grabbem88

355 30lb injectors cam stage 3 dart pro heads etc

got a reflash from pcmforless for all new mods

started up great then cel came on code 64
im running heated o2 so I double checked wires and fuses (93 m6) replaced O2’s still the same

so I used scan9495 to see what’s going on

on start up o2 working fuel trims working.

then o2 bank 2 is .054 bank 1 is .800’s
bank 1 LT fuel trim is 108 and 2 is 160

fuel pressure is 43 I can feel injectors pulsing

checked for vacuum

exhaust is tight.

I did try starting it before tune and it was very rich but no cel

am I looking at a tune issue or am I missing something?

Injuneer

Are you sure you have the left and right bank O2 sensor signal wires connected to the correct ECM pins? Maybe “swapped”?

What do you mean by “on startup ..... fuel trims working “? Wasn’t it in open loop on startup?

If you post the .csv data log, I'll take a look at it.

grabbem88

bought the conversion from someone on here a long time ago. Lol this car sat for awhile still ran but spun a bearing. So I built a new motor for it.

i did take a pic. But didn’t record yet. Cause I thought I had it handled. Guess not.

drives like crap tip in throttle is non existent it’s either yeehaa or nothing.

Injuneer

When you start it, it’s in open loop. It uses the stored long term trims (or 128 if PCM has been reset) and locks the short terms at 128. When it's in open loop ( 0 in “Eng. closed loop”) the fuel trims - meaning learning based on O2 sensor feed back - are not enabled ( 0 in “fuel trim enabled”). Even though it’s fully warmed up, and run time is over typical 206-second timer, apparently it’s not going into closed loop because of the problem with the O2 sensors. IAC counts are very high, struggling to maintain target idle RPM. Both fans are on at 181°F. How big is the cam? Stock or aftermarket throttle body?

When did pcmforless tune it? Since Bryan gave it up, results are not always what they used to be.

grabbem88

Working on iac that was yesterday.
edelbrock 58mm
double checking o2 wires now.

grabbem88

Got o2 working. Wire musta been pinched
Iac still keeps going to 160 though

grabbem88

Is this better?
but what’s the proper steps adjusting iac
one minute count is 70-90 then I adjust throttle stop and iac jumps to 160. Reset it car almost dies. Left it alone and now it’s 98

atleast banks are working and O2’s

Injuneer

Looking at a photo is relatively useless. Maybe pick out gross errors, but hard to pin down the cause. The ECM is updating as many as 10 times per second. That's why a log, with a scan rate of at least 5 frames per second is more useful. Knowing you have two O2 sensors that are no longer “stuck” is good, but is this going to correct the split/out-of-spec long term fuel trims (LTFT). Only watching how they respond, change, and hopefully stabilize over a period of time will show if there is still a problem, and perhaps suggest the cause.

Some aftermarket TB's contribute to high IAC counts, sometimes rectified by drilling an idle air hole in the TB.

grabbem88

I can record a log. But other stuff I needed to do before it gets late maybe a driving one as well

grabbem88

Do I adjust throttle with iac unplugged

had to do brakes but did get to drive it

runs a whole lot better. Drivable but not clean on start and take off.

Injuneer

With IAC connected, TPS connected, slowly turn the stop screw to open the blades. As the blades open the IAC counts should drop to hold the target 900 RPM. You are trying to drop IAC into the range of 20-40 counts, and hold the idle at 900 RPM target. Problem is as you open the blades TPS volts will increase. You can't let them increase above about 0.85 volts.

You may not be able to get the RPM, IAC counts, and TPS volts into the correct range at the same time. As mentioned, some aftermarket throttle bodies don't pass enough air through the IAC passage, and they apparently don’t have a hole the stock TB has to flow additional idle air from between the bores directly into the intake plenum. Some people bore a hole and add a small tube, but I don’t know the details. I have a Holley 58mm TB and never had a problem. But I am using my stock PCM to control idle RPM (along with fan on/off temps, and speedometer), and everything else is controlled by an aftermarket engine management system that can accept any TPS volts for closed throttle.

grabbem88

Lol I shoulda left it all alone. Until I got back under car and found o2 issue.

thanks once again for your help. Knowledge of your stature is one of a kind

grabbem88

grabbem88

Hope this worked

grabbem88

https://cdn.fbsbx.com/v/t59.2708-21/...=5F4ED182&dl=1