New gremlin to find

[metallicflame]

All right, so my 97 has developed a new issue that is driving me nuts. It starts and runs fine until you put a load on the electrical system by turning on the lights. After using the lights for 5-10 minutes the truck shuts off without warning as if someone turned the key off. When you try to restart it there is no power to the glow plugs or the lift pump and nothing you can do will get it to run. I let it sit for 15 minutes and everything is back to normal, turn the key on, the lift pump energizes, the glow plugs cycle and the engine will start. I've drove it during the day without a hitch, but if I have to turn the head lights on, the gremlin appears. We had the IP replaced last October due to the fuel solenoid started to go out. The PMD is a Heath unit mounted behind the front bumper. My feeling is it is one of the relays or breakers under the hood, but which one. Any help from the vast wealth of knowledge on this forum would greatly be appreciated.

[trbankii]

How is the health of the battery and starter?

[Robyn]

Check the voltage at the batteries with the engine running

Should read 13.5 to 14 volts at both batteries.

If this is OK then check other accessories for function when the thing quits.

The ignition switch may be going south.

Check the voltage to the batteries first.

The alternator connects to one battery and the crossover cable transfers the power to the other battery.

If the battery that feeds the main junction/relay box is not getting charged, you will see what you are seeing.

Bad battery cables, plus and grounds.


Keep us in the loop

Missy

[HeavyChevy95]

Just a Thought.

unplug fuel heater. check underhood fuse/relay center fuses, ENG1- ENG2- ECMA- ECMB etc etc, replace as necessary. repeat experiement..

If normal operation resumes, faulty fuel heater. Faulty fuel heater can disable GPs and LP when it malfunctions, if severe it could possibly disable PCM temperarily, until the affected internal circuit breaker(s) cool off and reset...

[metallicflame]

OK, So it was finally warm enough this weekend to work on this thing.
Saturday, unplugged the fuel heater and checked all the grounds. Started it up and let it sit and idle with the headlights on for 15 minutes. never died once. Sunday morning went to go to the auto parts to get everything to do an oil change, started it, ran 2 minutes and died. Got the oil chnage supplies and a new fuel pump relay. replaced the relay, and the ECM fuses (even though they looked good). Started it, got it warmed up, changed the oil. Drove it around for several hours with the headlights on, trying to recreate the problem. Ran great.
This morning, got 1/2 a mile from the house, died. Sat for 5 minutes started back up and got it back home.
It's got to be something electronic, for it to restart after 5-10 minutes and being intermittent like it is...

[DmaxMaverick]

Ignition switch.
PMD.
OPS.
Grounds.
(in no specific order)

[More Power]

If this problem is reproducible, use a multimeter or test lamp to check the various circuits in the fuse panel(s), looking for loss of power. Once you've identified the circuit, it'll be easy to find a solution.

Look at ECM & IGN, etc related circuits.