1991 4>8 swap finally finished - Turn key, no fuel pump prime/Run
10-20-2008, 11:47 AM
#1
Thread Starter
Join Date: Jul 2008
Location: TR, NJ
Posts: 37
1991 4>8 swap finally finished - Turn key, no fuel pump prime/Run
Hopefully you guys can help!!
The car is a 1991, and I got and engine, computer, and headlight harness for a 1991 v8, so i assumed all i would have to do is swap everything out, and fire her up.
Today was that day. I did a search, and I ran some tests. At the ECC port on the driverside firewall, i jumped the fuel pump and grounded it. Still no prime. Checked for 12v at the ECC fuel pump port when the key is on and i get .99 volts. At the rear of the car, the inertia switch has not been tripped, and i have NO power going to either wire going into the switch.
Now here is where its tricky, I have NO relay under the seat, and only ONE on the passenger side shocktower with 4 wires going in??!?!?!? I figured since i have only one on the shocktower i should also have one under the seat and this is not the case. I jumped a long wire from the positive on the battery all the way to the line on the fuel pump and i got her to fire and stall, but at least fire. So i know the fuel pump is ok.
Any ideas? it was a huge letdown after 4 months of work.
The part number for the one and only relay on the passenger side shock tower is FOAB-14B194-DC
Anyone who has swapped a 4>8 have any ideas?
The car is a 1991, and I got and engine, computer, and headlight harness for a 1991 v8, so i assumed all i would have to do is swap everything out, and fire her up.
Today was that day. I did a search, and I ran some tests. At the ECC port on the driverside firewall, i jumped the fuel pump and grounded it. Still no prime. Checked for 12v at the ECC fuel pump port when the key is on and i get .99 volts. At the rear of the car, the inertia switch has not been tripped, and i have NO power going to either wire going into the switch.
Now here is where its tricky, I have NO relay under the seat, and only ONE on the passenger side shocktower with 4 wires going in??!?!?!? I figured since i have only one on the shocktower i should also have one under the seat and this is not the case. I jumped a long wire from the positive on the battery all the way to the line on the fuel pump and i got her to fire and stall, but at least fire. So i know the fuel pump is ok.
Any ideas? it was a huge letdown after 4 months of work.
The part number for the one and only relay on the passenger side shock tower is FOAB-14B194-DC
Anyone who has swapped a 4>8 have any ideas?
10-20-2008, 12:08 PM
#3
Thread Starter
Join Date: Jul 2008
Location: TR, NJ
Posts: 37
Nope everything is stock. I wanted this car to be as stock as possible and be like my cruiser i can take on long road trips...
I was able to get her to fire using that long ghetto wire from the positive on the battery to the power wire going to the fuel pump.. so know the ignition is ok.
I was able to get her to fire using that long ghetto wire from the positive on the battery to the power wire going to the fuel pump.. so know the ignition is ok.
10-20-2008, 12:18 PM
#6
Thread Starter
Join Date: Jul 2008
Location: TR, NJ
Posts: 37
Well i have No power at the inertia switch.
I looked for a FP relay under driver seat - no dice
I only have one relay on the passenger side shock tower.. and those wires don't correspond with the wires that are supposed to be on a FP relay. I assume that is the WOT relay. So where do you guys think my relay would be? remember this was a 1991 4cyl car, that i put a 1991 v8 engine harness in with computer. I was under the assumption thats all that needed to be done in order to successfully swap a 4 cylinder to a v8.
I guess i don't know where else i should check for a relay/power to see if it is a relay.
I looked for a FP relay under driver seat - no dice
I only have one relay on the passenger side shock tower.. and those wires don't correspond with the wires that are supposed to be on a FP relay. I assume that is the WOT relay. So where do you guys think my relay would be? remember this was a 1991 4cyl car, that i put a 1991 v8 engine harness in with computer. I was under the assumption thats all that needed to be done in order to successfully swap a 4 cylinder to a v8.
I guess i don't know where else i should check for a relay/power to see if it is a relay.
10-20-2008, 12:24 PM
#7
This is going to suck but if it was me i would start at the inertia switch with a test light and start tracing the wire till you find a charge or a live wire. you should find a fault in the wiring somewhere along the way. may need to tear up your carpet or interior body panels
10-20-2008, 12:27 PM
#8
Thread Starter
Join Date: Jul 2008
Location: TR, NJ
Posts: 37
I have a volt meter, so i can check for voltage. i'm just a little weirded out by the fact that i can't find a fuel pump relay anywhere. Something must be different with the body wiring of a 1991 4 cyl and the body wiring of a 1991 v8.. 
10-20-2008, 12:31 PM
#9
I;m thinking the same thing but I doubt the wiring is different because only the harness should be different and they both have to run power to the fuel pump so keep your hopes up something may just have come loose but there should be one in there try googleing a wiring diagram
10-20-2008, 12:35 PM
#10
Thread Starter
Join Date: Jul 2008
Location: TR, NJ
Posts: 37
I have this link
http://www.veryuseful.com/mustang/tech/engine/
which lists alot of stuff. im going to be printing things out today at work, and go home and try to trace wires and stuff with a friend and a flash light.
Such a letdown though, to be working on it for so long and it won't fire haha
http://www.veryuseful.com/mustang/tech/engine/
which lists alot of stuff. im going to be printing things out today at work, and go home and try to trace wires and stuff with a friend and a flash light.
Such a letdown though, to be working on it for so long and it won't fire haha