1996 GMC K1500 4X4 5.7 / AUTO 140K MILES Turns Over, Won't Start...

Discussion in 'Chevy C/K Truck Forum' started by RON MASON, May 15, 2017.

  1. thegawd

    thegawd Rockstar 2 Years 1000 Posts

    man Im really thinking about this one???? hmmmm just for the sake of it... is the battery fully charged? im just wondeing because my buddy had a similar problem with his 98 sierra, same engine n all... and he replaced the cap n rotor, plugs n wires n it still ran like crap. he would clear the codes with a reader or by disconnecting and touching the battery cables together. nothing seamed to work and the codes persisted. but his battery was half dead. someome else told him to charge it up fully and try again, which he did and it worked. we were both left scratching our heads?

    I only know what I know from experience... I had 2 suburbans over the last 7 years, a 94 and my 97. I couldnt get my 97 to start one day and it turned out to be my cap n rotor, they were green, which I replaced with oem. inside the box had instructions to inspect the vents in the distributor housing. clean the screen or poke them out. well, I didnt have any vents in what appears to be an original distributor housing (whatever its properly called). lol. so I drilled 2, 1/8" holes and called it a day. she started the problem was if it cant breath it will trap moisture and corrode for sure in time, I had the truck for a year so I dont know how old it was. I gave her a complete tune up and shes ran amazingly ever since for an engine thats 21 years old and 100% original. I get around 15 miles/gallon, these are great engines.

    so I would charge up your battery if you haven't all ready and just have a look at those vents in the distributor.

    have a good night Ron!

    kennythewelder likes this.

    RON MASON New Member

    Thank you for your input Al... At this point I am taking any and all info as nothing seems too outlandish at this point. Yes, midway through all of this I went ahead and hooked the battery up to my charger just to give it a full charge and still same problem.

    Everything is new OEM.

    I don't know why, but I keep leaning towards the damn ignition switch and wires in the steering column. If it wasn't such a pain in the rear, I'd just change the damn thing and if I can't come up with an answer soon, probably will.

    It's funny you mention the distributor and the moisture. When I pulled the cap and rotor, the inside of the distributor was full of damp mud. The rotor was nasty so I replaced it and cleaned out the distributor really well.

    At this point I think I am going back to the beginning of the drawing board and start from scratch with the basics. Check to make sure timing is at DTC. Make sure the Fuel pump is still giving me 60+ lbs. of pressure with a slow release of pressure. Make sure I still have a decent spark.

    Thank you for your help.

    silverado002 and thegawd like this.
  3. kennythewelder

    kennythewelder Rockstar 3 Years 1000 Posts

    Nice truck Ron. Have you checked the cam position sensor? I agree, check all the above mentioned also.
    thegawd likes this.
  4. xPosTech

    xPosTech Epic Member 5+ Years 1000 Posts

    The backfire you're getting might be the engine telling you it's 180° out. Take the engine to cylinder #1 at TDC on the compression stroke and insure distributor is trying to fire cylinder #1.

    kennythewelder and thegawd like this.

    RON MASON New Member

    I have already replaced it. Thanks
    kennythewelder likes this.

    RON MASON New Member


    Let me ask- The truck was running great. Then suddenly without warning, any adverse sound, no clanks or bangs the thing dies never to start again. How could/would the timing jump 180 degrees? I suppose anything is possible in this life, but how could this happen? Also, I have already replaced the timing chain and gears. I have changed the CAM positioning Sensor, the Crank Positioning Sensor, the Distributor Cap, the rotor, the ICM. But it still does the same exact thing it did prior to making all of these changes.

    RON MASON New Member

    I want to repost this in case anyone is missing the original post.

    I was driving the truck one day with no problem at all.
    I was on a main street and turned into the left turn lane when suddenly the vehicle just died. I was in a forward motion roll and continued through the intersection into the parking lot.
    I tried to restart it with absolutely no luck. When it died, there was no clank, no smoke, no strange noise???
    When I tried to restart it, it would only turn over, After a couple of tries it began to backfire out through the intake manifold.

    We towed it home and began the process of trying to figure it out.

    I had previously replaced the fuel pump about 1 year ago with no issues. When testing, we got a solid 60 - 63 lbs. of pressure.
    when Using an OBDII tester, I'm sorry I don't remember the exact codes, but one was that one or more of the cylinders were misfiring.
    Then the Cam Sensor was faulty.

    Through the testing and out of wanting to just replace everything after 100k, I have replaced:

    Cam Sensor
    Crank Sensor
    Distributor Cap Rotor
    Timing Chain and Gears. Installed at O degrees as required.
    I have not timed it yet.
    After doing all of this, and turning over the engine. I get the same exact response as before.

    I just went out and checked for codes and it came up clean. No Codes at all.

    I have read some other forums in an effort to get some other ideas and they stem from opening and removing gas cap -tried no help.

    I turned on key to run position, let all dash lights go out and tried to start - same thing. Some people mentioned that the K-Switch or alarm might play a role in this, but no go.

    A couple of years ago I had a problem somewhat similar where it would turn over, but not start... No backfire though. It turned out to be the ignition switch. I had replaced it and it started and ran great.

    Before this issue had begun this time, it was very strange but I believe that the ignition switch had another short in it as it would turn over but not start. Then I would wiggle the steering wheel and it would then start.

    Could the ignition switch play a role in this? Would it turn over, cause backfires through the intake, and not start? Is that possible?

    I hope this has shed some light on what I'm going through.
  8. Differently

    Differently Active Member 100 Posts

    RON MASON likes this.
  9. xPosTech

    xPosTech Epic Member 5+ Years 1000 Posts

    Sorry Ron I saw distributor cap replaced and 'I have not timed it yet'. Are you sure the distributor shaft is turning?


    RON MASON New Member

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