seanny77

Hi Guys,

Was wondering if anybody could help me out. My stang keeps blowing fuel relays. Before it would blow the relay if I stomped on the throttle but now it's blowing relays even at startup. Any ideas on what could be the issue?

I'm currently in the process of running new wires in case there is a bad wire somewhere. I've follwed the two to the fuel pump and one to the cylanoid but there is a grey with green stripe wire that I would assume goes to the ignition but I can't seem to locate it. Can anyone tell me where each of the 4 wires should run too and also colour codes.

Thanks,

Sean

seanny77

oh it's a 1987 convertible gt.

mjr46

your wasting your time with that^^^^^^^^^^^ a simple continuity/resistance check on each wire would indicate a prob in a wire, and by blowing the relay, do you mean it's blowing the fuse in the fuse box?? if so I'd do a resistance check first on the fuel pump windings, could be locked up/ excessive resistance

seanny77

Hey thanks for responding. When it comes to electrical i'm extremely bad. I honestly don't even know how to do continuity/resistance check. I assume I do it with my multimeter but have no idea how.lol I wouldn't even know what numbers would be normal or what isn't to indicate which is the problem.

With the 87 there is no fuse for the pump. There is just a fuel relay which is located under the drivers seat. It has 4 wires going into it. One goes to the cylanoid. Another goes to the pump. Another goes to the inertia switch and from the inertia switch one goes to the ignition. Then the fourth I can't seem to locate where it goes to just yet.

Do you think you could explain to me how to do that continity check so I can give that a shot. Following these cables is a real pain in the ****.lol

Bubba 95SN

veryuseful.com wiring diagrams

seanny77

thanks man. Now that answered nearly all my questions. However, just one more. Am I correct in thinking that if the fuel pump relay keeps going it would have to be coming from the wire going to the cylanoid or EEC comp as everything else is after the relay (pump, inersia switch)

ttocs

where are you getting your relays? while I was a pro audio installer I put in literally thousands of relays but never hear of the blowing. EVER.......... Doed your voltage jump up when you get on it?

seanny77

hey man. relays only go when there is too much voltage going to them. They heat up and then poof it's gone. To be honest not sure if the voltage is eratic because my guage for that doesn't work and connecting the voltmeter up while driving isn't that easy. haha

seanny77

anyone else have any thoughts? I can't really test the circuit by disconnecting the two power leads to the relay because the relay doesn't always blow during startup. Sometimes I can drive it a few minutes or even days before the relay blows. I don't want to run new wiring as that's a real pain in the **** as there are 4 wires that turn into about 10 from the ECC to pump to inersia switch to cylanoid etc etc. I also don't want to run a direct wire from the battery to the pump...that's just asking for trouble....I can only assume it's a bad ground but with this circuit the ECC is the ground and all the connections look good with no breaks in the wire etc etc. Any thoughts?

ttocs

you have some bigger problem if it keeps happening. I would test your voltage with an external meter hooked up to the cig lighter or something to see what is happening. If your voltage regulator is going bad it could cause surges to blow it and it would be easy to tell with some king of quick hook up of a meter. They make them that just plug into the cig lighter if you don't want your dash working.

It could be a ground that has developed some resistance wich is adding up to more current but I would check your voltage first, its alot easier.