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GMC engine repair questions and answers

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  • ken lehtonen
    ken lehtonen - 2005 GMC C5500 Topkick - Engine - 8/29/2014
    Diesel engine wont start . when it starts it runs good
    seems like an electric problem , no power to fuel pump when trying to start but when it starts it works fine. replaced fuel filter and pumped up fine started and ran shut off and wont start
     
    0 answer
  • coreybaker86
    coreybaker86 - 1995 GMC K1500 - Engine - 8/28/2014
    No power to the OBD2 connection.
    Recently bought the truck and it runs good but cruising around 55 the engine rev's up suddenly by maybe 500-700 rpms then goes back to normal. I cant accelerate during this either. I plugged in a scan tool and it wouldnt turn on. I checked the scan tool on my other ...
     
    • jdl
      8/28/2014 jdl
      Some gm makes and models, 95 is a crossover year, It could be a hybrid connector, I can't you with that type connector. I'll check your wiring diagram.

      If you fully obd2 compliant, pin 16 should be hot. That voltage usually comes from cigar fuse, I'll have to double check.
      jdl
      8/28/2014 jdl
      If your system is obd 1.5, then you will need a scanner for obd 1.5.
  • glen
    glen - 2001 GMC Sonoma - Engine - 8/26/2014
    No start intermittent
    intermittent crank but no start fixes itself after days or weeks of trying to start it
     
    • jdl
      8/26/2014 jdl
      When the problem is ongoing, if it cranks good but won't start, have a helper crank it while you visually check for spark at the spark plugs. If you have spark everywhere, check fuel pressure. With intermittent issues, you need to test when problem is ongoing.

      Check for intermittent rpm signal? No rpm signal, no start. Can be intermittent.

  • glen
    glen - 2001 GMC Sonoma - Engine - 8/26/2014
    Intermittent no start
    mileage 125000 cranks but no start can happen anytime works fine most of the time but will leave you stranded let it sit for days or weeks and eventually starts and acts normal until next episode of no start
     
    0 answer
  • rlhanson58
    rlhanson58 - 2008 GMC Acadia - Engine - 8/25/2014
    Where is my oil pressure switch located on my engine.
    Having a problem with low oil pressure. I check oil it's fine. This only happen on a long trip. light come on dash board.
     
    0 answer
  • ql_lp
    ql_lp - 1993 GMC C1500 - Engine - 8/21/2014
    Truck starts when it wants to.
    Every once in awhile my truck won't start as if the starter was disconnected. But by leaving it for 30 to 45 mins it starts as if nothing happened. There is another way to start it quickly by boosting it off. Looking at the schematics it's pretty simple system. I ...
     
    • jdl
      8/21/2014 jdl
      I'd have to check starter electrical circuits when problem is ongoing, voltage and ground. Any testing at the starter, make sure tranny is in park or neutral and a functional parking brake is set.

      Make sure your battery has a full charge. The starter solenoid s terminal gets voltage from the ignition switch crank position then through the neutral switch, usually. I haven't looked at your wiring, yet. Use a digital multimeter and do some circuit testing, have a helper turn key to crank.
  • ql_lp
    ql_lp - 2007 GMC Sierra 1500 - Engine - 8/20/2014
    Sometimes the truck won't start as if no starter.
    Every once in awhile my truck won't start as if the starter was disconnected. But by leaving it for 30 to 45 mins it starts as if nothing happened. There is another way to start it quickly by boosting it off. Looking at the schematics it's pretty simple system. I ...
     
    • Chevy doctor
      8/20/2014 Chevy doctor
      Sounds like a ignition switch problem. We have had issues with the under hood fuse block failing internally.
  • Wayne
    Wayne - 1998 GMC K1500 - Engine - 8/19/2014
    Have whine coming from the front engine compartment that comes with rpm until around 2500.
    Replaced PWRs st fluid and flushed system and it got a little better. Could it be anything other than the pump? Has 190k and don't want replace it needlessly.
     
    0 answer
  • Wayne
    Wayne - 1998 GMC K1500 - Engine - 8/19/2014
    Have whine coming from the front engine compartment that comes with rpm until around 2500.
    Replaced PWRs st fluid and flushed system and it got a little better. Could it be anything other than the pump? Has 190k and don't want replace it needlessly.
     
    0 answer
  • Jacob
    Jacob - 1994 GMC K1500 - Engine - 8/18/2014
    Why is my truck idling and driving rough
    I have a question so I have a 94 gmc serria with a tbi 350. When it starts up the idle is really low. And drives really sluggish. It sounds like it has an upgraded cam in it but my truck does not. Don't know whats wrong with it any ideas. I just had a new intake ...
     
    0 answer
  • thollis
    thollis - 1990 GMC C1500 - Engine - 8/17/2014
    Truck won't start has new starter new wires and alternator and battery is just fine and i have no power or anything
    i replaced the starter on it because it burned up and we tested it and it failed from the old started i also replaced the ground wires and the positive wires that went to the starter i also got my battery charged up and it was good.. i also replaced my ignition ...
     
    • jdl
      8/17/2014 jdl
      Did you check for voltage, anywhere? Use a test lite. Follow the B+ from battery, it may go to battery junction block or where-ever, but, check for voltage. Check for voltage at fuse circuits/fuse box. Some fuse circuits are hot all the time, some go hot with the key on.

      The issue could be a problem with fusible link, somewhere?
  • thollis
    thollis - 1990 GMC C1500 - Engine - 8/17/2014
    Truck won't start has new starter new wires and alternator and battery is just fine and i have no
    i replaced the starter on it because it burned up and we tested it and it failed from the old started i also replaced the ground wires and the positive wires that went to the starter i also got my battery charged up and it was good.. i also replaced my ignition ...
     
    • alex
      8/17/2014 alex
      their is a third wire to your starter a smaller one that takes power from the starter to everything els you missed that one when you changed the starter. it will be hanging down somewhere right by the starter.
  • Tevon
    Tevon - 1998 GMC K1500 Suburban - Engine - 8/16/2014
    Why does my check engine light come on an off?
    My check engine light comes on a stays on for about 2 days, then goes off for 4 to 5 days I have a code PO440 PO306'
     
    • Jimm
      8/16/2014 Jimm
      P0440 means Evaporative Emission Control System Malfunction. P0440 is triggered when a part of EVAP control system is not functioning efficiently.

      Here are the possible causes of P0440

      o Loose or missing gas cap
      o Incorrect or defective gas cap
      o Loose or damaged hoses around the EVAP purge solenoid
      o Defective purge solenoid
      o Clogged or defective purge valve
      o Clogged or damaged EVAP canister

      Possible solutions:

      o Remove and reinstall gas cap
      o Replace gas cap
      o Repair or replace hoses around the EVAP purge solenoid
      o Repair or replace purge solenoid
      o Repair or replace the purge valve
      o Replace EVAP canister

      A code P0306 may mean that one or more of the following has happened:
      Faulty spark plug or wire Faulty coil (pack)
      Faulty fuel injector
      Burned exhaust valve
      Poor compression
      Defective computer
  • Darrell Cheeseboro
    Darrell Cheeseboro - 2003 GMC Yukon - Engine - 8/16/2014
    I have code p0332
    Check engine light came on no drivability problems
     
    • Jimm
      8/16/2014 Jimm
      Replace both knock sensors. Pay close attention to the condition of connectors and pins.

      The parts are readily available from these many on-line sources, www.partsgeek.com, www.rockauto.com, www.discountautoparts.com, www.autopartswarehouse.com, www.jcwhitney.com - to list only a few possibilities.
      In fact, they (RockAuto) list the knock (detonation) sensor from around $25.00 each for your vehicle.
  • gary woodard
    gary woodard - 2002 GMC Sierra 2500 HD - Engine - 8/12/2014
    Engine starts and quits immediately
    checked fuel pressure checked al wining and fuses bypassed the security system
     
    • jdl
      8/12/2014 jdl
      Can you check for applicable trouble codes to rule out the security system? If you have passlock that is a fuel injector disable.

      If not security issue, maybe the vehicle is trying to flood for some reason?