new to BMW's

[fisch325is]

I just bought my 16 yr old son his first car a 88 325is. He loves the 5 speed,
handeling, classic styling, the whole German feeling. Then all a sudden, the car starts bucking missing whatever. We buy the Bentley manual and start reading. With 152k miles and all mechanical documentation stopping at 98k we started with replacing plugs, wires,cap, rotor, filters and checking the timing. Still runs like sh..
Took it to our mechanic, he admits he's not having much experience with BMW's. He said the # 2-4-6 cylinders aren't getting the ground signal fron the Motronic unit.
We try our motronic unit in my freinds 89 and it runs perfect. We would appreciate
any help. thanks ghead

[BMWJNKY]

Well since you got the car to run perfect with the other Motornic it sounds like the Motronic in your car has gone bad. Unless you have excelent sodiering skills and feel confident sodering on a printed circuit board I would sugest getting a new/rebuilt Motronic. Also when buying a replacement Motronic make sure all the serial and part numbers match otherwise you may run into mysterious eletrical problems that seem to come and go. BMW used 3 or 4 different Motronics in the E30's so it is imparative that you get the correct one.

[fisch325is]

I must clarify this. I put my motronic unit in my friends car. Our unit works fine in his car. That elimiates a motronic unit problem. Has to be something else. Please keep thinking. thanks

[Aether]

Well given the nature of AJ's post, is it possible that your Motronic unit isn't the proper model for your engine? Maybe your friend's car has the matching serial numbers, and you don't.

[witeshark]

Have you checked the spark plugs in the miss firing cylinders?

[fisch325is]

The # 2-4-6 plugs have a gray color, not white or tan. Plugs 1-3-5 are totally carbon fouled black. The car will run. The idle is extremely rough with the fuel milage gauge bouncing to either extreme. It feels like its running on 3 cylinders. What should I check next?

[witeshark]

If new spark plugs don't help, the distributor and ignition system might need a look

[fisch325is]

Mystery solved. One of the wire connectos that goes to the fuel injectors was really coroded. I cut out the connector, soidered the wires together and used heat shrink tubing. I found a guy with the same problem on unofficialbmw.com. Thanks