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Discussion Starter #1 (Edited)
Hi all,

(E34 525i 1995, M50TU25, AUTO)

Need advice about the coils,

Symptoms:

- Idle is fine.
- Engine occasionally starts then die, starts again then idle.
- Random misfire: at acceleration, hill climbing (almost die), while driving shaking for seconds then misfire.
- Higher than average fuel consumption.


Checked vacuum lines for leaks (things seems to be fine), then wanted to check sparks and I found the following:

- Boots (Sockets): No. 1 cracked at the end, No. 2 to 6 no cracks but only heat damage near ends, some with oil in well and some looked brownish inside.
- Spark Plugs: as in photo.
- Coil Packs: ohm resistance 1.2 for all, No.1 cracked near plug terminal.



I believe that I've to do the following:

1. Replace Valve Cover Gasket set.
2. Replace Coil Boots (Sockets).
3. Replace the Sparks (Already I've OEM BMW-BOSCH).

My Doubt is the Coil Pack, Shall be replaced or not???

I appreciate if you check photos and give the advice..

Thanks in advance,,,
 

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Humble E34 lover
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5,515 Posts
I think you are on the right track. I would replace any cracked coils as well. Heck, if this is your daily driver and you plan to keep it a while, I would go ahead and replace all of the coils.
 

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Transplanted JrzyBoy
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226 Posts
From replacing everything from hoses to ICV valve and more...

I just finished answering a post on this very issue that was unbelievably vexing...and yes, it turned out to be the coil. I have a 1991 525i, M50. To make a long story short, I had a low speed miss and pulled the coils. One was a BAV AUTO coil that looked an awful lot like a Bremi, but private labeled. I could see where it was arcing to the head. Replace it, and some improvement. After removing the manifold to clean the ICV and reversing procedure, a job in and of itself, complete with 2 cracked hoses, one broken connector from the ICV to the manifold and a bear to reach, and a cracked MAF-throtle body boot, problem still there. So, back to the drawing board. Coil inspection (plus plugs), this time a bit closer showed a hairline crack in the coil. Replaced that. Incrementally better but... Still a miss. BTW, all the coils bench tested "OK". A search of the forums suggested changing out the coils one at a time with a known good one. What the heck did I have to lose? So with a known good coil, I used a paint pen, marked it with the letter "T", then put a number 1-6 on the rest and changed them one at a time on a short trip I took. Easy job if you have a drill with a chuck and a 10 mm 1/4" bit. Changed everyone and damned if it wasn't number 6! Isn't it always like that. Always the last one. Left the "T" or "test" coil in and car purrs like a 236,000 mile kitten. Mileage went up from 14.7 to 19.1 (new air filter probably helped a bit). Oh, and I had to disassemble the manifold again to replace the ICV--the one I cleaned probably wasn't working and since I had to pull the manifold off, I replaced the original octopus heater hose. Job and a half if you ever have to take off the intake manifold. Take LOTS of pictures just to get the hose routing and wires straight. Bremi or Bosch? I had a tech bulletin for defective coils from Bosch supplier "May & Christ" with the words ZUNDSPULE. If production date is prior to 91 M 01, i.e. January 1991, don't use them. One of the failed coils I had was a Zundspule with the BMW logo on it. Dunno which to recommend, but I now get mine out of the junkyard for 10 bucks a pop. Well worth it to have a spare. Hope this helps
 

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Discussion Starter #7
(Eyedoc1) many thanks for sharing tyour experience...

So far the only available here is the BREMI (new for 23$ each)...
The man at shop say they are original germany but I feel they are counterfeit...
If ordered new bosch set oniline they will cost me around (480$!!!!)..
So I will keep searching to find other option...

Thanks again

Sent from my E5803 using Bimmerfest mobile app
 

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Transplanted JrzyBoy
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226 Posts
This is just a guess but...

At some point in time, coils that sit on shelves generate no profit and suppliers will just discount them to clear inventory. I buy stuff from Rock Auto at times, and since I own some cars from the '60's and '80's, I get emails with cheap cheap prices on stuff that they're practically giving away and my sense is they're just moving inventory, since it costs money to store it, shelve it, light it, keep it dry, secure it, and pay rent on it. If you looked at my coils under the plastic, you'd find 2 BavAuto's, 2 Bremi's, 1 Bosch and 1 no name. Car runs great, now. Bremi's at 23 bucks a pop I'd take a flyer on in a New York minute vs a Bosch at 80 bucks a pop. Heck, you'd get almost 4 Bremi's to 1 Bosch. I'd take that Math challenge. I think my BavAuto coils had a 2 year warranty, so whaddya got to lose? Do the math brother. Besides, with the money you save, you can get a new air filter, PCV valve, replace some hoses, and have some cash in an envelope for when the radiator or radio goes...and they WILL go. Good luck with your project.
 

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Transplanted JrzyBoy
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226 Posts
Holy sweet Mother of Mary!

You're in Oman? Like the county of Oman? If you are, WOW. Just wondering if you had a heavily modified European version for the Middle East's specific conditions or just a standard European unit with German style lighting (which I prefer). How very cool. I thought getting questions from guys in New Zealand or Russia or Africa (Kenya) was interesting due to climate or road condition, but this is my first Middle East commentary. I looked at the pictures, and I assume you were tracking down a miss. That someone put the number "1" on the coil may indicate someone was doing the old switcheroo to try and track down which coil was bad, given that the Check Engine light was of no help when it came to a bad coil, at least on my 1991 525i E34 unit. And that coil looks like it's seen better days. I replaced my original coils with BavAuto coils in April of 2010, and they've lasted what, 7-8 years. And I paid $247 USD for all 6 with free shipping. Good luck with the rig. Oh, and the coil that was bad was a Zundspule. I think they are a BMW OEM supplier like Robert Bosch.
 

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Registered
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Discussion Starter #10
You're in Oman? Like the county of Oman? If you are, WOW. Just wondering if you had a heavily modified European version for the Middle East's specific conditions or just a standard European unit with German style lighting (which I prefer). How very cool. I thought getting questions from guys in New Zealand or Russia or Africa (Kenya) was interesting due to climate or road condition, but this is my first Middle East commentary. I looked at the pictures, and I assume you were tracking down a miss. That someone put the number "1" on the coil may indicate someone was doing the old switcheroo to try and track down which coil was bad, given that the Check Engine light was of no help when it came to a bad coil, at least on my 1991 525i E34 unit. And that coil looks like it's seen better days. I replaced my original coils with BavAuto coils in April of 2010, and they've lasted what, 7-8 years. And I paid $247 USD for all 6 with free shipping. Good luck with the rig. Oh, and the coil that was bad was a Zundspule. I think they are a BMW OEM supplier like Robert Bosch.
Greeting from Oman,,,,

Many thanks for the reply, yes It's Oman the county...

Mine is not the middle east version, it was imported from japan (national ver.).

Your words helped me to take the decision and I'll go for new Bremi set.

Thanks again

Sent from my E5803 using Bimmerfest mobile app
 
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