I'm a band director and a local business donated a 1996 GMC 3500 box truck. It has a 5.7L engine and I was having painted when it failed to start. I tried starting fluid but it will not fire. So I checked for spark and there is none. To date I have replaced the Coil, Module, and Rotor Button and still no spark. Any suggestions?
Band Truck
- Thread starter greybeard
- Start date
bgott
Well-known member
Have you tried checking for spark at the coil wire? If you have spark at the coil wire, replace the distributor cap.
We have juice coming out of the coil when you have turn on the key?
greaseyjockey
Well-known member
Weren't the pick ups in the dizzy a pretty common failure on those?
I'm a band director so "pick ups in the dizzy" don't make a lot of sense to me lol. What part is that?
Doesn't some member of the band have a dad thats a mechanic? Could be a lot more efficient than us training you via posts in the forum. 
http://easyautodiagnostics.com/gm_icm_test/gm_icm_diagnostic_1.php
http://www.truckforums.com/forum/chevy-silverado-gmc-sierra-forum-11/common-chevy-gmc-issues-9726/
http://easyautodiagnostics.com/gm_icm_test/gm_icm_diagnostic_1.php
http://www.truckforums.com/forum/chevy-silverado-gmc-sierra-forum-11/common-chevy-gmc-issues-9726/
The "dizzy" is the distributor.
thanks. So, it might be the cap, or the stator or both, right?
Actually I have 3 band parents working on this. One owns a car lot as well as a mobile home moving business, another is a machinist, and the third is a car buff. We spent most of the day and a few hundred bucks in parts and have gotten nowhere. Unlike posts that ask questions like "which hammer smashes your finger better, Snap-on or Harborfreight, this is a real problem and we need some of your expertise.Doesn't some member of the band have a dad thats a mechanic? Could be a lot more efficient than us training you via posts in the forum.
http://easyautodiagnostics.com/gm_icm_test/gm_icm_diagnostic_1.php
http://www.truckforums.com/forum/chevy-silverado-gmc-sierra-foum-11/common-chevy-gmc-issues-9726/
Thanks
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Wakefield
Well-known member
Can you check that 12 volts is going where its supposed to when the ignition switch is on? Any grounds to check?
any kind of weird antitheft system that disables the ignition system when it doesn't recognize a key transponder or something like that?
(just a couple wild guesses)
any kind of weird antitheft system that disables the ignition system when it doesn't recognize a key transponder or something like that?
(just a couple wild guesses)
No anti-theft stuff on this old heap. I will make sure it is 12 volts though.
cowboy73
Well-known member
Try the fusible link on the power wire to the ECM. The wire should be near the positive terminal of the battery. Probe the wire a few inches back with a test light and see if there is power. If no power in the wire cut out the fusible link and crimp a new one on. You don't want to solder on a fusible link. Just my 2 cents. YMMV.
greaseyjockey
Well-known member
sorry for being confusing, i was speaking of the ignition pick up coil in the distributor, the hall effect sensor, but when i went to look for a pic, it looks like the design changed from 95-96, and the 95 version was the one i was referring to, i can't say i remember ever replacing the newer style sensor, only the older ones.
ibedayank
Well-known member
Gm smallblocks are known for the timing chain to stretch just enough for the chain to jump throwing off the timing enough so the engine wont atart
It has no spark at the plug wires.
Coils not firing, is the coil getting 12v?
coil is getting juice, not sure if it is a full 12 volts
We crank it with starting fluid in the air cleaner, it will not fire. No spark
tcsalvage
Well-known member
was it running ok before the no start or was it running good then dying off a little bit then running good again? if it was running like that your plastic distributor took a ****. also you can start at the basics and make sure the chain is ok by running it up to tdc and checking the rotor to make sure its still pointing at #1 (or #6 if its 180 out). the spark controller is next to the map sensor on the pass side of the intake and also take a dump once in a while as does the coil so you should check those before you replace them. if you pull the distributor it MUST be set to 0 degrees + or - 2 with a scanner or you will set the mil and the van won't run very well.
Very funny...mtkst19
Well-known member
let me get this straight--you crank and have spark out of the coil, but none at the spark plugs. i would be looking at the distributor cap/rotor.
essentially you are telling me power comes into the cap, but not out of it. cap/rotor are the two items that control that. if you are firing at the coil, i would think then that the haul sender or whatever fires your coil is working. the center button in the cap may not be making contact w/ the rotor button. hence no spark out of the cap.
essentially you are telling me power comes into the cap, but not out of it. cap/rotor are the two items that control that. if you are firing at the coil, i would think then that the haul sender or whatever fires your coil is working. the center button in the cap may not be making contact w/ the rotor button. hence no spark out of the cap.
peterbilr98
Well-known member
is there a icm on that rig
bgott
Well-known member
If you have a good spark coming out of the coil wire, the fat wire in the middle, and you have none at the plugs, and you've changed the rotor, it needs a cap. This is a common problem. Those flat caps are ****, make sure you use a Delco, aftermarket caps will give you problems.