Truck won't start for 15 minutes following shutoff

[ASJT3]

Hey guys,

I've been experiencing this problem ever since I bought my '90 C1500 305 but its recently gotten worse. After long trips (over 100 mi) the truck refuses (will not even crank) to start for at least 5 minutes following shutdown. Now, it will intermittently not start for 15 minutes following shutdown after shorter (~10 mi) trips unless it gets a jump, which is strange considering the battery is not run down.

I first thought it was a bad contact in the ignition cylinder, but I noticed that the batt voltage would always droop when turning the key to start, so I guess that the ignition is being applied. Now I'm wondering if the starter motor might be bad?

It's a weird problem to have, I am 100% certain the truck will start if its cold. But after a long trip it just flat out refuses, will not even crank.

Any ideas?

Thanks,

AlexT

[aleekat]

1990. Original battery cables? My guess would be corrosion under the insulation encountering lots of resistance.

[Schurkey]

"Doesn't crank" is ENTIRELY different from "Cranks slowly".

"Doesn't Crank" is sometimes a fault in the starter solenoid, but more often a result of high resistance from battery to the ignition switch or ignition switch and the starter solenoid "S" terminal.

The typical response it to install a relay on the fender so that the vehicle wiring only has to trigger the relay, the relay triggers the starter solenoid. There are a couple of ways to do this. I have a "Ford" relay on the fender of my '88. Other folks prefer the smaller "Bosch" relay. A search for either should produce a wiring diagram. Very common.

Another option is to bite the bullet, do voltage-drop testing to find the faulty wiring, and replace the wire or clean the connections from battery, through ignition switch and ending up at the starter solenoid "S" terminal.

[j cAT]

my guess is the fuseable links are corroded. these are at the starter wiring connections. they are part of the wiring and look like stubby pencil shape an inch long. there may be another link running across the intake manifold also hidden in the loom covering.

I have found when cold no problem, but after the vehicle heats up this then occurs and these links are the problem.

my theory is the links heat up with the voltage drop. the longer the operation the greater the heat . as the temp increases the resistance increases.

make sure all the fasteners at the starter are clean and secure including the one with no wires running to it.[solenoid to armature]

[ASJT3]

Thanks for the responses everybody, will do some testing and report back with more info.

[danielsatur]

As Heat increases so does resistance!

[Tech II]

Check the battery condition(also alternator output)......check the battery connections....check the connections at the starter......if all check out ok, and there is battery voltage at the "S" terminal with the key in the crank position and it doesn't crank, need a starter....

If I remember right, some of these vehicles had heat shields to protect their starters from engine/exhaust heat......is the shield there?

[ASJT3]

Thanks for the replies everybody. As I was trying to loosen the battery cable lead from the starter solenoid the lead stud broke off and the solenoid housing broke in half along with it. No visible corrosion on the leads other than normal dust/crud.

I went ahead and replaced the starter motor and voila, problem solved! I think the solenoid was the culprit (rusty/dirty inside) and guess I could have replaced only that but the starter motor was cheap enough figured might as well do the whole thing. And yes, Tech II, there was a heat shield installed which I transferred to the new starter.

[j cAT]

Originally Posted by ASJT3

Thanks for the replies everybody. As I was trying to loosen the battery cable lead from the starter solenoid the lead stud broke off and the solenoid housing broke in half along with it. No visible corrosion on the leads other than normal dust/crud.

I went ahead and replaced the starter motor and voila, problem solved! I think the solenoid was the culprit (rusty/dirty inside) and guess I could have replaced only that but the starter motor was cheap enough figured might as well do the whole thing. And yes, Tech II, there was a heat shield installed which I transferred to the new starter.

a loose connection would do that .

[webbch]

Sorry to revive this old thread, but this is a VERY common problem in these rigs. The root cause is the small wire running to the solenoid from the ignition switch. As the engine heats up, the resistance of this wire (which runs RIGHT next to the hot exahaust pipe) increases to the point where it cannot activate the solenoid, especially if the solenoid requires just a bit more current to activate than it did when new. The heat soak right after shutting off the engine is JUST enough to make it not work. Once the engine starts cooling down for a bit (> 15 minutees or so), it starts working again. Granted, solenoids do go bad once in awhile. However, on my '90 silverado, I installed a ford solenoid on the inside of the wheel well and ran the ignition wire to this location which is much further away from the hot exhaust, then ran a heavier gauge wire to the starter solenoid. Never changed the starter, never changed the solenoid. That was over 7 years ago, and no hot start problems since.

You can get more information here, or google for "chevy hot start problem" or similar.

[j cAT]

Originally Posted by webbch

Sorry to revive this old thread, but this is a VERY common problem in these rigs. The root cause is the small wire running to the solenoid from the ignition switch. As the engine heats up, the resistance of this wire (which runs RIGHT next to the hot exahaust pipe) increases to the point where it cannot activate the solenoid, especially if the solenoid requires just a bit more current to activate than it did when new. The heat soak right after shutting off the engine is JUST enough to make it not work. Once the engine starts cooling down for a bit (> 15 minutees or so), it starts working again. Granted, solenoids do go bad once in awhile. However, on my '90 silverado, I installed a ford solenoid on the inside of the wheel well and ran the ignition wire to this location which is much further away from the hot exhaust, then ran a heavier gauge wire to the starter solenoid. Never changed the starter, never changed the solenoid. That was over 7 years ago, and no hot start problems since.

You can get more information here, or google for "chevy hot start problem" or similar.

the vehicles being this old do have this type electrical issue . replacing the fuse links and running new wire with the ends soldered and sealed normally fixes this for a lot longer than GM intended these to operate. even the newer vehicles have many ground failures due to the OEM defective materials and proceedure used at the factory. since the vehicle is this old the wiring heat shields and tie downs are long gone increasing these issues . protective loom has vaporized about 15 years ago

[Schurkey]

Originally Posted by webbch

The root cause is the small wire running to the solenoid from the ignition switch. As the engine heats up, the resistance of this wire (which runs RIGHT next to the hot exahaust pipe) increases to the point where it cannot activate the solenoid, especially if the solenoid requires just a bit more current to activate than it did when new. The heat soak right after shutting off the engine is JUST enough to make it not work. Once the engine starts cooling down for a bit (> 15 minutees or so), it starts working again. Granted, solenoids do go bad once in awhile. However, on my '90 silverado, I installed a ford solenoid on the inside of the wheel well and ran the ignition wire to this location which is much further away from the hot exhaust, then ran a heavier gauge wire to the starter solenoid. Never changed the starter, never changed the solenoid. That was over 7 years ago, and no hot start problems since.

Originally Posted by Schurkey

"Doesn't Crank" is sometimes a fault in the starter solenoid, but more often a result of high resistance from battery to the ignition switch or ignition switch and the starter solenoid "S" terminal.

The typical response it to install a relay on the fender so that the vehicle wiring only has to trigger the relay, the relay triggers the starter solenoid. There are a couple of ways to do this. I have a "Ford" relay on the fender of my '88. Other folks prefer the smaller "Bosch" relay. A search for either should produce a wiring diagram. Very common.

BT, DT, zero problems for three or four years now.