Short term fuel trims readings

[Dat5.0]

Hello, the other day i was doing some pulls to check the fuel quality and of course i was data logging, right around 6200 RPMS I’ve noticed that my short term fuel trims where getting higher than 1.5 till it peaked 1.12, I’m still new to reading logs and all but I think it’s getting lean and there is a possibility of a bad fuel pump !?, what do u think guys?

Car is 13 FBO GT with lund racing 91 tune.

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[markmurfie]

Looks like your long term fuel trims learned rich, now STFT are compensating against that. I would say reset your KAM and log again. This can be done either with the logging device or by disconnecting the battery for a minute or two.

 

[Dat5.0]

Looks like your long term fuel trims learned rich, now STFT are compensating against that. I would say reset your KAM and log again. This can be done either with the logging device or by disconnecting the battery for a minute or two.

I’ll reset my KAM and do some pulls and check the log again.

Thanks

 

[K4fxd]

I would also log commanded lambda. See if it is calling for .85 if it is your fuel system is fine.

LTFT's will reset anytime you add about 2 gallons of gas to the tank.

 

[Dat5.0]

Looks like your long term fuel trims learned rich, now STFT are compensating against that. I would say reset your KAM and log again. This can be done either with the logging device or by disconnecting the battery for a minute or two.

So i did reset the KAM and did a third gear pull, short term fuel trim peaked at 1.02 from what i see in the log I think my full system is okay.

 

[Dat5.0]

I would also log commanded lambda. See if it is calling for .85 if it is your fuel system is fine.

LTFT's will reset anytime you add about 2 gallons of gas to the tank.

I logged LAMBDA and at WOT it was .84 then at high RPM it went to .83

 

[ice445]

I don't see anything of concern really, a correction of slightly over 1 is not substantial. Both banks are even and AFR is the same on both banks so everything is working well.

 

[K4fxd]

That sounds like a stock fuel table, WOT it goes from .85 to .83

Lund tuned?

 

[Dat5.0]

I would also log commanded lambda. See if it is calling for .85 if it is your fuel system is fine.

LTFT's will reset anytime you add about 2 gallons of gas to the tank.

I logged LAMBDA at WOT it was .84 then at high RPM it went to .83.

That sounds like a stock fuel table, WOT it goes from .85 to .83

Lund tuned?

To be honest I don’t know much about stock fuel table, and yes it is a Lund tune

 

[markmurfie]

The stock WOT lambda table is fine. .82-.87 will not make much of a difference in power, .82 is on the richer side and gives a bit better knock resistance, which is great on 91.

The car isn't going in to cat over temp(under .75), since you are FBO, and have a free flowing exhaust, this is all you want to see as far as WOT lambda goes.

Timing is 28-29*, when load is 1.1 thats both on the higher side, unless you were running E85. You are on 91. max load of 1.18 is very high for a NA car. Probably where the fuel trim conflict came from.

If you haven't done revisions with your tuner I would send them logs and see if they can improve your tune. Sometimes this requires logs from a drag strip, but getting a revision from them would help. Even if you have to pay them again it would be worth it.

 

[Dat5.0]

The stock WOT lambda table is fine. .82-.87 will not make much of a difference in power, .82 is on the richer side and gives a bit better knock resistance, which is great on 91.

The car isn't going in to cat over temp(under .75), since you are FBO, and have a free flowing exhaust, this is all you want to see as far as WOT lambda goes.

Timing is 28-29*, when load is 1.1 thats both on the higher side, unless you were running E85. You are on 91. max load of 1.18 is very high for a NA car. Probably where the fuel trim conflict came from.

If you haven't done revisions with your tuner I would send them logs and see if they can improve your tune. Sometimes this requires logs from a drag strip, but getting a revision from them would help. Even if you have to pay them again it would be worth it.

Very informative, I didn’t get any tune revisions when I purchased my tune from Lund, they sent me a base tune and asked me to do a log for them then they emailed me saying we can’t do much to ur tune this is optimal for the fuel that I’m using at that time

I’m planning to do a tune revision cuz the car is slow, I’m using Dragy and my best 1/4 mile time was 13.28 at 111 miles DA was around 2500, I wasn’t shifting fast because of my clutch but the mile per hour at least should be above 115 with these mods.

Like u said i need a tune revisions.

Thanks a lot.

 

[markmurfie]

Yes, anything to give them a metric to show they are improving your tune will help. They get a lot of data from the log, but with out a goal changes are trivial. Even if its just your butt dyno as a metric. You have a draggy so show them that.

Their first thing they want you to change to improve is octane, so follow what they say, find some 93, or octane booster and say you fixed that for them to make an improvement.

You pay them for a tune and to a lesser degree advice, with a goal in mind that you share with them, they will spend three months with you to reach that goal. The only reason you can't reach the goal is usually money for what they recommend you do.

 

[Dat5.0]

Yes, anything to give them a metric to show they are improving your tune will help. They get a lot of data from the log, but with out a goal changes are trivial. Even if its just your butt dyno as a metric. You have a draggy so show them that.

Their first thing they want you to change to improve is octane, so follow what they say, find some 93, or octane booster and say you fixed that for them to make an improvement.

You pay them for a tune and to a lesser degree advice, with a goal in mind that you share with them, they will spend three months with you to reach that goal. The only reason you can't reach the goal is usually money for what they recommend you do.

Thanks for the advices brother, I will update u when i revise my tune soon.

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