i pulled the fuel pump today in my 1992 rs 3.1l and tested it. it turns on fine. i dont think im getting power to the pump or the pump is not working as well as it should since im not getting any fuel to my engine at all. . what could this be?

 

You know where you unplugged the wire for the fuel pump(the harness) under the car? Check that for 12vts when you key the ingition? See if you got power there. If not then youll just have to keep going back twards the engine till you find where the power stops.

There also a fuel pump relay on the firewall on the driverside.

 

I would be checking the fuel pump relay as fasteddi stated above.

 

And if you check the sending unit for power, it only primes the pump for a couple seconds when you turn the key fyi, so doing that would require two people. One to turn it on, and the other to check for power during, it should be a white or tan wire if memory serves, black is ground I know for sure, and pink is sending unit if I recall.

 

im getting a steady 7.33 volts to pump. now i didnt put the probes on the female end where the fuel pump plugs in i just plugged it back in and put the probes on the end of the fuel pump its self and i came out with 7.33. now 7 is low but i didnt charge my battery yet after having my headlight on with car not running while pulling it home so im thinking thats why. is there a certain number on the relay or a kind of marking where i know that its the one? theres like 3? i added picture of where i put the probes and the 3 confusing wannabe fuel relays. lol please keep in mind im 16 and if i get some terms wrong please correct me.
http://i479.photobucket.com/albums/r...-20-19_301.jpg

http://i479.photobucket.com/albums/r...-18-53_789.jpg

 

Hope this helps....The fuel pump relay is on the firewall, driver's side, just above the brake booster/the right side. It has a large red wire and a large orange wire to it along with small green and white, black and white, and gray wires. The gray wire is the output power to the pump.


I take it when you have the stock pump on it, it will not make the humming sound when the igntion is turned on, when the fuel pumps suppose to prime?
Start your testing by verifying power at the red wire. It should be hot at all times. It comes from the fuel pump/ECM fuse by the battery. Then jump between the red wire and gray wire to see if the pump powers up. Now you know the pump and its wiring is okay and that the fuel pump fuse is good. Then verify ground at the black and white wire. Next, attach the tip of your test light(you can use a test lead or a paper clip) to the green and white wire and turn the key on. The light should light for a second or two with key on. Then crank the engine, the light should light while the engine cranks. If these test all check out, you are good to replace the relay.

 

so the pump turns on when connected to a 12 volt charger. car is on battery charger and last time checked the pump was getting 9.52 volts connected to car and not turning on when i turn the key on... hmm... ?

 

also im starting to think my car came stock with a v8. when i google search fuel pump relay for the 3.1l its square and when i search for on for the v8 its rounded like mine?? sorry im kinda rambling.

 

My relays on my V6 look like yours, there rounded.

So when you turn the key on, you get 9-12vts to the pump connection? What about when you are just cranking the motor over? Try that. Also check the connection at the rear where you were testing it. Just some ideas

 

i didnt reload the page and see you replied. im gonna do what you said and ill let you know the results

 

im not sure if i did it right but i put the red probe on the red wire that connects to relay and the black on negative battery terminal and tried other grounds and i got .04 volts with key on. turned key off and back on then nothing. i dont have 2 people right now so i cant crank it and watch meter.

 

i havent checked any fuses yet. what fuse would do this and where is it located?

 

you need to get all the air out of the fuel line since the pump was removed. cycle the key on /off 3-4 times. use a fuel pressure tester to check the pressure. schrader valve on top of the fuel rail.

 

ive been testing it with the pump connected but out of the tank. and i dont have a fuel pressure tester, money, or a ride to get to autozone and rent one. :/

 

so at the relay im getting .04 volts then 0 volts after a couple seconds. when engine is turning over im getting around .50 volts with the red wire from relay.

 

so im pretty sure the problem is that im not getting power to my relay. im gonna look for a diagram. hopefully i cant figure this out.

 

Does this help? Heres the link to the diagram so you can sorta read it better= http://www.autozone.com/autozone/rep...00c1528008e871

 

omg, thank you sooo much. haha

 

Id do your self a favor and wire up a back up switch, and wire it to the fuel pump direct, bypass all relays and that bulk head connection. Only need a single wire.

if all else fails, I know with a flip I can give it a full 12v.

[just don't use a lighted switch]

 

i wired the pump to a battery charger and the car wont start yet i know its getting fuel cause when i unscrew the fuel line in front gas sprays out. ? im about to just send it to a shop. :/

 

Did you ever check the fuel pressure on the shrader port, its on the fuel rail next to the fire wall. Should be arround 43psi when it primes, and then drop a few psi when idleing(about 36psi)

 

Check the fuse under the hood. It provides battery backup to the ECM and +12 volts to the FP relay. In the diagram it is the upper right and states "hot at all times."

It is in-line with a heavy gauge wire, passenger side, runs from radiator support along the fender wheel then into the car. The fuse is in a rectangular plastic holder.

RBob.