When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
There might be, check the fuse box cover.
Early cars have one in the upper right labeled FUEL PUMP, later ones it's labeled AIR COND so the pump wiring might have changed to a different circuit.
There is also a fuel pump relay for the 1984/1985 under the dash next to where your right knee goes. They can go bad and cause the exact scenario. You can jumper the connector.
When I first tried the fuel pump it would prime with the key on, now nothin, unless I hook it up directly to 12v. Also there is no relay on my gas pedal or near it. Just a plug hanging down with some greenish wires but no place to plug it in. Ill try searching up in the ignition area behind the column cover
What are you working on? Series 1 and 2 (ish) ran the fuel pump any time the ignition was on. Series 3 12A ran the fuel pump only when there was an RPM signal coming from the trailing ignitor. So if the trailing ignitor is dead, you get no fuel pump (These are the models with relays, it does not look like a standard Bosch relay and it is mounted to the steering column on the right side). I am 99% certain that GSL-SE controlled a fuel pump relay from a switch in the airflow meter, but check me on that.
The fuel pump is controlled by the emissions computer under the passenger footwell. It switches a relay mounted on (or maybe right next to) the steering column. If your trailing ignitor does not work, the computer won't see the engine running so it won't turn the fuel pump on. (If your tach doesn't work, then your trailing ignitor is probably toast - the tach is te same signal as the emissions computer) This is 99% of the cause for no fuel pump, in a series 3 car.
The relay is a strange one, it's a normally closed relay. The emissions computer actively turns the fuel pump OFF. You can unplug the emissions computer and the relay should stay contacted.
Fuse wise, there is a fuse in the fuse box. I could have sworn that the S3 had a separate fuel pump fuse, but it's been a long time since I've had to do any repairs to my '84.
I did plug the emmisions harness back in, maybe that's the issue? There is no fuse in panel for fuel pump. I will look under the column cover. If the trailing ignitor isn't working will the motor still start and run?
Couldn't find the relay so I wired the FP to a toggle switch engaged with the ignition on, works like a champ now just have to set butterflies for correct idle. Running about 2k right now
At least put a switch and wire it for key-on power only. If not, someone might forget to turn the switch off and overfill the carb with gas. It's funny that the connector isn't even there. I'd wire in a relay, fuse and add a switch.
04-07-24, 02:54 PM
