nascar2496

iTrader: (2)

ok so i have an 86 iroc that came carb from the factory, I want to change it to TPI. I do not have any of the old factory carb wiring or anything like that. The dash harness is still original to the car. I have a complete 86 tpi set up and the dash harness from an 86 iroc tpi.

Now im not really sure i want to go ripping apart my dash...cause that is/can be a pita...I am looking into the painless wiring harness for the tpi this way i can leave my dash alone and have a running car.

I cant find anyone who used/uses this harness. does anyone have any opinions or used this? Thanks

ps: engine is 305 5 speed.

tinymay

I run a painless engine harness. It has been "painless" so far. All the right connectors, labelled and correct lengths... only thing to remember is the emissions devices come with their own harness. Since I did not buy the emissions kit, I've got to run a green wire from C15 to the EGR diagnostic temp sensor. Your app may be similar.

nascar2496

iTrader: (2)

yeah i read about that harness, Im not too worried about that seeing as how my heads dont have egr passages, and i dont have an air pump. I do have the charcoal canister tho.

nascar2496

iTrader: (2)

anyone else use the painless harness?

nascar2496

iTrader: (2)

someone else must use this??

tony_cogliandro

iTrader: (3)

where i can i use factory stuff. i would go to classic industries in orange county cal - 800-854-1280. you must be running a maf system and they should have that. i checked with them on a map and it was 400 factory new. gm used to charge 1200 for it.
there is also a place in arizona that sells factory stuff too but i am still waiting for something i ordered from them so i will wait to see if it is what they said it would be.
on something like a wiring harness i prefer the factory.

nascar2496

iTrader: (2)

tony_cogliandro, yeah I would agree with you on that one. I just really dont want to swap my dash harness out....such a pita. Unless someone has a list of wires needed for the dashboard part of a TPI harness compared to the Carbed harness.

Yes I am running a MAF, not a fan of the MAP systems I hear they dont react well to changes in the motor (cam).

primerk5

I actually did this. I went from an 85 carb car to TPI and retained the dash harness from my car and successfully hooked it to the TPI engine harness. IMO having the 86 tpi engine harness is a great setup to have. It seems to work out better as it is more of a stand alone harness then anything else, when using a factory harness. In reality you only need to add 4 wires to the dash harness to get your car running. Re-pinning of several wires will definatly be needed but it is actually pretty easy. Your fuel pump power wire is actually already run in your car. It is there from a connector at/near the dead pedal on the floor on the drivers side and runs back to the plug at the tank. It is missing from the dash harness though and is one of the wires you need to run. the other 3 are fused wires. 2 are for left and right injector banks. the other wire you need to run is for the fan relay power. I managed to use the factory fuse spots and hooked them in. You could go to radio shack and get a fuse block and run them from there.

If you are going to attempt to add the wires, I suggest that you attempt to get a dash harness from a car at the parts yard. I used a 2.8 v6 cars dash harness. You'd be surprised actually how easy it is to pull the whole dash harness without cutting anything. Doing this will get you all the right pin for the connectors and plugs you might need. From what I was told at one time on this board that the TBI and TPI 6 and 8 cylinder dash harnesss are the same.

A good wiring diagram from the 86 carb and the 86 tpi will help alot. I couldn't find one for an 85 carb car but I managed to figure it out. Surprisingly most of the wires like the speed sensor and such are all in the right place. I had to use some of the AT trans lockup wireing to get my reverse switch to work. I have a 5 spd car.

One other thing. I managed to find a set of stock fuel lines for my car they went in perfectly and worked great. They can be installed without bending them to get them where they are supposed to be. I actually managed to remove the stock Carb lines as well in one peice. It worked out great.

If you continue to go this route and not the painless route and have questions let me know. I saved alot of money not having to buy the painless harness. I'm not saying a painless isn't going to be easier but it will be more expensive. If your not pressed for time to get your car running again you'll be good to go.

Oh ya, I forgot to mention. I also used my stock Carb Engine ignition harness. I comes through the drivers side bulkhead connector and feeds the starter, alternator, ac, and other items, the power they need.

The 86 can definatly be made a stand alone harness if you want. Much easier than the later model MAF harness. I have an 89 harness I got off of ebay long before I got my swap. It actually ties in to both the driverside bulkhead and the passenger side ECU side. Much more complicated.

Sorry if my spelling and punctuation isn't all that great. I'm typing on a lap-top and its 10:50 pm.

Good luck

nascar2496

iTrader: (2)

ah cool, thanks for the info! that helped a lot. I do have an 86 tpi harness so thats good, I also have a complete dash harness from an 86 iroc tpi. so if i only really need 4 wires thats way easier than changing harness' or buying the painless.....one more question. what about the ALDL connector? the tpi one has different pinouts than the carbed.

Oh and as for the fuel pump, my car only has two wires for the gauge, not the pump i know that from when i changed the tank. I knew i would have to do that so im not concerned with that.

Oh and painless talked about a speed sensor for the 86-89 TPI, is that true the tpi had such a thing even though the speedo is cable driven? And more importantly, do i need it for my tpi to run well and correctly?

primerk5

The Serial wire isn't there or is in the wrong spot in the ALDL connector. I believe its actually not there. I haven't added this wire into my harness yet as I forgot to run it when I ran the other 3 wires I needed. This is the last thing I need to do to finish mine. I've just been checking my light through crossing the two pins in the ALDL connector. I'm pretty sure its just adding the one wire though that you would need. There is also a pin in the ALDL connector that isn't there to feed power to the fuel pump to test it but I don't believe you absolutly need that one. I'm not wiring it up in my car.

Are you talking more about the sending unit wiring? The chassis wiring should have all 3 wires What I'm referring to as the chassis wiring runs from driverside footwell back to behind the back seat where it gose through the body and becomes the plug that you plug your sending unit plug in. At least the wire was in my car.


This was funny. I had my car just about totally back together. my original Speedo was installed also. I figured due to my car not having Cruise control (which would require a speed sensor) it probably didn't have one. So when I got the wiring for the dash from the j-yard I also snagged the guage cluster that was with it. Well I had a check engine light on and I figured it might be the a VSS Code (vehicle speed sensor fault) and I didn't bother to check to be sure. One day I decided to swap clusters so I went and tore out my cluster and come to find out it actually had a speed sensor on it and was wired. I tested the wires all the way over to where the IP/Dash harness connects to the Engine Management/ECU harness and low and behold the wires ran from the Speed sensor to that plug and were in the correct spot. That worked out great for me.

I'd check that chassis wiring that gose to the fuel tank. I bet that your car is wired for the pump and the wire just isn't used. I don't know that for sure though.

Is your car originally a 5 spd car? And was your TPI harness out of a stick or automatic car? I have a way of getting your reverse lights to work as well using TPI harness if it is was an automaticTPI going into a stick shift car with out having to ad wires.

nascar2496

iTrader: (2)

The car was an original 5 speed with the 305 carb. When i got it, it did not have a trans as part of the deal (so i technially got my car for free minus drive train.) The car always came with cruise but it was a mess when i got it so i removed it hoping to one day get it working...but the parts were just bad.

The fuel pump, I only have two wires that run from the dash back to the tank. The car never had an electric fuel pump so i just figured GM never ran the 3rd wire. I believe the only ones i have are pink and black.

The speed sensor, I have a cluster from an iroc, it has this white box thing on the back of it that comes from the speedo cable and goes into the circut board near the tach...I guess its safe to assume that the speed sensor is that?

So i figure worst case is i can hack up the tpi dash harness i have to modify my original harness. i was just worried that there was a million differnt wires but from what your saying its only a hand ful, which i can deal with....especially because when i got the car, some moron put a remote start in it and then decided they didnt like it and ripped it apart and left it hanging from the dash in this tangled wire rats nest that led nowhere...

Now i just wish my car was in a garage so i could work on it over the winter!

I would like to get the aldl connector to work because i have an old laptop that i would like to set up for some logging and maybe get into prom burning.

primerk5

I guess they must of done it different for carb cars in 85 since mine was already wired.
You might be right. Mine is yellow in color.

Ya, I cut all of the tape/wraping off to expose the wires on the TPI dash harness. You'll notice that there is a 3 wire plug that connects to the harness at the ecu. Its a square plug. You will need that plug and the wires with it. The black and pink ones are the power wires for the injectors. The brown wire is the power for the fan relay. These 3 wires are fused wires. If your resourcefull you can use the fuse holders from the TPI dash harness at the fuse block and make jumper wires to power them up from other circuts. All you'll need to add after that is the fuelpump wire and the wires that go to the ALDL.
I know what you mean. Fortuantly most of what I have to do is paint-work. That stuff can wait till spring.

Ya, I'm going to get mine wired as well. I have plans to someday get in to the prom burning business as well.

If you've got more questions let me know. I'll try to check my book and see which wires do what on the ALDL plug.

tony_cogliandro

iTrader: (3)

the engine harness is separate from the dash. it connects to the engine via the ecm. it is self contained.