'870-'165 swap
Thread Starter
Le Mans Master
Joined: Sep 2005
Posts: 6,551
Likes: 36
From: Jenks OK
'870-'165 swap
I'm looking into swapping ECM's and have found some good write ups but I'm curious how this will affect my 4+3 transmission.
I have an early 4+3 with a console switch that I usually leave off and hit the switch when I want to drop down into 4th overdrive.
Anything special I have to do to allow the 4+3 to work correctly?
I have an early 4+3 with a console switch that I usually leave off and hit the switch when I want to drop down into 4th overdrive.
Anything special I have to do to allow the 4+3 to work correctly?
Melting Slicks
Joined: Aug 2003
Posts: 3,395
Likes: 393
From: Lakeville MI
Good question.
I would suggest that you configure the 165 ecm's connector like an 87-88 rather than an 86. This will permit the first gear switch to function and also permit use of normal 87-88 $32B bins.
Since 86's have no first gear switch, and the shifter switch is wired to the pin that 87-88s use for the first gear switch, wiring the ecm like an 86 would be problematic. Sorry I don't have the pin numbers handy. I should be able to dig them up, if you don't have a good 87-88 pinout available.
86 ecm pins:
M/T O/D Shifter switch: C8
O/D TCC Control: A7
A/T O/D switch: C7 (open in OD,N,R or P)
87-88 ecm pins:
M/T O/D Shifter switch: C7
O/D TCC Control: A7
M/T 1st gear switch: C8
A/T O/D switch: C7 (open in OD,N,R or P)
The M/T O/D switch on the shifter is on pin C8 for 86, and C7 for 87-88.
To configure like an 87-88:
Connect your existing 85 1st gear switch wire to ecm pin C8.
Connect your existing 85 console switch wire to the ecm pin C7.
Note: The operation maybe different since the later shifter switch is only a momentary switch. I'm assuming that the 85 style console switch latches either on or off.
I would also program the OD to be off by default in the new bin and then use the console switch like a momentary switch to trigger the OD when desired.
I would suggest that you configure the 165 ecm's connector like an 87-88 rather than an 86. This will permit the first gear switch to function and also permit use of normal 87-88 $32B bins.
Since 86's have no first gear switch, and the shifter switch is wired to the pin that 87-88s use for the first gear switch, wiring the ecm like an 86 would be problematic. Sorry I don't have the pin numbers handy. I should be able to dig them up, if you don't have a good 87-88 pinout available.
86 ecm pins:
M/T O/D Shifter switch: C8
O/D TCC Control: A7
A/T O/D switch: C7 (open in OD,N,R or P)
87-88 ecm pins:
M/T O/D Shifter switch: C7
O/D TCC Control: A7
M/T 1st gear switch: C8
A/T O/D switch: C7 (open in OD,N,R or P)
The M/T O/D switch on the shifter is on pin C8 for 86, and C7 for 87-88.
To configure like an 87-88:
Connect your existing 85 1st gear switch wire to ecm pin C8.
Connect your existing 85 console switch wire to the ecm pin C7.
Note: The operation maybe different since the later shifter switch is only a momentary switch. I'm assuming that the 85 style console switch latches either on or off.
I would also program the OD to be off by default in the new bin and then use the console switch like a momentary switch to trigger the OD when desired.
Last edited by tequilaboy; Aug 17, 2009 at 03:55 PM.
Advanced
Joined: Aug 2003
Posts: 82
Likes: 0
From: Nowthen MN
OP's sig says that he has an 85 - didn't they use a TV cable to control the OD not the ECM?
I read on another 4+3 site (5speed.com?) that the 86 cars were the only year without a 1st gear switch.
Either way, it sounds like they could upgrade to the 88 bin.
-J
I read on another 4+3 site (5speed.com?) that the 86 cars were the only year without a 1st gear switch.
Either way, it sounds like they could upgrade to the 88 bin.
-J
Thread Starter
Le Mans Master
Joined: Sep 2005
Posts: 6,551
Likes: 36
From: Jenks OK
I do belive that my kickdown is handled by a TV cable on the front of the throttle body. So does that mean regardless of ECM programming that my 4+3 will act the same way?
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
In either case it makes no difference to you as you will have it hooked up and you will find out 1st time you drive it.
Last edited by rodj; Sep 25, 2009 at 10:10 AM.
