Not sure if this is a newbie question or ecmlink section. But I feel like its something simple I missed.

Basically at idle I can get a good STFT hi/lo and combined fuel trim. Idles great.

However after a quick cruise or even just backing it in the afr becomes really rich like 11:1 or so. The rpm is also higher by a few hundred rpm.

Sometimes it would surge sometimes it wont. after a good 2 or 3 minutes of this it works itself out and back to normal.

I tried the auto maf calibration and it just made things worse.

Mods are in my profile. but basically gm maf/1600cc bosche/hy35/e85.

I did a 30psi boostleak and its solid. tb is rebuilt so no leaks.
new spark ngk brp8es and .28 if I remember right.
new wires/coil/alternator.

any thing else I need to check?

I added a log to show idle(which I thought was good FT) then a cruise that would peg my FT and mest up idle?

I can't look at the log on my phone but I'd guess that you're not going into closed loop once you come back to a stop.

Try simulating idle switch from the tps if it isn't making it back into closed loop.

That was my guess. But my log shows closed loop. And tps is simulated. Narrowband is simulated. Which is kinda odd because its stuck at .8volts at times

Check and recheck the deadtimes on those bosche 1600s, ecmlink doesn't like to work with them. My friend had to set his deadtime to over 600 to get them to work properly, and they were always choppy on idle and cruise

Time to get a tune. Shoot you can get a remote tune from people on here. I heard my1gdsm can get you rolling really good on a tune.

You might try logging isc position and see what the stepper motor is doing. You might have a marginal isc?

Giving help without viewing the log is appreciated, but please don't just start throwing a bunch of guesses out as to what's going on. It can be really confusing to the OP, and just clutter up the thread. If you're unable to look at the log, please wait until you can to help out unless you're somehow able to diagnose cars blindly.


You're starting to find out how hard the larger injectors are to tune. 1600's are notorious for being able to either idle or cruise well, but not both.

The idle at the end of your log doesn't look bad. Average wideband reading is 14.6 and average CombinedFT reading is 4.4%. Your AirflowPerRev average is a bit lower than it should be as you're seeing .23 and you want it around .25. Your ISCPosition is a bit higher than it should be (want it around 30).

One thing that is a bit confusing is your battery never really goes about 13v. Is there an issue there? You should be seeing higher voltage, especially at idle.

Hi how do you solved this issue?