Page 1 of 2 12 LastLast
Results 1 to 10 of 19

Thread: Bad computer?

  1. #1
    Senior Member
    Join Date
    Feb 2006
    Posts
    113

    Default Bad computer?

    Got a weird problem.
    01 truck tuned in SD 2 bar. Truck runs fine for 30 or so miles then truck goes into a limp mode. There is no codes other than the MAF which is there all the time.You can not reset the computer to get it out of limp mode.The computer needs to be reflashed(partial with EFI live) and runs perfect again for another 30-40 miles and goes out again.After it goes into limp mode the battery light will go on/off but the voltage stays at a steady 14volts.

    Anybody have this problem? I'm thinking the computer is junk.

    Also the truck has a new battery and altinator. When we got the truck the altinator was burn't up from a loose power wire which melted back a bit.

    Thanks
    Don

  2. #2
    Lifetime Member Doc's Avatar
    Join Date
    Oct 2005
    Posts
    744

    Default

    Hi Don,
    I take it that the repairs were made to the wire and alternator and you have swapped the pcm with another and the problem has gone away? Any speculation on the melt down in the first place? Big Bon Jovi stereo or something else>? With such a catstrashope as this the well being of the pcm sure does seem to be in question. Tough call to swap another pcm unless you are certain of the repair and underlying cause of the event in the first place.

    2000 Silverado Full Size 4x4: Forged 6.2, H/C F1R Procharger
    98A4 Z28: 02 PCM H/C Forged 347, 9" Moser 3.73
    V1 V2 99+up RR COS #5 OLSD Dual Stg N20
    www.efialchemy.com
    www.greatamericancarwar.com

  3. #3
    Senior Member
    Join Date
    Feb 2006
    Posts
    113

    Default

    Quote Originally Posted by Doc
    Hi Don,
    I take it that the repairs were made to the wire and alternator and you have swapped the pcm with another and the problem has gone away? Any speculation on the melt down in the first place? Big Bon Jovi stereo or something else>? With such a catstrashope as this the well being of the pcm sure does seem to be in question. Tough call to swap another pcm unless you are certain of the repair and underlying cause of the event in the first place.
    The wire's melted from shody work from another shop.The main power wire wasn't tight which caused a resistance and melted down the wire while blowing the circuit board in the altinator.The alt. was replaced but the PCM wasn't.

    We repaired the wires and everything the other shop screwed up(over 50hrs) and drove the truck alot but probly not over 20miles at a time.Now,the customer picked it up and it went into limp mode once -I drove there and found a reflash fixed it,Then he drove another 30-40 miles and the truck went into limp mode again.

  4. #4
    Lifetime Member Doc's Avatar
    Join Date
    Oct 2005
    Posts
    744

    Default

    Considering the shoddy work you have already witnessed have you taken the pcm connectors off and looked at the pcm's pins to see if any are pushed in/not seating all the way?

    2000 Silverado Full Size 4x4: Forged 6.2, H/C F1R Procharger
    98A4 Z28: 02 PCM H/C Forged 347, 9" Moser 3.73
    V1 V2 99+up RR COS #5 OLSD Dual Stg N20
    www.efialchemy.com
    www.greatamericancarwar.com

  5. #5
    Senior Member
    Join Date
    Feb 2006
    Posts
    113

    Default

    Quote Originally Posted by Doc
    Considering the shoddy work you have already witnessed have you taken the pcm connectors off and looked at the pcm's pins to see if any are pushed in/not seating all the way?
    Of course we did. I don't see a pin causing this.Runs great,turns to crap,clearing codes doesn't work,but you do a reflash and everything is great for 2 weeks of 20 miles trips then only 30miles,reflash -good for another 30 miles.????

    This truck is over 100 miles from us now. I'm hoping someone has run into this before and found the exact problem so I only have to drive there once

  6. #6
    Lifetime Member Biggsy's Avatar
    Join Date
    Jan 2007
    Posts
    410

    Default

    I have seen a similar problem in a non ls1 vehicle (vs commodore), PCM would go into limp mode, disconnecting battery and reconnecting would not fix the limp fault.
    Change the PCM and it would work again. Car would drive fine for a couple of days then the same problem would happen again. Change PCM back to the original, and off the car would go again.
    No fault codes were activated.

    The car originally had suffered from an electrical loom fire. Loom had been replaced but this problem occurred with limp mode.

    Eventually the problem was found, it was caused by a short in the engine loom (the new/secondhand replaced one ).

    Not saying this is your problem , but a possibility.

    Dave

  7. #7
    Senior Member
    Join Date
    Feb 2006
    Posts
    113

    Default

    Thanks Biggsy. That is a possibility.

  8. #8
    Member ace68's Avatar
    Join Date
    Jun 2004
    Posts
    97

    Default

    I would look around the loom that gose to the radio because that truck had an electrical problem from a radio install that went bad. Problably melted something aroung that area.

  9. #9
    Senior Member
    Join Date
    Feb 2006
    Posts
    113

    Default

    This is just awesome

    Got the truck back.Reflashed the computer and runs great.

    Get this, the altinator light flicks on/off every once in awhile(the voltage is steady at 14v) and the friggin timing goes up slowly by itself
    So,I leave the shop and timing is at 32 degree's at light throttle and 16 degree's at WOT. 30 miles later part throttle is at 54degree's and WOT is a 26 degree's The KR sensors verify this by pulling timing when they can.---AWESOME.

    So,before the altinator light would flick and the truck would go into limp mode by going to min. timing at load, now it adds timing slowly. Getting a new computer in a few days.

    This is just

  10. #10
    Joe (Moderator) joecar's Avatar
    Join Date
    Apr 2003
    Posts
    28,403

    Default

    Before you install a new PCM, try to ohm out all pins in connector for shorts to power or ground or other pins... I know it's very tedious and laborious (I've spent a various Saturday afternoons in my former life doing this), but it may save you from blowing the new PCM.

Page 1 of 2 12 LastLast

Similar Threads

  1. Can I put an 03 OS in an 02 computer
    By 98redorangeta in forum Gen III V8 Specific
    Replies: 0
    Last Post: May 15th, 2010, 12:45 AM
  2. do i have a bad computer?
    By bigtymn in forum RoadRunner Real-Time PCM Emulator
    Replies: 3
    Last Post: September 23rd, 2009, 03:55 AM
  3. 04 Corvette computer locked need to reflash whole computer
    By Precisionauto in forum Gen III V8 Specific
    Replies: 1
    Last Post: October 8th, 2007, 10:42 AM
  4. ZO6 Computer Won't Reflash
    By Stoichiometric in forum Gen III V8 Specific
    Replies: 6
    Last Post: March 30th, 2007, 07:48 AM
  5. Computer to Computer
    By 87gmc in forum General
    Replies: 8
    Last Post: January 29th, 2005, 08:28 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •