D-Jetronic Rebuild

[sfdon]

4 big wires come from ignition switch and connect to fuse box.
Red
Violet
Black
Green

Disco the big green from fuse box and run a home run wire to battery at same spade connector

 

[Bwana]

Done!

I found and disconnected the big green wire from the key harness and made a straight run to the battery from the same spade connector. When I touched the jumper to the battery, the dash lights came on, I could hear a couple of relays pull in and I think the fuel pump came on. When I disconnected the jumper from the battery, the dash lighs remained on (I couldn't tell about the relays but I didn't hear anything like them dropping out). I didn't start the engine as I wasn't positive I was doing the right thing and didn't want to fry something. But it acted exactly the same as before with the key switch.

So it looks like the key switch is good. The power must be being fed from someplace else. Again, I suspect the "new" harness but am not familiar enough enough with the internals to be able to guess how it might be cross wired.

This is getting frustrating. Thanks again for your patience Don. Maybe we can post this thread in the "tech" section when we figure it out.

Suggestions?

Seems like a next step might be to wire around sections of the harness (not unlike I just wired around the key) that might be suspect and leave that section of harness disconnected. But it would have to be not thru the ECU. Have to think about this.....

 

[sfdon]

Did you disconnect the black/ red wire at the starter?
Do you have a big stereo with capacitor ?
Pull your horn relay now and retest.

 

[sfdon]

Do you want to borrow a main relay?

 

[sfdon]

I could also send you a diode. That will prove up the location of the back feed.

 

[Bwana]

Back at it....

Did you disconnect the black/ red wire at the starter?
Do you have a big stereo with capacitor ?
Pull your horn relay now and retest.

Yes, I did this before back on post #110 with the same results. Do you mean I should try disconnecting the red/black wire with the green wire home run to the battery connected?

No stereo with capacitor. Just a normal power Becker

Do you want to borrow a main relay?

Yes, check your PM's

I could also send you a diode. That will prove up the location of the back feed.

That would be good too. Send it with the relay? Or if you give me the specfications I might be able to get one locally. Then where to put it.

Pictures of your wiring would be helpful too.

Sigh....

 

[Stevehose]

Are you driving your car to Amelia this year? No last minute adjustments this time!

I found and disconnected the big green wire from the key harness and made a straight run to the battery from the same spade connector. When I touched the jumper to the battery, the dash lights came on, I could hear a couple of relays pull in and I think the fuel pump came on. When I disconnected the jumper from the battery, the dash lighs remained on (I couldn't tell about the relays but I didn't hear anything like them dropping out). I didn't start the engine as I wasn't positive I was doing the right thing and didn't want to fry something. But it acted exactly the same as before with the key switch.

So it looks like the key switch is good. The power must be being fed from someplace else. Again, I suspect the "new" harness but am not familiar enough enough with the internals to be able to guess how it might be cross wired.

This is getting frustrating. Thanks again for your patience Don. Maybe we can post this thread in the "tech" section when we figure it out.

Suggestions?

Seems like a next step might be to wire around sections of the harness (not unlike I just wired around the key) that might be suspect and leave that section of harness disconnected. But it would have to be not thru the ECU. Have to think about this.....

 

[Bwana]

^^^^^LOL^^^^:lol:

And my e39 is down for cam chain guides too so no emergency backup!

We weren't planning on going this year anyway. We're off to Pebble Beach in August so I'm flat out of vacation time. I could spend more than two months of BMW show time this year without even trying. I need to retire!

 

[Bwana]

Runs AND stops

OK, for those of you that are following this, break out your FI wiring diagram. I disconnected the wire from the main resistor (item #20) that goes to the main relay (item #9) terminal 86 (the relay's power coil). I then turn the key and the dash lighs come on, the fuel pump relay switches, I can start the engine, it runs smoothly, and shuts off when I turn off the key. The car operates exactly as it should.

This wire, I think, is the one that energises the coil on the main relay that powers up the whole system. So if I disconnect it, there should be no power to activate anything.

WTF???

I guess the next step is to figure out where I'm getting voltage to this main relay coil when it's not plugged in.

 

[Christopher]

Have you checked the connection between the FI harness and the main loom ?

At the 3 way plastic connector block i've got the following

3 black wires from loom (left connector) to 2 white wires FI harness
1 green wire from loom (middle connector) to 1 white
3 green wires from loom (right connector) to no wire

 

[sfdon]

Sounds right- 2 battery positives to pin 86.
Kill one and the other is still connected.

 

[Bwana]

Have you checked the connection between the FI harness and the main loom ?

At the 3 way plastic connector block i've got the following

3 black wires from loom (left connector) to 2 white wires FI harness
1 green wire from loom (middle connector) to 1 white
3 green wires from loom (right connector) to no wire

We must have different setups. Mine is a multipin connector on the front right frame rail, wired directly to the ECU from there

 

[Bwana]

Sounds right- 2 battery positives to pin 86.
Kill one and the other is still connected.

Yes, exactly the conclusion I finally arrived at too. Now the trick is to find the other one.

 

[Bwana]

The rest of the saga...

Well, just found a $400 jumper wire :cry: After several weeks of on again, off again troubleshooting I finally gave up and took the car to my super tech who had originally found the problem with the ECU.

As usual, Don was heading in the right direction. A lot can happen in 44 years. This was in the fuel pump relay under the back seat (I forgot to ask my tech which pins were jumpered). The PO had installed it there for reasons that are lost to history. When Carl (Tony) rebuilt the harness against a known factory harness, they must have inadvertenly repaired what ever problem was there that prompted the PO to do this. So with a correct factory harness, this is no longer necessary. Took my tech several hours to find it. We had both been in there before because of the ECU problem but this wire was so tucked up in there, neither of us saw it.

I finally have my car back and it's running great! :-D

 

[adawil2002]

Glad it was found, sorry it cost so much.

I'd been having trouble with Athena. VSR found I had a bad MAP sensor. They also found while working the new seat belts an always live wire in the trunk that had grounded to the rear quarter panel. It was a shocking discovery for the poor mechanic to say the least. The wire was traced to the radio. Very lucky the car didn't catch fire over the years.

 

[Bwana]

So the saga continues but happily this time. Made it over and back to Pebble Beach with no issues. 5200 miles with A/C and 75 MPH!

Picked up a complete D-Jet system from a fellow forum member and have been going thru it to renew it for possible spare parts. Got the MAP sensor, ECU, and cold start injector checked out by Fuel injection Corp in Tracy, CA, all's good now. Been going thru the rest of the system and cleaned up the water piping to the cold start circuit. Ended up with a pin hole under the corrosion:

Cleaned up with media blast

You can just barely see the pin hole down inside the pipe

The pipe itself is pretty cool workmanship. Looks like the various pieces were hand brazed together. You can see the gold colored braze material in the pics. So the question is:
1) Do I try to braze up the corroded areas to make the pipe usable again or
2) Toss it and not bother because there's a bunch of these pipes out there, i.e., is this a common or rare part?

 

[adawil2002]

I had a new water return pipe made out of stainless. Worth a call to VSR for a new one.

 

[Bwana]

What did you do about the NLA air filter for the cold start circuit?

 

[adawil2002]

I used the aluminum case from the aux air slide and a small air filter from Advance Auto Parts and slid the filter in and peened the edges of the case to hold it in place.

 

[Bwana]

More updates and info. For those of you who haven't seen the inside of a D-Jet, here it is. Sort of a Heathkit project

Does anybody know what the dark thing is on the lower left. Sort of has tabs?

It has a number at the other end that changes some between units (7 to 8) but the guy at Fuel Injection Corp didn't think it mattered, just the Bosch part number on the outside. This may be a subassembly number.

And what are these items? This one looks like a water temperature sender, which probe is for the gauge and which is for the D-Jet? There are two probes in one housing, one at the top, one at the left side.

This is the extra air for the cold start, correct?

What is this?

My car was idling roughly and it would stall with the A/C on when I came to a stop. Long story short, adjust valves, plug gap (.28), new rebuilt D-Jet ECU (FI Corp), lots of fooling around with adjustments and it works brilliantly now. Pulls from 1500 RPM where it used to have to get to 3500 to do anything. Yeee haaa