EFIDynoTuning Forum

So I've been fighting a part throttle lean miss for awhile now. It happens at light throttle below 2k rpm. I've been going on datalogs today and noticed that the LTFT1 is actually lean at those spots. LTFT2 is not. Any ideas why this is and if it could cause my lean issue? I know most on here is tunerpro so I'll post up pic of the log.

Just curious but have you pulled the plugs to check them all for the heck of it?

Are you running CL ?

I am running closed loop. and i did not have time to pull the plugs. At the moment im waiting on the parts to put the lightning maf on. when i get those im going to start over with a fresh tune using tunerpro. im not a huge fan of binary editor but have the dongle so figured id use it. i think im going to sell it.

I have BE as well but haven't used it in years.

Update* so I finally switched back to tunerpro and loaded in the 90mm lightning simplified maf curve. I started the car and let it warm up for a few min then took it on a long drive. The low rpm miss is still there but not as bad, that leads me to think my fuel pump is on the fritz. Anyway, logging the fuel error table showed that the simplified curve is about 26ish% off. Not to bad I don't think. But the problem I had is after driving for a good 20 min or so. I get back home and as I'm getting ready to me with the decay rate on the iac the car starts to slightly surge then shuts off and won't start back. I have fuel pressure while cranking and spark. I tried adding fuel in the cranking pw at 160 degrees and up but it didn't help. Now I'm kinda stumped.
One other thing to note is when you crank the car the fuel pressure rises to about 40psi but it sounds like air in the fuel rails as its priming. I'll post up a log shortly when I get to my laptop charger.

Here's the tune and log

Another update* I came out today and the car started up but I had to crank it over several times before it would try to hit. Then it finally started. Idling kind of rough but it started. I know my fuel is not dialed in with this new maf. I couldn't get it to start back yesterday so I didn't fool with the tune anymore. Could the fuel being off by as much as 26-28% cause my issue on not starting when hot?

If you know the curve is off by 25+% why not just change the whole MAF curve? 25% is a lot

I'm going to. I ran out of time and have to go out of town for work tomorrow. Hopefully when I get back I'll have time to get it straightened out.