terramir

okies I am fed up, my car is a 92 4cyl. mustang convertable, now this is my problem everytime my engine gets hot, the car won't turn on after it's turned off and well also sometimes it stalls. I replaced the fuel pump and the stalling got a little better, however it is not really fixed. I've seen aftermarket products that wire around it, but that means that the fuel pump get's full 12V all the time when the engine is turned on, I dunno if the ecm(icm) or ecu is supposed to adjust the voltage on that fuel pump, however I do know the dam relay is inside the ecm(icm) now I look at that black box and well it doesn't look like it opens up. so here are my alternatives:
A. crack open that box somehow
B. find a nice little relay socket (I got like five wire harnesses from other cars sitting around so I should be able to find one and then just relay the fuel pump directly from the battery and wire it directly into a switched line and then the battery and on the other end the inertia switch. (would still be safe from accidents), but otherwise the ecu would lose control over the fuel pump.
What do you guys think?
terramir

hellion_79

do you have the 8 spark plugs?? Cause it could be your coil packs. They might be going out. This has been a problem for lots of people

terramir

Well I would say that except what rules it out period is that the fuel pump will not prime till the engine cools down!!!!!!! Once I hear the fuel pump priming it runs again.Anywhere from 15 minutes to an hour on the old pump a few minutes on the new pump, which electrically makes sense since a pump requires less electricity when it's new and a hot sucky contact may make less of a connection. So I'm pretty sure that other guy and me got the same problem the fuel pump relay or whatever the heck ford calls it on ours. 7V on a fuel pump when it's keyeddoesn't seem right either I'm pretty sure it's supposed to be higher than that, which explains why a lot of people have problems with autozone fuel pumps. (less voltage on a new pump wears it faster) the right voltage is proably around 12V and that's why they sell there aftermarket kits online http://www.autozone.com/R,NONAPP1811...ductDetail.htm
I can build one of those myself fairly easy I got the socket and well plenty of wire. the holley performance website tells you to wire it directly to the fuel pump connector, but then again it's generic instructions so I would keep the inertia switch. BTW I got a heck of a good spark so I doubt it's the coil packs.
terramir
terramir

sleeper_inc

Its your igntion box (that holds your fuel pump relay as well) just replace it and your problem should be solved. Stanggirl replaced hers for $150? less maybe?

If that doesn't fix the problem then return it and try new DIS moduals (those 2 boxes that send out spark)

hellion_79

well it doesnt needa very high voltage when the key is on. It will get higher when the fuel is needed. If the car runs fine, then it is fine. the pump is hooked up to the computer and all the sensors are also hooked up to it telling it when it needs fuel. 7v is the normal voltage for an idle. When it needs more gas like when you are giving it throttle the computer will send more power to the pump making it pump out more fuel.

terramir

then why do those aftermarket parts just deliver 12 V [&:].
I looked inside the icm and well this sucks but there are three relay's inside and I dun know which one to replace.
would it be harmful to keep a constant 12V on the fuel pump like those aftermarket's do ?
because I can't really find those relays anywhere right now and they'll be hard to replace, doable but hard.
terramir
PS: I'm asking about doing the copy of an aftermarket thing because I have no money right now to replace the icm!

sleeper_inc

It shouldn't hurt the pump to bad, I don't have a clue as to what they should be getting all the time, but remember you do have a return line

TBird232ci

Do you make stuff up and hope its right?

The fuel pump only should run for 2 seconds when you turn the key, then run when its running. It will always get 12v since it uses a return style system. It sounds as if your relay in the IRCM is weak. In all reality, the best way to fix it is to get a Bosch relay with a nice socket, and run your own wiring. The proper way is to get a new IRCM if you can find one. Depends on your abilities and money.

terramir

hehe that's what I wanted to hear so that fuel pressure thingy opens the return line kk , as for what you said that's what I was talking about I have another wireharness here for god know's what car because I needed the fuse box for a solar project,
I found it when we were picking up a car with my sis's tow truck. wanted the split loom and the fusebox, but now [8D]I can use one of the sockets to do my fuel pump relay. might have to pick up a new bosch relay though the one on there is a potter and brumfield vf4-15F11-z01 the fuse box has like 8 20/30A bosch relay's shouldn't I use 30/40's or will the potter or the 20/30's do?
if I can use the 20/30's or the potter one total cost for the repair = 0. Except if I had done this earier I would have saved about 160 bucks on the new fuel pump.
terramir

terramir

well hmm installed yes runs all the time, bosch 20/30 relay for now noticed that it idles lower now [&:]however I can rev it up as high as I want, no real hesitation got to field test it. I think the computer will have to adjust to always having fuel pressure handy[8D]. it probably hasn't had proper fuel pressure for quite a while.
Now an oil change and well that's all she wrote money wise, although this repair cost me $0, the fuel pump I just bought cost me $118 plus 50 bucks for my mechanic. he works cheap [8D], he's my bro in laws cousin though. But he's no good on the electrical side, this is why he's staying away from my wireharness.
This was almost as easy as building a computer, 4 wires one to the engine compartmentthough the speed odomeder hole 20 amp inline fuse (didn't have a 15 one handy). Cut the wire to the fuel pump somewhere on the driverside part of the trunk and spliced this thing in. if anyone has an analysis of what wire I could use instead of a keyed one, some computer one so it runs properly I'm all ears, but for now this will do
terramir