E28 Wont Start - No Spark

[Jimmy535i]

My friends 535i (e28) won't start.

(1) Car cranks over fine. Plenty of juice in battery.
(2) Fuel pump is working and engine is getting fuel.
(3) Airflow meter is working.

I removed spark plug and plug does "not" fire.

(4) I am guessing cap and rotor as next to look at.

Can anyone help?

[mrbmw1]

i would chech the pick up sensor

[MarkD]

A few years ago I posted a fix for this on a few boards. (when the problem is cold solder joints on the leads to the ignition coil driver transistor). Someone made a detailed repair guide from the info, which you can find here:

http://members.roadfly.com/louielouie/dme_fix.html

Even on DME's which are working, you will almost always find the connections to the ignition coil transistor are failing. Two people came over last week with E28's (for chips) and they both had the problem, but not yet to the point that they noticed more than a rough idle.

Mark

[Jimmy535i]

Thank you, I have a running E28 same year.
What is procedure for swapping out the ECU.

[Jimmy535i]

The car is a 1988 535is

I have a running 1988 535i so I have parts that I can swap.

Here is a list of the parts that I have confirmed to be ok:

1) Replaced Bosche Cap and Rotor with new from BMA.

2) Swapped Coil and Motronic.

Car still wont start.

I have removed the Crank Positon Sensor but I am not sure if this
is going to solve this issue.

The car has plenty of cranking power and the fuel pump is working.

Is it possible the coil is not getting 12 volts from the battery?

Any help would be great.

[George M]

Mark...have you seen similar solder failures on '89-92 E-34/E-32 big six DME's as well?
Thanks,
George

[Jimmy535i]

This 535is has a "Crank Position Sensor" which is in the front of the engine that has three wires to the diagnostic port. It also has a sensor near the back of the engine. See attached picture.

[Mr Project]

I'm curious if this solder issue would effect an earlier 533i E28. Does the DME for those earlier cars run the coil the same way?

[Reidal]

Hi, I know this sounds a little off beat, but I have had a battery create this kind of problem in the past in a Japanese car I had 20 years ago.

Good cranking speed, but no spark or hint of ignition.

Charge the battery for 15 minutes and away it went. Had a discharge test done on the battery and found the current flowed ok but the voltage was below par.

Replaced the battery and all was ok.

just a thought.

[Jimmy535i]

Hi, I know this sounds a little off beat, but I have had a battery create this kind of problem in the past in a Japanese car I had 20 years ago.

Good cranking speed, but no spark or hint of ignition.

Charge the battery for 15 minutes and away it went. Had a discharge test done on the battery and found the current flowed ok but the voltage was below par.

Replaced the battery and all was ok.
just a thought.

Thanks for the idea. I did check voltage to the coil and it was ok.