2.8 misfiring..

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HomerRamone
Joined: Wed 30 Sep, 2015 12:35
Posts: 21

  Z3 roadster 2.8

2.8 misfiring..

Post by HomerRamone » Wed 27 Jul, 2016 10:57

Apologies if this is covered already somewhere - I did a search and found some seemingly relevant threads but nothing conclusive...

My Z3 (1998 2.8) has starting randomly misfiring.

First started a few weeks ago.. driving along at a nice steady 70 and it suddenyl just felt wrong. Paused the music and right enough it sounded really rough and lumpy. Like it was running on 5 cyls or something
Was on the way to work so figured I would just wing it till I get there and take it from there. Just around the corner from work it sorted itself out.

Couple of days later it did the same. When I got to where I was going I switched it off and started it again.. and it was just fine.

Another couple of days and it does it again. This time I turned it off immediatley and restarted it.. and again it was fine again.

so I thought start with the simplest/cheapest option... the plugs. Got a new set and changed them...

Couple of days and it does it again. Turned it off and on and it sorted itself again, but then did it again around a minute after. Restarted again and it sorted itself and stayed sorted.
So I assume its not the plug.
I have ordered a couple of coils to set about switching them 2 at a time to see if its that.. but just wondered if anyone had any thoughts.

Couple of points:.
1. Its had an LPG conversion fitted. However I switched back to petrol and it made no difference.
2. Theres no engine light or anything. I do know someone with a snap on code reader (and I bought a deely from amazone to connect to the round connector under the bonnet and provide an ODB stlye interface. Theres an ODB interface under the dash but last time I tried to connect to reset teh service warning it wouldnt have any of it)

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colb
Joined: Sat 05 May, 2012 23:46
Posts: 579

  Z3 roadster 1.8 TU
Location: Newport South Wales UK

Re: 2.8 misfiring..

Post by colb » Wed 27 Jul, 2016 11:32

Give the code reading a go at least it should show some misfire info which may narrow the faulty cylinder(s) down.
Swapping the coils for known good ones is the way to go without codes to go by certainly sounds as though something is breaking down.
Colb
1999 BMW 1.8 Z3
1998 Honda Deauville NT650V

Del
Joined: Sat 19 Nov, 2011 18:35
Posts: 2121

  Z3 roadster 1.9

Re: 2.8 misfiring..

Post by Del » Wed 27 Jul, 2016 11:58

My car is 1998 and doesn't have an engine/sensor warning light on the dash. I use a simple OBD II/ service reset & air bag tool with a round socket converter for the engine bay socket. All works fine on my car. I would check for stored error codes as a starter.

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Robert T
Site Admin
Joined: Mon 12 Jun, 2006 11:35
Posts: 10004

  Z3 roadster 1.9
Location: Cheshire

Re: 2.8 misfiring..

Post by Robert T » Wed 27 Jul, 2016 12:52

Plugs, coil packs, camshaft and crankshaft sensors... A code reader is your friend here as if the ECU detects a misfire it actually logs which cylinder it thinks it is on.

Regarding the OBD sockets - the one under the dash is only connected to the engine ECU - for everything else, including the service lights, you need to use the round 20-pin connector under the bonnet.

Cheers R.
Arctic Silver '99 Z3 1.9 & Black '59 Frogeye 1275cc
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mrscalex
Joined: Fri 13 Mar, 2015 09:14
Posts: 795

  Z3 roadster 1.9

Re: 2.8 misfiring..

Post by mrscalex » Wed 27 Jul, 2016 13:57

Robert T wrote:Regarding the OBD sockets - the one under the dash is only connected to the engine ECU - for everything else, including the service lights, you need to use the round 20-pin connector under the bonnet.
Cheers R.
Robert T is not wrong about that as I know to my own experience this week :lol:
ImageImage
1999 Z3 1.9 Boston Green (Dimitri) - My brother's car owned from new and restored by me
2001 Z3 2.2 Topaz Blue (Trudy) - My car rebuilt from a write-off
2002 Z3 2.2 Titan Silver (Okus) - Project car waiting for a new engine
2001 Z3 2.2 Topaz Blue (Debra) - Donor car/breaker
1998 Z3 1.9 Boston Green (Allsworth) - Donor car/breaker now gone to Z3 heaven
Always happy to try and help with spares :)

HomerRamone
Joined: Wed 30 Sep, 2015 12:35
Posts: 21

  Z3 roadster 2.8

Re: 2.8 misfiring..

Post by HomerRamone » Wed 27 Jul, 2016 15:13

Thanks for the super quick replies folks !!

I have an adapter for the round connector under bonnet.

https://www.amazon.co.uk/gp/product/B00 ... UTF8&psc=1

Its the engine ECU I need to read though right ? Presumably thats where any relevant fault codes here are ?

mrscalex
Joined: Fri 13 Mar, 2015 09:14
Posts: 795

  Z3 roadster 1.9

Re: 2.8 misfiring..

Post by mrscalex » Wed 27 Jul, 2016 15:44

HomerRamone wrote: Its the engine ECU I need to read though right ? Presumably thats where any relevant fault codes here are ?
Yes but no harm having a snoop in the other systems while you're in there if you connect under the bonnet.
ImageImage
1999 Z3 1.9 Boston Green (Dimitri) - My brother's car owned from new and restored by me
2001 Z3 2.2 Topaz Blue (Trudy) - My car rebuilt from a write-off
2002 Z3 2.2 Titan Silver (Okus) - Project car waiting for a new engine
2001 Z3 2.2 Topaz Blue (Debra) - Donor car/breaker
1998 Z3 1.9 Boston Green (Allsworth) - Donor car/breaker now gone to Z3 heaven
Always happy to try and help with spares :)

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BladeRunner919
Joined: Fri 17 Feb, 2012 20:18
Posts: 2221

  Z3 roadster 1.9

Re: 2.8 misfiring..

Post by BladeRunner919 » Wed 27 Jul, 2016 15:50

Just do everything through the port under the bonnet - there's no point using the one under the dash unless that's all you have a cable for.

Fender2004
Joined: Fri 14 Aug, 2009 11:24
Posts: 877

  Z3 roadster 2.8
Location: Houghton-Le-Spring

Re: 2.8 misfiring..

Post by Fender2004 » Wed 27 Jul, 2016 22:04

I have a 97 2.8 and I thought that there was only one socket under the bonnet and that was it.

So is they another one under the dashboard?
Image

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Robert T
Site Admin
Joined: Mon 12 Jun, 2006 11:35
Posts: 10004

  Z3 roadster 1.9
Location: Cheshire

Re: 2.8 misfiring..

Post by Robert T » Wed 27 Jul, 2016 22:19

Fender2004 wrote:I have a 97 2.8 and I thought that there was only one socket under the bonnet and that was it.

So is they another one under the dashboard?
Not on a '97 car. Not sure of the exact date it was added, but my 01/99 doesn't have it, even though it has the later more OBDII-compliant electronics which were added around 08/98. I can use an USB OBDII reader with adapter cable, whereas I suspect you will need to use a proper serial port.

Cheers R.
Arctic Silver '99 Z3 1.9 & Black '59 Frogeye 1275cc
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Fender2004
Joined: Fri 14 Aug, 2009 11:24
Posts: 877

  Z3 roadster 2.8
Location: Houghton-Le-Spring

Re: 2.8 misfiring..

Post by Fender2004 » Wed 27 Jul, 2016 22:23

That's what I thought, but nice to be confirmed.
Thanks Robert.
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HomerRamone
Joined: Wed 30 Sep, 2015 12:35
Posts: 21

  Z3 roadster 2.8

Re: 2.8 misfiring..

Post by HomerRamone » Thu 28 Jul, 2016 22:34

Connected the diag tool today.

6 codes !! Lucky me :)

3 relating to a misfire. 238,239 and 240. Misfire Cyc 1 thru 3

202 O2 Bank 1 Control Limit
203 O2 Bank 2 Control Limit

and finally
123 Electronic thermostat control

My plan is this.
Use it on petrol for a few days see if it recurs.
Possibly at the weekend I may trim the ends of the pipes and replace the clips then back to gas and see if it comes back then.
If it does... then change the coils 2 at a time.

I could be totally wrong but...my thinking is possibly the O2 codes would indicate bad connection on this pipework that's let a bit of air get in there (or stopped the gas getting to the injector [or wherever it goes to get into the cyl] - causing the misfire and resulting in the codes etc... This is my speculation on my part though :)

Finaly the 123 thermostat code. No idea what thats all about :)

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BladeRunner919
Joined: Fri 17 Feb, 2012 20:18
Posts: 2221

  Z3 roadster 1.9

Re: 2.8 misfiring..

Post by BladeRunner919 » Fri 29 Jul, 2016 08:48

Bear in mind that the codes could be old, irrelevant ones. Clearing and seeing which re-occur is always the first thing - no point chasing a one-off code from three years ago!

Mugs
Joined: Wed 07 Aug, 2013 02:26
Posts: 341

  Z3 roadster 1.9

Re: 2.8 misfiring..

Post by Mugs » Fri 29 Jul, 2016 12:09

I had a 1997 z3 that had the same symptoms.
It turned out my cat was disintegrating and pieces kept blocking the exhaust. When I switched of and back on they dislodged and it was ok again until the next piece blocked it.
I read similar codes to you (plugging into the round socket in the engine bay) and I tried coil pack, plugs, Maf etc but nothing cured it.
I only found it, eventually, as a piece started to rattle and when I took the cat off pieces started dropping out.
It is worth a check.
I also had a similar thing on my E46 which turned out to be the air box to Maf joint jubilee clip being loose (the garage who did the service before I bought it :head:).
With reference to resetting the device lights on my z3,I had to use a special BMW reset tool plugged into the round socket as nothing else would work.
Hope it helps?

srichards
Joined: Sun 11 Oct, 2015 09:24
Posts: 61

  Z3 roadster 2.8

Re: 2.8 misfiring..

Post by srichards » Sun 31 Jul, 2016 10:12

Is the misfire occurring about 2750 rpm? I have that now on mine every so often. Another late 98 build 2.8.

Del
Joined: Sat 19 Nov, 2011 18:35
Posts: 2121

  Z3 roadster 1.9

Re: 2.8 misfiring..

Post by Del » Sun 31 Jul, 2016 10:28

If you suspect that the cat is breaking up inside (as they sometimes do with age), give it a good thump with the palm of you hand - if it is suffering from this problem, it will be very obvious and sound like a load of marbles in a biscuit tin :D There is also often a similar rattle at certain revs and on overrun.

HomerRamone
Joined: Wed 30 Sep, 2015 12:35
Posts: 21

  Z3 roadster 2.8

Re: 2.8 misfiring..

Post by HomerRamone » Sun 31 Jul, 2016 18:36

the misfire is across the rev range when it happens.
I trimmed one of the pipes on the LPG system @ the weekend... but have been running on petrol for the last few days.
Its not done it again - but will keep on petrol for the commute tomorrow then back to gas on Tue see how it goes.

Could do without it being the cat- but will bear it in mind

Thanks again for all the tips and suggestions...

Will likely report back soon with an update :)

HomerRamone
Joined: Wed 30 Sep, 2015 12:35
Posts: 21

  Z3 roadster 2.8

Re: 2.8 misfiring..

Post by HomerRamone » Thu 18 Aug, 2016 09:08

So further to this I spoke with a guy I know thats a bit good with this kind of thing. (cars, lpg... anything with wheels really)..

He said what has been suggested anyway. Change the plugs. did that - no difference. Replace the coils, maybe at a time.

I decided (being the impatient sort) that I would change a few at once to save time. Changed the ones on Cyls 1-3 (those reporting a misfire on diag) and its not done it since. Though it was intermittent but it deffo seemed more prone to doing it when givne a sound thrashing. Ive given it a few of those since coil change so hopefully its sorted !

Hanx for the help folks !

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Robert T
Site Admin
Joined: Mon 12 Jun, 2006 11:35
Posts: 10004

  Z3 roadster 1.9
Location: Cheshire

Re: 2.8 misfiring..

Post by Robert T » Thu 18 Aug, 2016 09:38

Coil packs often only seem to misbehave when warm, so clear the error codes, give it a decent run, then check the codes again.

Glad you seem to be sorted.

Cheers R.

Sent from my SM-G920F using Tapatalk
Arctic Silver '99 Z3 1.9 & Black '59 Frogeye 1275cc
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HomerRamone
Joined: Wed 30 Sep, 2015 12:35
Posts: 21

  Z3 roadster 2.8

Re: 2.8 misfiring..

Post by HomerRamone » Thu 18 Aug, 2016 13:20

Indeed. I think engines run a little hotter when running on LPG but also the guy I spoke to explained that since LPG is harder to ignite than petrol the ignition system has to work harder anyway. So anything like this is emphasized when running on LPG.

nang
Joined: Sat 25 Jun, 2016 04:27
Posts: 30

  Z3 roadster 2.8

Re: 2.8 misfiring..

Post by nang » Tue 06 Sep, 2016 05:38

Being a curious b.....d , why do you run on LPG ? My experience running vehicles designed to run on petrol on LPG has not been great. I'm talking of mostly commercial ones. Apart from a bit more torque and possibly a bit cheaper running cost {over here in NZ anyway} what do you achieve ?
Tony.

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BladeRunner919
Joined: Fri 17 Feb, 2012 20:18
Posts: 2221

  Z3 roadster 1.9

Re: 2.8 misfiring..

Post by BladeRunner919 » Tue 06 Sep, 2016 08:23

nang wrote:Being a curious b.....d , why do you run on LPG ? My experience running vehicles designed to run on petrol on LPG has not been great. I'm talking of mostly commercial ones. Apart from a bit more torque and possibly a bit cheaper running cost {over here in NZ anyway} what do you achieve ?
Tony.
It halves the fuel costs!

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