'96 Silverado - Engine quits, starts right back up. No codes

[khigh]

Yeah I know it's Tahoe/Yukon, but I'm already here - and this should be universal between them.

I've kind of abandoned this truck because it's undependable because of this, but I'd kind of like to get it going again - especially when I found out I'm only paying like a nickel a month to insure it on multi-car, and some days it would just be handy to have a pickup.

It' s a '96 Silverado 5.7 2WD

Hits one revolution, doesn't hit the next. A few times I've been able to restart it coasting in Neutral. A few times I've had to pull it over. One time I was on the side of the road for about 5 minutes. That was kind of the last straw - haven't drove it since.

I put a BT dongle in it - never shows any codes according to Torque, but it HAS to be something electronic. The LAST thing I want to do is limp it to the shop, spend a bunch of money on blindly replacing crap, and it not help.

Any thoughts on how to diagnose it?

Thanks for looking.

 

[khigh]

Update.

It hasn't run in a couple years - went over it a bit, charged the battery, etc (surprised it came back, but it has plenty of power).

It's pretty consistent now - run 3-5 minutes, die, start right back. I'm kind of afraid to take it to the shop and don't want a towing bill.

 

[jerryjoe28]

think It may have a grounding problem? mine would die for no reason when I first got it. then it may or may not do anything when I tried to start it. found a bad ground to the starter. replaced it and all better. this is what prompted me to do the big 3 upgrade

 

[khigh]

I won't rule it out, but all the shorts I've ever had have been more of a sporadic gremlin behavior with states in between on and off.

This is such an instantaneous binary thing. Boom. It's dead. Boom it's fine.

 

[SunlitComet]

so overall engine temp plays no role on start on quit timing?

 

[khigh]

No - can't think of any commonality at all. I never really took it on the freeway - it was all around town, so it never got particularly hot - mostly 2-12 mile trips.

I've been studying, and I've seen some references to the ECU, and one having similar symptoms being the ignition switch. On the one hand I can see it being the switch blinking off momentarily, but I don't think any of the accessories were affected.

 

[SunlitComet]

possibly. the accessory feed circuits use separate contacts and outputs from the ignition switch. do you need a diagram for testing?

 

[khigh]

Back again. I stepped away from that problem because I thought it was being exacerbated by a water in the gas problem - it did sit out in GA for two years with hardly any gas in it. I put Heet in, 5 gallons of fresh gas, and shot liberal bursts of WD40 into the intake. I think I have the gas stabilized, but it's no better. In fact it's worse.

It only runs for a minute or two - maybe three. Sometimes it will take pedal and rev high, and sometimes when you give it pedal it bogs down and dies.

We may be back to the short idea. possibly coupled with the ignition idea.

It clicks randomly in the engine compartment. Anyone know what that is?

Here's a video.

 

[khigh]

possibly. the accessory feed circuits use separate contacts and outputs from the ignition switch. do you need a diagram for testing?

Thanks - it couldn't hurt. I assume I'd take off the steering wheel housing and jumper the run circuit?

 

[khigh]

Finally had to give up diagnosing - called the shop and they sent a truck from a place they contract with. I could have technically eventually have made it there and thought about striking out in the middle of the night, but didn't know if the battery was up to all the starting.

So the tow truck driver shows up and I'm talking to him. He asks what it's doing and I describe the symptoms. He says "oh - the coil?"

D'oh! As much as I don't want it to be expensive, I'm going to hate it if that's all it is.