'89 560SL no start - PeachParts Mercedes-Benz Forum

rjk · #1 05-22-2011, 06:27 PM

Also posted in SL Forum

No spark.

So I went to the pull-a-part this morning & snagged a couple of Ign modules & a coil. Got them out of a 560SEL & a 420SEL, the only 2 on the lot. Numbers are not an exact match.

Swapped in the coil w/old module - no joy.

Swapped in a module & it starts right up. Joy.

Shut down right away & came in to post this.

How critical are module p/n's?

First, I do not know for sure but suspect the current module IS NOT original. P/N is BOSCH 0 227 400 695/MZB 0 410 545 67 32 (03), it has worked for years. I suspect it was a heat failure because the heat sink goo did not look to be making good contact; many ripples due, I think, to a missing hold-down bolt.

The unit I got out of the 560SEL is BOSCH 0 227 400 624/MZB 004 545 53 32.

The 420 SEL is a SIEMENS 5WK6 114/MZB 004 545 55 32.

So I figure the best match is the BOSCH unit from the 560SEL but am looking for trouble or just being overly cautious?

I see parts distributors list the BOSCH 0 227 400 695 (same # as the bad unit I just removed) as the replacement for all years/models of 560's & a BOSCH 0 227 400 693 as the replacement for a 420. So I surmise something is different (mappings maybe?) & I should avoid the module from the 420.

Would I be correct in assuming the different #'s (695 vs 624) from the 560SEL are just an older variant? Although I do not trust ebay, both are listed as 560SL replacements there.

Anyone want to chime in?

Pili380SL · #2 05-22-2011, 06:41 PM

According to EPC, there are several number changes but 004 545 53 32 is one of them, so that one you installed should be the right one.

rjk · #3 05-22-2011, 07:43 PM

Thanks, it is in and showing no signs of rejection, the patient lives!

I need to look at the alternator waveforms to see if there are any spikes which could have killed the other. Do that tonight. Still think it was heat however.