High Long Term Fuel Trim Immediately After Computer Reset

[Delano1981]

Hello Everyone,

I have had high long term fuel trims for months on my 2007 Ram 1500 5.7L. They are both at +15.6. Using a smoke machine today, I found a leak where the EGR valve attaches to the tube that goes to the exhaust. I thought for sure I had found the problem, but after replacing the EGR and resetting the ECU, the problem is still there. In fact, immediately after starting the engine after resetting the computer, the long term trims went straight back to +15.6 instantly even though the short term trims stayed right around 0. The o2 sensors are functioning fine, however they are old. I have put 70,000 miles on the truck since I bought it, and it has 193,476 miles on it. I have not replaced the the o2's since I have owned the truck. Anyways, something doesn't look right. Any ideas anyone?

Thanks

 

[Delano1981]

I forgot to say that when I rev the engine to 2000 rpm, the long term trims go to zero and then go back to 15.6 when I go back to idle.

 

[Delano1981]

It looks like this is an electrical issue. I noticed today that when I was idling in park, the long term fuel trims were at +15. When I put it in drive, the fuel trims instantly dropped to +8. When I put it back into park, they went back up to +15 again. I also no that the transmission module is not communicating with my scan tool which is supposed to be able to read the transmission module.

 

[Ncato]

It looks like this is an electrical issue. I noticed today that when I was idling in park, the long term fuel trims were at +15. When I put it in drive, the fuel trims instantly dropped to +8. When I put it back into park, they went back up to +15 again. I also no that the transmission module is not communicating with my scan tool which is supposed to be able to read the transmission module.

Hello,
Did you find an issue? I have the same problem on my grand cherokee.

 

[Ncato]

For me, it was EGR, after replacement and resetting the computer everything started working well.

 

[Hagar1]

I have essentially the same problem. My long terms are out in the 12,798 range