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[1985] Were The Engine Control Electronics Modified During The Model Year

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Old Aug 4, 2007 | 05:11 PM
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Default [1985] Were The Engine Control Electronics Modified During The Model Year
Does anybody know if the L98 engine control electronics were modified during the 1985 model year? In other words, would an early 1985's PROM/ECM be different from that of a late 1985's?
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Old Aug 4, 2007 | 05:37 PM
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No, they were not changed. They changed with the 1986.
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Old Aug 4, 2007 | 05:57 PM
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There were lots of prom/bccs listed for 85 though (from chevythunder.com):

1985 350 (5.7L) "Y" body Corvette

Prom BCC Prom Code Scan ID Trans Gear ratio Emissions Body
FTS 9529 0061 700R4 N/A Cal/Fed Y
FTT 9538 0071 4 spd Man 2.88 1st Fed Y
FTW 9573 0091 4 spd Man 2.88 1st Cal/Fed Y
FUM 0561 0101 700R4 N/A Cal/Fed Y
FUN 9737 0111 4 spd Man 2.88 1st Cal/Fed Y
HLH 3200 2531 700R4 N/A Cal/Fed Y
HLP 3266 2581 4 spd Man 2.88 1st Cal/Fed Y
HLS 2308 2601 4 spd Man 2.88 1st Fed Y
CSZ 2633 7101 700R4 N/A Fed Y
CTB 9032 7121 4 spd Man 2.72/3.07 Fed Y
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Old Aug 4, 2007 | 10:53 PM
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I was gonna say they had variations to work with manual vs auto vs rear gears.
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Old Aug 5, 2007 | 01:00 AM
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The standard electrics did not change, they used the 1226870 ECM throught the entire production year for 1985. They changed to the 1227165 ECM for the years 1986 through 1989.
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Old Aug 5, 2007 | 01:02 AM
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yea, but we are talking the prom within the ECM.
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Old Aug 5, 2007 | 06:17 PM
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Originally Posted by tequilaboy
There were lots of prom/bccs listed for 85 though (from chevythunder.com):

1985 350 (5.7L) "Y" body Corvette

Prom BCC Prom Code Scan ID Trans Gear ratio Emissions Body
FTS 9529 0061 700R4 N/A Cal/Fed Y
FTT 9538 0071 4 spd Man 2.88 1st Fed Y
FTW 9573 0091 4 spd Man 2.88 1st Cal/Fed Y
FUM 0561 0101 700R4 N/A Cal/Fed Y
FUN 9737 0111 4 spd Man 2.88 1st Cal/Fed Y
HLH 3200 2531 700R4 N/A Cal/Fed Y
HLP 3266 2581 4 spd Man 2.88 1st Cal/Fed Y
HLS 2308 2601 4 spd Man 2.88 1st Fed Y
CSZ 2633 7101 700R4 N/A Fed Y
CTB 9032 7121 4 spd Man 2.72/3.07 Fed Y
Hmm ... so four different PROM/BCCs for an A4 in one year. Is there any way to know when in the year they made the switches?

Would a dealer have swapped later ones in to fix drivability problems with the earlier ones? I checked the TSB list and didn't see anything obvious, but I talked to the one owner of a relatively early 1985 a couple weeks ago and he was sure the dealer swapped his when he complained about some issues.

I'm still learning here, so please be gentle ...
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Old Aug 5, 2007 | 07:36 PM
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that's a good question... and the only person I can think of who would know is Gordon Killebrew. It might be worth spending $20.00 with him to find out.
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Old Aug 5, 2007 | 07:53 PM
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Originally Posted by bogus
that's a good question ... and the only person I can think of who would know is Gordon Killebrew. It might be worth spending $20.00 with him to find out.
Or grabbing him at Carlisle ...
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Old Aug 5, 2007 | 09:32 PM
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an even better idea!
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