M3 E36 dodgy "hopping" idle

[m3f_Ignatius1]

Hello



My dad's vehicle recently had a new folding soft top roof fitted. The person who did it said that a BMW main agent needs to "intitialise" it. When we got the car back from the guy a dodgy idle was evident where it hops up and down. The car was stood for a fair few weeks so thought maybe the car just needs to go on a good run to clear it, but this didn't help.



As the car was going into our local dealer we thought that we may as well let them diagnose it. A couple of days or so later they thought that it could be the VANOS at fault (the VANOS was changed by a local BMW specialist 6 years ago to this month and has only covered 18-20k miles).



I've done a bit of research into symptoms of a dodgy rough idle & VANOS problems etc. Quite a bit points to the Idle Control Valve, Exhaust Advance Solenoid, weak flexi section to exhaust manifold , VANOS seals / o-rings / gaskets etc. Particularly this thread here at PistonHeads



Today, I went to the dealer to find out some more. They took me into the workshop where the technician (senior, apparently) said that he thinks it's a timing issue. I wish I took a photo of the state of dismantle the engine bay was in (I might do tomorrow when I go to test drive an i8). The cam shaft(s) were exposed, but the silver VANOS covers seemed to be untouched. The technician used some instrument which was inserted into a hole in the block to demonstrate to me that on one side it was flush, but when he rotated the instrument it wasn't flush. I don't know if what he showed me had any significance to the problem nor whether he was fobbing me off. I can be cynical with ANYONE in the motor trade.



Later today the service advisor called me and left a voicemail message telling me that he has spoken further with the technician etc and that they believe there are two options now left on the vehicle.



Option 1 - adjust timing, rebuild vehicle and test it. It may be that that solves the problem but then again it may be that it needs the "VANOS transmission unit" replacing afterwards. £1,340.39!! including VAT (this figure already includes oil service @ £173), investigation, timing check)



Option 2 - replace VANOS transmission unit and adjust timing (he said that the timing has to be adjusted when the transmission unit is replaced, that's why including both. This quote £3,168.37 including the VAT!!!



I have a call recording app on my phone (ultra useful) so will upload the 01m:47s recording to Dropbox, share it and provide the link below. I think it might be useful to listen to the guy's tone of voice and for feedback to be provided.



https://www.dropbox.com/s/5ml6681xmv...22222.AMR?dl=0



Can anyone help or advise with a) against what the dealer is saying and b) advice re. the dodgy idle, please?

[m3f_aeronaut]

Really need more info that just the words 'dodgy rough hopping idle' to provide help.

[m3f_Ignatius1]

Really need more info that just the words 'dodgy rough hopping idle' to provide help.

Okay.



The car's idle hops up and down. There may also be reduced performance though I haven't driven the car.



Please suggest other info.. thanks

[m3f_aeronaut]

"Hops up and down" is pretty useless as a diagnostic description.


Let me ask a few questions to possibly help.


How many rpm does the idle change?

What's the frequency of the idle change....every second? every minute?

Is the engine running rough?

Always, or only hot or only cold, immediately after starting?

If you run the rpm up to 1,000rpm, is it smooth?


Without more info, the first thing I'd check would be the ICV and associated vacum/plumbing hoses.

[m3f_Ignatius1]

"Hops up and down" is pretty useless as a diagnostic description.


Let me ask a few questions to possibly help.


How many rpm does the idle change?

What's the frequency of the idle change....every second? every minute?

Is the engine running rough?

Always, or only hot or only cold, immediately after starting?

If you run the rpm up to 1,000rpm, is it smooth?


Without more info, the first thing I'd check would be the ICV and associated vacum/plumbing hoses.

Yes, I wanted to state what range the RPM fluctuate by but didn't know this.


Approximately from normal idle which is just below 1k (right?) to probably about 1200-1500k.


Pretty much every second or so - just a constant thing.


The drive might be a little rough, though I haven't driven or been in it since the problem properly worsened.


Seems to be regardless of whether the engine is cold or hot. Yup, immediately after igniting the engine.


I believe that this problem has developed over the last maybe two years or so. I have driven the carriage like maybe 18 months ago or something and I'm sure I recall a hesitant engine at low RPM as if the engine was choking and the RPMs struggling to rise sort of thing. Maybe I did put that down to a need for servicing or something as it maybe only was intermittent back then.


I'm thinking ICV, solenoids or VANOS seals also.......

[m3f_frbz]

Guys remember this is a euro motor. Is it a 3.0 or a 3.2? OP you are probably on the wrong forum as this one is centered around the US spec cars.

[m3f_Ignatius1]

Guys remember this is a euro motor. Is it a 3.0 or a 3.2? OP you are probably on the wrong forum as this one is centered around the US spec cars.

I think I started this thread in the correct forum. (E36 M3 (1992-1999) {Euro - S50 B32 321hp @ 7400 rpm} {U.S. - S52 B32 240 hp @ 6000 rpm}). There doesn't seem to be a separate one for Euro and US spec....?



It is a 3.2 321bhp S50 unit.



To note that I called BMW today and requested they do nothing else except reassemble the engine. We went down some hours later. I went for the test drive in an i8 and, just for the record, would like to comment on how I was blown away by this incredible machine. I'VE FALLEN IN LOVE WITH IT.



So, we then sat down with the service people. Some minutes later I requested the Service Mgr. He seemed quite straightforward actually and talked some sense. Fault codes from the DME diagnosis and other job card documents have been photocopied and taken away for our own reference. Later, we negotiated costs and made payment of £436.**. That figure included oil service (£173.**), diagnostic (£99) and timing investigation (158.**). Apparently, it was a master technician that has been working on the car. The person (sales) sat next to me in the i8 told me this as did the service people, so maybe it is true.



Shortly after, we went out and ignited the M3's engine. Strangely, the rough "hopping" idle seemed to have vanished. Performance doesn't seem bad. Low end torque may have improved a bit - I'm not sure, though it does generally seem to run smoother.



Tomorrow we'll be taking the car to the same specialist that we got to fit a new VANOS unit 6 years ago. We may visit one or two other specialists because we need as many opinions as possible. In a way it would be good and bad for the dodgy idle symptom to return. The fault codes are still stored in memory anyway so any other technician should see them, if still causing issues. I don't have the paperwork with me right now, though.

[m3f_WestCoastin]

[m3f_M3AN]

I also have a 3.2 Euro and recently rebuilt my VANOS. I'm not sure you should take it to any more specialists yet.


£158 is awfully good value to time one of these engines!


Post the fault codes, you said you have a copy? The codes should have been cleared or you can't tell if they're reoccurring. You have a copy so no value in keeping them in the computer.


If it is the VANOS unit (doesn't sound like it to me) then it should be fixed, not replaced with a new one (same faults will occur). Look up Dr. VANOS in the UK.


Sounds like vacuum, ICV or TPS to me.

[m3f_Ignatius1]

I also have a 3.2 Euro and recently rebuilt my VANOS. I'm not sure you should take it to any more specialists yet.



£158 is awfully good value to time one of these engines!



Post the fault codes, you said you have a copy? The codes should have been cleared or you can't tell if they're reoccurring. You have a copy so no value in keeping them in the computer.



If it is the VANOS unit (doesn't sound like it to me) then it should be fixed, not replaced with a new one (same faults will occur). Look up Dr. VANOS in the UK.



Sounds like vacuum, ICV or TPS to me.

The £158.** cost was purely for the investigatory work on the timing issue, as BMW were telling me they thought the dodgy idle was related to timing but I wasn't convinced and was taken into the workshop where I suggested to the technician that proper troubleshooting should be done starting with small minor basic things to the most serious. I've read quite a few people have had this sort of symptom and it has been some solenoid or wire has come off and has been re-soldered to remedy the fault. Other causes do seem to be ICV and VANOS seals/o-rings. TPS, is Throttle Position Sensor? When we had the symptom it wasn't a high constant idle. The rev counter needle was just hopping up and down from normal idle (7-800RPM) to 1000-1100 rpm or so..



It's only seemingly after everything has been reassembled that the actual dodgy idle symptom hopping from a normal idle to 1100-1200 or so RPM has disappeared.... for now. This is why the technician hasn't (or shouldn't have) erased any fault codes from the memory.



I will post further info regarding the fault codes later today when I get the paperwork in front of me again.



Yes, I've scanned the web and looked at DrVanos, MrVanos, BeisanSystems and many forum threads.

[m3f_M3AN]

It's only seemingly after everything has been reassembled that the actual dodgy idle symptom hopping from a normal idle to 1100-1200 or so RPM has disappeared.... for now. This is why the technician hasn't (or shouldn't have) erased any fault codes from the memory.

I'd say that's exactly the conditions under which you should clear the codes. So if it happens again you have fresh data to compare to your baseline.

[m3f_Ignatius1]

I'd say that's exactly the conditions under which you should clear the codes. So if it happens again you have fresh data to compare to your baseline.

Fair point really. I guess that it's worth thinking about taking the car back to the main dealer and getting them to clear all codes ready for fresh codes to return if and when the dodgy idle returns as well.

[m3f_vmbray]

The suggestions of Icv etc are a good place to start. If the icv hasn't been cleaned, have it done. A smoke test would be a good idea to find leaky hoses etc.


I'm guessing they put a new valve cover gasket on? You may have had a vacuum leak there and now its solved?


What codes are you getting?


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[m3f_Ignatius1]

The suggestions of Icv etc are a good place to start. If the icv hasn't been cleaned, have it done. A smoke test would be a good idea to find leaky hoses etc.



I'm guessing they put a new valve cover gasket on? You may have had a vacuum leak there and now its solved?



What codes are you getting?



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Click here to see a PDF of some scanned documents (technician's report & diagnostic fault codes from the dealer).



I don't think the ICV has been looked at even though I suggested to them whilst they were looking at the car to look at solenoids, ICV, seals etc.



I'm not sure if any parts have actually been replaced. When I went to see the car the cover to the camshafts was removed etc but the VANOS silver covers appeared to be untouched. Later that day they called with the £1300 cost to adjust the timing and if that doesn't rectify the problem then it would be £3100 which includes timing adjustment and VANOS replacement. EXTORTIONATE and I'm really not convinced that we need to do this either.



I've now been able to scan all diagnostic documents including the technician's report from the dealer and shared a link to the PDF on Dropbox here.



The carriage is still running much smoother with a constant normal idle though I haven't properly driven it so cannot comment on performance. BMW told me that the fault codes should still be in the DME, but would it be a good idea to have these erased? If errors and faults still exist, would they sort of show up straight away after a diagnostic test? I guess they would. This way, removing the codes might be a good way of starting fresh. Perhaps somehow the problems have miraculously been rectified, but I might be being a little too optimistic.



We are still looking to find time to get the car to the specialist that replaced the VANOS for us back in August/September 2008. We want second, third, eighth opinions.

[m3f_vmbray]

Interesting - I don't think there are many people here familiar with dual vanos e36 engines. Maybe driving the car more has improved matters? If it's been sitting maybe the vanos is sticky or something. On single vanos the seals have to be really old to cause idle issues, like 150k miles from what little I've seen.


For starters you should troubleshoot the spark plug codes because that's so easy. Get new boots and plugs on there. Clear the codes and see if you still have codes. If so swap coil packs between cylinders with and without codes and see if the error moves. Anyone with a metric socket set and code reader can do this very easily. Get a code reader they're cheap.


Also get a new temp sensor in there or have someone do it for you. Has the cooling system been thoroughly serviced? That's just a general thing you should do.


Cover the easy tune up things first because they are cheap, easy, and need to be done anyway.


Lastly, if the vanos is out of time I don't think it got that way on its own. If its like the single vanos that would mean the specialist timed it wrong when they installed the new vanos. Obviously they should fix it if that's the case.


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