1988 v6 2.8 MPFI/5spd to 1992 v8 305 TBI/auto - harness questions
(FYI: First time engine swap)

I have tried to find the answer through many google searches and here on thirdgen, but most answers aren't 'dead on topic'...so I want to ask straight to the point and see if I can get the answers I need.

Situation:
Swapping a 92 305 tbi/auto donor into 1988 v6 rs 2.8mpfi/5spd receptor.

The 92 305 chassis harness has Passkey and an airbag, I do not want either; Can I plug the 305 engine harness and ECM into the 1988 chassis harness and have it work properly?

If so, what do I have to do so that I can turn the key and have it start?

If not, what are your suggestions?

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Ideally, I'd want to plug the 92 engine harness/ECM into the 88 chassis harness, but keep my 88 steering wheel/column and eliminate passkey and the airbag.

What problems should I expect?

Thanks in advance.

 

They are if you ask the right question

on here for VATS delete; which is what you are doing and independent to the engine swap
read
https://www.thirdgen.org/vats_passkey_system

What you do is get a custom chip for the 92 ECM made with VATS deleted
https://www.thirdgen.org/forums/post...781-post4.html

and then bypass the starter enable relay operated also by VATS

You would need the firewall connector pinouts for both years from the FSM to determine what wires are located where on the connectors
Something like
http://berlinetta.info/C100.htm

 

Thank you for your information. I did read the vats article, this is my first time and I didn't really 'get it'.

So what I do get from your reply, this isn't a simple plug and play.
Would it be more sensible to swap the entire chassis harness?

Then do the vats and airbag delete?

I suppose simple would be changing it all, keep vats and just skip the air bag, but I still need most of the steering column to do that.

 

VATS is a computer function; the computer is programmed to requires a input from the VATS module.
Deleting that requirement it is as simple as getting a custom tune with the VATS requirement deleted.( as well as the starter relay bypass)
or wiring in this module to the computer supply the correct signal

http://www.bakerelectronix.com/products_vats/

If you did however do the internal harness swap you can still do the popular " resistor bypass " where resistors are use to simulated the correct key being used in the Ign so the VATS reading column is not required.

 

So, if I understand you correctly - if I do a VATS bypass, I won't even need to change the steering electronics? (ignition and key cylinder)

I am still considering swapping those electronics and cylinder, because I have noticed if the wheel is in the up position, sometimes it simply won't get power. Assuming its a bad wire or bad connection, so to eliminate all issues I figured it would be good to swap all the electronics.

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After reading what you have replied with and what I have found researching.. it does make the most sense to simply swap the entire engine and chassis harness, swap the steering ignition wiring and cylinder, then bypass/disable the airbag electronics, which should give me what I need/want.

Or, If I decided to not swap the steering column electronics and do the 'resistor' trick for VATS, I won't need to get the chip reprogrammed and that would be saving me some $$. Not trying to be cheap, but I'm on a tight budget with this swap, that's why I'm not bothering to do a bunch of upgrades, just a motor/tranny swap and moving on.

I only intend on buying what I must as the motor is in great running condition and the tranny is solid. The donor is just a complete rust bucket and would cost more to restore than to do the swap.

 

I see no benefit in swapping the column unless you want that column.
The VATS requirement of the new computer is easily satisfied by one of the bypass means listed

 

The column electronics swap is to fix the issue of the dead spot when the column is tilted. Other than that, no I don't plan on changing the whole thing.

 

So this problem is solved, I just swapped the column and changed the wheel :-) wasn't too rough but I had to have a friend hold the wheel/column inside while I tapped the knuckle back onto the column.

 

https://www.thirdgen.org/forums/ltx-...formation.html

Compare the 86 to 92 pinouts. Dont touch the dash harness, instead repin the engine harness to match. You will have to run an extra wire or two between the C100 and C207 and add the C221 from your 86 V6 harness

 

I appreciate the reply, but it's pretty much done. I changed everything, the entire 92 dash + steering, entire harness is going into the 88. I wanted to stay away from modding as the donor was in good running/electrical condition.