March 1984 733 USA Model, Automatic.
It has the Siemens DME with two harness connectors, one yellow, the other black. The black one does not use all the connections.
Bentley only shows the tests for the Bosch DME with a single connector with 36 terminals. Perhaps they only used the Siemens DME in the 7 series?
Also, was the Siemens DME problematic? Mine has a little residue/slight corrosion on the outside but looks clean and new on the inside. It also has a removable chip. The car runs but has serious drivability issues. I think I have eliminated everything except the DME and harness.
Any help with the information or a link is much appreciated.
John aka Kenneth
1984 733 125K
1991 735 IL 190K
That Siemens is for the OBC1 as I recall. Passenger speaker area.
Engine ECU is by Bosch, ends in 008. Guy on mye28 is selling one with a Korman chip for $200 as i recall.
I make E23 parts.
09/1983 745i (stolen spring '13 around Houston, TX Achatgruen on nutria buffalo. 8481080)
10/1984 745i
11/1984 745i
11/1984 735i (10:1-265/6)
Ford, MB, and GM round out the pack.
I certainly messed up on that post! OBC worked fine! Thanks for putting me straight Hit Man X
Hey, I could be wrong. I have not operated an OBC1 car in about a decade.
I make E23 parts.
09/1983 745i (stolen spring '13 around Houston, TX Achatgruen on nutria buffalo. 8481080)
10/1984 745i
11/1984 745i
11/1984 735i (10:1-265/6)
Ford, MB, and GM round out the pack.
I've owned and worked on a number of big 6's over the last 25 + years and seems like I get them mixed up, probably old age too!
I was sure I had a spare DME/ECU for this car, I do and they both work, when I found it behind the passenger (right) speaker panel.
Something strange though, now the car runs different, still runs bad but different.
I have been working on this on-and-off for at least a year. Starts, idles very rough and very rich (plugs are black). Was running smooth at about 2000 RPM
With no load, then wouldn't accelerate much beyond that, misfire and popping and spitting back over 2200, my guess, now too lean (plugs are clean)
Seems like signal to injectors regulating fuel delivery is not responding to engine speed or load. But everything checks out according to Bentley.
Now, with either Bosch DME, runs the same at idle but will now run smooth from 2000 to 3000! And I don't know what caused the change.
The OBC module? probably not, only significant thing it does as far as I know is supplies power to main relay.
Changing the DME, no, both run the same. Messing with the harness? possible I suppose, tried jiggling it while running, didn't make any difference.
I have a theory it could be due to dampness. Unfortunately the car is outside. Like most/all E23s it leaks, despite best efforts to stop it.
Driver's side carpet is often wet. Electrical components look OK inside but I had a problem in the past in very wet weather when Alarm would sound when you tried to start the car!! Only remedy was to dry everything with hairdryer or portable heater, then it would run fine! no, I'm not kidding!
To get to my point. Weather here in coastal Carolina has been hot and dry, almost drought so, for once, everything inside the BMW is dry and for the first time in about a year it runs different. Don't know if it's a clue or not, I sure could use one.
Is your car white? I've only seen 2 other e23's around here.
Kind of a light metallic beige color, car has been around the area for years but last time on the road at least a year ago, probably more, I just puttered around town in it and don't think I ventured over the bridge. There have been a few old 7's over the years, really nice maroon one. Also a black 735 in Pick-n-Pull on 421 last year, very straight and original, I almost cried as I took some parts off it. Didn't last long there. Another old post above this one with an update on my car. Still battling with it and no closer to a solution.
Have you looked at the crank sensors? If they are cracked, moisture gets in them and your car will run like crap. Happened to me a few years back.
They look OK but the top connections are crumbling. I have a better pair that came off the car at Pick-N-Pull which I will put on as time permits.
I don't know how familiar you are with this area but here is what happened. I was on Wrightsville and took Wallace to Oleander. The traffic is busy so I accelerated hard then turned left at Pine Grove and cut behind Hugh McCrae Park. The car was running fine at the red light where Shipyard meets College. The next light on Shipyard is at Hoggard High School, it's only about 1/4 mile. When I stopped at that light the car was running very badly, almost stalled and the rest is documented on these posts.
Strange thing is it happened so suddenly.
I have been down a lot of rabbit trails. I thought it was an idle problem for a long time but now I'm not sure the root cause is the idle.
I am planning to go back over the list and re-check everything and your suggestion about the sensors is a good place to start. Thanks, John Kenneth
FAE new crank sensors are like $30/ea at Pelican. I would not dick with a used set unless for emergency use.
Check for missing teeth on the flexplate, we have not been down that hole yet. This will change input to the Speed sensor. Also, that the reference marker is in good shape. Did you have trans out recently?
What FPR is on there, a 3.0 right?
Are you sure that AFM is correct for your 008 ECU? Pop the cap next time at idle and check the wiper position, no telling how loose the spring is on it. The car was in the JY after all.
Pin out the harness for continuity.
That single wire O2 on there should not cause much to occur at idle as it is not heated.
I make E23 parts.
09/1983 745i (stolen spring '13 around Houston, TX Achatgruen on nutria buffalo. 8481080)
10/1984 745i
11/1984 745i
11/1984 735i (10:1-265/6)
Ford, MB, and GM round out the pack.
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