Fuel Pump Module

[SoCalSlaughter]

Have been having a problem with my Suburban. I came home one day and put the truck into reverse and it just died. It would turn over but no start. Came to find out the fuel pump would not prime. After 2 days of looking for a short (Because the ECM-B fuse would keep blowing everytime I turned the key) I ran a wire straight from the fuel pump relay to the fuel pump and it primes and the truck will run. Ive checked everything in the fuel circuit, oil pressure sender, relay, pump. I came across a "Hot Fuel Module" or fuel pump module and what Ive read from other posts that GM only installed those into heavy duty trucks with 454's. My Suburban is a 1990 V2500 5.7lt TH400. The module was by the fuse box under the dash and has 3 wires plugged into it. Once I got the circuit board out of its black box, I found on the bottom some of the solider spots have some brown corrosion on them. I'm wondering if this has gone bad and has kept the truck from running or keeping the fuel pump from running? Before I knew about this little box I had unplugged all components on the ECM-B circuit. Oil sender, relay and fuel pump and when Id turn key to accessories position the fuse would still blow. Ive looked at a few wiring diagrams and I can see the "Hot fuel module" is in the circuit with a Tan/White wire which runs into the ECM-B circuit. Help? haha Thanks

[VetteVet]

Here's some info on the module.
The second thread is very good with a diagram.

..........http://search.yahoo.com/search?fr=mc...uel+module+gmc

[SoCalSlaughter]

Well today I went to the junk yard to get a new pig tail for the oil sender unit, because the clip that holds it on had broken off, Once I put the new pig tail on, I tried to plug it into the oil sender and it wouldnt plug in, so I broke out the oil sender socket and took it off, and looked inside the socket and 2 of the pins where bent down and only the middle pin was straight and not jacked up. The truck ran with this unplugged, but would that keep the fuel pump from priming?

[VetteVet]

Originally Posted by SoCalSlaughter

Well today I went to the junk yard to get a new pig tail for the oil sender unit, because the clip that holds it on had broken off, Once I put the new pig tail on, I tried to plug it into the oil sender and it wouldnt plug in, so I broke out the oil sender socket and took it off, and looked inside the socket and 2 of the pins where bent down and only the middle pin was straight and not jacked up. The truck ran with this unplugged, but would that keep the fuel pump from priming?

The way I read it the module overrides the ECM which shuts off the prime after 2 seconds or so and it continues to prime the injectors until the truck starts.
The oil pump sender should cutoff the module priming function after a certain pressure is reached. without the oil sender, the truck may have to crank longer to build enough pressure start. Honestly I haven't had much experience with these so maybe some others can explain it better.

I would say that you could get away with replacing the oil pressure sender and either wire around the hot module or replacing it. VV