Dead Cylinder- help?!

Guy Braisted

Regular Member
American Zeds
Joined
Jun 23, 2020
Messages
8
Location
Morristown NJ
Model of Z
Z3
Just bought my baby and found out shortly after that cylinder 6 us dead!
Troubleshooting has brought me to the conclusion that the problem is electrical. Either the cylinder 6 plug on coil harness is bad or the trouble goes back to the ECM! Before taking it to the shop I thought I’d ask if there is anything this YouTube mechanic can do to verify my trouble. I have a multimeter but not sure I can test with it for this issue. Also looking for a trustworthy mechanic in the Morristown NJ area?!
Thanks in advance!
 

t-tony

Zorg Expert (II)
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British Zeds
#ZedShed
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Dec 31, 2013
Messages
39,848
Location
Torksey Lock,Lincoln, England
Model of Z
Z4 3.0 Auto
@FRANKIE can you help please?

Hi Guy, welcome from me near Lincoln, UK. Frankie is a member from NJ but I don't know how close he is to recommend a Mechanic.

Tony.

ps. Have you done a compression test one all cylinders? and/or swapped 2 fuel injectors to see if the fault migrates to another cylinder?
 

Guy Braisted

Regular Member
American Zeds
Joined
Jun 23, 2020
Messages
8
Location
Morristown NJ
Model of Z
Z3
@FRANKIE can you help please?

Hi Guy, welcome from me near Lincoln, UK. Frankie is a member from NJ but I don't know how close he is to recommend a Mechanic.

Tony.
@FRANKIE can you help please?

Hi Guy, welcome from me near Lincoln, UK. Frankie is a member from NJ but I don't know how close he is to recommend a Mechanic.

Tony.

ps. Have you done a compression test one all cylinders? and/or swapped 2 fuel injectors to see if the fault migrates to another cylinder?
ps. Have you done a compression test one all cylinders? and/or swapped 2 fuel injectors to see if the fault migrates to another cylinder?
 

NZ00Z3

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New Zealand Zeds
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Dec 9, 2014
Messages
903
Location
Timaru, New Zealand
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3.0L, 2.0L Z3 Roadsters
Welcome to the forum.

So you have purchased a Z3, which one? Telling us helps in solving problems.

Lets get you sorted for life with a Z3.

Look in the resources section of this forum and find the wiring diagrams that match the year of your car.

Have you purchased a good scanner with BMW software yet? I suggest that you do as it will save you money and help in diagnosing problems.

- Foxwell NT530 scanner with BMW software https://www.foxwelltool.com/wholesale/nt520-pro-scanner-with-bmw-software-installed.html

Now to your problem of a dead No 6 cylinder. You need an oscilloscope to back prob the coil harness and check that the "fire" pulse is being sent. You can also check the connections on the engine computer (DME) for cleanliness etc. Sometimes oil or coolant wick up the wires from the sensors to the DME and bridge out pins. Using the multi-meter, you can check the continuity and the insulation of the wires from the coil harness back to the DME.

You haven't said what you did to come to the conclusion that its the coil harness. So I take it that you have done the following:
- The spark plug is clean and the gap is correct.
- There is no oil down the spark plug tube that could short out the spark from the coil
- The bottom boot of the coil is clean and not covered in white deposits.
- You have swapped the coil with another known good cylinder to see if the fault moves with the coil.

Good luck in your fault finding.
 
Last edited:

mwpe

Zorg Guru (IV)
Supporter
Joined
Dec 8, 2011
Messages
3,606
Location
Camberley
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3.0
The first thing to do is swap the number 6 coil pack with one of the others and see if the fault moves. I had this on my E46 and the fault moved with the coil pack. A few minutes to fix.
 

Guy Braisted

Regular Member
American Zeds
Joined
Jun 23, 2020
Messages
8
Location
Morristown NJ
Model of Z
Z3
Swapped coil packs as a first test
Definitely just cylinder 6
Spark plug test does not spark so problem is in the wire to coil
My thinking is to test from ECM before replacing coil harness
Sound right? no need for compression test the way I see it
 

Guy Braisted

Regular Member
American Zeds
Joined
Jun 23, 2020
Messages
8
Location
Morristown NJ
Model of Z
Z3
The first thing to do is swap the number 6 coil pack with one of the others and see if the fault moves. I had this on my E46 and the fault moved with the coil pack. A few minutes to fix.
That would have been nice and easy to have found the fault in a coil pack! Nope
 

Guy Braisted

Regular Member
American Zeds
Joined
Jun 23, 2020
Messages
8
Location
Morristown NJ
Model of Z
Z3
Welcome to the forum.

So you have purchased a Z3, which one? Telling us helps in solving problems.

Lets get you sorted for life with a Z3.

Look in the resources section of this forum and find the wiring diagrams that match the year of your car.

Have you purchased a good scanner with BMW software yet? I suggest that you do as it will save you money and help in diagnosing problems. There are many options, here are two:
- INPA software (free) running on a laptop with special cable (cheap) https://www.bimmerforums.com/forum/...tions-Experiences-Discussions-Experimentation

- Foxwell NT530 scanner with BMW software https://www.foxwelltool.com/wholesale/nt520-pro-scanner-with-bmw-software-installed.html

Now to your problem of a dead No 6 cylinder. You need an oscilloscope to back prob the coil harness and check that the "fire" pulse is being sent. You can also check the connections on the engine computer (DME) for cleanliness etc. Sometimes oil or coolant wick up the wires from the sensors to the DME and bridge out pins. Using the multi-meter, you can check the continuity and the insulation of the wires from the coil harness back to the DME.

You haven't said what you did to come to the conclusion that its the coil harness. So I take it that you have done the following:
- The spark plug is clean and the gap is correct.
- There is no oil down the spark plug tube that could short out the spark from the coil
- The bottom boot of the coil is clean and not covered in white deposits.
- You have swapped the coil with another known good cylinder to see if the fault moves with the coil.

Good luck in your fault finding.
Thanks! It’s a 2.8 with Dinan tune, exhaust and intake(only after market stuff) I posted my trouble shooting journey in the thread. Pretty confident it’s electrical as cylinder 6’s coil does not give spark to plug
 

Guy Braisted

Regular Member
American Zeds
Joined
Jun 23, 2020
Messages
8
Location
Morristown NJ
Model of Z
Z3
The first thing to do is swap the number 6 coil pack with one of the others and see if the fault moves. I had this on my E46 and the fault moved with the coil pack. A few minutes to fix.
Well, I’m very green (Boston Green) in the z3 world and my overall capabilities are very very novice! I am just a musician who bought a sexy sports car! I do want to get educated and get my hands dirty but right now(had the car less than a week) I want to get it fixed the simplest cheapest way. If I can do it myself I’d love to! I was going to just purchase and install a coil harness but wondered if the problem starts behind it
 

mrscalex

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British Zeds
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Jun 10, 2016
Messages
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Swindon & Swansea
Pull the DME and check that there are no pins corroded. I had a dead cylinder once because the pin that carries the firing signal for that cylinder was corroded and not carrying the signal. I knew with 100% certainty the engine was fine.

In fact the full story of that car was I bought it as a project with a dead engine. When I looked underneath there was a hole punched through the sump from the inside. The reason? I think it was the DME corroded pin. Fuel was going to the cylinder but not being burnt. And something nasty happened. That replacement engine I dropped in might well have gone the same way if I hadn't fixed the issue.
 
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