Strange idle connected exhaust vibration

[220bhp]

Lou,
Was it always like this or has it detiorated. I think I read one one of the threads that it got progressively worse.
If you bridged the TPS, that should have forced an idle condition. Of course it does not eliminate either an unmetered air leak or indeed broken wiring between either the TPS or
the ISV. Again its something to test rather than assume it ok!

Robin I feal it has detiorated from the running in period with the n75 dissconected,but then when I was running the car in I avoided traffic as I did not want the car to get hot,plus I did not use to much WOT.I did feal that the exhaust was vibrating a bit, but not like it is now,this is definatly a drone caused by the engine running poorly at low revs
I have managed to get it to run without the drone at times by trying to adjust the TPS,
But it just gos back to it in a day or two.
You could be right over a wireing issue with either the tps or the isv, and yes I must check this out in order to find out one way or another.
Many thanks for all the help,I tell you this car from day one has been a pain.

[twoqu]

Just trying to determine that it idled ok after the mapping and that the high idle has developed subsequently.
Trouble with the codes is that we cannot be certain whether they are cause or effect.
However both the 00525 and 00533 are consistant with an air leak for example. Another cause of the 00533 is the ISV being stuck open which of course is also consistant with the high idle. I have read somewher that the 1200 RPM is effectively the ISV fully open against its stop which is either a fault with the ISV or that the engine is in limp home mode. I thought Paul N's site had a list of faults that puts the engine in limp home but cannot seem to find it now!
Would have thought that it would have been flagged up in a fault code if that is the case unless the 00525 or 00533 is one of those.
Have you physically inspected the ISV hoses, especially the one into the manifold from the ISV?

[220bhp]

Yes I have inspected all the hoses in that arier, I changed the throttle body and the TPS yesterday,I did this as JON 441 found a little play in the throtle body,but I have not as yet retested for a boost leak,but I did find the bottom two bolts on he throttle bodey where not as tight as the top two,I replaced the gasket when I fitted a different throttle body,and tps.

[220bhp]

Managed to find the time to pressure test the hole system,in between rain storms.
I went round and checked all the clips one by on and got a turn or to on a few clips.I tested using soapy water,it held 1bar and I am now sure there are no leaks ,vacume or otherwise.I also cleaned the maf and tps connections,and cleared the codes.
I am pleased to say the car is now running much better,idle is alitle high at 950, but the car is drivable at low revs now,and the exhaust drone has reduced considerably.
Boost is around 1.1 and not the 1.7 the original map was set at, so there still seems to be something wrong.
If the car reverts to its old behaveier in the next day or so I will change the ecu etc.

[newsh]

Is the WGFV plugged in?

[220bhp]

Yes John.

[twoqu]

OK! Few thoughts.
One issue is that we don't know what the car should idle at. If it should idle as std then it's still a bit high, unless MRC tweeked it a bit. However it's possible that the aircon on signal is present which would increase it. Need to research that one a bit! It would be handy to have the car idling at the right speed as we can then look at the measly 10 measurings blocks to see if that tells us anything.
That leaves the MAF and the TPS. I believe the TPS is responsible for boost regulation so perhaps the ecu is not seing the full throttle reading. I understand that the MAF could put the engine into limp home (hence the 1200 rpm idle) but perhaps it is the notorious connector. Think John has a post or two on doing a thorough cleaning!
Anyway lets see what happens.

For reference, John's post:

http://www.s2forum.com/forum/showpost.php?p=626516&postcount=45

[prj]

1 bar from the MAF and with the manifold attached in all hoses?
How long did it hold that after you stopped putting air in?

[220bhp]

1 bar from the MAF and with the manifold attached in all hoses?
How long did it hold that after you stopped putting air in?

I did not time, it but after pressure test I dissconected the comppressor and it was at least a minute or so before i took the bung out and it was still pressurized enough to scare me.

[newsh]

Was the pressure test done with just the MAF bung? If so that seems pretty good.

[CoupeWannabeS2]

Hey Lou,

Drop me a line if I can help with Vag-Com, or offer a sympathetic ear!

It sounds like the car is taking up a lot of your time. Hope it comes together soon.

[220bhp]

Was the pressure test done with just the MAF bung? If so that seems pretty good.

I did it just as you shew me

[newsh]

[220bhp]

Still got problems,It ran ok for a while but slowly reverted back to poor running at 1500/2000 revs,plus it cut out twice at a junction,and now the ocilating boost has returned. As boost comes on the kneedle climbs and drops,and it will continues to do this till you take your foot of,then if you put your foot down slowly it will boost ok
I am beggining to think I have some kind of wiring issue,because when I look at the history of this car, I have had nothing but trouble.Both times it has been mapped by MRC,Mineah could not get the car to make power. First time he thought it could be a result of some work I had done to my ECU. we spent 14hrs changing the map sensor for a new bosch 3bar and installed new chips in the ecu,still the same.then they thought it was a combination of the standard exhaust and the airbox,so I changed them for a wagner evo and 3inch down pipe and exhaust,from S2bo.
Second time at MRC and still I they could not get the ,orpower they thought it should make. Doug said it might be the cams possibly the gear pressed on wrong at the factory.
They have been changed now. infact the only things on thecar that have not been changed are the ECU and wireing.
I have a standard and unopened ECU on lone from Jon441,together with standard injectors and fpr, which I am going to try and change,weather permitting.
I am abit concerned about doing this as I have no idea what will happen or weather it is in any way detrimental

[220bhp]

Managed to change the ecu today, before it pissed down with rain. So I could not itwi change the injectors and the fpr.
I have since been advised that this is not the right thing to do,which I totally agree with,but with the weather the way it is today,I thought I would try the car out.
It started up fine with no obvious problems from cold.Idle at around 1050. Ran ok until the temperature got up, then it behaved the same at 1500/2000 revs,hard to drive and the drone came back. The car did boost to 0,7+ and semed to be ok at over 2500, but below that was rubbish.
I did manage to check the wiring from the ecu to the isv,n75,and tps, for continuity,and they all checked out ok.
I also checked the voltage at the TPS,which was 2.4v at closed throttle,and 4.6 at wot.
the only thing I did find was that testing between 1 and 6, it was 0 oms at closed throttle, and no reading at all at wot,which I now is not good but it was raining,so I will try again tomorrow.