming to a stop.

I dteremined that it seemed like the injector pulse width may be getting too short to lean out the fuel. I think that the injector drivers could run the injectors properly and would only fire the injectors on the peak part of the peak and hold. This would make for a very short pulse width, with a long time between peaks of the P&H signal form. I wouldn't think that you would be experiancing this however, being TBI.

Have you tried a lower fuel pressure? You may be forcing the injectors to stay closed at lower RPM, and need high RPM (frequency of pulses) to provide enough voltage to open the injector.

thewizzard

I haven't tried that no... I may give it a shot... But I thought I'd read (I think Fast355's budget TBI buildup may have stated this) that people had successfully run 65lb injectors down to 80BPW? Someone correct me if I'm wrong here, or if I've missunderstood something??
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I'm convinced that once I solve this no-idle issue, the rest of the tuning will be relatively easy (yet time consuming) by comparison... Just have no idea what to do next!!

Six_Shooter

iTrader: (2)

No, what I'm thinking may be your issue has very little to do with the BPW, it has to do with the pressure on the pintle in the injector itself possibly holding it closed. In just about every TBI thread I've read where idle has been an issues I seem to recall higher than normal fuel pressure being used.

thewizzard

Thanks Six... I will give it a try tonight...

Only thing that confuses me is that I haven't actually changed the FP from the last engine (the one with the bigger cam that was - for the most part - tuned in and ran great).... So I'm a little sceptical as it didn't seem to be an issue with the old engine....

But of course, it's fuel/timing requirements were much different than this engine, so it's possible that the amount that was getting through the injectors was enough to keep that engine running, but not enough for this one....

The other strange thing, is that I know it was popping out the exhaust in the 800-1200 RPM range before making some VE/BPW adjustments... indicating a rich issue, backed up by my BLM's being in the 105-115 area...

So if the FP was too much for the injectors to open at that RPM, why would it run pig rich in those cells?

Don't think I'm disregarding your input... as I VERY MUCH appreciate it... I'm just trying to understand why is might be an issue compared to what else the computer is telling me...
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Also... it seems to be happiest when my IAC counts are between 80-144??? Is that right?

thewizzard

Couple more questions.

So vortec heads and intake... read on TGO that initial timing should be about 10*... which it is. Set that in the puter too... copied vortec timing table into main spark table.... But what about warm/cold spark bias? Should this be adjusted as well to reflect the initial 10* advance?

Also... buddy of mine just mentioned to me that maybe I need to reset my valve lash as after break in, it might be possible that they've pumped up more than they were pre-break-in? Should mention that before break in, couldnt even start it as my valve lash was too tight... reset it, then broke it in... Is it possible that this could be the problem too?

Fast355

iTrader: (2)

My advice, having had a similar issue, is bring the engine up to TDC # 1 and check the orientation of the rotor in the distributor. The results may suprise you, my engine ran with the distributor 180* out of time. I even drove it on the road, just not much power, sounded like crap, and got the headers really hot. It would only idle with the timing cranked way up. It was a mess until I troubleshooted it and fixed the distributor.

thewizzard

Can't count the number of times now I've second guessed myself on the timing thing, but only so far as to move it forward/back 1 cog... As I was assuming (on account of #1 in/exh being completely relaxed at the point where I was dropping the distributor in)... never actually did the finger test on #1... so it is definately within the realm of possibility.

Think I've messed something up now though... as it barely runs... maybe fouled plugs??? Will have to check tomorrow it's -45C with the windchill here right now....

I'm so <expletive> grumpy right now I can't even laugh about it!!!

Keep 'em comming though.... I appreciate everyones input.... I know I'll get it going, just losing patience with it right now... And I'm sure it's something simple!

Ronny

iTrader: (1)

If it is in fact too small a PW for injectors to handle the ans may be run OL idle and lock synch(no asynch). In your datalogs you may be able to see the inj PW bouncing up and down which is evidence of above issues. That is what I evidenced in my logs. I also have a VAFPR past season and it too would help by reducing FP at idle.

thewizzard

Sooooooooo...... An update. Turns out one of my injectors was only firing half the fuel it should... replaced and immediately had a huge power increase. Could actually get it up to 100Kms on the highway... and has some good low end power...

Problems however... still idles like cr*p! Or rather not at all... low rpm cruising has a major stumble/bucking...

So Injector explains lack of power and why during break in I had a header start to glow... Still haven't tried reducing fuel pressure... think that may be my next step! Though again, wasn't a problem on the old engine that used the same FP???

Very frustrating and confusing!

thewizzard

Quick question.... How do I get my datalogs to output BPW and timing?

RBob

iTrader: (1)

Head over to the TBI board, in the sticky's, Come in for a Free Tune. I posted it for the '7747 and '8746 in that thread.

RBob.

thewizzard

So.... Can someone have a quick look at my spark table/graph (attached - hopefully)... and let me know if it looks decent for a vortec headed engine using an intial 10* advance?

FYI - the attached is not actually what's in the vehicle right now... I put a stock arht in just to be able to "kinda" drive around (Have to two footer to keep it going when stoped or coming to a stop). But thinking of putting this one in based on what others have posted as being their vortec spark tables.


Another thing to note... when in "limp home" mode... or while uploading a program while the vehicle is running... when the IAC opens up, it runs and idles "GREAT"!!! Ideas? I've tried adjusting the idle screw... as suggested in "IAC Logic" under 747 in the stickies... but the TPS doesn't reset itself??? :S

thewizzard

Thanks Rbob... is there any way to have them both output at the same time, if say I didn't care about knowing my temp? Or some other location?

Oh, and another thing I just noticed. Thought the cam was pretty mild (i.e. RV Cam)... And given I don't have the specs for it on account of the fellow I bought all the engine components from had lost the cam card (and all he could remember was that he had bought with having a relatively torquey engine in mind)... The engine, when it does idle, does so very roughly and at 50-60Kpa.... Is this an indication of a vacuum leak? Or just that the cam is bigger than I originally thought? Or just that it's idling like crap and therefor not pulling as much vacuum as it would if it was idling smoothly?

thewizzard

OK.... So I think I might know what I need to do. Perhaps it is that the vortec at idle, is breathing that much more than my LO5 used to.... meaning it needs more air to idle and run properly (evidenced by my high IAC counts). As such, and after much research on here, I think my next steps are:
1) perform IAC reset to have the pintle fully extended
2) modify TPS to allow additional adjustments
3) Open air screw whilst maintaing a 0% TPS to the point where the engine idles steadily at the desired RPM
4) Re-connect IAC and really start tuning

I'm hoping this will do the trick... just based on other folks having the same type of problem...

nedoss

iTrader: (1)

Something else to check which gave me trouble with stumbling and idle was I had installed the incorrect spark plugs in my vortec heads. I used the standard R45TS (1/2 in thread depth) where I should have used R45LTS (3/4 in thread depth) I never knew how much difference a 1/4 in could make .

Fast355

iTrader: (2)

Before you do any of this. Here is the easiest thing to do. The TPS will automatically zero itself to the lowest voltage reading it sees within specification. I would open minimum air screw a good 5-6 turns. Perform the IAC reset. Start the engine and bring down the idle to a reasonable amount. Then shut it off and reconnect the IAC. No modification to the TPS necessary.

I also remember Kurt (OldRed95) having this issue when he put vortecs on his 350 TBI. I run R42LTS plugs though.

thewizzard

Did the IAC/min-air adjustment, and was still having troubles. So figured I'd check the injector we didn't replace as the fuel stream seemed a little erratic. Found a whole whack of crud in there... I guess from sitting for so long without the hood on while I was rebuilding the engine... cleaned it out, and figured while I was at it to put the stock FPR back in (albeit with the pressure cranked)... started running WAAAAAYYYYYY better!!! I also put the above spark table in and have been able to drive it around with minimal "2-footing" to keep her going.

Strange thing is it runs fantastic when cold... but once warm it won't stay idling in gear, and begins to idle real rough... like it's got a miss or something.

Any ideas? Also it's still missing power down low.. once at higher RPMS it's not so bad... but not happy off the line... bogs even some times.

Cheers!!

thewizzard

The saga continues.. and need all of your help again very much as I'm now more confused than ever.

SoOOOOOO.....

Good news first. I see the light at the end of the tunnel! As I now have a definitive reason for my engine running like garbage.

Accidentally forgot to reconnect EST wire today after once again trying to figure out why it just wasn't running right... drove away and found I actually had some power!!!! woohoooo... but couldn't figure out why my ses light was still on and the codes not clearing for EST.... realized my err when back at the garage, plugged EST back in... runs like cr*p... Unplug... runs good again. Check the timing with EST plugged in, running at 0*???? (had 10* initial without wire connected, which is what vortecs are supposed to run at right?)....

So Bad news:
- Don't know what to do with this info... Is my dizzy toast? Rechecked my .bin after following the "SA Logic" sticky for the 7747.... found problem with my cold sa bias being 20 and having changed my "coolant comp sa" to 10 in operating temp fixed that, so what was showing in my main SA was supposedly my true timing... Still at 0*??? change main sa by +6 degrees, recheck and now at like 2*??
- Developed a moderate oil leak that I'm PO'd about and too PO'd to even crawl underneath and check where...


Any how.... now more than ever I need your folks help... cuz I'm feeling like this is some kind of quasi breakthrough... and can tell that once proper timing advance is introduced this thing is gonna SCREAM!!! At least I'm pretty sure it will...

RBob

iTrader: (1)

Either the ignition module is bad or the two wires from the pickup coil to the module are reversed.

RBob.

thewizzard

OK... So checked dizzy for the pickup coil wires with plans to reverse them and see what happens... AAAAaaaaaand... it only goes on one way....

So that can't be the problem. So......

Can someone explain to me how a ignition module going bad would actually retard the timing rather than simply do nothing with it? Or not work at all?

Is there a way to test it before going and spending 100 bones on a new one?


Thought... that would explain why it runs great when cold and like a bag when warm... if the ignition module is in fact cutting out or having the opposite effect than it's supposed to (i.e. retarding the timing). When I cleaned the dizzy while rebuilding the engine, I did take the module off the dist and cleaned... when re-installing put dielectric underneath instead of lithium (as I didn't have any)... but I wouldn't have thought that would make too much difference....

RBob

iTrader: (1)

The wires could still be reversed in the connector. If this problem happened suddenly then it most likely is not reversed wires.

Do you have access to a know good distributor? Just to drop in and try?

Another thought is that the cylinder count in the calibration affects the timing. Be sure that it is set correctly for the engine.

RBob.

thewizzard

I don't... unfortunately (have access to a known good dizzy that is).... :sad:

Double checked my cylinder count... looks good (i.e. 8)

As for when it started, I guess it depends on your definition of suddenly....

It "seemed" to work fine in the last engine I had in the vehicle... But has never been right since I dropped it in this one... And like I said, I did have it apart to clean it, though not so far as to have the pickup coil removed! Not for lack of trying, but couldn't figure out how to get it off the dist...

I don't recall ever having removed the wires from the connector... but if you think its worth a shot I'll try anything once!! Which should be green and which should be white?

Unless I'm missing something (in the SA logic), with my initial 10* advance at the dizzy, and idling at 700-800RPM in the 50-60 kPa cells, my advance with EST connected "should" be anywhere from 11.5-14 degrees...

I have warm bias at 0, cold bias at 10, coolant comp sa at 10 in operating cells, max spark at 32 (assuming an additional 10 at dizzy for a total of 42 which should be more than adequate), max retard at -9.5, and everything else zerod out.... I have not touched the latency correction... but assume it should remain the way it is stock...

Also thinking I may just go and pick a module up... as it does seem to start missing a little/run a little rougher once warmed up... maybe it is on it's way out.... I'm just having a hard time wrapping my head around the module retarding by 8-10 degrees when it otherwise runs well (and no knock counts so I can't see "knock retard" being an issue)....

thewizzard

Changed pickup coil and ignition module.... instantly knew things were better!!!!! I feel like mechanically, everything is now as it should be...

The shaking and missing was gone, ran AMAZINGLY smooth in comparison.... actually idles, and in gear as well - for the most part (stalled once but I think that's unrelated). stock vortec table didn't do so well at low rpm acceleration/off-idle tip in. Another SA curve that I kind of eye balled from another thread talking about vortec SA tables seems to work way better (more timing and a smoother curve)... boat loads of torque at low-mid rpm... but rich (I think).

So, can I keep asking questions?

Popping a few times at very low rpm at tip in, and low kpa too - i think (popping out the intake).... now I know that's supposed to mean too much advance right? But it was doing the same thing before when the computer was running the timing way retarded at 0*.... So what do I do next?

BLMs were all rich, so I've already started logging and modding... but:
- Is it spark?
- Is it VE (too rich?)
- Is it pump shot/acel pump?
- Or is it something else?


Again.... THANK YOU!!! I feel like a weight has been lifted - being my first engine build and all

RBob

iTrader: (1)

Popping out the intake at tip-in is one or both of: too lean, too low a SA. More SA can compensate for too lean. Don't go so rich that it drives the INT down.

RBob.

thewizzard

So... quick question to clarify.

Popping can be caused either by too lean or too low an SA, or both... But if my BLMs are all rich, what am I looking at. Acel pump? And more SA?

And when you say don't go so rich that it drives the INT down, you mean just dont richen it up to the point that it drops below 128? Or rather drops any lower than it already is?

thewizzard

Curious....

Put in a stock LT1 SA table from 94 caprice... has actually made a difference now.... and finally the knock sensor is being tickled just the slightest bit (was worried it wasn't working)... quite a bit more responsive than it was...

But... Still have the tip-in/popping out intake problem from a stop. Doesn't seem to be an issue as much from a roll... And only it seems when my RPMs are down right at idle.

Tried up-ing the AE, which seemed to help, but only to a point. Here's the interesting part... when cold (i.e. engine at 25C), tip-in isn't a problem. Once warm (~80-85C), it becomes evident. So, would the fact that the AE vs coolant multiplier is effectively doubling AE at 25C and straight 1:1 at 85 be an indication that I need twice the AE when up to temp?

Or is it still a timing thing? And further to that question, which cells should I be looking at? If at 45kPa I'm idling at 18* at 750RPM, then tip-in.... 600-1200RPM in the 60-80kPa range?(is that right?) And should my timing be closer to that of the 40-50kPA cells?

I apologize in advance that this thread has become so long! And do sincerely appreciate the help... as without it I'd be up the proverbial creek without a.... motor...

Please forgive my ignorance on this stuff as well... I've done the reading, just don't know what to do with it all (i.e. I'm relatively new to the engine tuning thing in general... and don't know how to recognize what the engine wants)

RBob

iTrader: (1)

There are many areas that contirbute to the required level of AE and SA. The first item to check is that the fuel pressure is OK. Any, and I mean even the slightest dip at tip-in, and there is a fuel delivery issue.

I don't like posting like this, but I have many posts relative to AE, fueling, and tip-in. Which is why I don't post as much as I used to. I've typed it in many times already (this is a hint to place my user name into the search 'author' box, among others [Grumpy for example]).

A Performer Vortec intake runners are on the small side. Don't see why an excess of AE is required. But at the same time I don't know how much heat you are putting into the intake and intake manifold. This makes it difficult to tune from a distance.

As another has posted here, are the plugs correct?

RBob.

thewizzard

Well I'm not sure exactly what the plugs are... but they are what the book says for a 98 chevy vortec 5.7 truck. I will double check them... but I think they're right...

However, I think you might be right (again... would you stop that!!! j/k - thank you) on the fuel delivery thing. The popping seems to be getting worse and it was doing the same thing before when I found the injectors clogged.... And last night I spent a good couple hours trying different things, AE vs TPS, AE vs MAP @ 80kPA (as that's where it seems to be doing it), taking 5 degrees out of SA at 70-100kpa, putting 5 degrees in, different spark curves.... nothing seemed to change when or how badly it was popping.

Vehicle was sitting without a hood on it for about 4-5 months while I rebuilt the motor, so I think the fuel lines are all rusted inside... Given that, I've decided to replace the entire fuel system... starting with a walbro 255lph in-tank fuel pump. Otherwise I feel I'm going to be chasing a ghost with the fuel thing... While I'm at it I'll also install a outlet for a fuel pressure gauge.

I know this is a little off topic for this thread, but I already have the pump... does any one know how I might go about replacing the two lines running from/to the TBI? By that I mean, what do I use, 5/16 high pressure fuel hose? Or 3/8? Do I need a special fuel filter with the 255lph pump? Is there a particular way that I should be connecting the hose to the filter, gauge adapter/T, TBI? Or do I just use barbed fittings with regular hose clamps on everything?

Thanks in advance

thewizzard

WOW... my head is SPINNING!!!!

OK... so will still be swapping out my entire fuel system... but I'm still puzzled by some things, and hoping someone can shed some light.

1) Why would the engine run fine (tip-in included) when cold/not-in-C/L? And then have issues with tip-in when warm? Is it a temperature thing? Or is AE somehow affected by O/L vs. C/L? Also runs much rougher when warm vs. cold...
2) What is "TPS vs Cool Coef AcelPump"? Is that the same a "Lag Filter"? And if so, do I reduce or increase it to increase the duration of AE?
3) Same as 2 but for "MAP Filter vs cool coef"?
4) The "Accel pump vs coolant"... is this a multiplier or does divide TPS/MAP AE by the factors in the table?
5) As a rule... the warmer the intake, the less AE is required? Or vica versa?

I know... use the "search" button... but I can't find anyting for those specific tables? I find Lag filter, filter, coeficient... but nothing specific to the actual table names used in 7747.xdf...

Ronny

iTrader: (1)

It appears you are using a Vortec spark table. Vortec= fastburn so maybe less is better. I would go conservative and if anything pull some timing accross the board off that table. At this point you are trying to get it drivable. Wont hurt to pull a few degrees.

with that much FP(28) you should not need much AE in tables. I have 80 lbs injs at 15-20 lbs and I have little msec in AE tables compared to others.

1. Open loop may cover some shortcomings in tune. It may be adding xtra fuel helping out the AE requirements. when CL it is leaner and no longer a crutch for AE.
2. not sure. As Rbob stated search for info. Those terms I am certain are mentioned in the search and stickies. I dont have TP here at office but as you stated there are filters to affect the duration.
3. same
4. I am certain the "pump vs coollant" modifies the AE for cold collant and or manifold. Cold manifold requires more AE as it condenses in cold air(IAT helps here) or cool manifold runners.

Verify timing with EST disconnected. As Fast suggested. Initail timing at dizzy must match I-T in bin. Do the finger test!

My engine likes rich although I admit it may coverup issues. I idle OL commanded to rich side. and seem to add more fuel in VE tables as weather cooled this fall. When it idles is the ext clean?

My xdf I used may be different than yours my 7747 was Tunercat yours Tunerpro. Now I an EBLxdf.

thewizzard

Well, didn't manage to get the pressure gauge installed... however, did replace fuel pump and filter....

Lean pop gone!!! At least in so far as the way it was manifesting itself...

Now running way rich down low, and lean up top... I also think my NB O2 is lying to me... as under load it seems much leaner than without....

Bottom line is I think it's tuneable now. "think" (and I've said this before), all my mechanical is sorted out now!

Question... will a knock sensor throw a code if it's not working right? Or just if it's not there?

And thanks again to all who have contributed their help to my problems!!!

thewizzard

SOOOOO... ummm... yeah.... Apparently I'm an idiot!
The other day had a tick/tap start at higher rpms (higher being above 1800 or so)... put it off on valve lash... got worse. Decide to check the valve/pushrods out after researching and thinking maybe collapsed lifter (sounded kinda like a sewing machine)...
Remember kindergarten and learning to count?
1, 2, 3, 4, 5, 6, 7!!! 7 - what I would call pretty badly - bent pushrods! And I wondered why it was running like cr*p!

So some questions:
- Would having overtightened the valve lash, causing backfires etc... have caused this?
- Would having overtightened to the point of it not running (i.e. valves open) have caused this? Note this happened at initial break in...
- Would having not understood - or rather put two and two together - that hyd. lifters will settle down to where the preload was set and seem to come loose, causing more tightening (while troubleshooting), potentially to the point of bottoming out the lifters have caused this?
- Would any of the above have caused any additional damage? and;
- Could enough bent pushrods cause enough racket to sound like rod knock every once in a while? Oil pressure is rock solid....

Sometimes sounded like an odd knock, but mostly sounded like a tapping border-line ticking... maybe both by the looks of things...

I HOPE.... for the love of the car gods... that I didn't severly f*** this thing up...

thewizzard

replaced all the pushrods... rotated engine by hand, no binding or other hard spots (FYI - did this before putting the engine in the truck too - so have no idea why this happened in the first place)....

Started... runs much better now. Noise still there, and getting worse....

Bad lifter maybe? Sticking lifter? Wiped cam lobe???

I'm about ready to give up!

JP86SS

iTrader: (1)

Check the converter bolts (and the trans mount bolts)
Can make a noise as you describe.

thewizzard

Thanks JP.... already checked 'em... nice and tight and no cracks in the flexplate.

Seems the stethoscope is pointing at #1 intake as being where the noise is loudest. You can hear it in the oil pan... but only slightly. I assume if it were rod knock it would LOUD LOUD... I mean, I've had knock 3 times now with various 350s, in this particular vehicle too, but wasn't sure if my memory was serving me or not in terms of how loud and what tone a knock vs/ a tap is...
These brought it all back, mine's making the latter/quieter sound:
Loud Knock: http://ca.youtube.com/watch?v=o0lEBI...eature=channel
Lifter tapping: http://ca.youtube.com/watch?v=BYNcQ1k0BHU

So.... I guess I'll be pulling the intake! YAY...
And guess I'll be changing all the lifters.... And then hope I still don't have a noise!

Some folks were saying it might be something gunked up in the oil passages not letting oil to the lifters... but I get oil at the rockers... so I don't think that's a problem?

thewizzard

I need to be put down like a lame horse!!!! PLEASE!!!!

Changed all the lifters... thought it had quietened down... but no... The noise is back. Re-adjusted the lash with it running again... no change.

All the lifters had pretty even wear on them except one. #4 Exhaust seemed more worn than the others... Wiped lobe?? Let me explain... all the lifters had a circle on the bottom with a diameter less than that of the lifter itself.... #4 on the other hand, was worn across the entire surface of the lifter.

That a wiped lobe?

Runs a bit better now... but still have a hesitation/surge while driving (like a cylinder is kicking in), and still seems like it's lacking power...

Strange part of it is, noise seems to be coming from drivers side, not passenger. So the lobe would explain my lack of power, but not the noise... Or maybe the noise/block/sound transmission is just tricking me...

thewizzard

Guess this thread can be closed... as it's apparent I have bigger problems than tuning!

Thanks everyone!!