E 28 problems

["Polands" <polands@xxxxxxxxxxxx>]

James H. BOYD III wrote about intermittent ignition on his E28.

James,
I've had identical symptoms recently, from two different causes.

In one instance it was caused by a loose ground strap, the one between
the rear of the head and the firewall "for continuity from the
injectors" I was told.

The other was apparently oxydized main relay spade contacts, because
vigourous wiggling, removal and reinsertion was the end of the problem.
I did go buy a new relay, but it's still uninstalled in the trunk.

Hope your problem is this simple to fix.
Steve Poland
'88 535is, 208,000 miles
Portland, OR
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Original message:
Hello all,
I have an 87 535is and 2 days ago, it began to do this unusual thing.
As
I was driving, it would suddenly act as if the spark had been killed,
and
then as suddenly as it had been killed, it would start again and it
would
continue running.  Overall running characteristics are unchanged.  It is
as if I turned the key off, and then turned the key on again just before
the engine completely stopped turning over, so that it would continue
running without having to start it with the key again.  It is not the
idle-control valve or control unit since it has also happened as I
accelerate onto the freeway.  I took the ecu out last night and all of
the solders look good.  The one or two that were even questionable, I
resoldered without effecting any change in this problem.  Usually, the
igition will "come on" again before the engine dies, but it has also
completely died twice in the last two days.  It starts imediately
however.  The primary and secondary resistence of my coil checked out.
The plug wires have roughtly the same resistence plus or minus 1 k ohm
(5.5-6.5k ohm).  Since it cuts off and on so quickly, it sounds more
like
ignition than fuel.  Do ignition switches ever go bad or is there a
relay
that might control it, or is there a bad component in my ECU/Motronic
brain.

Any suggestions would be greatly appreciated,

James Boyd

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