Strange idle connected exhaust vibration

[220bhp]

Just went out and tried that,and it makes no differance.
The thing that gets me is how the car runs well up to temperature,then rubbish.
When its coming up to temperature there is an entirely different note from the exhaust,much quieter with no boom. once up to temperature the throttle is jerky,put your foot down slowly,and nothing,then it lurches forword.
Even when cold, if you blip the throttle by hand ,the delay is poor,so I do not think its the cable.

[twoqu]

Lou,

Bite the bullet and put it all back stock. That includes any funky plumbing!
Get a reliable Vagcom so at least we can use the measly 10 measuring blocks the 3b gets! There is still valuable data to get from them and we can at least look at whether they are in or out of spec. Quite a few relate to the ISV.
Then that way as others have suggested, we can try and get it running correctly.
For example that 00533 code could indicate that there is to quote the manual "outside" air between G70 (MAF) and the N71 (ISV). We know that the N75 is probably sucking in air the way it is presently configured!
Backwards to go forward!

[220bhp]

Many thanks Robin.I have to at least try this in order to be sure.

[vertigone]

Hello Lou,
I've just read all you story about this problem
I can say I have exactly the same
here is my link : http://www.s2forum.com/forum/showthread.php?t=57862

Hope you can sort it out, I work on it too and keep you informed if I manage it

Regards,

Guillaume

[220bhp]

I sincerely hope one of us finds the cause. I did my injector seals,it ran better but did not cure thr problem.I wish you well when you turn the key

[vertigone]

Ok to resume you have (http://www.sjmautotechnik.com/troubl...g/20vcodes.htm)

00533 VAG1551/2 Fault Code Number
Idle Speed Control Valve (N71)
Idle speed adaptation maximum limit exceeded or Minimum adaptation limit not reached
Sticky or binding ISV, Mass Air Flow Meter (G70) offset, additional air introduced between G70 and N71
Symptom: Idle speed too low, or too high, Add air leak.


00525 VAG1551/2 Fault Code Number
Oxygen Sensor (G39)
Sensor Wiring or Sensor defective Heat resistor in sensor defective, Signal wiring shorted to ground, Fuel tank empty, Ignition system component failure, air leak at mass air flow sensor, air leak in exhaust pipe before catalyst, poor ECU ground wire connection at intake manifold.
Symptom: Emissions not within specifications, increased fuel consumption, rich exhaust, spark plug fouling,
Carbon Monoxide (CO) percentage above 3%,


00513 VAG1551/2 Fault Code Number
RPM sensor (G28)
Open or short circuit, sensor malfunction
Defective sensor & cables, metal fragments on flywheel teeth
Symptom: Engine will not start, misfires, may stop running
NOTE: I have seen this fault code occur after cranking the engine during a no start condition
in a few rare cases where there was nothing wrong with the RPM sensor


Ok what can we think about these ?

Perhaps lambda (0525) was because you were running too big injectors ? do you changed them back to stock ones ?

[220bhp]

The only code that comes back each time is the 00533 vag 1551/2. the car has bosch green RS2 injectors and is rs2 speck.
I am hopeing my son is going to put the standard injectors,fpr and ecu back in the car this weekend,as it is a bank holiday weekend,not for me though as I have to much work on.
MY son has fitted a new ISV and TPS with no change.

[newsh]

Lou, have another look at the 2 bunches of ground wires under the inlet manifold. We had them off when we took the manifold off to change the injector inserts, they are down near the dizzy. I think one of these wires will be the ground for the ISV. maybe one of the wires is broken or corroded.

[220bhp]

Thanks John

[220bhp]

Today the car was put back to stock with 3b injectors, FPR and ECU.
Car started soon as the petrol was up,and it runs ok.,idle is high at about 1100.. runs ok when cold, with exsactly the same symtoms when warm,Idel hunts at 1500,throttle jerky at between 1200 and 1500 and is pritty hard to drive at these revs.at 2000 the resonance from the exshuast is unbearable.Boost would not quite reach standard 3b of 0.85,only 0.7
I have done another boost leak test,all ok,i have done a vacume leak test useing propane
gas,with nothing found. I have another TPS on the caand another brand new ISV.
The first boost leak test revealed a leak at the back of this new ISV which I fixed with apoxy,also I found the 90% hose under the ISV had a small crack in the seam,aalmost undetectable, on the inner side of the bend,I have changed for another one.
The second boost leak test revealed no leaks.after all this effort and clearing the codes it is still the same.
I even tried running the car without the ISV and the TPS connected and it still hunts at between 1200 and 1500,
so where to next,

[Greg_S]

I'm watching this thread closely too as I have exactly the.same issue with mine. See the get it going in 2012 project thread. Goto get a compressor to do full leak test when I'm home.

Have you checked the main engine earth strap too?

[newsh]

Oh dear.
The brown wires under IM are ok then? Although you'd expect a fault code if one was off..
So is it running rich when warm do you think?
Have you tried changing the Lambda yet? Did you have a connector issue with the lambda, I seem to remember?
Have you got your Vagcom working? If so you can do an output test of the ISV to check it's actually connected.
TPS, on the 3B I think you'll have to meter up from the ecu connector and make sure the idle switch is connected through.

[220bhp]

Forgot to mention John, I changed the lamda, I tested the voltage on it and it was fine ,but as it was in the car when the engine blew,I thought it could be contaminated because of all the oil exetra,it also made no differance. strange that the car is the same on both ECU,s in some ways I am glad because I now no it is an indepentent fault wihtin thr car,I just have to find what it is

[twoqu]

Lou,
Are you saying that the idle characteristics are effectively the same with and without the ISV/TPS connected?
I would think that disconnecting the TPS alone would disable the ISV anyway.
As you say its unlikely that both ecu's have their idle capability disabled. I think its pointing toward a wiring fault.
Try the bridging on the TPS connector to force an idle condition. The ISV will not control without that signal. Its going to be a pain but it would be ideal to trace that back to the ecu pins to verify continuity.
I am not sure what the default state of the ISV is, open or shut. But the only way the car can idle that high is through the introduction of more air, either through the ISV or the throttle plate not being in the closed condition.
Here is another wild stab! Is the wedge on the throttle plate still there. If somebody has removed that and not blanked the two holes then that might be a cause.

[Carfreak]

Lou,
Are you saying that the idle characteristics are effectively the same with and without the ISV/TPS connected?
I would think that disconnecting the TPS alone would disable the ISV anyway.
As you say its unlikely that both ecu's have their idle capability disabled. I think its pointing toward a wiring fault.
Try the bridging on the TPS connector to force an idle condition. The ISV will not control without that signal. Its going to be a pain but it would be ideal to trace that back to the ecu pins to verify continuity.
I am not sure what the default state of the ISV is, open or shut. But the only way the car can idle that high is through the introduction of more air, either through the ISV or the throttle plate not being in the closed condition.
Here is another wild stab! Is the wedge on the throttle plate still there. If somebody has removed that and not blanked the two holes then that might be a cause.

Should u bridge between pin 2 and 3 or 4 and 6 ?