Brain surgery D-jet

[bill]

Welp, the brain in my coupe is apparently hors de combat. Started her up today, engine misfiring. Pulled plug wires one at at time and found #1,#3 and #5 not firing. Suspected the brain right away, fortunately I have another one in my stash. Replaced it and everything is fine.
Does anyone repair the brains?

 

[sfdon]

Robert at FIC in Tracy

 

[Bert Poliakoff]

+1

 

[JayWltrs]

For posterity and those who collect service contacts:

FUEL INJECTION CORPORATION
2246 N. MacArthur Dr.
Tracy, CA 95376
http://fuelinjectioncorp.com/
209-840-6551

 

[bill]

Thank you SF Don, Bert and Jay. Curious to see if my brain can be fixed.

 

[Bwana]

Mine runs excellent after being refurbished by them. Hopefully yours doesn't have really bad corrosion, that's the death of these ECU's. They're generally super reliable, any idea why yours went bad?

 

[bill]

Bwana: No idea yet why it went bad. I haven't yet removed the cover to look around for anything obvious (burned out resistor, transistor, etc.) It worked fine, then after sitting for a week, the misfire (or lack of firing to 1,3, and 5) started. Without a schematic it will be very difficult to diagnose, and even then Dr. D-jet says replacing any components means the ECU has to be "re-calibrated" (Not sure if Dr. D-jet is even active anymore--no response to my request to register yet.) Glad I bought a spare from a 72 years ago...

 

[Markos]

Bwana: No idea yet why it went bad. I haven't yet removed the cover to look around for anything obvious (burned out resistor, transistor, etc.) It worked fine, then after sitting for a week, the misfire (or lack of firing to 1,3, and 5) started. Without a schematic it will be very difficult to diagnose, and even then Dr. D-jet says replacing any components means the ECU has to be "re-calibrated" (Not sure if Dr. D-jet is even active anymore--no response to my request to register yet.) Glad I bought a spare from a 72 years ago...

Give Robert a ring. He is super helpful. If you send in the computer, use the downtime to rebuild the d-jet pump as well. They are $600+ new and $200 to rebuild. Easy to access as well.

 

[Bwana]

This (hopefully) will link to the D-Jet wiring diagram in the Teck Wiki

http://www.e9coupe.com/tech/autobooks/appendix/autobooks_manual_160.htm

http://www.e9coupe.com/tech/dljet/dljet.pdf

The D-Jets in our Coupes are set up for a four cylinder engine or something as you can see cylinders #1 #3 fire from the same node #155, cylinders #2 #4 fire from #154, and #5 and #6 are on their own. They have power transistors in the ECU that provide the voltage to open the injector. I burned two of mine out by grounding the timing points in the distributer and had the same symptoms as you. (Jump in here anytime Don)

 

[bill]

This (hopefully) will link to the D-Jet wiring diagram in the Teck Wiki

http://www.e9coupe.com/tech/autobooks/appendix/autobooks_manual_160.htm

http://www.e9coupe.com/tech/dljet/dljet.pdf

The D-Jets in our Coupes are set up for a four cylinder engine or something as you can see cylinders #1 #3 fire from the same node #155, cylinders #2 #4 fire from #154, and #5 and #6 are on their own. They have power transistors in the ECU that provide the voltage to open the injector. I burned two of mine out by grounding the timing points in the distributer and had the same symptoms as you. (Jump in here anytime Don)

I'll check the points. How did you find/fix the problem?

 

[Bwana]

Be careful fooling with the points. In retrospect, I'd remove the dizzy from the engine first. As part of going thru the whole car on a system by system basis, I had decided to replace the timing points in the distributer as they were of unknown age, probably original equipment. Of course I artfully dropped the little screws that hold the points in down into the engine bay, never to be seen again. I replaced them with ones of the correct diameter and thread pitch from the big box store but they were about .5mm too long but I didn't notice that. So when I started the car, the curved spring backs that hold the actual points backed into the too long screws and shorted out the power transistors (you can trace it down on a good wiring diagram). The guy I work with on the D-jet stuff (Dave @ Autobahn in Humble, awesome tech skills) had a cool set of trigger lights that can be plugged into the FI harness to see which injector was not getting the correct current. The short answer is I sent the ECU to Fuel injection Corp and they rebuilt it. Ran terrific after that.

 

[bill]

Be careful fooling with the points. In retrospect, I'd remove the dizzy from the engine first. As part of going thru the whole car on a system by system basis, I had decided to replace the timing points in the distributer as they were of unknown age, probably original equipment. Of course I artfully dropped the little screws that hold the points in down into the engine bay, never to be seen again. I replaced them with ones of the correct diameter and thread pitch from the big box store but they were about .5mm too long but I didn't notice that. So when I started the car, the curved spring backs that hold the actual points backed into the too long screws and shorted out the power transistors (you can trace it down on a good wiring diagram). The guy I work with on the D-jet stuff (Dave @ Autobahn in Humble, awesome tech skills) had a cool set of trigger lights that can be plugged into the FI harness to see which injector was not getting the correct current. The short answer is I sent the ECU to Fuel injection Corp and they rebuilt it. Ran terrific after that.

Very good advice, Bwana. I was going to ask if the points are adjustable or not?

 

[Bwana]

I don't think so, I'm not sure how the FI injection timing is adjusted, if at all. I don't like points in general so I finally opted for a 123-Ignition full solid state dizzy and eliminated both the ignition and FI timing issues.