John Winkeler

Guys,
My 1996 Z28 was running and then abruptly stopped, cranking would not start and I smelled no fuel. When I used the fuel pump prime connector the pump ran and the vehicle started and ran like previously. With that in mind I checked the following at the fuelpump relay:



Pin 87 is Hot reads 12v
Pin 86 is continuous to ground
Prime Connector (87A) to 30 runs the pump when voltage is applied at 87A

That leaves Pin 85 (PCM signal) as the culprit. I don't read a signal on that pin with my multimeter.

The BCM is bad in the car, it was recently replaced and promptly failed, so stuff like power door locks and keyless entry aren't working. I had figured that would just be an inconvenience, until I stumbled upon a sketch that listed the BCM as having a Fuel Enable Signal as part of the security system.

My only scan tool is a hypertech programmer, not sure if it can read the fancy DTC. I will check tomorrow morning when it's light. [EDIT: No DTC present or Hypertech can't read it.] There is no "Security" light currently lit, though and the vehicle runs just fine using the Fuel Pump Prime Connector.

What direction should I go next? Try to scan for DTC and then check continuity between, PCM and relay? If that's good pull and replace BCM or am I looking at a PCM failure? How can I separate these parts of the puzzle?

Any help is appreciated,
John

John Winkeler

Figured it out, potentially. More and more things were pointing to the PCM, fuel pump not on, only one cooling fan being signalled on, etc. I pulled the PCM on a whim and found this picture along with some chewed up acorns where some soon to be dead rodent was calling home in my car over the winter. Replacing the entire harness looks to be a fricking pain, so my current thought is to strip back the electrical tape, separate wires, catalog what is destroyed and then try soldering in a confined space. I feel a solder fix is worth a shot since the alternative is a harness replacement.

Any words of wisdom?





John

Kevin Blown 95 TA

Coulda been worse I guess -

GaryDoug

Holy cow!!! That has to be the worst possum infestation I have ever seen!

GaryDoug

I would unwrap as much of that harness area as possible and separate the wires. Work on each one like you described. The hardest part will be getting the wires clean enough to solder. I recommend Oatey Liquid Soldering Flux before soldering. To make it neater, you could get some heat-shrinkable tubing and slide it over the wire before soldering, taking care not to heat that too much until it's in place. The spliced wires will then be shorter than unrepaired ones, but you can figure out how to arrange them. Cover the harness with ordinary electrical tape or heat-shrinkable tape.

For the future, sprinkle some Cayenne (Red) crushed pepper around the engine compartment to keep away the critters ;-)