Very odd issue idle/fuel

[Blueprint]

Backstory.......

This entire setup was in another car. Top to bottom. Customer wrecked his car. Still ran fine. We took the setup and put it in his new car. Same tune, same fuel system, same turbo kit. Brand new OEM wideband sensors, brand new spark plugs.

ID1700. Fuel pressure set with car off, pumps on, 55 PSI. All injector data entered correctly.


The issue:

Everything works properly in regards to MAF and stft/ltft while driving. As soon as you stop, stft goes to zero and widebands read way rich .73-.79. Start moving again they come back online fuel trims back to normal. Threshold seems to be roughly 2-3mph or over 1200rpm.

Also noticed and I will attach a log. If I let it idle AC off, eventually fuel trims will ZER0 out, and it will read way rich on the widebands. As soon as you turn the AC on, the stft comes back on and the widebands start reading where they should be matching commanded 1.0.



Post this one.hpl

Fuel trims are off in attached log. STFT have been within 1-2% throught the maf transfer while driving though previously. I have been playing with different fuel pressures, idle speeds, adding and subtracting from maf. Absolutely nothing has helped this issue which happens only at idle, this issue did not exist on previous car or my car which pretty much has the same tune (same setup)

[Blueprint]

Going to try a new MAF. I guess it's the only thing that makes sense at this point, atleast to me.

Every other sensor on this engine is brand new OEM. Aside from throttle body and MAF.

I will report back.

[Blueprint]

So this makes zero sense to me.

Tried a new MAF, no change. Another set of new WIDEBANDS, no change. Car has been gone over by myself and another very experienced tech nothing out of the ordinary. Grounds are clean and tight, no loose connectors. Pretty much every sensor is OEM brand new.

This tune works perfectly fine on other cars with same setup previously tuned by me. With zero adjustments aside from minor MAF transfer variations.

I also, switched to another strategy with a stock tune, only changing injector values. NO CHANGE same issue. Not tune related.

Hardware right? Well everything is brand new, has been gone over multiple times. Ive also tried everyones "give it more air" etc etc., but lets remember this tune is perfectly fine on other vehicles as is! So I oblige, more air, open throttle, more RPM at idle, NO CHANGE in widebands, pig rich.


So I went back and looked at the only time the widebands are not reading crazy rich. Which is when I turn the AC on. Everything looked pretty much the same, nothing that would make a drastic difference. I did see however that the spark was at negative three degrees AC on.

So I figured wth, lets try it and wouldnt you know. My widebands were right back around 1. I thought I was seeing things. So I flashed a tune with 14 degrees at idle. Back rich they go! There is not much difference in what im seeing in the scanner load wise etc. Flashed back the tune with negative three degree, and widebands read 1.0 or about there.

What could be causing this?

[wayno]

If you notice in those logs when it goes rich you are sitting on the min pulse width of those injectors @.4500 ms

[wayno]

Have you tried kicking up the low slope a bit. When i get those injectors i always have to mess with the data a little to get them to play nice down low.

[Blueprint]

If you notice in those logs when it goes rich you are sitting on the min pulse width of those injectors @.4500 ms

I did notice that, however I do not think that is ALL of the issue.

This engine had no issues running that pulse width before when it was in prior car. Also the other cars with this same tune and setup, have no issues idling at the minimum pulse width with this tune zero changes.


I will see if I can dig up the logs I was looking at march of this year and post them. It was actually idling .6 min maf, min pulse width and 700 RPM, 14 degrees timing with no issue.

I just think there is more to this.......all things considered.

[06300CSRT8]

Can you post a copy of the tune? I noticed a funky limit on the voltage offset table, might be your issue.

[txcharlie]

Backstory.......

This entire setup was in another car. Top to bottom. Customer wrecked his car. Still ran fine. We took the setup and put it in his new car. Same tune, same fuel system, same turbo kit. Brand new OEM wideband sensors, brand new spark plugs.

ID1700. Fuel pressure set with car off, pumps on, 55 PSI. All injector data entered correctly.


The issue:

Everything works properly in regards to MAF and stft/ltft while driving. As soon as you stop, stft goes to zero and widebands read way rich .73-.79. Start moving again they come back online fuel trims back to normal. Threshold seems to be roughly 2-3mph or over 1200rpm.

Also noticed and I will attach a log. If I let it idle AC off, eventually fuel trims will ZER0 out, and it will read way rich on the widebands. As soon as you turn the AC on, the stft comes back on and the widebands start reading where they should be matching commanded 1.0.



Post this one.hpl

Fuel trims are off in attached log. STFT have been within 1-2% throught the maf transfer while driving though previously. I have been playing with different fuel pressures, idle speeds, adding and subtracting from maf. Absolutely nothing has helped this issue which happens only at idle, this issue did not exist on previous car or my car which pretty much has the same tune (same setup)

Did you nail this down? I'm having a similar issue.

[small tuner]

Did you nail this down? I'm having a similar issue.

pull it from the past if someone have dial ID1700 successfully. having same issue at idle

[aaronson]

I did notice that, however I do not think that is ALL of the issue.

This engine had no issues running that pulse width before when it was in prior car. Also the other cars with this same tune and setup, have no issues idling at the minimum pulse width with this tune zero changes.


I will see if I can dig up the logs I was looking at march of this year and post them. It was actually idling .6 min maf, min pulse width and 700 RPM, 14 degrees timing with no issue.

I just think there is more to this.......all things considered.

How much power are you making?

[superman07]

When it doesn’t make sense. CHeck what you “know to be true” forget the old car, it’s gone. This is a new car.

I would take a idle vacuum measurement, and verify fuel pressure at the rail at idle. You have not mentioned what engine, or car, or what type of fuel system.

[small tuner]

11 Turbo coyote, Return Fuel system

[superman07]

fuel pressure gauge on regulator?

what pressure do you have it set to?

[small tuner]

fuel pressure gauge on regulator?

what pressure do you have it set to?

1:1 fuel pressure @55 psi with pressure gauge mount on rails