I put an 87 motor with it's wiring harness in my 85 corvette. Their are some connectors from the engine harness through the passenger side fire wall that wont plug in to the cars under dash connectors, I'll try to take some pics of the harness but wanted to know if anyone had a wiring pin out diagram for this or any advice on how to go about this?

 

You may be referring to the VATS plug along with a few other extras that were added starting in 1986. Only thing I don't know is if your 85 ECU will recognize there's a MAF power and burn off relay in place instead of a burn off module that was standard in 1985 only. Unless you got the 87 ECU as well, then disregard that concern, but then you have to contend with VATS in place. I did the same thing with a 1986 Corvette harness, so I feel your pain on the extra plugs and wires.

 

I understand the '85 ECM is unique to that year. Also added in '86 was anti-lock brakes.

I've an '87 FSM in the garage and will check for the pin info, but it'd help to know what plug UR referring to.

 

Many years ago I believe I confirmed these for a fellow, but that means "squat" today. They would need confirmed.

http://www.chevythunder.com/fuel%20i...%20pinouts.htm

For the connectors you have questions about post the connector color, number of wires and the wire colors. That should simplify the identification for someone attempting to help.

I believe I have both year FSM available if that interests you. Click on my "user ID" and send an email, I prefer email vs. a PM.

 

I do have the 87 computer, here are a few pics.
The first pic is of the 85 harness with the grey and black connector under the dash, the second is of the harness from the 87 engine harness, the 85 and 87 connectors are different. also there is 2 tubes with a connector on it from the 87 engine harness that im not quite sure what they are to, but are in the first picture. also what is an fsm?

 

im not really sure what to do at this point, I'll I want is to drive this car and I'm finding more of the harnesses aren't right by the battery tray. if anyone has any advice on this please let me know. I'm also finding theirs different sensors on the engine.

 

FSM = Factory Service Manual

The vacuum connector I'm quite sure is for the AC Programmer for a car with C68.

 

I have the same vacuum connector on my 87 with manual climate control. One tube provides the engine vacuum to the climate control, the other tube feeds the water shutoff valve for the heater core. Sorry, I can't help with the electric stuff.......

 

yes - that would make sense. I often forget/don't recall the earlier cars with hot water valves.

 

86 started the use of a junction terminal, which is probably what you are talking about near the battery tray. You will notice extra red wires with ring terminals in that area, they are suppose to all fasten together on one specifically designed pole. The local parts store should have a generic version you can pick up or you can probably make your own. The black plug in your second picture appears to be related to courtesy items. The grey plug in your second picture could possibly be related to the operation of door electrical items. If you have the 87 ECU, then you have to deal with the VATS system before you can drive it.

Because VATS relies on reading a specific resistance off a pellet in a key, you would need a key with a pellet that had the same resistance value the VATS decoder is programmed for AND the wiring running off the ignition lock cylinder to send that signal, which didn't start until 1986. So you'll have to bypass the VATS or eliminate it altogether. I did a starter relay bypass and turned the system off in the chip programming. If you notice a tiny little eraser head sized plug with two wires near your column that is hanging down, it's suppose to plug into wiring coming off the lock cylinder but just tuck the wire out of the way.....you won't need it.

You're going to have to be patient, you have a few minor areas to tidy up and address before you can drive it.

 

ok, so far I have it cranking, it will turn over with starting fluid briefly, 46 psi at fuel rail but no injector pulse?

 

Again, it's VATS (Vehicle Anti Theft System) related. Your 87 ECU is waiting to see a signal from a coded key inserted into the steering column. Because your 85 column has no provision for an electrical circuit to relay info to the ECU, nor the coded key, the 87' ECU will not allow the fuel injectors to operate, therefore, no fuel.

You can bypass the starter but you can't get pass the injector pulse disable by the ECU if it does not consider the VATS conditions satisfied. It's not as simple as just getting a coded key either as the VATS system had 15 or so different codes used in keys. They stuck a pellet in the key that created a particular reistance. A decoder for the VATS system diagnosed that measured resistance and the ECU gives the all clear to start the car.

Edit: In your case, you would need to have the VATS disabled via different PROM chip. You COULD take the existing PROM and re-solder it in once VATS is disable on it but that's a lot of work. Don't know how familiar you are with working on these types of things in software.... If you don't want to do that, you'll need a 86+ ignition column with the VATS wiring attached which runs through the column and plugs to a specific plug for it on that dash harness. That means taking apart the steering column to some degree. Then you'd have to know the exact resistance out of the 15 +/- value choices GM used and have a replica key so the ECU is happy and lets the injectors fire.

Or someone may have a much simpler fix.

 

We can reprogram the Prom to get rid of Vats. If you need this you can call me Monday at Zip Products.

 

Is there any chance you can get ahold of a key that went with that 87 ECM even for a little while? If you can, read the pellet on the key with an OHM meter. Assuming you have the part of the wiring that normally would plug into the steering column, you can get a 'Vats Bypass' dongle (with the correct resistance) from many sources that plugs into the wiring and takes the place of the pellet on the key. You need to find the chart online that list the various codes and the resistance value for each. This is the easiest way.
If you can't get ahold of the key, use the chart and using various resistors make them up one at a time for each code and plug them into the wiring where the vats wire from the steering column goes and see if the injectors pulse, when they do you have the right combination. You can then solder it up or get the dongle with that value. One thing to remember is each time you try and fail there's something like a 10 minute wait before attempting the next one.
The last is I believe the VATS code can be taken out of the chip, but far as I know that means you have to have a new chip burned without the VATs in it.

Best suggestions I can give. Good luck.

J. put the response in while I was typing. Might be the least problematic way to get rid of it.

 

Did the 85 corvette have VATS? I plugged my 85 computer in which the key to my 85 does not have a resistor to, and I get the same thing, fuel to the rail but will only start with starter fluid and runs for as long as im spraying starter fluid.

 

No the 85 doesn't but I believe the pinouts are different so be careful about doing that. You could provide voltage to a ground or vice versa and do some damage. the only way for you to get rid of the Vats is going through the PROM.

 

Ok so this is what I got, I unplugged the computer and all other wiring harness under the dash. The only harness I did not unplug yet is the one that bolts into the firewall by the battery tray. I test both prongs of the fuel injectors and get continuity from both wires. So im assuming a short? one has to be ground and the other positive? I hope im on to something.

 

You're Vette is going to be sitting a while until you decide you want to deal with VATS. Good luck....