86 V6 - V8 conversion help (mainly wiring related)

EazyE-CPT · 09-12-2002, 09:56 AM

The car was a V6, now I got the V8 engine in the car(86 HO) but the engine isn't getting spark and the coil/ignition module are fine. The only thing that I'm sure isn't hooked up right is the alternator. Theres 3 wires coming from the back of the alternator, and I only have 2 hooked up becuase there only 2 alternator wires coming from the front wiring harness. On the alt side of things, one wire is large, the other 2 are small. The big one is hooked up correctly. The small one thats hooked up appears to be going to the silver box by the coil.

Where should the other wire coming from the alternator be hooked up?

The HO engine came from a Mark VII if that makes any difference.

Also, anyone know where the smog pump vacuum line hooks up? Its really long and reaches kind of towards the back of the engine...Theres no more vacuum ports open for it to hook up to. Woudl it be alright if I just plugged it off?

Also, where does the MAP sensor vaccum go? I think its the back of the intake, but I dont think theres any spots open for it. Is it alright if I dont have a vacuum hooked up to the MAP sensor? I know you can do that with Mass Air, but Im not sure about Speed Density....

Just one more Q . Theres a large round plug on the pasenger side of the front wiring harness that doesn't have anyhting to goto. Would that have anyhting to do with the engine not getting spark? Does it have to be hooked up?

I have a feeling Im just gonna have to end up buying a V8 front wiring harness

bigblockcoupe · 09-12-2002, 02:09 PM

ok you are going to need the v8 harness because the wiring is different you have to use the v8engine control harness and computer you can't just plug the v8 into the v6 harness it is entirely different and you probably will need the v8 headlight harness that plugs in under the starter solenoid on the driver side and wraps around the front of the car this also includes the correct alternator wiring and will plug into the v6 harness under the starter solenoid you don't have to change the interior under dash harness.

EazyE-CPT · 09-12-2002, 02:12 PM

I have already changed the Main wiring harness/computer.

I know theres ways to make teh front wiring work with the V8 engine, I just need to know where teh alt wires need to be going.

09-12-2002, 09:56 AM	#1
EazyE-CPT Registered Member Join Date: Jul 2002 Posts: 48	86 V6 - V8 conversion help (mainly wiring related) The car was a V6, now I got the V8 engine in the car(86 HO) but the engine isn't getting spark and the coil/ignition module are fine. The only thing that I'm sure isn't hooked up right is the alternator. Theres 3 wires coming from the back of the alternator, and I only have 2 hooked up becuase there only 2 alternator wires coming from the front wiring harness. On the alt side of things, one wire is large, the other 2 are small. The big one is hooked up correctly. The small one thats hooked up appears to be going to the silver box by the coil. Where should the other wire coming from the alternator be hooked up? The HO engine came from a Mark VII if that makes any difference. Also, anyone know where the smog pump vacuum line hooks up? Its really long and reaches kind of towards the back of the engine...Theres no more vacuum ports open for it to hook up to. Woudl it be alright if I just plugged it off? Also, where does the MAP sensor vaccum go? I think its the back of the intake, but I dont think theres any spots open for it. Is it alright if I dont have a vacuum hooked up to the MAP sensor? I know you can do that with Mass Air, but Im not sure about Speed Density.... Just one more Q . Theres a large round plug on the pasenger side of the front wiring harness that doesn't have anyhting to goto. Would that have anyhting to do with the engine not getting spark? Does it have to be hooked up? I have a feeling Im just gonna have to end up buying a V8 front wiring harness

09-12-2002, 02:09 PM	#2
bigblockcoupe Registered Member Join Date: Aug 2002 Location: broken arrow Posts: 212	ok you are going to need the v8 harness because the wiring is different you have to use the v8engine control harness and computer you can't just plug the v8 into the v6 harness it is entirely different and you probably will need the v8 headlight harness that plugs in under the starter solenoid on the driver side and wraps around the front of the car this also includes the correct alternator wiring and will plug into the v6 harness under the starter solenoid you don't have to change the interior under dash harness. __________________ Rice Haters Club member #68 '93 Cobra 10.20@135 '89 Gt Coupe 12.20@115

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09-12-2002, 02:12 PM	#3
EazyE-CPT Registered Member Join Date: Jul 2002 Posts: 48	I have already changed the Main wiring harness/computer. I know theres ways to make teh front wiring work with the V8 engine, I just need to know where teh alt wires need to be going.