ok here is my question and have a bunch of threads posted and nobody replys hope fully someone on here can help here goes i have a 1986 trans-am that came with a 305 tpi i took the motor and wiring harness and ecm out and swaped it with a 1989 350 tpi and 1989 harness and ecm i have hooked up most of the connectors but i been told i have to repin the bulkhead connector because the harness is 1989 and the bulkhead wich is stock is from a 1986 now i have some bulkhead diagrams that i found and if u guys can figure it out and explain as simple as posible im not to bright on how to accomplish this ....
here is the 1987 bulkhead diagram

and here is the 1989 bulkhead diagram

 

The pics show the connectors (note that they are in reverse order comparing one to the other) and the locations of the pins.

The chart tells you the location of the wires.

Assuming that the plugs are the same, it's just a matter of moving the wires to match the new harness. Just go through the diagrams, pin by pin, and change your existing pin locations to match the diagram for the new harness.

BTW, the pins 'lock' into the connector with a little spring tab. Insert a thin pin or paper clip into the hole for the pin. It may take a little finessing to release the tab, and then the wire pulls right out from the back. Obviously, you should move the wires one at a time to avoid mistakes.

 

Ok, lets put this to bed

3 connectors you need to mess with are the engine side C100, C207 (clear) and C221 (gray)

Since you dont have the C221 from the 89, youll have to splice them or adapt some other 3 pin inline connector on there

Move these:
89 C100 G4 cut free and lengthened about 10 feet. Splice to 86 dash side C207 pin D. Fuel pump 12v, needs to be 16ga
89 C207 B to 86 dash side C221 A (INJ1 fuse)
89 C207 G to 86 dash side C221 D (INJ2 fuse)
89 C207 D to 86 dash side C221 C (fan fuse)

You may need to swap the VSS on the 89 trans for a mechanical one to drive your speedo. 86 was a wierd year for birds, some got the mech, some got electrics

 

ternandes thanks for the help

 

ok i understand what u mean pocket but i need a visual picture to know what u mean and the 86 has the electric speedo and so does the 89' harness that i got...how to u go by the 202 for instance all i see is a,b,c a1,a2and so on ill take pictures so u can help pin point like i said in not to smart

 

https://www.thirdgen.org/forums/post...046-post2.html

C100 has no pins identified on the connector. Use the diagram at the top of the page. C207 and C221 have tiny letters cast onto the body to designate pin locations

 

Let's see what you need here...

For instance, F7 is your coolant temp guage, F5 is the coolant temp guage for the '89.
F8 is the alt wire for the '86, it's not used in the '89....etc. etc.

If you are not proficient in understanding wiring you are in a lot of trouble here.

The C100 is full of tar for protection, it must be removed to get at the pins, plus the locking device has to be removed (it's white).

You need to find an '86 harness and use the '89 program for tuning.

The '86 harness was two separate parts, the '89 was all in one.

HTH

 

ok now i understand so the for instance correct me if im wrong on the c207 part that whole section of wires ..now each wire has tiny letters in on them right

 

also some guy sent me a message that he has for sale the bulkhead from the 1989 year for $75 would that be a good deal to go ahead and buy it and save me trouble with repining and just hook up the one the '89 bulkhead

 

If I may add my two cents here, you can take whatever Pocket tells you to the bank. He has walked the walk on a lot of high tech swaps on thirdgens... he has been there and done that.

 

u have a point on that ternandes i trust on everyones opinion and on pockets also but i was thinkin to save my self time why not buy the 1989 bulkhead harness from a 1989 trans-am gta so now that being said what is all of ur opinion on that?

 

IMHO its more work with no gain. You'd still be missing the 89 C207, the wires still need to be rerouted and youd now have to splice about 30 wires instead of the ones listed

Repinning what you've got is very simple

 

(For instance, F7 is your coolant temp guage, F5 is the coolant temp guage for the '89.
F8 is the alt wire for the '86, it's not used in the '89....etc. etc.)

Did you not read this....

The coolant guage will not be hooked up. The alt. wire will not be connected, among other things.

Is that all you want is the motor to run, nothing else to work?

Just use the '86 harness and run the '89 program for tuning.
Ignore the cold start injector stuff.

 

@ pocket u have a point there but i was thinking i may be wrong but since its a 1989 wiring harness i was thinkin of just buying the rest of the inside part of the bulkhead where ur dash is i was thinking since it was comin out of a 1989 gta it would have the missing connector u stated on one of ur post but i just put minutes on my cell and gona take pictures of my harness and and bulkhead another thing is on the G4 and legthen about 10 feet why so long i dont see the visual picture but ill take pics its more easy for me to understand

 

@ dyno don i understand what u mean i can read it but i cant visualize im a tech in training at UTI, Rancho Cucomonga,CA math and wiring are not my strongest fields but basic wiring i understand like i said in training everyones has been in my shoes i just need the experience but using the 86 harness requires more splicing than the 89 harness that i already have its just the bulkhead that requires some splicing and relocation that seems simple in theory but to do hands on for me is a nightmare

 

F5 is coolant gauge for all years 82-92. The diagram up top is misleading because the designations are not inline

If you use the 89 dash harness, all will be fine. Remember the dash harness is enormous and goes all the way back to the tail lights

 

Wow... you are close enough to me to drive by and I will walk you thru everything.

I am in Orange.....92867

 

@dyno don how much would u charge for something like that

 

@ pocket now that being said i could use the 89 dash it would just be plug in and play right....and i heard they are long but its just a matter of removing the carpet and seats and geting to some parts of the dash

 

Pretty much all of the interior trim and carpet on the drivers side has to come off. The fuel pump grommet is also attached via rivets. Its going to take you a while to get it all out

 

0$

 

@ pocket thanks for the info there is a junkyard close by and gona practice taking out the bulkhead wiring on a 1988 trans-am that still has the 305 tpi, so if I do buy the bulkhead wiring from the 1989 gta I would know how to install and know how long it will take me and what to take off

 

$0 I wouldnt feel confortable I feel like im talking advantage of ur knowledge and skills

 

I am semi retired and I do this stuff because I enjoy it, I'm not trying to make a living at it. I share with others anytime I can.

After all, keeping thirdgens alive is what it's about right>>>>>

 

@ dyno don u have a point got to keep thirdgens alive they are the least liked genaration but for me they come on top first anyway back to the point I have to see if some guy on here will sell me his harness and if not well see if u can help me out hows that sound

 

Ok, I just finished a job like yours,

I put an '88 harness in an '84 because someone did hack job on his old one.

 

If u can help me out when would u be able to

 

update on the bulkhead here are pics of the bulkhead and ecm side

 

here are the coonectors with out being connected, keep in mind the bulkhead harness is a 1986 the ecm connectors are 1989

 

and here they are just connected and there is a couple of connectors that have no were to be connected they are the ones im holding in the pic

 

and here are the bulkhead pics

 

Hey, I'm sorry but I can't help you with your problem, I've got the same problem myself...took out a 7.4 vortec and replaced it with a 5.7 vortec. I hope you don't mind, but I'd like to ask you a question...where did you get your bulkhead diagrams? Man, I have been looking all over the web and locally trying to find someone who handles them. My chilton's books don't have them, as you probably know. Any help you can be I really appreciate.

Thanks

Jerry

 

Alldata or a GM service manual

Chiltons/haynes are basic guides at best, not to be used for technical data

 

as pocket stated you can use ALLDATA a.k.a. SomeData or mitchell on demand or a service manual i had to buy a service manual for my specific model year it helped i had the work done by dyno don at his shop as for locally i would only get work done by someone who only deals with thirdgens as his specialty like dyno don or other members on here depending on where you live, alot of people came thru with help on my threads ,pocket he is very knowledgable you can try to send him a private message or dyno don they may be able to help solve your problem