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-   -   signs of bad PCM (https://ls1tech.com/forums/lt1-lt4-modifications/734240-signs-bad-pcm.html)

LT1_King 06-18-2007 07:04 PM

signs of bad PCM
 
i was needing to know if any of you guys have had a bad PCM? what are the typical symtoms if any. let me know of bad experiences.

1slot/a408 06-18-2007 09:26 PM

i would really like to know this too! does a bad computer affect performance? like fuel to injectors and quick heatin? misfires? sorry for askin questions in your thread! i think mine is bad

LT1_King 06-18-2007 09:37 PM


Originally Posted by 1slot/a408
i would really like to know this too! does a bad computer affect performance? like fuel to injectors and quick heatin? misfires? sorry for askin questions in your thread! i think mine is bad


mine has all these symtpoms. my performance is very poor. i would like to really know.

1slot/a408 06-18-2007 10:03 PM

i tried checkin it with the code readers and none read it! hopefully someone helps out!

dhdenney 06-18-2007 10:12 PM

I think failed communications is also a sign of a bad PCM.

LT1_King 06-18-2007 11:14 PM


Originally Posted by dhdenney
I think failed communications is also a sign of a bad PCM.


what do you mean by this? would it be in the wires and stuff? cause i looked at the wires and everything is in place.

siniSSter 06-18-2007 11:22 PM

I had a bad computer on my LT1. Mine just wouldn't start though.

dhdenney 06-19-2007 06:37 AM


Originally Posted by LT1_King
what do you mean by this? would it be in the wires and stuff? cause i looked at the wires and everything is in place.

1slot/a408 said the code readers wouldn't read it. I am assuming he meant that it wouldn't connect. I thought my PCM was bad once cuz it wouldn't connect. But I looked and the com ports were mismatched on my laptop and I was relieved.

Formula350 06-19-2007 06:43 AM

In my computer experience, when a part goes bad, it's done. When a processor breaks, it's broken. It'll cause instability in the computer, but that doesn't make sense for a car. Cars have solid state components, unlike a computer which has a hard drive. The data gets corrupted and then fragments causing further instability. I don't see how this can translate to a car. If it got bad signals/data from a chip, I would think that it would not only run like shit, but I mean RRREAAAAALLLLLLYYYY shitty. You wouldn't be able to drive. Like an injector would decide to just not pulse, and then next stay open way too long. Sparks would happen at random times.

dhdenney 06-19-2007 07:31 AM

There's a girl on here (Zralou) that said her fans don't come on anymore and she speculated the PCM was bad. So yeah, random shit.

Formula350 06-19-2007 12:12 PM


Originally Posted by dhdenney
There's a girl on here (Zralou) that said her fans don't come on anymore and she speculated the PCM was bad. So yeah, random shit.

Something happening, the same way, always, isn't random.

Odd explanation but here goes:

Every day, you're getting 5s. Then something happens and you're getting 2s every day. That's what's happening to Sara. Something happened and her fans don't work and the PCM won't communicate. Now by random, I mean you're getting 5s, then something happens and you're getting 2s, then 8s then 3s, etc. No pattern, total arbitrary randomness. Like my computer right now is on the fritz. It will lock up, or crash a program randomly. I can stress the CPU to 100% for 20mins and nothing will happen, but if it's just SITTING here, it'll crash and reboot. THAT is random. I can play games fine, and it'll crash just the game, and I can load it back up and play like nothing happened heh.

dhdenney 06-19-2007 03:14 PM


Originally Posted by Formula350
Something happening, the same way, always, isn't random.

Odd explanation but here goes:

Every day, you're getting 5s. Then something happens and you're getting 2s every day. That's what's happening to Sara. Something happened and her fans don't work and the PCM won't communicate. Now by random, I mean you're getting 5s, then something happens and you're getting 2s, then 8s then 3s, etc. No pattern, total arbitrary randomness. Like my computer right now is on the fritz. It will lock up, or crash a program randomly. I can stress the CPU to 100% for 20mins and nothing will happen, but if it's just SITTING here, it'll crash and reboot. THAT is random. I can play games fine, and it'll crash just the game, and I can load it back up and play like nothing happened heh.

Well by random I meant one didn't know what the PCM was gonna quit doing.

buffman 06-19-2007 03:19 PM

I've been wondering about mine. I have this weird miss at roughly 1000-1200 rpm on cold start up only in open loop. Everything is new if not close to new. Sometimes if you start it up, and do something like press on brake, or turn on AC it tries to die, but recovers. Miss is gone above 1500rpm. Once it hits closed loop it dissappears. Unless there's something wrong with MY SVOs, I've been wanting to pick up a spare PCM to see if the problem follows. I've even used my original flash and redid the whole tune, waiting to see if that helped.

1slot/a408 06-20-2007 01:36 AM

i tried havin it read for codes but nothin was able to connect to it! the previous owner had a hypertec programmer to it! any idea if that would of messed it up? any bad experiences with that programar you guys might of heard?


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