Epic89lx

Ok i posted on here a while ago probly two months ago, with a question and it didnt get answered really.

so far i have done alot to my car (89lx5.0) and this is the only problem i am having lately. only certain times like early in the morning when i get up to go to work is when the car wont start. what happends is normally when you just turn the car on, not the engine, you hear the fuel pump cut on and then cut off when it builds up enough pressure.

but in my case in the morning(or whenever the car has been shut off for a long time) the fuel pump will stay on and the car will not start. only if i spray lets say carb cleaner or intake cleaner or whatever into the throttle body is when i can actually get the car started. but i have to keep my foot on the gas til the car warms up then it will idle on its on, other than that it will die unless i am giving it constant gas.

when i am coming home from work lets say around 6-7pm i get in the car and the car starts right up no problem, idles fine. but if i park the car and sleep and go to work the next morning the same problem persists. this is what i have done to the car to try and fix this

1.coolant bypass hose, upper rado hose
2. thermostat
3.fuel pressure regulator
4.coolant temp switch
5. ignition switch
6.fuel pump relay under the driver seat
7.MAF
8.fixed timing.


i took the car to a local mech and all he said was left was that my computer was fried. he didnt give me any detail of to what is exactly wrong with the computer, he just said it was fried. i reluctantly declined their service and i am still having this problem. can someone please help me because this is very frustrating. and i am wasting gas like crazy sitting there for sometime up to 20 min for the car to idle on its on.

if the problem is the computer, would i be able to just snag one from any 87-93 5.0 mustang or do i have to do something different. thanks for the help

samseed101

Has this always been a problem or did it just recently become a problem? What mods or repairs were done at or around the time that this problem began? It's a long shot, but do you have access to anything that can datalog your car / computer while it's trying to startup? Does your fuel pressure seem ok when trying to start up or is it really low?

I know it's a lot of questions, but it helps narrow it down. It could be a computer problem, but I don't often see them fail for no reason. I try to look for the less complicated stuff first.

Epic89lx

this has always been a problem with the car. i have only had the car for about two months and replaced all those other things. the only actual mods on the car are 3.73 gears and there aren't any cats on the car. but everything else is stock. and no i don't have anything to diagnose the car while its running, like i said i took it to somewhere and they checked everything and said it was just fried but didnt explain to me what exactly was wrong with it. also, i don't know what the pressure is actually reading when its starting, simply because if i start the car and let go of the gas it will die

86_GT_Mustang

Dude do you still have you green vert?

samseed101

A fuel pressure gauge is fairly cheap and you can set it up so that you can read it from inside the car while leaving it outside. Or at least turn the key forward (but don't start it) and read the pressure. Then if you can try to see once it is starting and running.

Again, it could be a problem with the computer when it's starting and before it gets to closed loop. But usually something would trigger that kind of failure. But the part about the pump coming on and staying on... that's something I'd often see when a "bad tune" was loaded in... which would pretty much be the same as having a bad computer. But I have also seen something similar with a bad fuel pump. Has the pump been replaced / messed with?

samseed101

Unfortunately, no... just never changed the sig, lol. Most likely gonna be grabbing another stang soon though. Maybe turbo instead of supercharger this time? I'll still run nitrous and meth though

86_GT_Mustang

Yea that sux that you sold that car. You been gone for a wile wernt you?

samseed101

Yeah, been away about a year or so. But couldn't resist any longer lol.

Epic89lx

i personally do not know about the fuel pump, it may have been replaced because when i bought the car i had an extra used one in a box. so again, i have no clue if it is. but if the fuel pump was bad, why would it work some days, and then again not?, and please stick with the current topic, (sorry not to be a dick, im just frustrated)

crusin92red5.0

i don't know if its the fuel pump but i do know that if you hook up the fuel gauge to the rail and buy a remote starter at sears for 12.99 and hook it up to the solenoid on the fender then you can turn your key to the on position and crank the car from under the hood. then you can push the throttle under the throttle body to keep it running. just make sure the car is in nuetral or the sucker will jump forward on ya.

or just use a screw driver and touch the two studs together on the solenoid.