JasonBoes

Hi Everyone,

I have installed the fuel pump and gotten the relay on the 928 in now. Here are the specs:
1982 928 US Car. It has the Auto trans and 69,000 miles on it. I do know that they are actual miles too.

I have my suspicions as to what it can be but I want to get your inputs on this and draw from the years of experience here to save a little work and hopefully parts money. Here is the issue:
Fuel pressure at the rail is 38psi. Turnin it off it will drop to 20psi. I can run the car on starting fluid just fine. I actually ran it all the way to 4000rpms just fine with starting fluid. Without starting fluid it will only run for 3 - 5 seconds then it will die out.
I have eliminated the fuel pump or the relay as the problem. I have also verified it as a fuel issue as the car will run quite well with starting fluid. So there shouldn't be any issues with spark delivery.

What do you guys think?

Jason Boes

kelanel

A few things come to mind.

Was the relay for injectors replaced? (Separate relays)
Has the injection ground circuit been cleaned? (all shared on passenger side cam tower)
Is the fall in fuel pressure immediate? Have you vacuum tested all of your diaphragms on the fuel rail to ensure they hold vacuum and are not smelling of fuel?
Any idea when the last successful running state of the car was? (Injectors sound like they could use a cleaning)
Best of luck. I'm sure someone else will chime in on things I missed. You will need a noid light most likely to troubleshoot past this though.

soontobered84

Relay....Relay.....Relay
4th relay from the right on the top is fuel injection relay. It is a specific relay. Buy it from a 928 parts vendor that specifically supports our cars. Do not try to buy it from your local O'reillys. (928.615.119.00)

JasonBoes

Left a message with 928 Secialists. Waiting for a return call. We will see how it does after I hear back. Also why do you not recommend the parts stores. Are the wires thinner on the winding and they burn out. Or is it just a forum loyalty thing.
Not knocking loyalty. Just want to know the logic of it.

MainePorsche

Even some of the 'simple' relays are not pure SPST relays. If you look at the Central Electrics page on the Wiring Diagram you will see the innards of the relays. Get your relays from one of our trusted vendors.

j.kenzie@sbcglobal.net

You can probably jumper the fuel injection relay, similar for most relays. Use a 1/4" male crimp on at each end on a 3 or 4 inch piece of wire. Pull the FI relay and insert one end of the jumper into the 30 terminal, and the other into the 87 terminal. The FI now thinks the relay is activated. See if it starts, and if so, you may just need a new relay.
Good luck,
Dave

Alan

Dont do this - for safety's sake - get an inline fuseholder and crimp the 1/4 blade connectors to the pigtail ends of that - insert a suitable fuse for the circuit you are working on (e.g. match the actual fuses). Use this as your jumper - if you plug into the wrong thing you will be at least partially protected.

Don't ever just use a wire - folks are often mistaken about which relay socket is which, terminal locations are equally confusing for many. Play it safe

Alan

j.kenzie@sbcglobal.net

Good advice! I've never done that, but it is the right way, I'm sure. I guess I always depended on the car's circuit fuse.
Thanks, again, Alan.
Dave

James Bailey

You can also remove the cover of a suspect relay and carefully wedge the points closed as a test or to get home use none conductive material like part of a toothpick. And yes generic relays may not be rated high enough for the loads involved and heat damages the enameled wire of the coil windings.