No fuel pressure
 

Hello everyone. New member on these boards. I have been having trouble with my zr-1. The car randomly died on the highway. It would crank over but not start. I checked for spark and used a noid light on injectors, both passed. Next I checked both fuel pump fuses, they were good. I then proceeded to check fuel pressure. My readings were 0. I listened for the pumps to turn on while switching the key to on. All I could hear was a real quick click from the tank leading me to believe the pumps were shot. I replaced them last night and still getting the same symptoms. Will be searching for the test terminal today.

My questions:
1. What else should I check or do if the pumps do not kick on with terminal test?
2. There is a four wire harness at the pump. What is each wire?
3. What if the pumps DO kick on? Relay issue I'm assuming?

Re: No fuel pressure
 

The fuel pump test connector is a RED wire with a black connector, poking out of the wire loom, just center of the diagnostic connector near the ECM.

Start with this: WITH THE KEY OFF... If you place an ammeter in series between the battery (pos) and the test connector, you should read approx 4 to 5 amperes per pump, for a total of 8-10 amps. Also, if you have a fuel pressure gauge connected to the fuel rail, you should read approx 53# with both pumps running.

If the current draw is correct, and the pressure too, then it is something else; a ground? VATS? Something...

BTW, what year? And do you have an FSM? And, where 'bouts in Illinois??

Welcome to the ZR-1 Net Registry Forum!

Paul.

Re: No fuel pressure
 

Check the in line fuse?

Re: No fuel pressure
 

Had one relevant issue on an 88 worth mentioning - the connection through the filler bulkhead went bad. While it's unlikely you'd lose all connections all at once, but if both pumps share a common ground it could be that same/similar connection.

It was hell to debug. With the pumps "on" by key or test lead use a sharp VOM probe to poke through the hot wire(s) "outside of the bulkhead". If you have 12v there but bench tested pumps aren't running, Bob's your uncle.

Good luck,
- Jeff

Re: No fuel pressure
 

It is a 90. Having trouble finding the test lead. Going to switch relays with other known working relays but need to know if they are in the car or under the hood. I can't seem to find a diagram that depicts specific location. Also, there are four wires at the harness so I'm not sure which should have x amount of voltage/amps.

Re: No fuel pressure
 

"Bob's your uncle"
I like that...

Re: No fuel pressure
 

Found the relays. Swapped them with no luck. Decided to run power directly to the pump harness. Still had no action. Pulled the sending unit out and the large metal grounding plate was dangling. So problem should be solved soon.

Re: No fuel pressure
 

Where in IL are you at?

Re: No fuel pressure
 

Oh sorry. I missed that question. Havana.