• The site migration is complete! Hopefully everything transferred properly from the multiple decades old software we were using before. If you notice any issues please let me know, thanks! Also, I'm still working on things like chatbox, etc so hopefully those will be working in the next week or two.

16.41 LTFTs on decel/sometimes idle

D

digitaloutsider

New member
This started after installing the 60# injectors and moving to E85.

Actually, I can say it started after putting the injectors in. I noticed high LTFTs on decel on the way to the gas station to get the E85. This only happens on decel and sometimes at idle (but they're still high at idle, usually 8-10). If there's a vacuum leak somewhere, I can't find it. I have gone over every vacuum line with propane, brake clean, and soapy water. I have also tried taking the EVAP vacuum line off the TB and blocking that. Took the middle vacuum line off the S/C tree and capped that. Nothing different.

The car is tuned for the injectors and for the E85 (using frosty's method). Last night I was cruising along and I watched the wideband go nearly full rich (.70 lambda), and a few seconds later it tripped P0171.

Now, I have read that some people suggest re-tuning the MAF after swapping injectors.. other's don't. Could that cause the LTFTs to go haywire? Any other ideas or places to look for a vacuum leak? I've spent the last hour searching through threads on here and other forums trying to find something that I haven't tried yet, but I'm coming up very short. Getting .72-.73 lambda at WOT, 3.2 pulley, the car runs like a raped ape. Just trying to track down the stupid LTFT problem..
 


Don't even be a little concerned about a lean fuel condition in deceleration. Your car is programmed to do that. I wood verify your injector flow rate is correct and tat your cylinder gain is where it should be, and maybe check the actual ethanol content of your fuel and if those all check out right then do a Maf adjustment.
 
You always have to tune the MAF curve when going to larger fuel injectors. Just scaling tables to fudge numbers is not the correct way to do things. The MAF sensor is controlling how much fuel is going into the motor based on airflow calculations.

Decel is decel, it's not needing the fuel so it takes it away and very oftens enters DFCO to shut off the injectors completely.
 
Did 1 MAF tune with the Table Modifier last night and it's already getting better.

My question is this.. doesn't Eddie's table modifier only look at the MAF when you're not under boost/PE? How would it smooth out and fix the rest of the table? Maybe I just have a fundamental misunderstanding of what it does.
 
the idea is to run through the rpm's and cover each kpa cell slowly without much boost. if you hit boost the rpms will go faster to the end of the maf cells.
 


Yeah I've been rolling into the throttle slowly when I scan it. So does that mean the higher frequencies of the MAF table never gets adjusted?
 
They can still be adjusted, it's just a matter of if you need to remove or add fuel to match your commanded AFR under WOT.

If you commanded 11.5 but saw 11.8 on the wideband you'd add like 2% worth of fuel to the MAF curve to richen it up and see how close you get to your target.
 
You must log in or register to reply here.
Back
Top