Can't figure out this misfire, possible bad PCM?

[bnca1980]

Can someone help me out with this?

Basically got a 408 lq4 that had it's PCM fried when my old laptop decided to power down right in the middle of a reflash, so I went a got another one and ever since the truck has an awful misfire, but only while in gear (I guess you could say under load). It will idle in park all day and even when revved it won't misfire, but the moment you put it in gear and give it any throttle it misses badly. I've run this exact tune before on the old PCM and had no issues whatsoever.

I've tried just running in open loop to see if maybe that helps but no luck. Anyone got any ideas on where to start, cause I'm lost.

Thanks in advance,
BC

[5.7ute]

Just a thought , but have you done a case relearn?

[bnca1980]

Seems like I did, it's been awhile since i've had time to mess with it, but i'm sure it wouldn't hurt to do another one to make sure.

[joecar]

BC,

Welcome to the forum...:cheers:

Do you know anyone near you who has an automotive oscilloscope (capable of tracing CKP signal, injector voltage/current, secondary spikes at the time the misfire occurs)... [e.g. something like what www.autonerdz.com has]...?

Post some logs of when it misfires.

[bnca1980]

Thanks for the warm welcome!

Im afraid I don't know anyone with such a device, and weather permitting i'll log it tomorrow and post it up, but it's missing so badly it almost impossible to drive any distance, but i'll see what I can do.

Thanks again for the replies!

[bnca1980]

Went out to start it up today and the damn battery was dead. :cussing:

It's charging, maybe I'll get those logs posted up tomorrow. Has the crank relearn changed in the newer versions? I just got the latest update and I cant seem to find it. Seems like it used to be under bi-directional/LS1-LS6 Control Panel?

[joecar]

Goto the DVT tab, and enter your controller type (e.g. 99-08 LS1), then the CASE tab will show up.

[bnca1980]

:doh2: I saw that but I wasn't sure if it was the same thing or not. It's been a year or two since i've messed with this so i've got some catching up to do.

Thanks again!

[joecar]

No worries...:cheers:...let us know how you go.