SD2 very Lean Cold start

[jmendlik]

My car cranks and starts ok but poor idle when cold but till it gets to 130 degree or closed loop it seems to be way too lean (14.5 ish) but once it runs into the 130 warmup range it seems to "take control of the 12.5AF I have set in cell 2.....I have Par 11 at 145 adding fuel but still is an issue...any thoughts?



im going to record a cold start this morning and look into it further but wanted to post for advice to see if someone had similar issues..Runnung E85 and 120lb injectiors...base fP 38lbs inj offset 20 pph 115


any feedback??


JM

 

[TurboDave]

You could try bumping your injector offset to 30 and see if that helps, and if it does, try 35. Of course this may require more tuning elsewhere to pull some the fuel the additional offset adds.


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[TurboBob]

E85 can require a lot of coldstart fuel, I would try more warm-up fuel.

Bob

 

[TurboDave]

Or a better, more direct approach is to bump up cell 11 (cold start fuel). That's what I did. Mine is set to 138. Yours may need more.


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[jmendlik]

Thanks for all the advice--going to try in the morning again when its total cold.

What should the correct MAF numbers cold idle?.

 

[BEATAV8]

What is your AFC correction at low idle when the car has warmed up? If the correction is positive, you can add fuel to the idle base fuel. Any fuel added to idle base fuel will also richen up the warmup period in the event that the engine is still running open loop.

If your idle fuel correction is already negative, then better stick with the cold start parameter #11.

For 120Lb injectors I usually stick with 25-28 for injector offset.

 

[TT/Ameasap]

I have this same problem right now. As soon as the car goes into closed loop, no more problems. My car hunts for idle and will die. Did not do this last year, but I have changed many things since then. Cell 11 is what has cured it in the past. E85 cars like a lot of fuel on start up. I just need to find time to adjust mine. I used to tune mine to 11.0-12.0 and got greedy because E85 kills fuel mileage. Im guessing that is why mine is running lean, I probably leaned it out last year and forgot I did so. Play with cell 11 tho.

 

[jmendlik]

I will try all above suggestions in the morning when stone cold. My Idle AFR number in cell #1 is already negative at 117 with 125 in cell 2 so its pulling fuel to run 12:5 at warm idle. My car has 281/224 billet roller and likes 12:5 idle.

If I move the injector offset to higher than current 20 I may not be able to pull enough fuel out from cell 1 with the method I'm using and may need to go into the VE table to pull enough out.

Thanks for the help guy's...

 

[TurboDave]

I will try all above suggestions in the morning when stone cold. My Idle AFR number in cell #1 is already negative at 117 with 125 in cell 2 so its pulling fuel to run 12:5 at warm idle. My car has 281/224 billet roller and likes 12:5 idle.

If I move the injector offset to higher than current 20 I may not be able to pull enough fuel out from cell 1 with the method I'm using and may need to go into the VE table to pull enough out.

Thanks for the help guy's...

Then your best bet is to bump more fuel in cell 11.


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[jmendlik]

Fixed my issue--i feel pretty foolish!!!!-i was reading the wide band incorrectly. The car was running way rich not lean at idle...Ughhh set cell 11 to 128 and now on cold start up it runs around 12:5 ish and warms up nice. I had 145 in cell 11 so it was adding a ton of fuel.. Sorry for the mistake but thanks for the help....

Last question-with 120lb injectors is any issue running the offset down at 20 ? I see other say 25 or more is what they run. Any downside to a 20 setting over a 25 ?? I'm not looking to change VE table at this point so using 20 I can control idle correction with cell1

 

[TurboBob]

the offset also affects tip-in fuel. so you can create a stumble if the offset is too low.

with a cam with some overlap, you idle in a spot in the VE table that most other cars don't, so any tweaks you do without tuning the VE table are a compromise.

Bob

 

[jmendlik]

Fixed my issue--i feel like a dummy-i was reading the wide band incorrectly. The car was running way rich not lean at idle...Ughhh set cell 11 to 128 and now on cold start up it runs around 12:5 ish and warms up nice. I has 145 in cell 11 so it was adding a ton of fule

 

[jmendlik]

Bob-I have a 218/224 Roller Cam. With the offset at 20 I'm not experiencing any tip-in but could I not tune that out with cell 12 possibly?

 

[TurboBob]

whatever runs the smoothest...