[93horseman]

Well I went to leave work last night and my 93 5.0 would not start! The engine will turn over strong but never start. i tried switching out the coil and coil wire to no avail. I noticed that when when I turn the key to the on position I don't hear the fuel pump come on. Is there any way to test the pump to see if it is the source of of my woes? Would disconnecting the line at the filter to see if its flowing be adequate? Also where is the relay and would a bad relay cause this? Thanks in advance for any help.

[ryanw]

I know that in 1991 and under the fuel pump replay is under the drivers seat, but i think in 1992 they started putting that relay on the passenger side strut tower under the hood, im not 100% positive on that though.

You should have about 39psi at the fuel rail. Check it with a fuel pressure gauge, im unsure if the fuel pressure is the same when its primming or not.

[93horseman]

Thanks for the reply Ryan. i think i found the relay near the fender. The pump doesn't prime at all. I'm gonna get a bucket and friend to see if its pumping fuel at all. Do you know any other ways to test it?

[ryanw]

have you replaced your fuel filter ? Im not sure of the best way to test the pump and the relay, sorry i coudnt be more help. I guess you could probe the wires near the fuel pump and if you have power id take a guess and say its bad...but the good thing is, that fuel pumps can be bought new for just a little over a 100 buck, over the computer

[89lxstang5.0]

a quick way to check and see if the pump is pumping is to push in the shraeder valve under the hood (carefully) and have someone turn the key to the on position, if no fuel comes out , you know your pumps not running. or should i say your not getting fuel to the rail.

if not running you have to go from there to find out why.

however, if fuel does come out of the shraeder valve, this does not mean that your getting enough volume of fuel/ pressure.

have you checked to see if your getting spark? (not very applicable if you figure out that ur pump is infact not runnimg) hope that helps

[mustangmaniac95]

i put a fuel pressure gauge on my fuel rail and when the car is running it shows 28psi, does that mean my pump is bad? just bought 255lph fuel pump and new fuel filter

[93horseman]

Haven t replaced the filter. Ill try the schrader valve idea. The main reason i suspect the pump is that i do not hear it come on any more when the I turn the key to the on position. It used to make a very audible whining/buzzing sound.

[fb93]

93horseman - I had the same problem once. Went to leave work one night and the engine wouldnt start. Tried a jump thinking the battery went dead. it was then i realized i couldnt hear the pump. I just happened to have a spare relay and plugged it in. She fired right up.

Get a buddy to turn the turn the key to RUN as you lean in close to the pump relay and listen for a click. If it clicks, the relay is working. If it does not click, check the EEC relay behind the passenger side kick panel. Power goes thru it before the pump relay. I can hear the EEC relay in my 93 click from the drivers seat. If it clicks as you turn the key to RUN, its working. If it does not click, make sure the battery has 12v.

You should be able to run the pump momentarily using the EEC test connector next to the brake booster. Its the one with 6 terminals. With the flat side down, ground the terminal on the far right to run the pump. If the pump wont prime, check the inertia switch. If the button is up, the pump wont run. If the button is down but still no pump, check the switch for power using a test light. Remove it still plugged in and turn the key to RUN. If there is power i would have to say there is a problem with the pump ground or the pump itself.


mustangmaniac95 - 28 psi sounds low. Could be a bad regulator. Prime the pump a few times, shut the engine off and pull the vac line on the regulator. If you see fuel the diaphragm is leaking or the lines could be dirty. I think thats how you check the regulator. A bad pump is always possible. Even a new one.

[93horseman]

The inertia switch is down. How do i check it for power? Can i use a multimeter? Do I probe the wires? I'll listening for the relays tomorrow when I have help. Thanks for the advice everyone.

[93horseman]

I went out and grounded thee eec test connector as suggested. the fuel pump did not come on but i did hear the relays by the fender click. I repeated this several times to be sure. i also got the bright idea to scan the car for fault codes. Koeo codes 95 showed up fuel control circuit failure. Under memory codes 95 showed up again as fuel pump secondary circuit failure. Does this indicate the pump is the culprit?

[93horseman]

Anybody? Does secondary fuel circuit mean the pump?