I want to be 100% sure that the fuel pump is bad before I go replacing it. Where is the relay and the fuse for this thing? Any tips or tricks to figure out if fuel pump is bad? I have no way of getting my car out of the garage and can't change the fuel filter so keep in mind that hasn't been checked.

Thanks,
Justin.

 

See this thread for relay locations: https://www.thirdgen.org/forums/tech...344-relay.html
The fuse is by the battery, at least in my '87.

 

i just had to replace my fuel pump ('90 5.7L TPI), it was definitely bad, conclusively, certified. the relay on my car is by the vacuum brake booster. I think (can't remember, alzheimers) the fuse was under the dash.

i hooked up a fuel pressure gauge to the rail, zero. replaced the relay, no change, now i have a spare relay. jacked up the rear of the car, crawled underneath and checked for voltage at the multi-pin weatherpak connector going to the fuel pump, fuel tank: when the key is turned on, the relay was providing the "priming" voltage, but no fuel pressure, no sounds coming from the tank. that's pretty much the final indicator.

had to siphon the half-tank of fuel out of there (yuck, ptooie). that's when you discover the performance baffling on the tank is a hindrance. unfortunately the tank is ABOVE the rear axle (who's brilliant idea was that!!!), so had to drop the axle pretty far down to get enough clearance to lower the tank. the panhard bar, chassis cross-brace, muffler & tailpipe, and heat shields all had to come off. i disconnected the driveshaft, the stabilizer bar links, shock absorbers, the torque arm from the diff, and unbolted the brake line bracket from the car to allow more "flex". probably didn't need to do the torque arm nor driveshaft. anyways, it took quite a few choice swear-words to get that tank out of there. that was the hardest part of the job, and putting everything back. of course, one of the poly-U bushings from the stabilizer bar link rolled down the storm drain...

took me the whole weekend. and since i was in that area, also replaced the fuel filter while i was at it.

after that drill, the car started right up. i'm now "Walbro-ized".

 

I picked up a relay today and when I went to go install it I found to weird things.
First there was a red wire that had looked like it melted right next to the relay and I thought that that was very odd. So then I looked at the relay and it looked like they were pretty much toasted. So now I am doubting the fuel pump. Is there a way to directly power the fuel pump???

Heres that wire. Where do you think it goes???




Heres the fuel pump connector. It looks more melted in person.



I an't find my camera so I used my phone. Sorry!!!

 

A failing pump will draw more current and generate more heat at connection points. See this thread on running it directly: https://www.thirdgen.org/forums/tpi/...leak-test.html

 

I tried that but I didn't hear the pump. Is it loud? Should I be able to hear it if I am underneath the car?

 

Also that makes sense BUT wouldn't the FP fuse blow before enough amps were drawn to melt the wires???

 

Sometimes it draws just enough to create heat and not blow the fuse. You should be able to hear the pump running from under the car and you should have fuel pressure if you force it on.

 

I couldn't even hear it under my running one. Maybe I am deaf?

 

You mean if you forced it on while the car is not running? Then yea, you must be deaf :-)

 

You will not hear the fuel pump when the car is running,wheather you`re under it or not afaik.You will hear the fuel pump whine if you turn the key on but do not start the car.If you dont hear it whine when you turn on the key I would think its either the relay or the pump.However,My fuel pump fuse did wok its way loose one time while driving.Car died,wouldnt resatart.Heard no fuel pump whine,checked fuse it was loose,pushed it in and got whine and start up.My fuse is also by my battery in my 87.It wasnt secured properly after engine swap and I was hot ******* it must have jarred it loose.No problems since I secured it.

 

I hate threads that just end with no conclusion. Did you get your fuel pump fixed?

Also, never saw any pictures on how that top came out either? Did you get it on? Mike

 

Well I ended up replacing the fuel pump. Still nothing, replaced the fuel filter, still nothing. So I figured it would be electrical. Found a thread about the difference of wires and was told the orange was a 12v Constant, Grey was fuel pump. I checked the orange and it was dead! Checked the fuse and it was fine as well. So then I had this great idea to check that one stranded red wire (Top Picture) and it was a 12v constant. Followed it back to the direct connection to the battery and there was no fuse, what a great fire hazard!!! I then took the 12v constant and put it into the relay and it just so happened to fit PERFECTLY. The guy that owned it before me was kind of a tweaker. So I split the orange and put that 12v constant in and then added a fuse. Then started car up on 1st try, before it took about 3-4 tries. Then when I shut it down the fuel pump stayed on, found out why my battery died. Looked around and found it to be a stickey relay. Tried to take the relay and guess what!!! The guy @#%$@#%@#$%$%# glued it. So I just spliced that 12v constant and ran a switch to my dash.
What this did to my car:
Starts on 1st try
Battery doesn't die
Safer
Killswitch/Auto Theft Device

I haven't been able to finish my top, it's to cold.