So, it happened, drove the '91 to breakfast and back, did some maintenance.

* Oil and filter change
* Replace broken and leaking oil level sensor
* Service transmission and filter (700R4, yes we completely removed the X brace)
* Installed a shifter shaft seal on in the 700R4 to stop it marking its' spot
* Dad cleaned up and repainted the X brace pieces

I attempted to start the car, for leak check, no start, cranked until I had oil pressure.

Hooked up a fuel pressure gauge to the test port, "0" psi and I can't hear the fuel pump.

I'm trying to get far enough under the passenger's side dash to find the fuel pump relay. FSM for 1991 Vin 8, in figure C2-11 says the relay is located on the "passenger's side multi-use bracket (under dash)."

I've got the lower part of the dash down, I can't see the relay, or the bracket.

If I'm reading what others have written here in the C4 forum correctly, I should be able to hook a test light to the 10A "FP" fuse in the lower forward socket of the passenger's side fuse box, and if I get power for two seconds after turning the key to "run" the ECM, relay and fusible link are functioning.

Does anyone know if that is correct?

I'd rather not tear the dash further apart if that is a valid test.

Not looking forward to pulling the pump, but if it has power and isn't running, there's not much for it but to get after it.

I've not looked it up yet, but I expect in a convertible, I have to drop the tank to get to the fuel pump.

Side note:

Yesterday, while we were out getting the parts I previously mentioned, we stopped at the local dealership to get a spare key made, they verified which PATS (spec / code ?) so they could order the correct blank. I don't believe that has anything to do with this issue, as I understand it PATS disables the starter, not the fuel pump. I would also expect the security light to be on, with the key on, if it didn't recognize the key. It's not, but with the key out and the door open, the security light does come on, so I know it's not burned out. Just for clarity, we don't have the new key, yet, we hope to pick it up today, so yes, we're using the same key that worked before.

 

It occurs to me, I should mention the car isn't home in Alaska, it's at Dad's winter place in Arizona. He's near a town called Queen Creek.

 

I recently pulled the fuel pump from my 96 convertible. it comes out from the top of the tank, pretty easily. I had a no start situation so I bench tested the pump but I wanted to see the condition of the inside of the fuel tank as well. I recently also had to access the relays under the the passenger side dash. They are tucked up there along the forward edge of the dash. I had to get my head down there and look up to see them.

 

Easy way to isolate the problem. Unplug the pump at the top of the sending unit. Use a multimeter and see if you have power going to the pump when turning over. If you do the relay and fuse are fine. Then just put a new pump it. At least fuel pumps in these cars are easy to change. If you really wanted to double check you could use a set of jumper wires and a small 12v battery to test the pump directly while it's unplugged. I use my 12v DeWalt batteries for stuff like this all the time.

 

Thank you.

Thank you.

I was trying to verify it was no fuel, then I was chasing the relay, as it shows that as a next step in the troubleshooting chart. I'll look into how to change the pump in the FSM, as this is the first C4 I've worked on, and it's taking me some extra time to get familiar with the format of the GM manuals of that era. Other FSMs I've used all seem to be organized somewhat differently, Dodge, Ford, Douglas, Curtis...everybody seems to have their own "best" idea.


Glad to hear it's easy, just earlier than I had hoped to attempt is all.

 

Yes, it was easier than I was expecting. Thank you to all that suggested help.

A few minutes ago (20 ish) I sucessfully (I hope) bolted in the new Delphi HP10031. Not the cheap option, but what I could get quickly. I had the old pump out to match the new assembly. New one looks like a current production version of the old one. Fuel level float arm travels in a visually identical arc (within minute of eyeball) and the level sensor reads within 2 ohms of the old one at each end of their respective scales.

I was able to pull the old gasket off in one piece, with only residue and possibly some very light corrosion. I was able to scrape that off with a long handled gasket scraper, the kind with the single edge razor blade. I used it rotated the other way to normal which resulted in a nice scraping angle when you scrape the opposite side of the sealing surface so as to scrape away from the tank opening. I was able to bolt the unit in with its' new gasket, I used a drive adapter handle (like a screwdriver but with a 1/4" square drive for sockets). I'll check them in the morning for snug, in case the gasket compreses. I've hooked the evap and return hoses up and intalled the new filler cap. I'll connect the pressure hose tomorrow, after I change the fuel filter.

 

New fuel pump was a success. I'll change the fuel filler boot (scupper?) when I get it from Ecklers.

Fuel gauge seems accurate, as I recall it was showing just under 3/4 tank and it took 5.993 gallons (~20 gallons -(20*.75) = 5 I believe).

Thank you again to all that commented.