88 Silverado, TBI 350/700r4. About 400k miles.
Twice it's failed to start. The first time, I cycled the key repeatedly, and got zero response, no dash lights and silence from the starter. I figured the battery was dead (I don't drive it as much since the AC needs replacement).
I checked the battery. Terminals were clean and tight (something I stay on top of), and it had about 12.3 volts. I put the charger on it anyway.
It happened one other time, but that time when I cycled the key again it started. It's started every time since.
Since this has been intermittent, I expect to need to load the parts cannon. I've had cars that failed to run due to a bad ground, so I will add an extra ground from an accessory bracket to the battery, but I don't think that's it.
Is the ignition switch the first part to replace?
I would look at the fusible links under the cover on the firewall first, coming from a lifetime of driving tbi gmt400 trucks
Patrick said:
I would look at the fusible links under the cover on the firewall first, coming from a lifetime of driving tbi gmt400 trucks
I thought that would be a permanent no start. That can be intermittent?
Check the battery cables very carefully. They pass by the exhaust manifold and tend to deteriorate without necessarily being an obvious problem. Check resistance in the cables and see what values you see.
In reply to dj06482 (Forum Supporter) :
That's a good idea.
In reply to Floating Doc (Forum Supporter) :
On my olllld 89 corroded fusible links were giving me all kinds of intermittent issues
Switch can fail, but unlikely. Starters frequently get dead spots on the armature and don't like to engage. Next time it happens, stab the starter body about 10 times with a broomstick or tap it with a hammer. Sometimes that magically makes it work... that one time. But it's a good diagnostic tool. If it suddenly works you know it's time for a new starter.
Fusible links do corrode, good call to check there as well.
88 likely has VATS as well. Does your key have the little chip in the shaft? Like this?
If it does, that chip has a specific resistance value. The VATS reads that value and assigns a go/no-go value for the starter circuit. Over time those chips wear down and don't make contact, or they fail completely. Dad's 88 GMT400 did have a chip in the key, but other 400 trucks I've seen sometimes do and sometimes don't. I heard it was something to do with the factory they were built in.
Slightly different beast: on my 01 Sonoma 4.3 my failing starter gave intermittent no-starts. dash light behavior was normal.
since your dash lights aren't lighting, I'd be looking at power or grounds upstream of the interior, ie B+ and B- and fusible links. A jumper cable and remote start button alligator-clipped in place would be handy for diagnosing wiring vs starter.
At that mileage I would replace the ignition switch. Sometimes on a no start you can wiggle the key and the worn contacts will connect. I had a friend with a GM motor home who replaced everything but the switch and it was the switch that was the problem.
In reply to Curtis73 (Forum Supporter) :
My key doesn't have that
I just finished four hours of yard work, too hot out to do much else now, but I figured I would take a look at the truck before going in.
So frustrating, it started on the instant the key was bumped, runs perfectly. I drove a 15 mile loop since it's been sitting.
I need a nine volt battery for my multi tester so I can check the battery cables, and I'll do an internet search for the location of the fusable links.
In reply to Floating Doc (Forum Supporter) :
They are under the black cover on the firewall, passenger side, with the fuel pump relay
Patrick said:
In reply to Floating Doc (Forum Supporter) :
They are under the black cover on the firewall, passenger side, with the fuel pump relay
Thanks! Rather than check them for resistance, should I just replace them?
Cousin_Eddie (Forum Supporter) said:
88 has no VATS system
I know dad's 88 GMT400 did because I helped him solder in a resistor to bypass it.
I know it was on some cars as early as 1985, mostly Caddy, Corvette, and Buick. Glad Doc's doesn't have it. Just one thing he doesn't have to check :)
GMT900 so not terribly applicable. Mine was turn the key and it would kill the dome lights, etc and obviously no crank, no sounds, all dead. Only once every 30 starts or so. I found it by leaving the door open so I could see the dome light and realized when I jiggled the neg cable somewhere along its length the light would go out and then come back. Replaced the cable which, once out, looked perfectly fine. Problem solved.
