Ignition problem on 500SL

[Optimist]

I have an '88 500SL 107 series, which has no spark and will not start. The problem was intermittent for a short while but is now permanent.

From reading other posts on this board, it would seem that the most likely culprits are the crank sensor or the ECU.

Can anyone tell me:

1. Where is the crank sensor and how do I check it?

2. I have an ECU unit off another car (6 Cyl), which has the same connections but a different, part number. Can I test my ECU by swapping for this one without damaging anything?

3. Has anyone any other ideas?

Thanks in advance for your help.

 

[Optimist]

ttt

 

[NormanB]

Hi

I doubt if it is ECU.
Do you have an alarm?

NormanB

 

[Optimist]

Thanks for that interesting thought NormanB. I don't think it is the alarm because I never use it and I have power to the coil but I will definitly check it out?

Does anyone know how alarms normally interface with the ignition circuit?

 

[Optimist]

I finally isolated the problem which unfortunately is the Bosch Ignition Control Unit.

MB want £1K plus for this unit which is legalised robbery so I want to repair the existing one or get a second hand one.

Does anyone know how these units work?

I can get a similar but not identical unit on Ebay is it possible to transfer the program chip from one unit to another?

 

[RayHeath]

Send to the ECU Doctor

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=2469955962&category=9895

 

[Optimist]

Thanks very much for that link Ray

I've spoken to them and they are going to have a look at it.