JMS

This will be my first post here and im looking for some backup before I drop the tank 85 Mustang 5.0. I have a fuel pump not turning on, I can not hear the FP nor is gas pumping out the line by the carb. I suspect I can eliminate more than half the components (really all the components) supporting the FP by the fact that the fuel pump relay is clicking - twice when the key is in the on position. Also when the key is move from on to start the FP relay clicks again.

I feel like I can assume that the issue does NOT involve the ECM, EEC Relay, Inertia Switch, fuse links, and Fuel Relay. By looking at the wire diagram it seems the next stop to check is the path from the FP Relay to the Fuel Pump itself which involves dropping the gas tank to check power to the fuel pump. If the test light lights then it has to be a bad fuel pump.

Am I on the correct path here or did I miss something

AdderMk2

run a 12v lead from the battery, back to the inertia switch. if the FP doesnt kick on, its dead.

lxman1

A carburated 85 GT 5.0 uses a mechanical fuel pump bolted to the timing cover. No electric pump unless it is an auto trans and has a CFI fuel injection.

JMS

yea its a CFI Automatic. This Fox has two pumps, one tiny one like a squirt gun in the tank and one big one outside by the rear passenger wheel. Dropped the tank by undoing two bolt straps, two fuel lines, one neck holder bolt and unplug one wire harness. No need to jack the car up as advertise, its better not to. You can place a motorcycle tire underneath oose it down and slide it out, its only about a foot+ drop. However, held the tank up with a jack while undoing the two bolts to prevent fighting against pressure on the bolts.

Having a very hard time finding a replacement squirt pump (low pressure). You can buy the complete assembly or just the pump that mounts to the original wired bracket. I tried the Airtex complete assembly for $98 but the top wire plug was different and didnt drop straight down into the special sealed off tank chamber, had to do some bending of the pump bracket about 7mm off. And since the wire plug didnt match the bending was a waste of time - the plugs were different on two different Airtex model# for the 85 CFI Fox. Then ordered the stand alone pump only, original Denso Pump for $128.00. Will pick up tomorrow. Dont ask me why its more than the complete assembly, I guess because its Denso.

While I had the Airtex about ready for return I powered it up for a few seconds to hear what im supposed to hear. It basically makes NO noise. its a super small hummp and a little twitch, impossible to hear if inside a sealed tank submerged in gas.

Nevertheless dont do this too long on your own pump as the pump is designed to cool off and Lubricate from the gas.