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fuel trims

I have a new working theory.

After discussion with my father he doesn't feel that there are any intake or exhaust leaks.

His feeling is that something is up with the timing.

So the question now is, would a tensioner that isn't up to par, le thte tension slack enough that it could be off at idle but when it gets full oil pressure under load would tension the chains correctly? the enigne starts and idles fine so it might not be a hugh emount, but just enough ..

also when we built my engine I reused all timing components from my 2.5L engine. they had 95k on them at the time and all looked good.
 
yeah, I over thought that one. Wasn't sure ... but all the timing components I used where is great shape.



SicSE said:
I have to ask... why are you still so doubtful of the EGR theory even after your fuel trims changed by blocking the inlet?
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discussions with my father. Although maybe I should revisit this myself. But all I can say is my father knows his stuff and was able to reduild his 289 for his mustang by memory, minus torque specs, etc and time it by ear.

We have been very successful in the last few years blending his knowledge of mechancally controlled enignes with my knowledge of computer controlled engines. So I trust what he is telling me and he believes that the issue lies in the timing.
 
so would seeing ~14.7 at the wideband while under a cruise condition mean that the engine is running correctly a/f wise? btw there are no cats on the car either.

also from what I could see during data logging the short term fuel trims on a testing tune (adaptive learning disabled) seemed to be the same about 90% of the time in this case.
 
SicSE said:
I would say there are too many variables to consider a given A/F correct or incorrect at cruise, as long as it's running okay. Plus, with your trims evening out off-idle, cruise A/F is inconsequential IMO.
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well that is the thing, the trims are even at idle now. And they stay that way most of the time it appears. then again at cruise the trims are even. thus the pcm is commanding the A/F correctly to maintain stoich combustion hence its staying around ~14.7 a/f.

it felt like it had more power last night also. punching second starting at 4k rpm just spun the wheels. and from what i observed its commanding the proper amount of fuel also as its reaching at least 12:1 under boost if not high 11s. Also the turbine temps stayed steady indicating that it wasn't going lean.

it seems that the imbalance issue is gone, but I am waiting to heard from Joey on that.
 
SicSE said:
Sounds that way. Good sh*t. What fixed it?
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well they will differe some still, like after accelerating they will be different then come back together.

what fixed it? well I am waiting for confirmation from NPG that it is better then it was but it sure looks like it. Well friday night I swapped in the stock injectors and intake and ran the engine to data log, turbo was bypassed. Last night I swapped the 42# injectors back in and hooked everything back up. watching the numbers via livelink the short term trims where just about always the same.

when i installed the injectors I pulled the lim. I made sure the injectors where seated in the lim before installing the fuel rail. the first time I think I had them in the fuel rail first. I also swapped the injectors from bank to bank. so I installed them 1 to 6. when i removed them I marked where they came from so I picked 6 to 1 as I installed them. I also noted that the nozzles on the bank that was running lean had two of the three holes pointed towards the lim where as the other bank had none or one. So I twisted the nozzles around to make it more like the other bank. I also made sure the injectors was all the way into the lim after the fuel rail was installed. Used some grease when installing the injectors to make sure the o-rings when in smoothly and nothing happened there, first time I used oil on the o-rings. then I just reinstalled everything and put the testing tune back on the pcm and ran it. so like I said I noted that the amount of fuel being commanded was good and that the trims where just about always balanced right around 1 via live link (0.9xx most of the time). Then while at a cruise condition the trims where the same and the wideband was reading ~14.7.

so it seems something I did seems to have corrected the issue. Just waiting for NPG to confirm so the final tweaks to the tune can be made.
 
I will take a look tonite on the datalog I just drove 10 hours straight to a hotel I will try my best to analyze it tonite I am getting up early to head into town with my generator to address my house. Joey
 
BurritaSVT said:
I will take a look tonite on the datalog I just drove 10 hours straight to a hotel I will try my best to analyze it tonite I am getting up early to head into town with my generator to address my house. Joey
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Joey thanks for taking the time last night to look at the datalogging. You didn't have to do that at all. It is appreciated.

my best to you and your family as you recover from the storm. I hope all goes well.
 
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