TrentBarton

For anyone else considering changing the 6u0611931D pipe and check valve... In the end I used a 12mm check valve from carbuilders along with 1m of 13mm vacuum hose and standard clips: https://www.carbuilder.com/products/aluminium-non-return-valve-12mm-2 https://www.carbuilder.com/products/heavy-duty-spring-band-hose-clamp https://www.carbuilder.com/products/vacuum-hose-13mm-id Worked fine. Removing the line from the booster is a bit fiddly without damaging the connection on the booster. I used a heat gun to warm up the old pipe so I could get it off relatively easily. Sadly, the issue remains so presume leak is in the booster itself but it was worth trying for the sake of £20 and 30mins of my time.

Hey @Papez Thank you for checking. I had also gone through my workshop manual and struggled to find any direct electronic link between clutch/ brakes and ecu so good that you have clarified this. It must be based on a load change I suppose. It is very unusual, I have taken the issue to a couple of garages and to some friends who are more knowledgeable about mechanics than I am and have not found an answer yet. Perhaps a strange niggle in the ECU itself? I have cleaned all on my earth connections. I have also replaced the vacuum pipe and check valve to the booster. The issue remains! I have to replace my rear brakes soon anyway so might do the booster at the same time and see if that helps. Failing that, will start looking at ignition system!

Hello all, Back to this again, after trying a few other things to fix idle and rev hang issues, I decided to stick a clamp hose on the brake servo vacuum pipe and see if it made much difference and it did. Without the clamp on, if I am sat at idle and pump the brakes, the revs go up. This does not happen when I clamp the pipe. So perhaps this is the cause of my issues. Either a leak in the pipe or the servo itself. I am going to replace the pipe to start off with. Finding this part now seems to be very difficult. I was planning to just create my own with a vacuum pipe and a non return valve as they are cheap and quickly available. Does anyone have any experience of this? The fitment onto the servo itself looks fiddly.

New Lucas throttle body today but still getting intermittent rev hang and slightly odd idle. An interesting part of the rev hang is that it stops the moment I touch the clutch or brakes. My understanding is that when you slowly lift your foot off the accelerator, the TPS sends a signal to the the ECU to gently reduce fuel input so you don't have a sudden jolt effect. However if you touch brakes or clutch to change gear, it drops fuel more rapidly to idle level. However, what I seem to have is that the the ecu is holding the fuel input longer than it should, unless I touch brakes or clutch which instantly overrides and says 'drop fuel now'. Separate to this, I had an issue the other day when it was raining very heavily and the revs went very erratic and the car stalled. This had led me think about possible earth/ connection issues. Decided to sit and look for voltage drop between the -ve on the battery and the engine block to see if there is a bad earth that might be causing a messy signal between the TPS and the ECU. At idle I am getting 0 volts most of the time but very occasional flicks up to 0.2 or 0.3 volts for a second or less every minute or two. I might be grasping at straws now but perhaps this is giving me the problems. So next step, I will get under the car and have a look at the strap from block to chassis. Any advice on known troublesome earth connections and locations would be very much appreciated.

Did a lot of cleaning this morning and put it all back together but sadly, still getting rev hang and a some strange idling. I am going to order a new throttle body today and hope that a new throttle position sensor within the body will solve the problem.

Hello @Rsedmonds I've just got back yesterday from working abroad for a couple of weeks. I have the tools, cleaner and new ring next to the car in the garage, ready to give it your treatment this weekend so I will let you know how that goes. Keep me updated on your end. Glad to hear that it is still looking good.

Interesting. I wonder if the reset process through the OBD has the same effect as the battery reset. Well, I've ordered my seal, thank you for the link. I am abroad for a couple of weeks from Monday but if the seal arrives before then I will give it a go and let you know the results. In case you need it for your one, the throttle body mounting bolt torque wrench settings are 10nm according to Haynes.

That sounds like a good idea. I've given mine a clean in-situ but not been bold enough to take it off yet and clean properly due to fear that there might be a gasket under there, and in the absence of an off the shelf replacement, might have to make up a new one with gasket paper. However, after some more research and speaking to a few friends with old VWs, I am pretty sure it is just the ring seal described in the Haynes manual above so time to be brave, take it off and give it a really good clean as you say, hope the ring seal doesn't disintegrate in the process.

Nice work, inspired to give mine a go now

Sorry to hear that @Rsedmonds . Your big discovery led me to looking at my negative connections to the block but they were all in good condition so no quick fixes for me either. Do you really think the ECU will need a reset with a new throttle body? My manual does not suggest it does. See Section 6 below. I thought just a battery disconnect after replacement would do it (see the smaller screengrab below).

Hello all, Thank you @Papez for all the information. I have the same issue as @Rsedmonds with no diagnostics, see here. Perhaps also related to immobilizer, interesting to read about this. Glad you got your sorted @Rsedmonds . I'm still struggling with mine, seems tricky to get a clear method of diagnosing using the multimeter. Tempted to just put a new throttle body on and hope for the best unless anyone has any other ideas? There's a few brands out there for 030 133 064 D. - £50 - Allcarb, Apriciter - £75 - Lucas, Intermotor, Vika, Lemark - £120 - Febi Anyone got experience with any of these and how they have found them? From what I can tell, there is no gasket, just a ring seal? Correct?

Ah nice one. Can you put a link to that youtube video so I can catch up?

Hey @Rsedmonds . Not at all, all the help we can get here is helpful. Sounds like you have a very similar problem to me. Mine started in the way you describe and has recently developed into this intermittent 'rev hang' thing. Pondering whether to get a replacement throttle body and just give it a go if there isn't a clear diagnostic pathway.

Yes that is all true. But I was wondering if anyone has had experience doing the pin test on the throttle position sensor, if my diagnosis is correct, and experience replacing the body.

Hey @Thefeliciahacker , that's right. 1.6l 2000.