E30 vibrates/rumbles when cold

[svenga]

1989 325i cabbie..

Symptom..

Car starts fine from cold, idles correctly no misfires or vacuum leaks (from what I can see) rev gauge nice and level no blipping or bouncing. Slight vibration/rumble can be felt in the footwell, upon pulling away the car vibrates and this can be felt through the steering wheel. This can be felt until reaching higher speed in higher gears. Once the car has ran up to temperature, the vibration and rumble noise is gone! nothing can be felt when stationary in the footwell and the car pulls away correctly.

The car had a new clutch 500 miles ago (full kit, clutch, release bearing, pressure plate etc) and this was my main concern, could it be connected?

The mystery is the car only has these symptoms when cold?! once at temperature it disappears!

No visual problems from what I can see, fluids appear to be fine, no leaks, no noises from under the engine bay.

Any ideas?

All help appreciated!

[Brianmoooore]

Am I correct in thinking that the vibration and rumble are present when cold and the gearbox is in neutral? If so, what is the effect of first lightly pressing the clutch pedal, just to take up the 'slack', and then the effect of pushing and holding the pedal right down?

[Brdjo]

Did you have same problem before servicing clutch?

[svenga]

The problem was not present before having the clutch fitted (which scares me)...

The rumbling is present when the engine is cold and idling, with the gearbox in neutral.

HOWEVER..

This morning, no rumble present. But upon pulling away from the drive, and the majority of my journey to work.. The car would vibrate when pulling away. I tried the peddle anyway in case Brian, but there was no noises either way.

Basically, pull away in first, vibration comes through the car and steering wheel. fades out once the clutch is completely released and moving into second. I think it must be clutch related.. The car does not shake or jump or hesitate, it simply vibrates finely right through the front end of the car whilst going through the motions of pulling away from a standstill in first.

Somebody suggested the exhaust rubbing somewhere (when stationary in neutral revving the car.. No vibration.)

Another suggestion was the gearbox oil level, however there are no visible leaks and the output and selector seals were changed only late last year.

Again, once fully warmed up after maybe 20-30 minutes driving... This 'vibration' seems to disappear.

[Brdjo]

Did you changed clutch yourself? If not go back to workshop...

[svenga]

OK... Had another study this morning.

The car made a slight rumble noise upon cold start in neutral but idled happily.

Playing with the clutch pedal and feeling and listening for noise made no difference.

Upon placing in reverse and gently moving backwards, the car did NOT vibrate (low revs just going with the engines own torque). Placed into first, and pulled away slowly applying revs as normal but in no rush.. The car began to vibrate! through the steering wheel and foot well, moved into second gear and it vibrated still but not as profound. Once in third and up to general driving speed nothing noticeable. Once I arrived at work and reversed into a parking space, nothing!.

It seems as the engine warms up this problem phases out, which leads me to think it is an engine related issue? although the car idles correctly wether hot or cold, and there appears to me no misfire from what I can hear or feel.. Perhaps there is an engine running issue.

[Brianmoooore]

I think it's time to check out the propshaft centre bearing mount, the centring bush in the middle of the gearbox output flange, and the possibility of the two halves of the propshaft having been reassembled incorrectly.

[svenga]

Thank you for your suggestion Brian, the car is going back in Monday for an inspection and problem solving.

Will let you know.

[fixedwheelnut]

Are the engine mounts OK, the sump might be hitting the rack vibrating through to the steering.

Does the vibration get faster with road speed or engine speed?
If faster with road speed check the Propshaft and running gear, don't forget tyres if out of shape they can rumble and soften up as they get warmer.

[svenga]

*UPDATE*

After some delay I have managed to get the car back to the garage.

It seemed the past few days upon cold start a profound ticking noise could be heard, the revs dropped a little once warmed up and idling (around 600 on the gauge but a lumpy vibration could be heard). I began to think could there be a slight misfire? vacuum leak? fuel Injector/supply issue?

Anyway they have put her on the ramp and visually seen nothing, when plugged into the diagnostics it is stating error codes for the lambda sensor (which is does not have nor the wiring for) and AFM sensor. We are currently looking for vacuum leaks and going to clean the AFM with the hope this resolves the issue. Otherwise I will have to have my AFM fixed.

Fingers crossed I have better issues to spend my money on like a new manifold and exhaust system

[svenga]

Ran out of time today at the garage..

The error codes read..

02 temperature sensor
Airflow sensor circuit

I will clean the AFM tonight carefully with some cleaner and see if that resolves the issue.

Is the 02 sensor the lambda sensor? which is not present on my car and never has been causing no issue. Could the blue temp sensor have any effect?

[BenHar]

Any garage that is trying to read error codes from an E30 doesn't know what they are doing.

Try and find an old school backstreet place.

Ben

[blazed]

I would get some brake cleaner and spray around the intake to make sure you don't have an air leak. I have had the exact same symptoms on two different cars and both times it was a hidden air leak. When you spray you are listening for a change in engine noise (revs picking up slightly)
As benHar said it needs a mechanic not a computer
If there is no change I think blue temp is next to TEST as per the wiki

[Brianmoooore]

This seems to have strayed a long way from a transmission vibration/rumble!

[pianist]

Think maybe the garage reassembled it wrong or missed few bolts on bell housing or center bearing or put prop missaligned etc. If it started right after clutch change I would be suspicious if it is a coincidence

[pierce]

If they're plugging the e30 in to "diagnose" find a new garage.

Based on your first post, could it be a cracked flywheel?

[svenga]

Hi Guys,

Originally I presumed the vibration through the car when first setting off when cold was something to do with the recent clutch change. Either the exhaust touching, the UJ or centre support etc. The fact it phased out once the car warmed up seemed strange but could of pointed to the gearbox oil which was fine. The car was checked for and the UJ and centre bearing seem ok as well as the guibo (no bolts missing too), the exhaust was not touching anywhere.

During this time though the car developed what appeared to be a 'slight' misfire, which would explain the rumbling sensation. I started the car from cold and left it for 30 minutes and took it for a drive with no vibration or rev drop when I pulled away. Thus once the engine warmed up the issue disappeared, however the car began idling (hunting, slight hesitation, slight vibration) hot or cold.

Plugs were checked, vacuum hoses. boot, re-clipped and checked for leaks (alloy plugs sealed and refitted), AFM & ICV cleaned, as well as related plugs and connections, still no joy but did improve slightly.

Today i fitted a new Blue temp sensor, the old one was completely corroded and fell to bits so needed doing anyway. But again, the car still hunts slightly. So i will take a look at the distributor cap & arm next, followed by a new fuel filter.

They plugged the car into the diagnostics after the basic checks, i actually suggested it out of curiosity what error codes would pop up. In the past i had another e30 plugged in for a fault and it told me the error code (and resolved the issue). I had no idea the diagnostic plug and system on the e30s was so unreliable/frowned upon so apologies The garage i took it to are actually ok, im fussy.

NB; something that was spotted, x2 bolts are missing from the exhaust manifold, and as well the flexi pipe on the downpipe is worn through causing an exhaust leak. Could this cause an idle issue?

[Brianmoooore]

as well the flexi pipe on the downpipe is worn through

What flexi pipe?? Shouldn't be one of those on an E30, or need one on any car where the engine is facing the correct way

[svenga]

My terminology might be different, just after the downflow.

The exhaust system is not the best.

NB: not my picture but I have the same flexi part where I describe (scuffed and frayed from touching speed bumps when the previous owner had the car lowered)

[pianist]

Never seen flexi on e30 before and yet here it is

[Brianmoooore]

"Here it is", but I don't believe it should be. Engine movement with a N-S engine is around the longitudinal axis of the car, so any strain on the exhaust is easily taken up by slightly rotating the whole system.
The situation is completely different with an E-W engine. With these, the movement is around the lateral axis at the front, and the exhaust has to bend to absorb these forces.
There's also the small point that this is a 325i, and the entire system should be twin pipe, so if there's one flexi, there should be two.

[svenga]

Thank you for your input Brian.

The exhaust system is stainless and very council, it will be getting chucked very shortly anyway.

The blue temp sensor has made a difference, but not entirely, I decided to test the TPS last night. The switch read correctly until the throttle was 2/3 open as per the wiki, I doubt this could be the issue but I will take it off and give it a gentle clean and check the contacts and micro switch.

despite visually checking the plugs and testing for a spark, I have decided to buy a new set of plugs and leads just in case (the leads were cracked in places and starting to break down).

[Brianmoooore]

The blue temp sensor has made a difference, but not entirely,

If it made any difference, then the original was faulty.

I decided to test the TPS last night. The switch read correctly until the throttle was 2/3 open

The idle switch MUST open as soon as the throttle leaves its stop, consistent with reliably closing again when the throttle is closed.
The WOT switch should close around 2/3 throttle, but the actual position isn't at all critical.

I have decided to buy a new set of plugs and leads just in case (the leads were cracked in places and starting to break down).

This suggests that your leads may already be aftermarket - I've never seen cracked OE leads yet. A good second hand OE set will do as a replacement.

[svenga]

New NGK spark plugs & ignition leads fitted.

The car seems more responsive for this, but the engine is still running very shakey (not on Rev gauge) but the engine itself (a can on top of the intake manifold will rattle away).

I will clean the TPS next, and check the contacts. Could this cause the lumpy idle? I presumed it caused more irratic idle issues?

Am I correct in thinking I can not simply attach another AFM sensor?

Cheers.

[Brianmoooore]

You can fit another 325i AFM without any problems. Preferably one where the bypass screw has not been disturbed, and the plastic cover never removed.
Has the inlet tract from the AFM onwards been checked for air leaks?
Have the injectors been rebuilt in the last 50,000 miles?

[svenga]

The system has been checked for vacuum leaks, as well as being re-clipped and the alloy inlet pipes being sealed going into the throttle body. The only inlet part I would be insure on would be the manifold gaskets but a liberal amount of fluid In that area did not make any idle difference.

The injectors have not been cleaned in my ownership (six months and under 15K), but there is a receipt for injector cleaning and resealing dating to 2013, but that could mean anything!

I have come to the conclusion it is 'overfuelling' and running rich opposed to lean, this can be noticed from the exhaust. There is also a slight hesitation when doing any speed usually in third or fourth and 'slightly' pressing the accelerator.

[svenga]

Cleaned the TPS sensor today and drilled a hold in the casing.

Made matters worse, the car is idling even more lumpy.. Still no visible, liquid traceable vacuum leaks.

The car is overfuelling and it is strong from the exhaust, I am completely baffled.

[bosers]

I had an over fuelling issue with mine once, turned out to be a duff Ecu. Are you able to borrow a known good one to test?