From digest.v6.n721 Mon Jun 2 11:56:19 1997
From: David E Hall <dehall_at_ecn.purdue.edu>
Date: Mon, 2 Jun 1997 10:39:48 -0500 (EST)
Subject: Re: M50 cracked coils symptoms?

I haven't seen a response yet (although I get my digests about 2 days late), so I thought I'd contribute my $.02. The first batch of coils on our '92 325i went bad on our way south to visit the in-laws. When getting on the on ramp to the interstate the car severely hesitated between 1000 and 3300 RPM. Above those engine speeds, there was no noticeable difference in performance. We drove on to Louisville, and the dealer replaced 3 of the 6 coils.

The second occasion occurred when the dealer did an eprom update that mysteriously took out the DME. (Side note: this experience prevented me from ever putting an after market chip in--I don't mind when the dealer blows out the DME under warranty, but I sure wouldn't want to be stuck with the bill!) When they replaced the DME, the same hesitation from the first set letting go reappeared. (I was disgusted that the dealer had not noticed the hesitation before I showed up to pick the car up. The result was that we got a loaner 318 that we had to drive to PA for a wedding.)

You can check the health of your coils by checking the resistance between two terminals on the coil. This is outlined in Chilton's (which I don't have handy--e-mail if you want details.) The rough idle you're experiencing is most likely normal. The early M50's have a terribly rough idle for a $30K+ car. I believe it was the venerable Jim C. that mentioned the low idle surge might be due to the air mass flow sensor, but I don't recall the details.

The entire experience with our '92 E36 lead us to sell the car and vow never to buy a first year BMW production model or engine again. Even after our experience, though, the next car will be an M3 sedan. I guess it's one of those love-hate relationships.

>
> From: Don Eilenberger <deilenberger_at_monmouth.com>
> Date: Fri, 30 May 1997 11:44:01 -0400
> Subject: M50 cracked coils symptoms?
>
> Given that I have this nice $0.00 deductable warranty, and that
> there has been discussion on the eventual (not when) cracking of
> the original coils installed in the early M50 engines (mine is a '92)..
>
> Wadda the symptoms? Last week, after the car sat for a day (was using
> the real BMW - two wheels!), and after it had rained.. for a short
> period of time after starting the car (mebbe 5 minutes), I noticed
> surging at low speeds - with the MPG meter dropping to 0 rather
> rythmically.. seems like all the symptoms of cracked coils with a bit
> of dampness to cause them to misfire. Also - the car doesn't idle as
> smoothly as it did when I bought it (where it got a Service-II, including
> new plugs).
>
> Your symptoms were?
>
> TIA!
>
>
> ==================================
> Don Eilenberger, Spring Lk Hts, NJ
> deilenberger_at_monmouth.com
> ==================================
>

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