This can be done in the bin??? Gotta go look...time permitting that is.
Ecu question
Thread Starter
3rd Gear
Joined: Oct 2020
Posts: 3
Likes: 0
Ecu question
Hey guys, working on a 88, I swapped over the 4+3 to an automatic for my father in-law, it has 3.07 gears. After the swap the car is a dog. Do I need to swap the computer prom from the same year from an automatic car? Or do I need to swap the whole computer? What years would be compatible?
Pro
Joined: Aug 2020
Posts: 647
Likes: 126
From: Liliha Bakery stuffing my face with coco puffs!
You can swap the PROM from auto '87-'88. You can also get away with a auto '89 but you would need to disable the cold start injector. Also I believe you need to add the Park/Neutral switch so the ECM will know if the vehicle is in gear or not.
Drifting
Joined: Apr 2020
Posts: 1,925
Likes: 610
From: Orange, CA
You also have to reverse the polarity of the cooling fan relay (or change it in the '89 code before burning the chip).
Drifting
Joined: Apr 2020
Posts: 1,925
Likes: 610
From: Orange, CA
Melting Slicks
Joined: Aug 2003
Posts: 3,394
Likes: 393
From: Lakeville MI
Bit 5 at address: 0x17 is not set in any of the Corvette $32, $32B or $6E bins. F-body bins are a different story, so this can be an issue if trying to use a Corvette bin in an F-body or vice-versa or when working with a converted 85 car. Always a good idea to check the bin and/or switch first before changing anything.
One example shown below:
LC017: FCB $00 ; 4th AIr Flow Mode Word, 0000 0000
;
; b7 = Use TCC out to Cnt'l A/C Clutch
; b6 = Use Pwr Steer Pressure Sw
; b5 = N.O. Cooling Fan Req input
; b4 = TCC lk'ed Hwy Mode Spark Ck On.
;
; b3 = If CCP Chg, force Int to 128
; b2 = 4th Gear Hwy Mode Spark Adv on
; b1 =
; b0 = Use Ld Val for BLM not dispflow
;----------------------------------------
Last edited by tequilaboy; Nov 1, 2020 at 06:54 PM.
Melting Slicks
Joined: Aug 2003
Posts: 3,394
Likes: 393
From: Lakeville MI
Fueling is the same, timing is slightly different mostly at load low rpm and high load since a manual may be lugged in high gear. Idle control settings are also a bit different between manual and auto bins. Biggest difference is that the TCC lock-up will be screwy since it will be using the 4+3 logic, and is likely locking the converter early. Did you leave the first gear switch connector open?
Where did the trans come from? Perhaps the governor shift point calibration is way off. Is the car over-revving and shifting too late or too early? What is the WOT shift rpm?
Of course, it could just be a dog.
Where did the trans come from? Perhaps the governor shift point calibration is way off. Is the car over-revving and shifting too late or too early? What is the WOT shift rpm?
Of course, it could just be a dog.
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