D-Jetronic Rebuild

[sfdon]

Greetings Bwana....
Pin 50 is at the bottom 6:00 it cranks the car
Pin 30 is at the side 3:00 it powers the starter.
Pin 16 is at the top 12:00 it powers the coil only when the engine is cranking
Connector 168 is what is giving you a problem- there is no mention of the color changing from black to red

Csi's are a little confusing at first.
Unlike the carbed cars there are TWO red wires down there by the starter that are in the same bit of engine harness and they BOTH connect to the starter. Lucky for us that one has a spade connector and one has an eyelet connector. The spade connector red wire goes at the bottom (6:00) and it gives the crank the engine signal and the eyelet goes on the threaded post with the positive battery cable and it powers the engine circuit at pin 30 of the main relay.
Where the trouble starts is that there are more damn red wires down there too.
Look for the bit of harness that has the oil pressure wire ( green / brown), the extra hot wire to the coil (black/red) and a double black wire to a spade connector. It's the double black you need. Now that goes to a red wire with two white wires on a spade connector. They need to connect together.

Pm me if you need pics or want to be talked through the process of what goes where.
I think you'll be surprised how easy it is

 

[sfdon]

Hi Bwana- can you do a test for me?

With the key in the off position would you test the coil for DC voltage? (12 volts)

Test for voltage at either connection of the coil.

If you have 12 volts at the coil with the key off- please disconnect the black/red wire at the starter and test for voltage at the coil again

Let me know...

 

[Bwana]

Look for the bit of harness that has the oil pressure wire ( green / brown), the extra hot wire to the coil (black/red) and a double black wire to a spade connector. It's the double black you need. Now that goes to a red wire with two white wires on a spade connector. They need to connect together.

Pm me if you need pics or want to be talked through the process of what goes where.
I think you'll be surprised how easy it is

Don, I'm 100% with you up to here. I think I'm battling something the PO must have done. This is a shot of the original solenoid setup after I had removed the FI harness. The red/black, twin black, and battery leads are still in place. You can see the black/red wire in the 12:00 position and the twin black wires in the 6:00 position. When I remove the twin black wire from the spade connector, I get ground on the starter spade and nothing on the twin black wires. I've seen the twin black wires in a aftermarket service manual diagram as one wire to the ignition switch and the second to the analyser tool connector, they don't show on the previously posted diagram in this thread.

Should there be voltage on the twin black wires with the key in the "start" position?

These are part of the sub-harness (not part of the repaired FI harness) that includes the green/brown oil pressure wire and the red/black coil/hot wire that goes back up over the booster snout and into the cabin.


(original setup shown, car ran great)

I had a thread around here not too long ago asking about some "spare" wires down by the solenoid that were not connected. to anything I'll see if I can find it as it identifies some more of the original setup.

I also found this picture of the original FI harness with the twin white/red connector but I can't find it in the new harness. You can also see the eyelet connector for the red wire and the "second" red wire too. I'm going to pull this section of harness back out and recheck everything as the red/twin white wire may be hiding up under the manifold where I can't see it. (I've been hesitating to do this because it's such a PITA to pull the connectors thru that little hole in the manifold support.)

So if I understand you correctly, I should have the twin black wires plugged into the red/twin white connector (or what ever it is now) and the red spaded wire plugged into the 6:00 position on the solenoid. Do you have another wiring diagram that shows this? I've now found several "interpertations" of D-Jet harnesses that have some significant differences

I wonder how the car ran with the twin black wires on the 6:00 solenoid position? Is it possible I may have a non-stock solenoid? :confused:

 

[Bwana]

Hi Bwana- can you do a test for me?

With the key in the off position would you test the coil for DC voltage? (12 volts)

Test for voltage at either connection of the coil.

If you have 12 volts at the coil with the key off- please disconnect the black/red wire at the starter and test for voltage at the coil again

Let me know...

Yes, will do this tonight after work. I'll also check to see what shows up on the twin black wires in both the "start" and "run" positions.

Thanks for the help.

Stand by!

 

[sfdon]

It's possible to have anything 40 years...
I have 2 csi's here in my shop.

 

[sfdon]

Let's see if I can explain this- (after a long phone call with Mr. Srennoc)

The black wire comes from the ignition switch and goes to the spade connector in the yellow/ brown/clear rectangular connector. There are two wires at this point because it twins off to the diagnostic plug.
This connects to the spade connector with the big red wire and the two white wires.
One white wire goes to pin 18 at the ecu and one goes to the cold start relay.
That red wire goes about 5 inches and connects to the starter at 6:00.
Now you know about 2 whites, 2 blacks, 2 reds.
The last red is simply battery power to the main relay from the starter.

Why BMW went from red to black to another black to red connecting to white and to starter is beyond me. God love the Germans....

 

[Bwana]

OK, I thinkI've got it. Odd how it ran OK before but I'll check the wiring per the above when i get a chance (work and Christmas are backing up my diagnostic time).

I did the voltage check at lunch and no volts at the coil with the key "off". Didn't have a chance to check for voltage at the twin black wires, on the "to do" list.

Thanks again, this is world of help!

 

[sfdon]

The black wire the starter wire- it will start the car. But it doesn't go to the starter directly

 

[Bwana]

The black wire the starter wire- it will start the car. But it doesn't go to the starter directly

Yes, the car starts fine! The problem is it won't shut off! I can turn the key to "off" and remove it and the engine continues to run. I have to disconnect the battery to make it stop. If I go to the "start" position (crank the engine but don't actually start it), the idiot lights come on and stay on even after I turn the key to "off". Then they are off after I re-connect the battery.

Is this a relay or wiring problem?

 

[sfdon]

Wire it right and then find the problem.
testing a relay when the wires aren't connected is meaningless.
Connect the two black wires to the red wire with 2 small white wires
Connect the red wire with spade to the starter at 6:00

You tested the black/red wire with the key off.
Now test pin 87 of the main relay with key off.
Then start the car, measure 87 again and turn key off and
measure one more time.
Let us know.
Do you have a spare main relay?
There are 3 wires that can backfeed your electric circuit to keep the car running

 

[Bwana]

Stand By

Officially delayed by work and Christmas. Have to stop work on it for about two weeks.

Thanks a bunch Don, I'm sure I can sort it out now. I'll report back when I do.

 

[Bwana]

I'm Baaack!!!

And now with DATA!!

I went over the previous suggestions from Don and finally did some experimenting and data collection. Here are the readings from the "original" configuration. You can see what the "before" wiring looks like in post #103 above. The pin number corresponds to the pin on the master relay. Numbers are VDC

The engine, as usual, continued to run after I shut off and removed the key. I had to disconnect the battery to make it stop. The red generator light on the dashboard glowed faintly. Oddly, the engine did not stop immediately on removing the battery wire, it motored on for 2-3 seconds more but it was NOT dieseling. It was really smooth.

I then rewired the harness per Don's suggestion in post #110 above with the paired black wires connected to the red/wt/wt and the loose red wire connected to the 6:00 spade point on the solenoid. It fired right up and ran smoothly with these readings

These are essentially the same with a little better charge on the battery (I think). So there appears to be no difference between the two wiring configurations and the engine still does not stop when the key is turned to the "off" position. It also ran on for 3-4 seconds smoothly, to the extent I started to panic and wondered if I might have to ground the coil to stop it!

It appears that the coil in the master relay does not drop out when the key is shut off. It is fed power via pin #86.

The only difference between the engine running properly before and now is the re-worked FI harness. Possibly Carl did something different without meaning to? Is there some way to check the harness to verify it is correct?

I guess the question is: How can power be fed to pin #86 after the key is turned off and is this the actual problem?

 

[sfdon]

Let's try this...
Remove the green wire that comes from the ignition switch from its spade connector at the fuse box.
Attach a length of wire to that same connector and hook it up to the battery positive.
Start the car.
After running for 10 seconds, disconnect that wire from its battery source.
If the engine stops- your switch is faulty.

 

[sfdon]

Now try this- disconnect the black/red wire from the starter
Start the car, after 10 seconds turn key off

 

[sfdon]

Question- did you replace your main relay yet?

 

[Bwana]

Roger! Thanks Don, I'll try both tonight.

Although I still think it may be something inside the "new" harness as that's all that has been changed lately. I did find the two white wires in the red/wt/wt bundle had broken their insulation where they left the main harness. Had to peel back the outer cover and retape and insulate. Apparently missed in the original repair work. I'll have to study the schematic but are there two wires inside the harness that could be rubbing together that would cause this?

Is the harness outer casing really stiff or is mine just old? I had to use a pair of dykes to cut it back.

 

[Bwana]

No main relay replacement. I can't find one on the 'net and haven't yet check a couple of local suppliers. Did my test earlier show that it may be bad?

 

[sfdon]

And last interesting guess is your fuel pump relay is stuck on which will supply power to the coil and keep the car running.

 

[sfdon]

Have to ask- did you ever have a 745i turbo?

 

[Bwana]

Have to ask- did you ever have a 745i turbo?

No, but I did speak to you once about the difference between an M102 and an M106 from a 745i. I picked up the M102 from a forum mamber in Farmington. Planning on eventually grafting it into this stylish Bav

I've gotten a little ahead of myself with it as it's in New Mexico right now in my new shop I haven't finished and only visit on an irregular basis

So someday for sure.

But back on topic. I did the test of removing the red/black wire from the 12:00 position and the engine continued to run after the key was shut off so no luck there.

I'm not sure how to check the fuel pump relay. I suppose I can measure the voltage on the wire to the main relay, I'll try that tonight.

Which is the "green" wire from the ignition switch? I took a photo of the wiring harness under the dash but can't upload it right now. The only candidate appears to be a black wire with green spots, at the top of the connector block. Does that sound like the correct one?

I'm still leaning towards someting being wrong with the harness repair but haven't had the time to figure out the diagram yet......