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Electric Gremlins (UPDATED)

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Innerpiece, Jan 14, 2002.

  1. Innerpiece

    Innerpiece 1/2 ton status

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    Hi folks -- Just looking for a little validation before I start ripping stuff out.

    Background : 1987 Silverado K5 tbi 305
    I am losing electrics to things that are "hot at all times" like the interior lights, headlights, fuel pump, etc. All of these things get power direct from the battery by way of the starter solenoid and a pesky orange wire (a common bus for everything except p/w p/l that gets hot at all times juice). The really odd thing is that it's an itermittant problem ... everything can be dead and then working again an hour later (through no action by me). The best part is, the truck still cranks, so the wife has killed the battery a few times cranking the truck with no start (no juice to fuel pump)

    So here are the questions....

    (1) Best I can figure, the starter solenoid itself is breaking the chain and not giving juice on down the line. The cap of the solenoid (the end with the electrical connections) is cracked. Obviously I have to replace this anyway, but could the solenoid be sticking or screwed up and not letting juice on down the "orange" wire?

    (2) Is there a fuseable link just downstream of the solenoid on the orange wire? Some of the chilton's stuff shows a 20A fuse, some of it doesn't. Anyone know?

    (3) Are there fuses / fuseable links / circuit breakers anywhere else in the "hot at all times" stuff on the positive side? I know some of my components have fuses on the ground side, but when one thing goes, they're all dead.

    Thanks for all of the help....

    <P ID="edit"><FONT class="small">Edited by Innerpiece on 01/15/02 05:41 AM.</FONT></P>
     
  2. Topless84

    Topless84 Registered Member

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    Re: Electric Gremlins

    Sounds like the first thing to do is replace the selenoid. Because that is the most obvious thing. But if that dosen't fix the problem here are somethings that have happened to my trucks over the years. Most recently my 87 K5 had the same
    problem you are having. tracked the problem to the ignition switch on the steerring colume. That is two peace connector
    of which half of mine just came off. Then awile back on my 84 K5 The junction block on the fire wall was full of corrosion.
    Just put new terminals on all the wires there, wire brushed the posts and reassembled it . No trouble since.
    by the way there is a fussible link at the starter (10 gage Purple) that supplys power to the junction block, but once those links blow they are blown.
    Hope this helps

    4X4 Once I got one, won't ever be with out one
     
  3. Innerpiece

    Innerpiece 1/2 ton status

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    Re: Electric Gremlins

    so if it turns out to be a Fuseable Link ... how do I fix that ... cut it out and splice in some more thin wire?
     
  4. sosamantx

    sosamantx 1/2 ton status

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    Re: Electric Gremlins

    hmmm, I don't think it's the starter soleniod??, not really sure of anything right now (morning). lol, but if you think it's a fusible link, they do sell them at the auto parts store, you just cut out the old one and install the new one. I'd also make sure you have a good ground as well.

    <font color=blue>Steve Sosa a.k.a. "sosaman"</font color=blue>
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  5. Chris Demartini

    Chris Demartini 1/2 ton status

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    Re: Electric Gremlins

    <font color=blue>The fuseable link is there for a reason. Dont replace it with wire, replaceit with another fuseable link. You can just cut the old one out and replace it with a new one
     
  6. heaj1

    heaj1 Registered Member

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    Re: Electric Gremlins

    I would think that if a fuse of fusable link blew it would be dead all the time. Might want to steer more towards corrosion or the solonoid thing. Just a thought. Hope it helps.

    Jamie

    Swimming like a rock, Slinging like a stock, but not for long!
     
  7. Innerpiece

    Innerpiece 1/2 ton status

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    Re: Electric Gremlins

    well -- now that I really sit and think about it ... let me know if this sounds plausible.

    All of those wires sit damn near the exhaust mainfold collector. Could a fuseable link or chunk of wire partially burn out? I know fuses are all or nothing ... but could a fuseable link or wire go partially? that would explain the sometimes it works sometimes it doesn't (although that sounds more like a sticky or corroded solenoid). I don't think that the orange wire is grounding out anywhere ... everywhere else looks real good except near the starter, and the battery doesn't drain when the juice is gone.

    I had noticed in the past that when I would drive over a curb (why not!) sometimes the engine would die ... It stopped and I never thought much of it ... but it sure sounds like a momentary interruption of power to the fuel pump now (too bad I didn't notice if the lights quit too).

    Could a solenoid problem prevent juice from getting to the "orange" wire or is that a direct link (bolted to the same terminal as the battery cable) to the battery? could a frayed or melty wire cause something like this?

    I'm just trying to put together the best picture before I start ripping sh!t outta there this afternoon. Thanks for all of the inpu so far
     
  8. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Re: Electric Gremlins

    So when did you get the new motor?
    The ground strap off the back of the passenger side head to fire wall is off. The body of the truck is trying to pull ground through the core suport and fender. Paint,minor corrosion the galvanizing on the body are all poor conductors.
    Very hard to see the strap. It's easiest to feel for it. It is supose to be bolted to the head. If the bolt is missing it's a 3/8's (9/16 socket size) 1/2 inch bolt that you need. If the strap was ripped lose when the engine was removed you can get new straps in the help section at you local parts store.

    Women dig dents and flat paint!
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  9. Innerpiece

    Innerpiece 1/2 ton status

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    Re: Electric Gremlins

    do tell -- how can you so definitively answer? (bows down before your massive cranium) There are also queer-trons running through my non-stock radio ... but that may just be the cheap ass spark-o-matic for ya ... could it be as simple as a ground strap?? the motor has been out before (previous owner) ... would that cause everything to sometimes work and sometimes not? would that missing bolt cause a minor oil leak? could this be the answer to all of my problems!!??!!

    <P ID="edit"><FONT class="small">Edited by Innerpiece on 01/14/02 09:22 AM.</FONT></P>
     
  10. Innerpiece

    Innerpiece 1/2 ton status

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    Re: Electric Gremlins

    anyone?? last chance -- I'm about to start splicing ...
     
  11. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Re: Electric Gremlins

    That strap is overlooked ALL the time. You can't see it. Damaged lots of times when you try to pull the motor and forget to disconnect it.
    Let me fill in your symptoms. Gages bounce when turnsignals are used or brakes are pressed. at night sometimes everything will quit but the headlights and motor. This may fix the stereo also.
    The way GM runs the grounds is EVERYTHING but the the pig tail off the battery terminal that goes to the core suport goes to the block. From the block you then get a body ground strap that I'm betting is the problem. With paint and stuff you don't get a good ground back to the core suport. Your also trying to pull all the ground from the body including blower motor, lights the works through that little wire at the battery. This will casue electroisis to form at the bolt from the fenders where they attach to the body.

    Women dig dents and flat paint!
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  12. CaptCrunch

    CaptCrunch 1/2 ton status

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    Re: Electric Gremlins

    I agree with Grim.... almost always overlooked by the shadetree and weekend wrenchers... heck even the garages sometime biff this one.

    -Mikey
    1987 Chevy K5 Blazer- 350 TBI
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  13. Burbinator

    Burbinator 1/2 ton status

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    Re: Electric Gremlins

    The groundstrap does not necessarily have to be missing, per se, just loose is all it needs to be for intermittent problems. A fusible link is all or nothing; they do not become intermittent. A cracked solenoid is just inviting problems, I'd replace that quickly.

    Good luck!

    Haze gray and underway...<font color=blue>or blue, in my case.</font color=blue>
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  14. dyeager535

    dyeager535 1 ton status Premium Member

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    Re: Electric Gremlins

    Fusible links CAN be an intermittent problem. If the wire burns through, but gets jiggled enough to make contact, it can still work, sometimes. I've seen it happen. But I'd also say thats not the norm.

    The solenoid however, if its cracked, may be cracked because someone tightened the terminals down too far. There is a SOLID piece of copper joining the terminals to the solenoid, and if the terminals are twisted, they can, and will, break. Ask me : )

    Ground sounds plausible too, but thats easy to test too. Hook a good ground up to the body and the - batt terminal. Spare battery wire would work well for this probably.

    Question for electrical masters, if the ground for the engine is ineffective, if you measured continuity between the block and the body, would that show some resistance or not, since the engine should be grounded through the frame as well. (alternator ground to battery, battery to frame)

    Before you start ripping stuff out like the orange wire, use a voltmeter and test voltage and continuity. (on everything you can think of thats related) Virutally everything is 12volts, and when testing continuity, wiggle the wire being tested, to check for a bad connection.

    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>www.dorianyeager.com/index2.html</a>
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  15. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Re: Electric Gremlins

    The frame is not grounded. Everything that attaches to the frame is on bushings. The FI trucks may be the exception to provide ground for the fuel pump. Trace the ground and you will see what I mean. the Ground does not make any direct connection from the block to the frame that I have ever found on either my 75 or the Lady's 79. What ground it pulls is through the body mounts. Nowhere on the truck will you find anything that has ground wires to the frame. They all go to the body.

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  16. shoeless

    shoeless Registered Member

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    Re: Electric Gremlins

    I understand all the talk about grounds, but my brother had the same problem with his Thunderchicken. It turned out to be some of the battery cables had corroded inside, and the simple fact that they weren't very tight on the terminals. You may have checked that already, but that's my $.02 for what it's worth.

    Shoeless
    '88 K5
     
  17. Innerpiece

    Innerpiece 1/2 ton status

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    Re: Electric Gremlins

    The TBI Pump has a "ground Strap" from the sending unit to the driver side frame ... The frame is grounded somewhere
     
  18. Innerpiece

    Innerpiece 1/2 ton status

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    The Update --

    Well-- I threw a new starter in there (just b/c the solenoid was cracked) ... and spliced in a new Fuseable link ... the other one was fairly fried, either from current or from being really close to the exhaust collector. The ground strap to the firewall was missing (great call) ... so I replaced that also. disconnected the EGR ... sealed up a 208 (I'm convinced that ATF is less viscous than a fart and damn near unsealable) ... I got fired up and was going to replace the front wheel bearings ... but lost interest ..

    I did learn that when you're working with (1) an impact gun (2) a confined space (3) a U-joint in the line b/w the gun and the socket it's important not to try to hold the socket on the nut with yer hand ... because when the socket comes loose of the nut cranium it will smack the living shite out of yer thumb six or seven times before it registers to (1) move yer hand (2) stop pulling the trigger

    Ouch! (but the truck's running again)
     
  19. dyeager535

    dyeager535 1 ton status Premium Member

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    Re: Electric Gremlins

    I could take a picture if I had a digital camera and I wanted to, the frame IS grounded...no idea when this started though. My '83 was this way, and so is my '86. The - battery cable has TWO leads that come out of the batt terminal, one that is bolted to the frame with a large (3/8"?) self tapping screw, and the other that goes to the engine.

    Dorian
    My tech/links page: <a target="_blank" href=http://www.dorianyeager.com/index2.html>www.dorianyeager.com/index2.html</a>
    Why insist on counting when the ring gear has the tooth counts stamped in?
     
  20. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Re: Electric Gremlins

    Hmmmmm Different than my 2 trucks then. Just the pig tail off the battery terminal to the core suport and then the main big lead goes to the block. Then the ground strap off the head to the fire wall. Now there is a tie down for the POSITIVE cable on the top of the frame to keep it in place. Your not confusing that with a ground lug are you?

    Women dig dents and flat paint!
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    75 Jimmy, Dollar
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