1.9 awx 130 manual vibration at idle

[mrnice]

Hi, I have an issue with the car (above). Recently there has been a high frequency vibration at idle that wasn't there before. It only happens at idle when warm (smooth as anything when started in morning) and can be felt through seats and gear nob. Car is otherwise running fine, good mpg etc too. Just drove 800+miles on round trip to London with no other issues.

Recent work on the car includes clutch & dmf (LuK kit at trusted Indy garage). Timing belt & water pump (water pump I fitted 1 year ago leaked so did it all again). I set the synchro angle to 0.0 after this with the help of vcds. Oil & filter changed 4 months ago. Left hand engine mount changed as it had leaked its fluid all over the place and snub mount as it had half turned to dust (these reduced the vibrations some but didn't cure). So far I've checked idle stabilisation in vcds and no injectors are out of spec according to it (reading between 0.61 to 0.02).
I also carefully cleaned the maf (or amm in non us-speak). I doubt it would be at fault anyhow since the engine runs nicely through the revs.

On my list of things to check are injector loom (swap for new?), check cam lobes and some more investigations with vcds regarding the health of the injectors (I only have vcds lite freeware but it has the functionality to check measuring blocks etc).
I know a slight vibration is a hard thing to track down on any diesel and a certain lack of refinement is to be expected of a 1.9 but if anyone has any other ideas to add to my check list I'd very much appreciate it,
Cheers

[mrnice]

Ps I've also ruled out alternator clutch pulley (only free-wheels in one direction with belt off).
I've also considered that the new dmf is faulty but it is oem and surely it would happen when cold and cause a noise too, whereas this vibration seems to appear exactly when engine gets up to temp (90deg), then remains there when idling.

[Rob69]

Injector loom on that age of engine, maybe the cable insulation softening and moving once up to temperature?

[mrnice]

This has occurred to me (relatively cheap & easy fix too), just wandered if there's any values to check in vcds lite
Which could suggest injector/injector loom problems? Don't think I can run logs in the freeware version tho.

[mrnice]

Also should have said scanned and no fault codes at all.

scratch that,

now have 17552 Mass Air Flow Sensor (G70): Open or Short to Ground
P114 - 35-00 - -

I ignored my own advice to leave it well alone when I removed the Maf and cleaned it but was very careful and gentle about it.

I'll check wiring first and clear codes and get back with results from measuring blocks etc.
Curiously car isn't actually running like a bag of nails, just curious vibrations.

As an aside the scan results in vcds lite start with this line of text-

Address 01: Engine Labels: 038-906-019-AVF .LBL. Does 'AVF' refer to engine code? Mine's an AWX. Thought label might cover both or something. Just curious.

[mrnice]

Cleaned maf connector, cleared fault code, re scaned and it didn't return after half hr drive. Prob result of disconnecting maf connector.
Have taken pics of any relevant measuring blocks at idle and will uplode later (learned I can actually do logs in vcds lite but will do it later). I'll keep this thread going with any further results.

[mrnice]

Here are some engine measuring blocks values all taken at idle-

Do these values look unhealthy? It appears that cyl's 2,3 & 4 are compensating for Cyl 1 somewhat.


This is what I used to set timing to 0.0, though some say depending on specific engine it may be happier either retarded or advanced slightly.


The maf (actual) was jumping around quite a lot at idle, normal?, i took some logs to 4000rpm, results in graphs lower in this thread.

[mrnice]

some more values-

Seems these should be logged really but I just checked this with engine at 90deg, assuming this (intake air temp) is measured by map sensor?

[Dean_1987]

sorry to jump in off topic but what version of vcds are you using and where did you get it from? I want to invest in a copy for my a6 1.9tdi sport

[mrnice]

I'm using vcds lite which is a freeware version of the software with limited functions (it has everything I need so far anyhow) and a generic cable bought from eBay (£10ish) It's $100 to register for full version but I've not done this yet as I'm running it on an ancient MacBook in boot camp and the registration only covers you for 2 computers. A cheap way into diagnostic stuff.