new ecm - license???

[Wolfie]

Need a new ecm.
I'm sure this has been asked before... but...
I think the ecm in my 07 van is bad,
I need to replace it. Do I need to get another license just
to transfer my os to the new ecm????

[joecar]

Wolfie,

Yes, to flash a previously unseen (by FlashScan) ECM you need to use up one license (regardless of full or cal only flash, regardless of OS).

Doesn't your FlashScan still have one license left...?

How did your ECM go bad (what did you do...?)...?

Cheers
Joe

[Wolfie]

It's a long story, but in a quickie...

I have a random missfire, but not noticable.
Once in a while thr 0300 code.

Lately when coming to an idle the engine would run rough and
more often than not, stall.

When it stalls the 2,4,6 cylinders show missfire.

After much diagnosis...

I have replaced...

Coil packs with MSD (8)
Spark plug wires (twice)
Spark plugs (twice)
Crankshaft Position Sensor
Camshaft Position Sensor

after much discussion with multitudes of mechanics and a couple
dealerships, the general opinion is that the ecm is bad.

Kinda sucks that I have to waste a license to replace the ecm though...

[joecar]

Hi Wolfie,

Hmmm... interesting problem... yes it sux to waste a licence, and it sux even more to replace the ECM and have the problem persist...!!!

Some questions/comments (just want to be sure):

Has anyone eyeballed the crank reluctor wheel to see that it turns true (can look in CKP sensor bore while turning crank)...?

Has anyone connected an oscilloscope to view the CKP and CMP signals and verified for correct amplitude, pulse shape/counts, and phase relationship...?

Has anyone inspected the end of the CKP sensor to see if the reluctor wheel hit it...?

If they haven't done those 3 steps, they can't condemn the ECM yet...

Is it always those 3 cylinders...?

I assume you have tested for these things:
- coolant leaking into combustion chambers or vice-versa ("block tester kit"),
- compression and leakdown, all cylinders are same/good...?
- checked for blockage in bank 2 exhaust/cats,
- coil and injector harnesses have continuity and correct voltage drops,
- other things.

If your claibration close to stock...? If so, is it possible to borrow a stock ECM and try to make the problem happen...?

There's a very good chance that the ECM can detect if itself is bad... and there's a chance it may not.

Be sure to keep your receipts for any parts replaced.

Which vehice/year/model is this...?

Joe

[mr.prick]

Did you try a CPK Relearn?
IIRC you can get a license for a new PCM
as long as it is installed by a dealer and you have documentation.
Ask Blacky

[Wolfie]

2007 Chevy Express 2500 Extended Van 6.0liter LQ4 240,000miles on it.
The first engine ate a camshaft at 97,000 miles. Our lousy local Chevy
dealer did the work (there was a tsb on that) but insisted that although
the cam and lifters were worn out, there was NO metal in the pan.
Well 30,000 miles later the oil pump failed and the pan was full of metal.
I had a NEW engine installed at 130,000 miles.
I driver this over 12,000 miles a month.

I can not eyeball the crank reluctor wheel as the starter has to
be removed to get at the sensor.

I have not put a scope on it as I never gave that a thought.

Acording to the scan, the missfire is random and all cylinders,
but I can not feel anything.

Once in a while, after driving quite a distance, when comming to a stop,
the engine has a noticable miss, and usually, but not always, shows up
as 2,4,6. Stalls as well.

Also, while the engine is running rough, I did an injector balance test, and
killing each injector results in almost the same drop in rpm & miss (felt).

We all have eliminated anything mechanical as it is random.

I did the case relearn quite a few times.

Unless I buy the pcm from the dealer, they will make me wait over a week to flash it... go figure!

[Biggsy]

Does the problem only show during/near idle conditions?
Feel anything whilst cruizing or under accelaration?
Sounds like a problem I am currently chasing, I have changed everything you have mentioned plus more.
I will see if another computer makes a difference in mine. (I have a spare for mine)

I feel your pain,

[Wolfie]

Yes, only at or near idle.
Can not feel anything while driving.

[ChipsByAl]

What are your fuel trims at idle? A leaking intake manifold is common for this concern. Also cats clogged on one side like JoeCar said could cause this. PM me when you can.
Al

[Wolfie]

no cats.

the new computer seemed to have fixed it.
SO FAR!
(I shot you a pm)