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Grey seems to be back in fashion because that's the colour of the one I just bought from Ford. Black per their computer but mine came grey. Same codes as George's previous post. Regards, David.

This post was extremely helpful, thank you. However, having spent many hours lying under my Gal I suspected the sensor location was reasonably accessibly from beneath the car, which it is. So it's a much easier job from the bottom without needing anything except a screwdriver to help push the wiring connector off the sensor (it has a latch which when pushed with a flat screwdriver pops off quite easily). The photo with the red arrow shows the location of the sensor from beneath the car (left side of engine), and the green arrow points out the plastic clip which holds the sensor in place. It's easy to pull out by hand. As already suggested it it best to leave the cable connected because water pressure forced my sensor out unexpectedly and I got a bit of unpleasant coolant shower! So once the clip is removed move to the side and expect a sudden burst of coolant as you pull the sensor out. If you are prepared you should be able to avoid the shower I got. Regards, David

Hi folk. I'm trying to diagnose a 'Charge Pressure Control' error. I have a separate thread for that and this one is to try to understand Vag-Com and my Gal better. ElsaWin shows three valves relating to 'charge pressure' and I would like to know which measuring blocks in Vagcom relate to these please: 1. N75 'solenoid valve for charge pressure control' - Is this Block 11 'D.cycle MAP'? 2. N239 'change-over valve for intake manifold flap' - I can't find this one 3. N18 'EGR valve' - Block 3 'EGR duty cycle'? Thanks, David.

The limp mode occurs at 1400-1500 which is why I don't think it is the turbo. It's my understanding that the turbo will be at full boost until over 2000, some say over 2500. If I accelerate firmly to move through the troublesome spot quickly, the car performs correctly and does not trigger limp mode. The jerkiness appears to happen at 1400-1500 irrespective of ground speed. So does this suggest it could be something mechanical in the engine but less likely to be transmission? If transmission, would it be more likely to relate to ground speed? I pull out of my drive onto a twisty residential road on a slight decline. So other than establish motion I travel quite slowly with little power applied for a few hundred yards. Under low load or consistent cruise at any speed, the auto seems to always try to select a gear that runs the engine at 1400-1500 rpm. The car surges and slows and can get into a non-violent but nevertheless noticeable oscillation which rocks me back and forth a little if I let it stay at that rpm at low speed. Something that controls acceleration seems to stick. I think this implies something physical that moves rather than electronic. I don't have the full version of Vagcom so I doubt if the free version does the graphs? Thanks, David.

Hi. My 2001 auto Gal MkII (60,000miles) has become jerky at what appears to be one engine speed of about 1400-1500rpm. This is probably because most of my driving seems to be at that rpm. It is most noticeable when the motor is cold and when driving slowly. I suspect that something mechanical is worn out and is sticking. At low speeds and gentle acceleration the torque of the engine makes the car lurch a bit unless I either back off or accelerate through it. At higher speeds I can sometimes feel a slight 'oscillation' but it is damped by the inertia of the car. It's rare for the issue to cause further problems, but sometimes it cuts power until I stop and restart the engine. Having cleaned sticking turbo vanes some months ago I recognise the symptom and I don't believe it is a turbo problem (I believe turbo vanes open at a higher rpm). I suspect now that it is either the boost control solenoid or the vane mechanism in the inlet manifold. VagCom gives the errors below. I've had the 17664 for some time so I think the main error is the good o' 17965. I assume either the solenoid or inlet manifold vane sticks. Would both cause an over-boost situation? Advice please. Thanks, David. 17664 - Engine Coolant Temp Sensor (G62): Open or Short to Plus P1256 - 35-00 - - 17965 - Charge Pressure Control: Positive Deviation P1557 - 35-00 - -

Yes, well spotted. This definitely has something to do with it!

I've had the car since new, over 5 yrs, and its been like this all along. I don't believe it will be a fault. The box will have been programmed to change under predetermined conditions and these just happen to result in a flat spot just above 5mph when the engine revs have also decayed to idle. We need revs to generate turbo boost and it takes that second or so to get enough to give some urgency. I guess I'm curious if this is something that the full version of vag-com can change, or other chipping techniques? I can use the manual override but you don't know in advance of arriving at an intersection if you need it. The auto is pretty smooth over the rest of the rev/speed range. The most reliable approach for taking a gap is to stop to ensure it is in first and then it charges off just fine. But sometimes you arrive and see an opportunity but have to remember that it may just coast for a scary moment...

OK, since you helped me fix my turbo problem so well, here's a 'fine-tuning' question... My auto does not change down from 2nd to 1st until below about 5mph. In practice this is usually slightly slower than my arrival speed at roundabouts. So its very common for me to enter a roundabout just over 5mph in 2nd. With low engine revs it takes well over a second to develop much urge so trying to nip through a gap can be risky. Hitting the accelerator hard does not help as the kickdown to 1st takes that second or so anyway. Do other auto drivers have the same flat spot? I think I would like the auto to change gears from 2nd to 1st at a slightly higher speed. Can this be adjusted? Thanks, David.

Happy to share my experience. Thanks for the pinned link. David.

The job is now done. Thank you for the help in diagnosing the problem and inspiring me to fix it myself. I've had a few 'cold' starts where I have pushed the car without any problems. No error codes on VagCom. I've tried to record many of the challenges on a new site: http://galaxytdi.googlepages.com/turbo1 Thanks again, David.

Oh bother! As I have been trial fitting things I noticed the one gas recirculation pipe has been chaffing. The 'dent' actually bulges on the inside and is nearly warn through. It seems to have been caused by the clamp indicated. I hope another mate can weld stainless (which is what I think the metal is).

Latex gloves, scouring pads and lots of elbow grease and sore fingers. The soot comes off very easy. However there is a 'varnish' buildup in many places which is very difficult. Vagcom/revving engine will help with the soot but the varnish is less likely. The thin disc still shows some of it. On initial reassembly, some vanes were still catching a little. So I took fine wet&dry to it to remove the remaining varnish and to deburr the scratches. Now it is fine. The metal on both discs and the vanes is so hard I think it would be fine to use fine emery cloth on all the hard bits. I decided not to touch the impellor as it is quite delicate.

The tolerances in the vane chamber are extremely tight. Having started reassembling mine, simply swopping the three spacers around made a difference in how freely the vanes moved. The spacers are only 1/100th of a mm different in length. The design relies on the vanes being exercised to keep a clear arc. The vagcom feature sounds excellent for those of us who don't use the whole rev range frequently. I agree with Tim that penetrating oil on the actuating arm will do no good. Even if you get any into the chamber it will simply drain to the bottom and evaporate away or get blown out. The vanes move between two discs. Both are extremely hard although the main one through which the vanes are mounted is thick and solid. The other one is fairly thin. It appears to have the same hardened surface on the one side but the other side reveals two finishes. This probably means it is coated or has some fancy case hardening. I think the thin one is not as as hard because mine is scored where I suspect the vanes spent most of their life and the vacuum probably keept trying to make them move. I thought you might be interested in how much movement there is. My actuator arm moves about 11mm now that it is clean. These are the approximate vanes positions in the closed and open positions.

Well the torx screws freed quite easily after an overnight soak in WD40 and a bash with a hammer/nail. Even the circlip crawled out of a corner so things are looking up. So now time to get the turbo clean and my hands black with soot...

I've got the turbo open now. One bolt needed heat and another was very difficult. I ended up cutting its washer with a dremel cutting disk and this relieved some tension and gave another surface to exert leverage against with a punch. Having removed the vacuum actuator, the arm coming out of the turbo still only moves 2mm. The actuator itself moves freely against its internal spring. The dirty side opened easily with some light hammer action. After removing the actuating ring some vanes are fee, some are notchy and some barely move. The Torx head bolts are not unscrewing yet. I presume an overnight soak with WD 40 might help. The circlip holding the actuator arm on went zooming off into an unknown corner of the garage so if I don't find that I will need another from somewhere. Ideas? A post somewhere said a new turbo cost

Well, the job has started. I have the turbo off and will try to crack it open tomorrow. However, it turned out to be a much bigger job than I expected. It took two of us most of the day. Nevertheless, provided you have a good jumble of tools between you it is not all that hard; just very tricky getting access to the bolts. I was unable to loosen any of the 'easily' accessible bolts that hold the exhaust part of the turbo together (despite having applied WD40 almost even night since Wednesday). So the only other option is to remove the exhaust manifold with turbo which we did. I had hoped to be able to drop the manifold out through the bottom but this looks impossible (without removing the drive shaft). So we then removed the inlet manifold and exhaust recirculation bits. We did not realise until the end that the big cover across the top of the engine compartment gives considerably more space when working from the top. So although it remains necessary to remove all the inlet parts, we may have dismantled more than necessary. We will see if we can get stuff back in a more assembled state later. The big 17mm nut holding the oil feed pipe would not unstick from the pipe (as described in the above PDF). So I have the extra hasle of replacing this. However, another writeup I've seen recommends replacing this anyway. The exhaust bolts have thick washers; one of those are still missing. Many gaskets to replace and probably many of the nuts.

Tim, I don't have a firm view on this but would prefer to get the whole thing out for cleaning. I've been photographing it quite extensively and have a few pics on the link below. I think our approach will depend on our limited abilities, tools and rusted bolts! I've started soaking them with WD40. http://galaxytdi.googlepages.com/turbo1 Hijacker, its my understanding that the EGR valve ('N18') is part of the vacuum system. If I'm right it won't be soot that's causing any problems you may have. The 'goo' passes through the compressor and cooler, gets burnt in the engine and exhausted through the vanes/exhaust. My, am I starting to understand this engine? David.

Although the actuator seems to be spring-loaded, with the motor off it is possible to move by hand the arm coming out of the turbo. Mine is very rough and notchy; no wonder its not happy. Sometimes when I hold a constant rpm with the throttle, it surges and fades which I interpret as the vanes sticking and then freeing up as the vacuum tries to move it. Since I'm expecting this dirt to be trapped between the ring used to change the vane angle and the housing, I don't see the goo making significant progress. I can see that it could help free vanes from sticking, but not the ring. I will try to remove the actuator in situ next to confirm that it is not sticking. At the moment the two bolts holding the bracket are not budging. The vanes part of the turbo is built into the exhaust manifold. So removing that is likely to be 'somewhat difficult'. I hope to take a closer look on Saturday, removing it if it is within me and a mate's capability. I'll try to record the process if we do it.

I received the Power Boost that I ordered from http://www.gbdriver.co.uk/. Good price and second day delivery included. I have slightly greater actuator movement now when cold (~4mm vs the ~2mm previously). Movement when hot is no greater. I think I get slightly more revs before it goes limp when cold as one might expect. I have been revving the engine between changes so it's hard to say whether its from that or this gunge.

Scrote, I've not noticed the oil leak you mention. My Glaxy does also manifest the problem after leaving it parked for say 20 minutes after running at full operating temperature. The turbo does have space around it so I would expect it to cool quicker than the rest of the engine. This remains consistent with the temperature-related occurence, and clearly my reduced vane movement is something that needs attention. In trying to rev it more, I realise that my style and the very nice 5 speed auto usually keeps the revs well under 2,500. Unless my changed driving style and this magic goo does its stuff, I am psyc'ing myself (and a mate!) to take a closer look at the turbo. Thanks for the Power Booster lead. Their web site has many encouraging reports although the ASA found little scientific evidence to justify their claims a year ago. At

I've been trying to get my mind around how the VNT works and how this could explain my problem. Thanks for the link and other advice Tim and others. It seems that the vanes should normally be wide open when the engine is off (the no vacuum failsafe position), fully closed when the engine is first started (to maximise low rpm boost from the small exhaust flow), and opened again as rpm increases to manage the turbo speed/boost (as exhaust flow increases). My photos suggest that I get stuck somewhere in the middle of this movement when the engine is cold. Exercising this movement with different rpms should free it up a bit and help confirm that this is all or part of my problem. I will drive with a wider rpm range initially to see if this helps. How hard is it to remove the turbo and how practical is it to open it up to clean? What I am now a little puzzled about is how limp mode works. It feels like and is described as 'no turbo boost' but the turbo speed is mechanical and it seems to me that this can only be influenced by the vane position. I would be interested in knowing what the ECU 'switches off' when it goes into limp mode. David.

Good idea. I will do this for a while and see if it helps. David.

I have now also tested it when hot. Much greater movement. The shaft is about 6mm diameter so the movement is about 8mm when hot and I would guess about 2mm when cold.

I have now checked the VNT movement. It is very small between starting and stopping the engine. I have two sets of photos below to illustrate this. There is a audible vacuum 'action' and obvious physical 'jolt' from the actuator when switching the engine on and off. So I think I have good vacuum but sticking vanes? I assume the vanes free up when the metal heats up and expands. Does this sound likely? Next steps?