squirrel

I have the 6299 ECM, 7706 bin, in a PU. Been tryin to fix a serious bog issue, off the line. WinALDL shows a lean condition, BLM's = 134. I took out some timing, as the fuel was maxed, 98-99 area. Last record I made, no bog, but my BLM's went up , to 135. In Tunercat, do I need to be looking at the table, Power Enrichment Spark Advance Vs. RPM, instead of Main Spark Advance table, never been there before. Do I work at evening these 2 tables out somehow, together, or, work on 1 or the other, need some direction, Thanks guys

7Point4

I could be way off here, and i am sure someone will correct me if wrong, but if your fuel is maxed as you say, and it still shows lean..

Either increase fuel pressure a little, and start over,
or increase BPW or injector constant.

I am using a '8747, TBI, so it maybe setup different, but...

Anyone else?

BMmonteSS

Backing the timing off is a crutch to cover up the lean bog. You really need to increase your BPW constant or injector size (depending on what it's called in tunercat) so you'll have more room in your VE curve. You get this room by universally richening up your tune with the BPW constant then taking fuel out of your VE till it comes back into line, then you can add fuel into the lean area's. This is all fine and dandy till your injectors run out of time to inject the fuel your asking them to inject. You need to look at your injector duty cycles to see if your having problems there. I don't know how to get your ecm to spit the duty cylce out the data stream like we can with the 747's and 746's. If this is an off idle bog I doubt your running out of time to inject the needed fuel, this is usually a top end problem.

I would go ahead and try what 7point4 and I suggested and see what happens. You might have to look at your AE or pump shot stuff and see if you need a little more fuel there. If the bog is only when your opening the throttle, then AE might be the way to go.

squirrel

Thanks guys, I would say I'm abt. 90% to where I would like with my VE curve, starting over and being "green" at this , mercie. Stupid ? here, do I go up with #"s with the BPW to increase which is now at 135? I know it would be hard for you guys to say for sure, but, how much of an increase should I start with. At abt. the top end of first and shift into second is when it bogs. Some times it will sometimes it want. Thanks again

BMmonteSS

You wont' really be starting over by increasing your BPW (increasing richens), you'll just be globaly richening up your tune. I would increase your BPW by 10 then subtract 5% off of your VE curve and go from there scaling your entire VE curve untill your back to where you were. Then you'll have the extra room needed.

Ohh yeah, as for your timing question. Pwr enrich spark is only added in at WOT or when your over your Pwr enrich TPS threshold.

I'm still a little confused as to how and where the bog happens. Is it when you smack open the throttle or does the engine just bog down when it gets to that particular rpm and map value. A blm of 135 is lean but not horribly lean. Only about 3-5% lean. Your ecm is already compensating for this any way. Your bog has to be from something else.

Dewey316

when exactly is the bog happening? just when you mash the gas? From your first post, it sounds like it is a medium RPMs, not just high RPM. If it happens when you open the throttle, you need more AE.

squirrel

Thanks guys, more in the area of the latter range of first gear, then shifts, then an immediate bog at second gear, hope that makes sense. Not, at the initial pedal to floor. Mid- latter stage of first gear. And, only thing that shows up on WinAldl is a decrease in RPM's, as far as, O2, things appear normal, during WOT it hits in areas such as .044, .057, .043, then goes back to hitting hgh's and lows which is normal, ?correct?, when back to normal drving.
Thanks for good word on not startin over, I'll get into looking at that. AE, I know I should search, I got blasted at Sallee for not Searching, but maybe just a hint of where I need to go for that, to , ck. it out also, nothing that I know of right off that Says AE. in my version of Tunercat. Thanks again for the help.

Dewey316

It will likely show as 'Pump Shot vs MAP' and 'Pump Shot vs TPS'

There are two tables for AE.

If you o2 readings are in .044, then you are REALLY lean. the o2's will stop switching when you hit WOT, because the computer stops doing its corrections. BUT, the voltage should be in the 850mv range or so.

Maybe some more info on your combo is in order, what is the engine, what modifications, what injectors, etc.

Ronny

iTrader: (1)

Quote: serious bog issue, off the line.
Quote: WinALDL shows a lean condition

sounds like two issues. i would work on underlying VE first and get that house in order. fuel pressure increase/ injector constant/ larger injectors(maybe). as others have stated. AE i dont believe can be datalogged ALDL. seat of the pants. i made small adjustments/changes and looked for improvement in "my bog". unfortunately i went over the edge as was too rich on AE aka pumpshot. the WB02 should me the error in my tuning.

i used conservative timing maps until my fueling was in order. actually will look there this spring.

squirrel

Thanks guys for offering suggestions, each one of you. I did add a 10 count to the BPW Constant from 135 to 145. I had low batt, did not get a good chk. on all areas i have been workin on. My WOT bog, still there, still at the 135 BLM, and again it comes in abt. mid - later range of first gear, takes a nose dive, comes back in kickin. What other areas I could chk. did show somewhat richer. I want bother you guys very much, for this is not a daily drvr. But I will ask for direction in which to search for info on the"Pump Shot Vs. Differential Map. What does differential refer to. I wouldn't know how to change the "usec" part. Anywhere to get specfic word meanings for this stuff? Not given up. Its a 350, TBI, 700r4, all OEM stuff, true duals, have OEM air cleaner made into a dual intake with parts from another thats not suckin in fresh air yet, got to do some core support work there. I'll dig deeper into the "differential" thing and try that route. Only way I can learn is by doin. Thanks again, I'll be back. forgat to mention its gettin a little tired 172000+ and 1 thing that might contribute is, the original Fuel pump, in the near future will be changed.

Ronny

iTrader: (1)

QUOTE: original Fuel pump

basics. check FP. i would set 13 lbs. your fuel pump i would replace. it is a time bomb and may contribute to your issue. i would replace with a TPI pump. install a FPG same time..

vernw

iTrader: (2)

Also - check put what your injector duty cycle is. Usually an 80-85% duty cycle means you're maxed out with those injectors at that fuel pressure.....

squirrel

Many different ways to go I see. Ronny, the fuel pump, TPI, would this in any way be comparible to the original, size, shape,etc. Would I need to make any modifications for it to accept it with what I have in there now, phew. I have a Vortec lng. blk. on stand
just waiting on this one to retire, 172000+. That would fit my needs with that change and setup, if no mods are needed. Time bomb, yeah, I don't wonder to far from the house. Thanks Vernw, I copied all this off, I'll get around to lookin at these. Would a part num. be possible, Ronny? Thanks again folks

Ronny

iTrader: (1)

not sure of part number. i asked for a 1985 vette tpi pump. gmpartsdirest.com. it is a higher FP application but dont let that bother you as the regulation dumps off fuel back to tank. it will provide capacity. there are instructions somewhere here and on crossfire forum to install. pretty straightforward. actually my buddy did it at his shop. cost me lunch.

squirrel

Update: finally replaced fuel pump, been putting it off toooo long.
Dreaded dropping tank. New 1 in, problem at WOT solved. Rich across the entire curve now will have to correct. BM monte SS,could you explain how to take a percentage out by scale in Tunercat. Man, I come up with some..... funky numbers when I do this. Thanks once again to all who replied and offered help.

Ronny

iTrader: (1)

i think TC has that info on their site. owners manual so to speak. i have never done it. just addressed the VE cells individually as was never globally rich/lean.

BronYrAur

iTrader: (1)

When BMmonte said to take out 5% across the board, I think he meant just subtract the value '5' from the whole VE table. All the values in the VE table are %VE, so just subtract 5 from every cell is what he meant.

Ronny

iTrader: (1)

i think TC can do that in one sweep.

BronYrAur

iTrader: (1)

Yeah, I'm sure it would. Tunerpro has that functionality and it's free so I hope TC does too.

squirrel

Owners manual? one day i might learn to listen to wife and read directions..... I'll check thier site, not much help, in the help section. I'll try the "5" or whatever it takes, i was hoping on the one sweep thing myself. Thanks again folks for the suggestions on directions

Ronny

iTrader: (1)

yea. on their site. tuner program reference manual. "add value to selected table location" all or any.