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5speedxr7
08-28-2004, 10:04 AM
I'm have finished swaping a 89 3.8 SC motor into a 90 SC body. and i cant get it to run
when you turn the key on. the rad fan starts running the ac compressor clutch kicks on but the fuel pump wond run , its a good pump but it wont run in the car. every once in a while it will buzz as i'm turnig the key into the Off position. but it wont run in the on position.
do i have to swap the harnes from the 89 body to the 90 body?
thanks in advance
Josh

J.D.
08-28-2004, 11:02 AM
So was the 90 a running car before the swap? Are the fuel pump, relay, etc., original to it. Are you using the 89's EEC?

5speedxr7
08-28-2004, 12:06 PM
the 90 was a running car last year when i pulled the motor. i then had to sell that motor to pay rent. i now have a 89 doner car that was also running but the body is shot so i pulled the motor and trans and put it in the 90 i tried puting in the 89 eec and still wont start

J.D.
08-28-2004, 12:16 PM
If you unplug the fuel pump relay (in the trunk on the driver's side fender), and then short pin 3 (pink/black) and pin 4 (black/yellow) in the plug, the fuel pump should come on. I'd try this to verify that the pump works.

J.D.
08-28-2004, 12:28 PM
The pink/black wire powers the fuel pump (through the relay). On an 1989 it also runs to pin 19 on the EEC (called the "fuel pump safety switch to fuel pump motor"). On a 1992 it runs to pin 8 and not 19. This could be your problem. The EEC may not know that the pump has turned on and so it immediately turns off the relay. If someone has the schematics for a 1990, please check if there is a change in this pin between the 89 and 90 models.

5speedxr7
08-28-2004, 12:51 PM
If you unplug the fuel pump relay (in the trunk on the driver's side fender), and then short pin 3 (pink/black) and pin 4 (black/yellow) in the plug, the fuel pump should come on. I'd try this to verify that the pump works.

do you men the safty cut off switch or is ther an actuall relay there too?

5speedxr7
08-28-2004, 01:04 PM
okay sorry the relay when i cross those 2 wires then the fuel pump runs. but it still wont start
sonow the motor trans eec, fuel pump and the fuel pump relay are all from the 89, the only other thing i can think of is the main harness from the eec to the engine bay. but with the motor in this is gona be a bit*h to change.

J.D.
08-28-2004, 01:09 PM
The actual relay next to the cutoff switch (follow the white wire from the cutoff switch to get to the relay). Be sure to short the correct wires. To avoid causing damage from shorting the wrong wires, first unplug the connector for the cutoff switch. Shorting the cutoff switch won't help you if the EEC is turning off the pump.

J.D.
08-28-2004, 01:14 PM
First check the wiring diagram for the "fuel pump safety switch to fuel pump motor" as I explained in post #5. You may only need to move that wire at the EEC connector.

5speedxr7
08-30-2004, 05:02 PM
i compared both harnesses. the 89 to the 90 and all the pins are in the same locations.
any on else have any other ideas????

Bleed_Ford_Blue
08-30-2004, 05:33 PM
This is probably a stupid question, but have you tested your ignition switch. If I were you I would start with the simple stuff and move toward the hard stuff. Get out your multi meter and check your ignition switch, then check all the critical system wires then non critical. This more methodical system might help you pinpoint your power loss a little more quickly.

Im not trying to condescend here, but sometimes we overlook the obvioius ( I once flushed a radiator, changed a water pump, and replaced all the hoses on a car with a bad thermostat........doh!)

5speedxr7
08-30-2004, 07:05 PM
I cant see the ignition switch being the problem, the motoer cranks fine it just dosn't fire. because the fuel pump wont run.


i did notice that on the fuel shut off switch. when you unplug it both the red wire and the white wire running to it have power. this shouldnt happen.
some how its back feeding power into something. . but i don;t know why. i'm just about to go through and check every plug in the car, for the 20th time. maby i have something hooked up wrong.

J.D.
08-31-2004, 12:54 AM
I cant see the ignition switch being the problem, the motoer cranks fine it just dosn't fire. because the fuel pump wont run.
Okay, so if the motor cranks but dosn't fire because the fuel pump won't run, then short the relay output contacts as you did in post #7 and then try to start the car.



i did notice that on the fuel shut off switch. when you unplug it both the red wire and the white wire running to it have power. this shouldnt happen.
some how its back feeding power into something. . but i don;t know why. i'm just about to go through and check every plug in the car, for the 20th time. maby i have something hooked up wrong.
You're right, the white wire should not have power during normal operation. The only way it can get 12v is from the Passive Restraint Module (gray box near the cutoff switch) or the EEC (pin 22). So if you unplug the Passive Restraint Module, will the white wire still have power? If it doesn't, then this module is causing your problem. If it does, then it means that the EEC is, for some reason, not allowing the fuel pump relay's coil to energize (it is cutting off the fuel supply). If you were able to start the car by shorting the relay, then the EEC is sending a wrong signal to the white wire. If you were unable to start the car, then (I'm theorizing here as I have nothing written on this topic) the EEC is cutting off the fuel supply because your ignition system is not working as it should (wrong spark timing?).

5speedxr7
08-31-2004, 01:14 PM
okay i replaced the ignition switch. and it didn;t do anything

i jumped the relay the fule pump was running and i tryied to start the car, no luck,.
i'm not sure what you mean by the pasive restraint modual.
the only modual by the fuel cutoff switch is the keyless entry modual. there are 2 other plugs there but neither one of them were pluged in before on both cars and both cars ran before.
a local mechanic said it sounds like a bad ground and he told me to use jumper cables to ground the block to the neg. terminal than the block to the body. did this still no change.

I'm at my wits end with this thing. i need this car on the road. I'm half way through my holidays and have not been able to go any where. if any body can help that will be greatly appreshiated.,

thanks again
Josh

J.D.
08-31-2004, 03:27 PM
So if the fuel pump runs and the car still doesn't start, then I think you need to check the ignition system (assuming there's fuel in the tank and the injectors are being energized). Are you getting a spark at the end of the plug wires?
The passive restraint module operates the seatbelts, but it's not important now.

5speedxr7
09-03-2004, 12:40 PM
thanks again.
I'm heading back to my parents house tonight. so i guess this weekend i check out the ignition system