Fuel pump question

ecm911 · 10-07-2004, 01:04 PM

Quick ? on fuel pump.

Car is euro 83 Sc. Has been in storage for 3 years. Time to try to start.
I have two fuel pumps. Org and another from a 78 US SC. Car had a clifford alarm - PO installed, and I have no remote do wiring is a big problem. Go started going , etc.

?'s;

1. What should the voltage be at the fuel pump. Must I get is 6.8 volts. ( Both pumps.)

2. I bypassed the relay still just 6.8 volts to fuel pump.

3. So I lost patience and went direct from battery to each ( sepaerately of course) pumps and nether ran. They did get hot though.

4. Do I have two bad pumps??

TIA

Earl

Jim Sims · 10-07-2004, 05:23 PM

If the car wasn't stored properly the fuel pumps may be just the beginning of the problems. If the car has set for three years the pumps could be frozen/jammed with varnish or debris. Also did you have the polarity (plus and minus) correct? 6.8 volts is not enough; what voltage did the battery supply when you hooked it up directly? If the pumps became hot there is a chance they are ruined; these pumps depend upon gasoline flowing through them for cooling. Running them dry or with sludge in them can burn out the windings. Remove the pumps (any gas in the tank/system should be discarded anyway) and bench test them with a good 12 volt source (get the polarity correct and run them for only a 5 or 6 seconds).
Jim

ecm911 · 10-08-2004, 06:42 AM

Thanks Jim for the post.

To clarify, the engine ( 83 Sc Euro) has been in storage ( removed from pre car) . The current car ( a 78 sc) was acquired as a roller, but had no fuel lines etc. I have replaced all of the fuel lines.

The car had a clifford alarm installed that to me surprise was still operational. I found this out when I installed the engine and connect the battery and the alarm sounded!

I have been trying to undo the alarm installation, which clearly has had a number of hands in the pot, based on the number of spices , etc.

I believe I have 1) wiring problem and 2) at least one bad fuel pump ( possibly two).

Wiring:

1. Fuse 16 ( fuel pump) was removed- now part of alarm.
2. I now have power to the started.
3. When I by-pass the fuel pump relay ( black not red) with the key in the ON position I get 6.8 volts at the fuel pump.
4. I have no ground at terminal 85 on the fuel pump relay ( air mixture), with key in any position. I need to investggte this further.
5. Benched tested on of the fuel pumps ( direct from battrey) - dead.
6. Double checked polarity on installed fuel pump - OK.

These are my next steps.
A. Investigate term 85 on relay- should have continuity with Key in Off Position.
B. Confirm ags tank in not clogged for any reason ( gas is NEW)- just want to make sure.
C. Reestablish fuse 16 outside of alarm.
D Bench test remaining pump.

Should I have 10-12 volts at the fuel pump. I would think so.

Any suggestions or insight would be greatly appreciated.

TIA
Earl

ecm911 · 10-09-2004, 12:08 AM

Well, I am convinced I have two bad fuel pumps.

The latest ,

I have 11.9 volts at the fuel pump, when key is on and relay by passed. Also have 11 volts when air/mixture lever is up.

Clean fuel is at fuel pumop no clogs in tank.

When installed, both draw under 7 volts ( 6.8 and 6.4). Benched test both fuel pumps. One has slighht hum, other nothing. Even loosened banjo fitting to se if any fuel pumping - nothing.

Order another fuel pump.

I assume there is no fix to old ones.

Thanks

Earl