[Alfa2k]

I recently purchased a 1989 Graduate. It ran very rough when I bought it and when I checked the in-tank fuel pump I found that the sending unit was corroded and the pump was not running. Replaced the pump and sending unit but the bracket would not fit so I put hose clamps on the step hose and car ran better but not perfect. I was happy that it would start and run so I could continue trouble shooting, replacing vacuum hoses and on and on.
The last time I tried to start the car, the low fuel light came on and the gauge registered zero; car would not start. Checked the 10amp fuse by the fuel pump relay that the po had installed and it was blown. Pulled the in-tank pump and one of the hose clamps had allowed the hose to slip and the two wires were holding the pump to the fuel tank sending unit. I thought that probably the wires had shorted. Decided to cut the bracket to fit properly and put everything back together minus the hose clamps. Put in a new fuse, turned key and fuse blew. Replaced fuel pump relay with one from Centerline, turned key, big flash and fuse blew. I am using 7.5amp fuses.
Disconnected all wires from in-tank pump, turned key, fuse blew without big flash. Re-connected pump wires, removed fuel pump relay, turned key; fuse did not blow. Put a jumper wire on 30 and 87 on relay, turned key and fuse blew. The fuses blow before I can turn the key to start.
I have been reading all that I can find on the forum to solve the problem but I am getting ready to take it to a mechanic and spend a lot of money to have the car fixed.

 

[Gubi]

Do you have a wiring diagram? I *think* on the L-jet cars that fuse also powers the AAV heater, oxygen sensor heater, and main fuel pump. Not 100% sure as this is from memory.

Anyway, as a quick test try also unplugging the AAV (on the valve cover), the sensor heater (two wire Bosch connector on the firewall near the brake booster...should be next to a single-wire brownish connector) and the main fuel pump. If it doesn't blow then plug them back in until it does and you found your problem.

Maybe someone else can verify on the wiring diagram if I've got the right circuit.

 

[Alfa2k]

Thank you for replying. I am going through the wiring diagram but any other insights would be appreciated.

 

[Gubi]

Yep, just checked the wiring diagram. 8A fuse is stock on the fuel pump relay, it protects the AAV heater, O2 sensor heater, main pump, and booster pump. Gotta be one of those.

My money's on the sensor heater or the AAV heater. Unplug both and see if that fixes it. It should run okay with both of those things unplugged.

 

[Alfa2k]

Thanks again Gubi. Will trouble shoot tomorrow.

 

[GV27]

Don't give up - but sometimes we all need a little professional help!

 

[Alfa2k]

A huge thank you to Gubi for the trouble shooting advice. The problem was the main fuel pump. I replaced it with a spare that I had and the car is now running. I can now move on to other issues. I will not give up until I hear those awful words, "you need a new head gasket."
Hopefully that will not happen but there are some problems that I may be asking for advice to solve.

 

[Gubi]

Glad you figured it out.

Don't panic about the head gasket possibly failing someday. It's not great but it's completely fixable.