wiring help
06-19-2008, 06:17 PM
#1
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wiring help
alright so im trying to put my 90 mustang together. i bought it as a 4cyl and i want to put my v8 in it from another car. i got it all together but now im having some wiring trouble. i bought a 90 v8 engine harness and kept the stock 4cyl dash harness. when i go to start my car the starter does not start and the computer does not get power. me and a friend have been going over everything all day and cant seem to figure it out....
any help will be great
thanks gary
any help will be great
thanks gary
06-21-2008, 02:27 AM
#3
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RE: wiring help
The 4 cylinder harnesses have some wires pinned in different spots. On the dash harness there's a power wire that needs to be jumped on the passenger side of the engine harness where it joins to the dash harness. It's a key-on 12v wire.
Also make sure you got your wires on the drivers side that go out by the coil grounded.
A volt/ohm meter will help out alot for this to tell if things are getting power with key on. I'd say you're probably not getting power to the relay or it's not grounded. Obviously the problem is on your engine harness (you already know your dash & body harness work) One of the wires on the engine aren't getting power or not grounded.
Let me know what's going on. Check the connectors where they go together first I'd say they're more than likely pinned different
Also... on both of the harnesses you have, were the relays in the same spot? There were a few different types of harnesses, the dual plug (two plugs on drivers side fender), single plug & a difference in where the fuel pump/engine relay is. Some fuel pump relays are under the drivers seat, some are underhood on the passenger side. Make sure you have ONE fuel pump relay & ONE eec relay.
[IMG]local://upfiles/1583/CE27EF407EC1476A94C747B1CA7207E0.gif[/IMG]
Also make sure you got your wires on the drivers side that go out by the coil grounded.
A volt/ohm meter will help out alot for this to tell if things are getting power with key on. I'd say you're probably not getting power to the relay or it's not grounded. Obviously the problem is on your engine harness (you already know your dash & body harness work) One of the wires on the engine aren't getting power or not grounded.
Let me know what's going on. Check the connectors where they go together first I'd say they're more than likely pinned different
Also... on both of the harnesses you have, were the relays in the same spot? There were a few different types of harnesses, the dual plug (two plugs on drivers side fender), single plug & a difference in where the fuel pump/engine relay is. Some fuel pump relays are under the drivers seat, some are underhood on the passenger side. Make sure you have ONE fuel pump relay & ONE eec relay.
[IMG]local://upfiles/1583/CE27EF407EC1476A94C747B1CA7207E0.gif[/IMG]
06-21-2008, 12:42 PM
#4
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RE: wiring help
ok so imalmost 100 percent positive that its a 1990 v8 engine harness because it has 2 or 3 white connectors near starter solenoid and mass air for airbags and it has 2 connectors that join the engine and dash harness together..... there is 1 relay on passenger side stut tower but i believe that it is for ac cut off.... the fuel pump relay is under the seat. but im not sure if the problem is with just the engine harness because wheni go to start the car the starter does not engage but when i go to jump the solenoid it works. all of my lights work tho, headlights and blinkers. if i need to change wires from the 4cyl dash harness do you have any wiring diagrams that i could use to lign the right wires up?
thanks for the help
thanks for the help
06-21-2008, 01:36 PM
#5
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RE: wiring help
i cant seem to find what pins need to be changedanywhere online, i also bought a guage cluster that was said to be from a 1990. any way to check if thecluster is bad and causing it to not start? basically about to give up on this project im so fustrated because its so close to firing but yet so far away.....
06-22-2008, 04:29 AM
#9
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RE: wiring help
The car will start without gauges in.
Starting issue:
Since you've changed the engine have you bypassed the neutral safety/clutch switch?
There are two ways to do this, you can either jump where the connector is or run a new wire. I always run a completely new wire when doing it.
Try this. Look on your steering column at the keyswitch. Where all of the wires go to it find the single White/Pink wire. It's a fairly small wire that goes from the keyswitch to the two safety switches (one will be bypassed from the factory), then out to the solenoid.
Anyway, run a wire from that wire (you can even push it up in there to where it's snug & have a friend hold it on the small terminal of the solenoid, then try turning it over. Should work (this wont get your engine started obviously, but best to fix one problem at a time)
Btw, you'll have to take the rubber boot off of the solenoid to be able to touch the wire to the terminal. you're basically bypassing that whole wire completely.
Oh & I HIGHLY recommend you get the v8 engine harness to work with the 4 cylinder dash/body harness. Mixing & matching more than 1 v8 harness is NOT a fun process in the least. I've done quite a few v8 swaps on fox's & i've seen 5 different wiring harnesses where neither would match up with eachother. The plugs may match up perfectly, but the wires were generally in the wrong position on the plugs.
Unless you have an entire v8 harness (engine/dash/body) out of the exact same car I wouldn't recommend it unless you're up for doing quite a bit of splicing. I've found it's easier just to mate v8 engine harnesses alone to 4 cylinder body/dash harness.
Oh btw, your tach is going to be 2x higher than it's supposed to. It's fixable, but i'm not sure what size resistor you'll need. You can use a potentiometer like a variable resistor, but you'll need a different gauge to get it right. Best to use a v8 tach.
As for wiring diagrams for specific cars. I'm about 99% sure you're not going to find one, as i said there are quite a few variations in wiring on the cars... I mean that in the dash/body harness mostly. I've checked chilton & haynes manual's wiring diagrams & every one I could find on the net. None of them matched any that i've worked with. The engine harnesses are most of the time 100% accurate though.
I'll help you out as much as possible when I can get on here to reply to your posts.
Starting issue:
Since you've changed the engine have you bypassed the neutral safety/clutch switch?
There are two ways to do this, you can either jump where the connector is or run a new wire. I always run a completely new wire when doing it.
Try this. Look on your steering column at the keyswitch. Where all of the wires go to it find the single White/Pink wire. It's a fairly small wire that goes from the keyswitch to the two safety switches (one will be bypassed from the factory), then out to the solenoid.
Anyway, run a wire from that wire (you can even push it up in there to where it's snug & have a friend hold it on the small terminal of the solenoid, then try turning it over. Should work (this wont get your engine started obviously, but best to fix one problem at a time)
Btw, you'll have to take the rubber boot off of the solenoid to be able to touch the wire to the terminal. you're basically bypassing that whole wire completely.
Oh & I HIGHLY recommend you get the v8 engine harness to work with the 4 cylinder dash/body harness. Mixing & matching more than 1 v8 harness is NOT a fun process in the least. I've done quite a few v8 swaps on fox's & i've seen 5 different wiring harnesses where neither would match up with eachother. The plugs may match up perfectly, but the wires were generally in the wrong position on the plugs.
Unless you have an entire v8 harness (engine/dash/body) out of the exact same car I wouldn't recommend it unless you're up for doing quite a bit of splicing. I've found it's easier just to mate v8 engine harnesses alone to 4 cylinder body/dash harness.
Oh btw, your tach is going to be 2x higher than it's supposed to. It's fixable, but i'm not sure what size resistor you'll need. You can use a potentiometer like a variable resistor, but you'll need a different gauge to get it right. Best to use a v8 tach.
As for wiring diagrams for specific cars. I'm about 99% sure you're not going to find one, as i said there are quite a few variations in wiring on the cars... I mean that in the dash/body harness mostly. I've checked chilton & haynes manual's wiring diagrams & every one I could find on the net. None of them matched any that i've worked with. The engine harnesses are most of the time 100% accurate though.
I'll help you out as much as possible when I can get on here to reply to your posts.
06-23-2008, 10:58 AM
#10
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RE: wiring help
thanks for the replys! i got the car to turn over. the nuetral safety switch wasent connected by tranny... got it to work. i already bought a gauge cluster out of a 90 v8 mustang so that is taken care of. now i need to figure out how i get the 90 v8 engine harness to work with a 90 4cyl dash harness? my computer has power going to it but nothing coming out.... are all computers that same 89-93 cause im not sure what year it is but it is a a9l. and im hopeing to go over to my buddys house today to check my computer in his car to see if its just a bad computer.
thanks for the help
thanks for the help