CSI fuel injection controller

[mark55]

I am having intermittent issues with my fuel injection on my 73 CSI. Has anyone ever opened the Bosch controller and attempted to troubleshoot?
I actually assemble printed circuit boards for a living so this is not a complicated task but I am hoping that there is someone who might know if there are certain components that are weak and might be the cause of my issues. I have tried to locate a schematic but have had no luck.

Thanks,

Mark.

 

[sfdon]

Have you tried fuel injection corporation?


http://www.fuelinjectioncorp.com/testing.php

 

[mark55]

I'm hoping to fix it myself but thanks for the lead. I like to tinker with electronics but I found this too:

http://www.epartsland.com/products/71-76-bmw-630csi-ecu-d-jetronic-ecu-computer-0280001007

Pretty cheap if it works.

Thanks for your help.

Mark.

 

[sfdon]

Nice find! Buy it ASAP.
Have you tested your TPS and MAP?

 

[E911]

Per sfdon's last post, I would double check all sensors as well as system vacuum and fuel pressure before dissecting or replacing the ECU... all are more likely culprits. The "brain" is pretty durable and not very smart.

It's critical to trouble shoot and tune a Djet system in a specific sequence as well... there's a good tuning reference guide out there somewhere for the system- can't recall the publisher/title.

There's enough collective knowledge around here that a brief description of the symptoms might lead to some fruitful suggestions.

 

[Tom M]

This link might help.

http://w107.pbworks.com/f/DJetronic.pdf


Tom

 

[Luis A.]

Is there anything to repair manual's admonition that the ECU and pressure sensor should be matched per the color dot on each?

http://www.e9-driven.com/Public/Library/BMW-E9-Manual/pages/en/13610010.html#refertoc

 

[sfdon]

The shop guy says there is nothing about any color dots in his repair instructions- he rebuilds them all the same.

 

[pamp]

Yeah...the color dot. I have been over this time and again....just how to match the ECU to the MAP? Found no difference using MB, Volvo to BMW on D-jet with mixed units and part numbers. What would help me and Don as to help you is a description of the symptoms you have. The D-jet can give troubles for simple reasons and I have yet to see a bad ECU unless it was baked on a paint job or water doused. Intermitant can mean anything....bad points will do that. Keep it simple before going on a wrong tangent. This would be the collective knowledge. I still run D-jet and have resisted Mega-squirt and other conversions so far. My car runs so well at this point it is almost scary....I am not willing to change a thing.

 

[sfdon]

Trigger on the csi dizzy is the other item to watch for..

 

[pamp]

Indeed....Also to check is the coolant block mounted to the bottom of the #3 intake runner. This is what the aux. air valve or "air slide" is bolted to as well as the temp. sender for the ECU. This is a cast alloy bit and will plug up due to corrosion over the years. When it plugs the sender says "cold engine" to the ECU and the car will run over-rich all the time and foul plugs quickly. Murray called me once as he was brokering a sale of a CSi and his mechanics were having fits....he told me the symptoms and I said to have his boys pull and clean this piece....messy job and coolant drain required....he e-mailed back one word "bingo" This you can troubleshoot with an I.R. thermo gun. Very affordable tool these days and invaluable to me...hit the hoses in and out of the coolant block, cold to hot and the temps should be the same across the board. The aux. air valve is a thermostat of sorts....open when cold to the intake and closes upon rise in temp. This you can check by pulling the hose to the air filter can and putting your finger to it....warm engine there should be slight vacuum here, yet there should be no drop or rise in RPM's when you plug this hose with a warm engine. This part is rare as hell....currently I use a piece from a MB 1973 280SE. I have the real deal in stash however NIB....I will not sell this for anything! Curiously it has a yellow dot....
I always use the IR gun for troubleshooting coolant system issues, possible bearing issues, etc. and this tool saves me a lot of time. Good luck sir.... Oh, one more thing I do is to have an additional 14 gauge ground wire run from the battery ground back to the ECU. Seems to keep everything happy....ECU, fuel pump and rear lighting. Then there is the MAP....."mighty vac" show....pull to 20 inches of vacuum and it should hold, if not the diaphragm is NG....sfdon has a resource for repair of this piece and I have one in the pipeline ....just for the stash as mine is good yet the spare was not. The D-jet pieces are becoming "unobtainium" Sooner or later, I hope later, I will give it up for cost reasons.

 

[DerSchwede]

Yeah...the color dot. I have been over this time and again....just how to match the ECU to the MAP? Found no difference using MB, Volvo to BMW on D-jet with mixed units and part numbers. What would help me and Don as to help you is a description of the symptoms you have. The D-jet can give troubles for simple reasons and I have yet to see a bad ECU unless it was baked on a paint job or water doused. Intermitant can mean anything....bad points will do that. Keep it simple before going on a wrong tangent. This would be the collective knowledge. I still run D-jet and have resisted Mega-squirt and other conversions so far. My car runs so well at this point it is almost scary....I am not willing to change a thing.

+1

There is nothing as crispy and eager as a BMW D-jet M30! Gotta love it

 

[pamp]

Goddamn right....just back from a blast and she really runs well. 3.3 motor, 1 1/2 short tube headers necked to 1 3/8 at the two to one merge and dumped to 2 1/4 pipe. Volvo 036 injectors, 320i intake runners. Stock cam. 3.63 LSD rear. It pulls like crazy. I have an A/F guage and my readings are on average 13. I love the sound as I back down, a burble as the exhaust does what it should do, evacuate yet provide back pressure to the balance of the intake. I cannot tune better than this on an 8 year project. A joy to drive. I am happy....on to suspension tweaks! Not too good for MPG however....

 

[Stevehose]

Well, I blasted around the lake roads today and the intake symphony from the triple Weber trumpets sure sounded pretty sweet

+1

There is nothing as crispy and eager as a BMW D-jet M30! Gotta love it

 

[DerSchwede]

Well, I blasted around the lake roads today and the intake symphony from the triple Weber trumpets sure sounded pretty sweet

Hey Steve, tripple Weber is a more crisp setup - absolutely! But for a stock or near stock application the D-jet takes the price in my eyes (ears). 20-24 mpg average with 5sp is ok as well. ;-) will see what the 3.5 tripple Weber engine gains when ready later this year

 

[mark55]

Sorry - away for the weekend

Thanks to everyone for the help so far.
Here's the symptoms in a nutshell:

Start the car in my driveway. Starts fine. Back up and shift to first, hit the gas and she coughs and sputters and dies. Start her back up instantly and she runs fine up to about 4K revs and then seems to either starve for fuel or get a little too much.
Sometimes she runs fine from the start and others are crap. Some times I can run for 15-20 minutes before symptoms slowly return. If I accelerate hard, I can almost always get her to crap out.
Any thoughts?

Thanks again,

Mark.

 

[pamp]

Try my ground wire back to the ECU/ fuel pump ground trick. This sounds like the fuel pump....these cars are old and much like an old dog....the grounding to the rear is not sufficient. You can run the wire outside the car to the ground spade on the fuel pump to check....do this first and report back. A gauge on the cold start injector hose will tell us more as well. Rare but I have seen the regulator go tits and cause your symptoms. To be more definative...it sounds like fuel starvation. Many causes for this. Hate to ask, but have you changed your fuel filters? I would check the mechanical bits before you buy an ECU.....fuel pump ground, fuel pump delivery, rail pressure (28 -30 psi) There are two relays that can give "intermittant trouble" as well. We can get to that later. You guys are probably asking yourselves "what the hell, the whole car/body is a ground" Yet, I had the same problem as Mark describes and just the addition of the light ground wire back cured it.

 

[mark55]

Here is a picture of a clamp I reattached that the previous owner had on. With it in place, runs fine. Not sure why.

Mark.

 

[sfdon]

You have a leaky cold start injector or one that
Is getting stuck on it appears.

 

[DerSchwede]

The cold start injector should only fire if the coolant temp is below 35 degC and for maximum 12 seconds at -20 degC (valid for cold climates) for all other parts of the world the coolant temp switch is active up to 15 degC and will allow for max 8 seconds at -20 degC. The fuel pressure should though be steady at at least 1.2 bar (better 1.5) after 10 minutes after the engine has been shut off - if not the back release valve in the pump is not working properly (easy fix) or one or more injectors are dripping (could ruin the engine - either clean, rebuild or get new ones)

Cheers
Anders