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Recommendations for ECU repair on 85 M635?

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Pat_M635csi
Posts: 49
Joined: Wed Dec 11, 2013 9:28 pm
Location: Boston

Recommendations for ECU repair on 85 M635?

Post by Pat_M635csi » Wed Jun 06, 2018 10:24 am

My ECU has died.

From talking to my local independent mechanic. It looks like the importer in the 80's had installed a piggyback system to get the cat and o2 sensor to operate for federalization purposes. All the emissions stuff has been gone for 20 years and it has a new stock oem european exhaust system. Car always ran fine. Repaired the speedo and a month later after reinstalling car would run poorly at start and finally stall.

Mechanic removed the piggyback and tested the main ECU which came back NG. Would like to repair and get back to stock if possible.

Was looking at ECU Technologies in the UK seems reasonable at 125 pounds.

Any help would be appreciated.
1985 M635CSI M88/3
1997 Z3 2.8
2010 535xi Touring w/Dinan Stage 3 upgrade
following were sold but not forgotten
2000 540it
1972 3.0CS Polaris
1972 3.0CSI Polaris
1986 735i 5sp
1983 733i
1969 2000 tilux
1972 2002 tii
1973 2002

brickwhite
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Posts: 506
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Location: Jackson, MO USA

Re: Recommendations for ECU repair on 85 M635?

Post by brickwhite » Wed Jun 06, 2018 1:44 pm

You will need a 055 ECU.. pretty tough and expensive to come by.
- 12 535i
- 92 325ic
- 85 M635csi
- 63 Triumph Tr-4

CSGuy
Posts: 24
Joined: Fri Mar 09, 2018 2:40 am
Location: SoCal

Re: Recommendations for ECU repair on 85 M635?

Post by CSGuy » Thu Jun 07, 2018 12:19 am

Have you tried these guys

https://www.programainc.com/item_list.aspx?idcategory=1


They rebuilt my MAF for me for a big improvement.

bpoliakoff
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Re: Recommendations for ECU repair on 85 M635?

Post by bpoliakoff » Thu Jun 07, 2018 3:04 am

Try fuel injection corp of America. It's a one man band but the guy is some far out engineer type. Dealt with him many years ago and he was decent enough to tell me my ecu was still good.
81 Euro 635 M90 with motronic. Currently under a complete nut and bolt restoration. Pictures at
flickr.com/photos/bertsphotos.

cofred
Posts: 47
Joined: Wed Jul 24, 2013 5:38 pm
Location: Frisco, Tx

Re: Recommendations for ECU repair on 85 M635?

Post by cofred » Sun Jun 10, 2018 1:01 pm

I used Specialized ECU Repair in FL a number of years ago: https://porschedme.com/pages/about-us They did a great job. The manager is Jorge Morales. It looks like they might have a reconditioned one in stock for a cool $1245: https://porschedme.com/collections/bmw-m6-1984-1987 I just sent mine to them, they repaired and it's been perfect since.
Heath
'85 M635

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Pat_M635csi
Posts: 49
Joined: Wed Dec 11, 2013 9:28 pm
Location: Boston

Re: Recommendations for ECU repair on 85 M635?

Post by Pat_M635csi » Wed Jun 13, 2018 11:06 am

Thanks for the input. Making calls to each today. Thanks again
1985 M635CSI M88/3
1997 Z3 2.8
2010 535xi Touring w/Dinan Stage 3 upgrade
following were sold but not forgotten
2000 540it
1972 3.0CS Polaris
1972 3.0CSI Polaris
1986 735i 5sp
1983 733i
1969 2000 tilux
1972 2002 tii
1973 2002

User avatar
Pat_M635csi
Posts: 49
Joined: Wed Dec 11, 2013 9:28 pm
Location: Boston

Re: Recommendations for ECU repair on 85 M635?

Post by Pat_M635csi » Thu Jun 14, 2018 5:35 pm

Here is what I pulled out of the car today. Anyone ever used www.g7computers.com ? They are in upstate New York quoting $250 for the repair.
i also think the second unit is a piggyback for when the car had emissions on it to pass federalization
ECU piggyback_s.jpg
ECU piggyback_s.jpg (63.25 KiB) Viewed 74 times
ECU 055_s.jpg
ECU 055_s.jpg (72.95 KiB) Viewed 74 times
.
1985 M635CSI M88/3
1997 Z3 2.8
2010 535xi Touring w/Dinan Stage 3 upgrade
following were sold but not forgotten
2000 540it
1972 3.0CS Polaris
1972 3.0CSI Polaris
1986 735i 5sp
1983 733i
1969 2000 tilux
1972 2002 tii
1973 2002

cofred
Posts: 47
Joined: Wed Jul 24, 2013 5:38 pm
Location: Frisco, Tx

Re: Recommendations for ECU repair on 85 M635?

Post by cofred » Fri Jun 15, 2018 12:54 pm

Yes, the second unit is often referred to the "Johnson Box" for emissions. I'm not sure if my car ever had one....the wire from the O2 Sensor just dead ends in the glove box.
Heath
'85 M635

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