1986 Iroc LB9 with and 85 ECM
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From: Indiana
Car: 1985 IROC
Engine: TPI
Transmission: 700r4
Axle/Gears: 3.42
1986 Iroc LB9 with an 85 ECM
I was having a hesitation with an 86 iroc with 14k miles. When hooked up to the OBDI and programmed in for an 86, there was no data stream. So thought ECM Bad. The car was built 11/85 and the shop tried setting the OBD in 1985 mode and the data stream appeared. So I know it has an 85 ecm in it. Is it possible it has the 85 cam as well??? How would I find out???
Last edited by Skihorse; May 8, 2007 at 10:14 PM.
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From: Beaufort South Carolina
Car: 1983 Camaro Z/28
Engine: LU5 305 CFI
Transmission: 700R4
Axle/Gears: J65/G80/G92-3.23
Re: 1986 Iroc LB9 with and 85 ECM
My '95 Jimmy was an early build(09/94)so she is OBD1.5 but with the OBD2 connector.I ran into this the first time I connected my scan tool to her.
On the cam the only idea I have,and I don't know if it will help you,is checking the build date of the motor.But then you have to know when they engine plant changed cam style.
On the cam the only idea I have,and I don't know if it will help you,is checking the build date of the motor.But then you have to know when they engine plant changed cam style.
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From: Readsboro, VT
Car: 85 IROC-Z / 88 GTA
Engine: 403 LSx (Pending) / 355 Tuned Port
Transmission: T56 Magnum (Pending) / T5
Axle/Gears: 3.42 / ?
Re: 1986 Iroc LB9 with and 85 ECM
I seriously doubt your car has the 85 ECM. That means it would have the old ECM, old wiring harness, old MAF & related circuitry and even a different bulkhead hole in the kick panel area. The ALDL communication stream may be similar enough between the 85 and 86 that the scan tool may be able to read it. I've had glitch issues with my own car where I've had to fool around with different year settings to get it to work sometimes.
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From: Readsboro, VT
Car: 85 IROC-Z / 88 GTA
Engine: 403 LSx (Pending) / 355 Tuned Port
Transmission: T56 Magnum (Pending) / T5
Axle/Gears: 3.42 / ?
Re: 1986 Iroc LB9 with and 85 ECM
Even that isn't necessary. When you pull down the 85 ECM you'll see the giant MAF Burnoff circuit piggy-backing it. Speaking of which... you can just look under the hood on the firewall. The 85 will have 2 relays near the brake master cylinder... the MAF power relay and the fuel pump relay. The 86 will have a third relay for the MAF burnoff.
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From: NE Pennsylvania
Car: 85 Iroc-Z
Engine: 383 TPI Procharger D1SC
Transmission: TKO600
Axle/Gears: Strange S60 3.73
Re: 1986 Iroc LB9 with and 85 ECM
Just like cdartz said, pull out your ecm and read the number on it. Here is a list that will help you.
Model Year GmpartNo EngineF,Y 1985 1226870 5.0L/5.7LF,Y 1986-1989 1227165 5.0L/5.7LF 1990-1992 1227730/16198262 5.0L/5.7LY 1990-1991 1227727/16197128 5.7LY 1992 16159278 5.7L LT1F 1993 16159278 5.7L LT1Y=Corvette F=Camaro ,Firebird, Trans-AM
Model Year GmpartNo EngineF,Y 1985 1226870 5.0L/5.7LF,Y 1986-1989 1227165 5.0L/5.7LF 1990-1992 1227730/16198262 5.0L/5.7LY 1990-1991 1227727/16197128 5.7LY 1992 16159278 5.7L LT1F 1993 16159278 5.7L LT1Y=Corvette F=Camaro ,Firebird, Trans-AM
Thread Starter
Junior Member
Joined: Feb 2006
Posts: 73
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From: Indiana
Car: 1985 IROC
Engine: TPI
Transmission: 700r4
Axle/Gears: 3.42
Re: 1986 Iroc LB9 with and 85 ECM
Even that isn't necessary. When you pull down the 85 ECM you'll see the giant MAF Burnoff circuit piggy-backing it. Speaking of which... you can just look under the hood on the firewall. The 85 will have 2 relays near the brake master cylinder... the MAF power relay and the fuel pump relay. The 86 will have a third relay for the MAF burnoff.
Thanks!
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From: Jacksonville, Florida
Car: 1985 Pontiac Trans Am
Engine: 6.6 Liter 406 c.i.
Transmission: T-56 6 Speed/ McLeod Street Twin
Axle/Gears: 3.42 9 Bolt Posi w/ girdle
Re: 1986 Iroc LB9 with and 85 ECM
Something awfully odd... I've got an 85 Trans Am, with the stock 2-6870 ECM, but it has no MAF Burn Off module piggy backing it. It looks like mine is mounted further up into the dash. Is that normal? Or is my car a freak of nature? I've only got the 2 relays on my firewall. Wierd eh?
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From: Trevose,PA
Car: 85 IROC Z
Engine: 350 TPI
Transmission: TCI TH350 TCI 2400 STALL
Axle/Gears: 3.42 WORN OUT POSI
Re: 1986 Iroc LB9 with and 85 ECM
Sorry for the hijack but my 85 has the big piggyback on the comp. But I only have 1 relay on the firewall and thats the fp relay. I know my maf still works,I actually just replaced it. Any ideas where that relay could be?
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