"Gage/Idle" fuse keeps blowing on '91 Sub

[timmyrandalls]

I have been trying to find an intermittent short circuit causing repeated blowing of the "Gage/Idle" fuse on my '91 Suburban. I can't find a wiring diagram for a '91 R1500 Suburban with a 6.2, so I really don't know what all is on this circuit. I do know that when it blows, I lose a bunch of the gauges, the glow plug controller, and the alternator--and with the headlights on, the fasten seatbelt/lights on/key in warning buzzer sounds...

Could it be a solenoid in my injection pump? I am ashamed to say that I don't know what the wires to the pump actually do, but the terminals on top of my pump seem to be grounding out. (Without any additional knowledge, my instincts say that the terminals should be insulated from the surrounding pump housing, and it seems that mine are not--a continuity check shows a closed circuit exists from both terminals to the chassis, and a resistance check shows that there isn't very much...) But then again, one of the terminals has a ground strap on it, so I just don't get what is going on in there.

Anyway, if anyone has had this problem or has any ideas about where to find my short, my Suburban and my wife would be thankful!

--Tim

[chief4101]

Happened to me on my 94 6.2 it was a bad alternator. it was shorted out inside and got to the point that soon as the motor cranked it would blow. a buddy of mine told me he had this happen and it ended up being the fuel heater.

[joe bleaux]

The terminals on the i/p are connected to a fuel solenoid inside the pump. When measuring both terminals, you are measuring the resistance of the coil on the solenoid and you WILL see some resistance. One side of the coil is grounded with a strap, as you have seen. The other terminal receives 12 volts when the ignition is on and that allows fuel into the pump.

I doubt that is your problem, however.

I would look for chafed wires.

Joe



I have been trying to find an intermittent short circuit causing repeated blowing of the "Gage/Idle" fuse on my '91 Suburban. I can't find a wiring diagram for a '91 R1500 Suburban with a 6.2, so I really don't know what all is on this circuit. I do know that when it blows, I lose a bunch of the gauges, the glow plug controller, and the alternator--and with the headlights on, the fasten seatbelt/lights on/key in warning buzzer sounds...

Could it be a solenoid in my injection pump? I am ashamed to say that I don't know what the wires to the pump actually do, but the terminals on top of my pump seem to be grounding out. (Without any additional knowledge, my instincts say that the terminals should be insulated from the surrounding pump housing, and it seems that mine are not--a continuity check shows a closed circuit exists from both terminals to the chassis, and a resistance check shows that there isn't very much...) But then again, one of the terminals has a ground strap on it, so I just don't get what is going on in there.

Anyway, if anyone has had this problem or has any ideas about where to find my short, my Suburban and my wife would be thankful!

--Tim

[timmyrandalls]

Without any accurate wiring diagram, the easiest way to track it down was to unplug various components one at a time and just keep replacing the fuses... Eventually, it turned out to be the wires leading to the vacuum control system (next to the brake master cylinder)--they were up against an injection line and had worn through the insulation. A few inches of electrical tape has me back on the road. Thanks, guys, for the responses.