ECM / PROM question 86 corvette
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Joined: May 2001
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From: Oisterwijk, NB, The Netherlands
ECM / PROM question 86 corvette
Can anyone tell me if there is a difference between the PROM of a 86 and a 88 Corvette?
The tranny of my 86 shifts better with the prom of a 88 corvette.
But we do not know if we can let this chip inside my ECM... what other errors can we expect when we leave this chip in my car?
This is a verry odd problem.
How does a 86 corvette have to shift? How many times should it shift in DRIVE? When I keep it in DRIVE the last shift will be at approx. 140 km/h.
With the 88 chip this last shiftpoint will come much earlier (at 80 km/h).
Sooooo..... I'm looking for a person that can give me a lot more information about this.... :confused:
How many gears should I have in a 86 corvette?
In DRIVE I have 3 gears (the fourth will come at 140 km/h), but I shift into Overdrive when I reach the 80km/h, that's why I never knew that there was a 4th gear....
HELP..........
Thanks anyway.
Wilhelm
The tranny of my 86 shifts better with the prom of a 88 corvette.
But we do not know if we can let this chip inside my ECM... what other errors can we expect when we leave this chip in my car?
This is a verry odd problem.
How does a 86 corvette have to shift? How many times should it shift in DRIVE? When I keep it in DRIVE the last shift will be at approx. 140 km/h.
With the 88 chip this last shiftpoint will come much earlier (at 80 km/h).
Sooooo..... I'm looking for a person that can give me a lot more information about this.... :confused:
How many gears should I have in a 86 corvette?
In DRIVE I have 3 gears (the fourth will come at 140 km/h), but I shift into Overdrive when I reach the 80km/h, that's why I never knew that there was a 4th gear....
HELP..........
Thanks anyway.
Wilhelm
Team Owner
Joined: Sep 2001
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From: Athens AL
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Re: ECM / PROM question 86 corvette (wilhelm86)
Yes there are differences between the chips. The 86 has a slightly different cam and different heads that the 88 chip may not perfectly adjust to. (idle, gas mileage, etc.)
The 86 transmission is not controlled by the ECM. The ECM only controls TC lockup in OD.
the 700r4 has 3 gears and an overdrive
The 86 transmission is not controlled by the ECM. The ECM only controls TC lockup in OD.
the 700r4 has 3 gears and an overdrive
Le Mans Master
Joined: Apr 2000
Posts: 6,341
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From: Shelton CT
Re: ECM / PROM question 86 corvette (vader86)
Yes there are differences between the chips. The 86 has a slightly different cam and different heads that the 88 chip may not perfectly adjust to. (idle, gas mileage, etc.)
The 86 transmission is not controlled by the ECM. The ECM only controls TC lockup in OD.
the 700r4 has 3 gears and an overdrive
The 86 transmission is not controlled by the ECM. The ECM only controls TC lockup in OD.
the 700r4 has 3 gears and an overdrive
My '85 shoudl be very close to the '86 when it comes to the tranny, (I knwo the ecm is different), and I just started getting into burning my own custom proms for it, and I've noticed the ecm has full controll of lockup in 2-3-and OD.
I also have a performance resources chip that eliminates all lockup other than OD.
Stock chip locks at speeds in 2,3 and OD.. (Very annoying to say the least).
Team Owner
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From: Athens AL
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Re: ECM / PROM question 86 corvette (MrNuke)
Interesting, id never noticed that it controlled lockup in 2nd or 3rd.
But the chip shouldnt control his shift points at all, nor the firmness of the shift.
But the chip shouldnt control his shift points at all, nor the firmness of the shift.
Le Mans Master
Joined: Apr 2000
Posts: 6,341
Likes: 1
From: Shelton CT
Re: ECM / PROM question 86 corvette (vader86)
You're right about the shiftpoints. That's controlled by the pressur ein the tranny/TV cable adjustment.
ANother thing I noticed, btu can't explain (yet) is that when the lockup is disabled in all gears, my tranny slips (albeit quickly) into 2nd and 3rd at WOT, instead of shifting hard as with the stock chip and lockup. Wonder if it's a function of luckup somehow.. Havnt foudn that yet..
ANother thing I noticed, btu can't explain (yet) is that when the lockup is disabled in all gears, my tranny slips (albeit quickly) into 2nd and 3rd at WOT, instead of shifting hard as with the stock chip and lockup. Wonder if it's a function of luckup somehow.. Havnt foudn that yet..
