Converter unlocking at 80 mph

[Cool28]

Went for a nice long drive this weekend and discovered my converter unlocks alway around 76-80 mph just cruising. The lockup and release for tps is set right but it still unlocks. It will also relocks at 70 after a couple mins. Is there anything else that could be making it unlock?

[joecar]

Log the misfire count pids, and brake switch state (it's in one or more of the TSTATExx pids).

[Cool28]

Ok going to try and log it today. I know tstate12 was blinking yes/no at idle thought that was weird

[Cool28]

well ran a log its unlocking cause of misfires very strange doesnt feel at all like its misfiring.

12868

Guess my next question is why is it misfiring. put brand new o2 sensors in.

[joecar]

I see the LTFT's pegging high, indicating a lean condition (over the entire log), the HO2Sx1 voltages support this;

so either a lean condition exists which causes misfires (but I see only 11 seconds worth of misfires),
or misfires occur which causes the O2's to report lean (O2's see unburnt oxygen);

Is this a newly installed stall converter...? Did anything change on the crank (e.g. converter, flexplate, pulley)...? If so, did you do a CASE relearn...?

If this started happening without any parts/tuning mods, then check for:
- airleaks (MAF, intake, injectors, exhaust, O2's, cats, PCV, AIR, EGR),
- check ignition components,
- internal coolant leaks;

If this started happening after tuning changes, then check that the VE and MAF are not under-reporting air.

Only 11 seconds of misfire occurs (what triggered it...?), but LTFT's are pegged positive for the whole log (why...?).



BTW:
your log shows 31 pid channels (shown at bottom of PIDs tab)...
if you can reduce the pid channel count to no more than 24,
then the sample rate will be highest (10 Samples/second vs 5 S/s)...
for future misfire logging, you can remove these pids:
- TRQENG (2 channels),
- EST_BASE_DMA (2 channels),
- STFT1/2 (together 2 channels),
- TFT (1 channel);
[ you now have 24 pid channels ]

:)

[Cool28]

Well I've noticed misfires since I change the PCM. Ever since then when I load a program it always wants to add fuel. then it evens out and is fine. I'm been also getting heat performance on bank 2 sensor 2.

With the new PCM and when I put in the new converter I did a case relearn.

Don't know if this would do it or not but when I installed the PCM I had a couple evap codes that I ended up setting to not report. It could be that I don't have it plugged in. Would that have anything to do with this?

[Cool28]

I had 4 extra wires leftover from the repin

[joecar]

If you have EVAP, AIR, EGR emissions systems, check that each one is not leaking...

The EVAP system might be allowing an airleak, I would have to read the description of it again.

[Cool28]

If it help I believe it was setting p0443 dtc before I turned it off

[Cool28]

Hmm now checking my repin those are the first 2 pins to change so I must have another issue going on for evap.

[Cool28]

Did another case relearn just incase. I'll set those pids and run it when I drive it again. Tried the evap test but ect were to high. Just got done driving it so probably has something to do with that

[joecar]

Sanity check:

Which of these did you have or deleted: EVAP, AIR, EGR, PCV...?

If you have them, is their plumbing leaking...? If you don't have them, did you block off the ports...?

[Cool28]

I still have them all I put not report to egr and evap.

[Cool28]

Well I have no leaks as far as I can tell after the Maf. Sprayed carb cleaner all around and didn't here the engine do anything. Isn't the evap cause I unplugged the tube and the motor idled different then plugged it back in and was fine.

As far as the evap I think mice might have struck again after they ate the abs wire lol. Have to check the canister itself I. The back and see what's up.

Drove it around and still unlocked at 76+ mph.

[Cool28]

Now throwing this out there if I had the crank sensor set wrong it would run like crap right?

[Cool28]

Ok well evap white wire was mice attacked and off -.-

[joecar]

Now throwing this out there if I had the crank sensor set wrong it would run like crap right?You mean the CKP sensor not seated correctly...?

(it has a bolt holding it home, so I'm not sure that it can't be seated right unless the bolt was loose or something obstructed it from seating)

[joecar]

Ok well evap white wire was mice attacked and off -.-I'll have to check the wiring diagram to see what this does.

[Cool28]

Hmm I wonder... 98 have a low resolution crank right? If so the platform setting for that is set to no.

[Cool28]

Another thing I noticed is my stock 98 PCM the misfire number look almost double that of this 02 PCM tune

[Cool28]

Good news put the misfire 32767 where they were in the 98 tune and it stays locked up. So guess could just be something at that rpm for the motors.

[joecar]

Yes, GM has figured out where the motor makes noise and has tuned out those regions by disabling misfire detection there.

Good job :cheers: good observations

[Cool28]

Do you I think i should copy all the 98 tune misfire numbers to the new tune?

[Cool28]

Update copied over the entire misfire tune to my new tune and car hs very little misfire counts at idle now also:). Also runs better