Sharan 140 SE Hunting on Acceleration + other issues

[barlidge]

Ok so my old 2003 Galaxy finally threw the big ends on Friday at 266k miles, that car never broke down on me or left me stranded in the 10 years I had it and believe me it did some graft.

So on to the next adventure - not having much time I have quickly picked up a 2007 Sharan 140 SE, I expected a few problems and it hasn't disappointed:

Issue 1
On acceleration it's doing what I can only describe as hunting, the power is fading in and out as if my foot on the pedal was lightly going up and down (its not).  Acceleration is still good and better than my 115 Gal was but something is not right.  VCDS showed up EGR errors P1404 (short to ground) and P1440 (open circuit), I have removed the EGR and cleaned all the gunk off and run VCDS output test on it and it seems to function and after a 10 mile mixed drive of motorway/back roads the error codes have not come back but the hunting is still there.

[attach=1]

Issue 2
Difficulty engaging gears
So the problem is mainly 2nd, but sometimes 4th and prob once or twice 6th - the gear stick seems to go into position but the gear is not engaged, seems to be ok with the engine not running and not so bad at low speed/revs.  The clutch doesn't show any other symptom of failing and I have tried bleeding it and checked the gearbox oil level and removed the battery tray and all the linkages seem to be freely moving so could this still be a linkage issue or is it def a box/clutch issue.

Issue 3
Not so important although would be very nice to have working, aircon shows pressure switch fault P0532 (short to Gnd), the system has some pressure in it and the display not flashing but I hope the compressor clutch isn't engaging due to the fault on the pressure switch, I am planning on just swapping the switch out to see where that leads next.

[johnnyroper]

Issue 1 itââ,¬â,,¢s hard to say what could cause that without looking, have you checked measuring blocks to see whatââ,¬â,,¢s happening when it is hunting? Maybe run a log of MAF,MAP,EGR etc

Issue 2, sounds like gearbox end shim to me.

https://www.google.co.uk/amp/s/www.darksidedevelopments.co.uk/amp/products/02m-02q-gearbox-input-shaft-shim-kit-and-end-cap.html

Issue3 I would disconnect the pressure switch and see that it goes open circuit rather than short to ground, but it does look like the switch has failed. Good thing is on VW you can usually replace without degassing etc as itââ,¬â,,¢s on a valve. I wouldnââ,¬â,,¢t rule out a regas though as if itââ,¬â,,¢s not been working for a while it could well have lost some pressure aswell.

[Chrispb]

I have a couple of the cheap MAF sensors off a MK2 that give that hunting symptom, not saying it is that but does yours look like it may have been changed recently.

[barlidge]

Some extra info I forgot to put yesterday, its done 104k miles and looking back at the MOT history and by all the child car seat bits and headrests, it's only ever been used for the school run.

Issue 1 itââ,¬â,,¢s hard to say what could cause that without looking, have you checked measuring blocks to see whatââ,¬â,,¢s happening when it is hunting? Maybe run a log of MAF,MAP,EGR etc

Issue 2, sounds like gearbox end shim to me.

https://www.google.co.uk/amp/s/www.darksidedevelopments.co.uk/amp/products/02m-02q-gearbox-input-shaft-shim-kit-and-end-cap.html

Issue3 I would disconnect the pressure switch and see that it goes open circuit rather than short to ground, but it does look like the switch has failed. Good thing is on VW you can usually replace without degassing etc as itââ,¬â,,¢s on a valve. I wouldnââ,¬â,,¢t rule out a regas though as if itââ,¬â,,¢s not been working for a while it could well have lost some pressure aswell.

Thanks Johnny, are those gearbox shims straightforward to fit?  Will look at running measuring blocks, only used them a couple of times, is it possible to record a session?

I have a couple of the cheap MAF sensors off a MK2 that give that hunting symptom, not saying it is that but does yours look like it may have been changed recently.

Thank Chris, the seller had dosed the airbox with shiny stuff so hard to see if it looked like it had been changed, will try disconnecting the MAF and see what happens.

[barlidge]

So driving into London, disconnected MAF half way, result was slightly down on power but no hunting.

[barlidge]

Little update, on the way home I went via GSF, picked up a MAF and AC pressure switch on the off chance. 

The pressure switch cleared that fault and the compressor clutch has is engaging, still no cold air but at least it's in a position to take it for a regas now.

New Bosch MAF sensor has made a difference, it seems quieter and smoother but still hunting on acceleration, doesn't seem to be do it when cold is something else I have noticed.

[SirDavidAlhambra]

Hello my friend.

Why not check your fuel filter. Maybe it has an air leak or a blockage!

Why not check your hoses.

Injector leak off pipes?

Boost diaphragm?

Idle solenoid?

Busbar and heaters?

Sometimes an Italian tune up can help a dodgy engine.

Failing that, give it a damn good thrashing like Basil Fawlty would with a branch u ripped off a nearby tree.

[johnnyroper]

You are definitely at the stage to run some logs and see whatââ,¬â,,¢s happening, could be several things causing the hunting.
EGR could still be a suspect even though you have cleaned it,not familiar with the 140bhp is it a PD engine still?

[SirDavidAlhambra]

Would it be worth spraying some EGR cleaner through the system? If that helps, then change the EGR.

EGR works by recirculating a portion of an engine's exhaust gas back to the engine cylinders which is the mechanical equivalent of breathing in your own farts and is terrible for the engine as it makes it clog up with soot and breaks the turbo.

[johnnyroper]

He has had it off and cleaned it already so spraying a cleaner in wonââ,¬â,,¢t have any effect.

[SirDavidAlhambra]

Could it be worth checking the fuel filter

[barlidge]

Have changed the fuel filter today which hasn't made any difference.  With running the logs is there a way I can record a session?  The hesitation/hunting occurs when acceleration/under load so not easy to look at the laptop.  Which specific measuring blocks should I be looking at?

[johnnyroper]

Yes you can set it to record before you head off and then when finished stop it and plot on to an excel graph so itââ,¬â,,¢s easier to see whatââ,¬â,,¢s going on.

I would start with maf,boost specified,boost actual,n75 duty and egr first to see if anything obvious sticks out as too many items on a log can be confusing. You can always do another run with different items on.

[SirDavidAlhambra]

I know this might sound crazy but is there any possibility there could be water in the engine.

I had a Ford once and gave the engine a steam clean and it would hesitate sometimes on the motorway. I think the mechanic also said something about the valves but I was too young at the time to understand what he was talking about

I really hope u get this fixed soon somehow

[Chrispb]

Measuring blocks 003, 010, and 011 it's usual to do these together especially if you convert them to a graph.
You need to get fully up to temperature first, 003 specs are for idle but 010 and 011 need to be around the 3000 RPM with throttle to the floor, ideally an uphill incline try and get a good few seconds before backing off repeat if necessary a few times.

[barlidge]

Apologies for the delay in responding, on my first  tow with it I ended up with a passenger footwell full of hot water, turns out the plastic top of the heater matrix had cracked so spent a day and a half stipping out the dash to replace that and then fount the cooling system wasn't bleeding itself properly as it was all gunked up so cleared the blockage with an airline, ran some flush through it and it seems to be better now.

Finally got to destination with the caravan two days late - on the way home I set it up for doing some logs, there were lots of roundabouts with inclines straight after so plenty of loading on there, I have a attached the logs but not really sure how to interpret them.

[barlidge]

I might be way off track here but looking at the data in block 11 and transposing into a graph (graphs are not my thing)  Would I be correct in think the grey is required boost and the orange is actual boost?

[johnnyroper]

It looks that way to me as grey line is fairly constant for periods of time where orange is all over the place.  That would certainly account for the hunting as boost isnââ,¬â,,¢t really being controlled looking at that. Itââ,¬â,,¢s rising and falling constantly.

I would check the turbo vnt actuator for smooth operation and also try and temp blank egr valve off. Blanking egr will give a fault code but it would rule in or out an issue with the boost.

Also worth checking all vac pipes for splits etc and map sensor for gunk build up causing iffy readings.

Specified boost and actual boost should be fairly similar. The log you have done shows it isnââ,¬â,,¢t but if you could do a full throttle log in 3rd from 1100rpm up to 4000rpm that will give a better understanding or actual versus specified and how well itââ,¬â,,¢s being controlled.

[Chrispb]

That does look very erratic hopefully Mark will see this and give an explanation, I did notice as Johnney said you need to reach at least 3000 to 3500 RPM with wide open throttle.

[Chrispb]

Just been reading about the hunting problem on another forum, a few people seem to be convinced it's to do with the clutch pedal switch, whether it be by riding the clutch pedal or a weak pedal return spring.

[barlidge]

Ok, was at work today but at lunch took the MAP out to give it a clean, it wasn't gunged up but I gave it a good spray with some IPA and a blow out - while taking it out I noticed one of the screws wasn't the correct one and was just in the hole for show so I replaced it with one that tightens up but although the engine seems quieter the hunting is still there.  When I got home I changed it for the one in the old Galaxy (115), slightly different part number but it fitted and so did a run, interestingly the hunting is very much more noticeable with the Galaxy MAP than the original so I did two runs one with the original and one with the Galaxy MAP which are attached below.  The graphs attached are just of the section that is foot to the floor in third from around 1500 to 4000 RPM, both on the same roundabout exit road going up a slight incline.

Hopefully tomorrow I will get chance to check the boost mechanism but my feeling is its too rythmic for sticky vanes.  Whats the purpose of the clutch pedal switch? this one doesn't have cruise control.  Can I disconnect it to give it a try?  Will also blank off the EGR when I get chance.

[SirDavidAlhambra]

Wow that looks terrible, it would drive me nuts if my car was surging like that.

Whenever Iââ,¬â,,¢ve had problems like that Iââ,¬â,,¢ve tended to put in a double dose of redex and give the engine a dam good thrashing. Might be worth a try?

One of the more technically minded people on here might have a more scientific suggestion, maybe something to do with injectors or something technical like that?

[Chrispb]

Ok, was at work today but at lunch took the MAP out to give it a clean, it wasn't gunged up but I gave it a good spray with some IPA and a blow out - while taking it out I noticed one of the screws wasn't the correct one and was just in the hole for show so I replaced it with one that tightens up but although the engine seems quieter the hunting is still there.  When I got home I changed it for the one in the old Galaxy (115), slightly different part number but it fitted and so did a run, interestingly the hunting is very much more noticeable with the Galaxy MAP than the original so I did two runs one with the original and one with the Galaxy MAP which are attached below.  The graphs attached are just of the section that is foot to the floor in third from around 1500 to 4000 RPM, both on the same roundabout exit road going up a slight incline.

Hopefully tomorrow I will get chance to check the boost mechanism but my feeling is its too rythmic for sticky vanes.  Whats the purpose of the clutch pedal switch? this one doesn't have cruise control.  Can I disconnect it to give it a try?  Will also blank off the EGR when I get chance.

Ok, was at work today but at lunch took the MAP out to give it a clean, it wasn't gunged up but I gave it a good spray with some IPA and a blow out - while taking it out I noticed one of the screws wasn't the correct one and was just in the hole for show so I replaced it with one that tightens up but although the engine seems quieter the hunting is still there.  When I got home I changed it for the one in the old Galaxy (115), slightly different part number but it fitted and so did a run, interestingly the hunting is very much more noticeable with the Galaxy MAP than the original so I did two runs one with the original and one with the Galaxy MAP which are attached below.  The graphs attached are just of the section that is foot to the floor in third from around 1500 to 4000 RPM, both on the same roundabout exit road going up a slight incline.

Hopefully tomorrow I will get chance to check the boost mechanism but my feeling is its too rythmic for sticky vanes.  Whats the purpose of the clutch pedal switch? this one doesn't have cruise control.  Can I disconnect it to give it a try?  Will also blank off the EGR when I get chance.

A lot of cars have switches on  the clutch pedal regardless of whether it's got cruise control. It reduces the torque available when using the clutch for a smoother gearchange.

[SirDavidAlhambra]

Interesting. So is it possible that if this clutch switch were malfunctioning, wobbling on and off, the car could be ââ,¬Ëœwobblingââ,¬â,,¢ a little bit when it comes to how much power is being put out? Hence the speed dips a bit when it powers down a little because of a random erroneous input from the clutch switch then it throttles back up again to compensate for the loss of power as the speed stops dropping while throttle position remains constant or when the switch wobbles back into the previous position, that sort of thing?

A very curious phenomenon... what sort of sum would our hapless Sharan owning friend be looking at if he were to get this curious switch changed? Is it a job he could do himself with parts off ebays maybe?

[johnnyroper]

Seems a strange fault to be caused by clutch switch,I would expect the requested boost to drop rather than staying rather stable. The difference in boost with the 2 different MAPââ,¬â,,¢s is quite substantial.

The actual boost doesnââ,¬â,,¢t ever reach overboost it reaches the requested boost level and drops off before building again. That looks to me like n75 is trying to back off the vac to vnt to keep boost stable but it is struggling to control it so boost drops too far and then ECU tries to build it again.

Defo concentrate on turbo control side of things vnt,vac pipes and n75

[Chrispb]

Link to another forum
http://www.vwaudiforum.co.uk/forum/showthread.php/104648-surging-when-accelerating

[johnnyroper]

Just had a read if that,itââ,¬â,,¢s crazy a clutch switch can cause erratic boost. Certainly worth trying the things mentioned in that thread to see if it makes a difference.

[barlidge]

Dave, it is a little annoying on longer journeys but keeping the driving style moderate its not as noticeable.

Chris, thanks for that link, I had a little read and did as they suggested, holding the clutch pedal up while accelerating but no difference, I may swap the switch with the one of the Gal if they are the same just as a double check.

Johnnyroper, all the vac pipes that are visible appear to be intact as far as I can see, I cut a piece of coke can out today and placed it alongside the gasket on the pipe leading into the EGR valve housing but that made no difference and strangely didn't bring the engine management light on.  Have checked turbo mechanism with a hand held vacuum pump, it seems to move freely - see video below.

I'l check to see if the N75 is the same on the Gal and if so swap that out as a trial.

One thing I did find while underneath which I'm seriously wondering if it's the cause, there is a small pipe (pic below) leading from the exhaust manifold that I noticed had soot round it, on idle it is leaking so I'm thinking when the engine is under load its behaving a bit like wind from a bumhole cuasing exhasust pressure fluctuations as it opens up releasing pressure then closing until pressure builds again and opening again but obviously very rapidly.  Somehow need to identify the part anyway as it needs changing.

Turbo mech Vid
https://youtu.be/Bihpr0CXj9w

[johnnyroper]

Thatââ,¬â,,¢s the egr pipe and yes a leak there could cause issues with lost exhaust gasses so probably best to change that and see how it performs then.

[barlidge]

Thatââ,¬â,,¢s the egr pipe and yes a leak there could cause issues with lost exhaust gasses so probably best to change that and see how it performs then.

Yes it feeds into the EGR cooler and there seems to be many variants, I'm tempted to make another coke can blanking gasket in the interim but not sure it will stand up to the heat there.

[johnnyroper]

Probably right there a coke can is a bit thin. A baked bean can might work for long enough for testing purposes?

[barlidge]

Probably right there a coke can is a bit thin. A baked bean can might work for long enough for testing purposes?

Good idea, thanks

[Mirez]

Late to the party on this one! Its going over the prescribed limit when boosting, however the ECU is still able to lower the boost level before you hit the upper limit which is why its not flagging an over boost code.

The surge is because it's controllable by the ECU (as opposed to being stuck such as VNT vanes) which is why its able to reduce the power enough to come below the line. However 'the issue' isn't reacting instantly which is why you are getting this surging as the ECU increases the level of retardation and then has to reverse the effect as the boost suddenly drops away, essentially its stuck in a cycle of over and under correcting.

1) The split in the EGR pipe is a very likely candidate as it will be allowing un-metered air in/out and but because its such a small pipe, it'll be slowly enough to not be an instant reaction.
2) N75 is the next likely candidate, the ECU will be directing the valve to back off boost so if its sticky or the vac pipework to/from it has a split then that will slow the rate of change.
3) The VNT central spindle that drives the vanes could also be on the verge of sticking although less likely as normally the vanes will clog way before you experience that.
4) Finally if the turbo itself is badly worn then you'll get these symptoms as it takes longer to reach boost so again the ECU will try harder to get to boost which then arrives later then expected so it has to back off.

[johnnyroper]

So orange is requested and blue is actual then, had that wrong way round🥴

[barlidge]

So orange is requested and blue is actual then, had that wrong way round🥴

I could be wrong but I think what Mark meant was as soon as its delivering max requested boost its trying to back off but over correcting and then having to counter correct to bring the boost back up?

Late to the party on this one! Its going over the prescribed limit when boosting, however the ECU is still able to lower the boost level before you hit the upper limit which is why its not flagging an over boost code.

The surge is because it's controllable by the ECU (as opposed to being stuck such as VNT vanes) which is why its able to reduce the power enough to come below the line. However 'the issue' isn't reacting instantly which is why you are getting this surging as the ECU increases the level of retardation and then has to reverse the effect as the boost suddenly drops away, essentially its stuck in a cycle of over and under correcting.

1) The split in the EGR pipe is a very likely candidate as it will be allowing un-metered air in/out and but because its such a small pipe, it'll be slowly enough to not be an instant reaction.
2) N75 is the next likely candidate, the ECU will be directing the valve to back off boost so if its sticky or the vac pipework to/from it has a split then that will slow the rate of change.
3) The VNT central spindle that drives the vanes could also be on the verge of sticking although less likely as normally the vanes will clog way before you experience that.
4) Finally if the turbo itself is badly worn then you'll get these symptoms as it takes longer to reach boost so again the ECU will try harder to get to boost which then arrives later then expected so it has to back off.

Thanks Mark.

Good and bad news, I removed the pipe and the split was larger than I originally thought, so have made two replacement solid gaskets, one for each end of the pipe.  I had some old HDDs kicking around and the stainless steel covers leant themselves nicely to the cause.

The result is much better low end torque and responsiveness but the hunting is still there and if anything slightly more noticeable while driving, also towards the higher end of the rev bracket it seems to be down in power and took a lot longer to reach 4000.  I could be mistaken but the turbo doesn't look 13 years old and someone has definitely been poking around down there, the vac pipe was not routed correctly and the N75 heat shield had been a little butchered but judging by how much trouble I had getting the screw on clips that retain it off it I'm not sure its been off and it doesn't look like a new valve so for the sake of Ã,£40 I'm going to pick one up today and if nothing else eliminate that.

Pics and graph/CSV attached.

[Mirez]

It'll be tricky, but can you see the part number on the turbo?

[barlidge]

It'll be tricky, but can you see the part number on the turbo?

Will give it a go with the phone camera and endoscope camera on laptop, whereabouts would it usually be?  I guess your thoughts are if its the correct turbo?

[johnnyroper]

It is usually either a plate or engraved on to the ally input housing

[SirDavidAlhambra]

@ using HDD covers to get a handy little metal sheet for fabrication into an EGR blanking plate.

I usually end up cannibalising things like baking trays for that purpose. I find that the Ã,£2.99 ones from Tescos are best - nice thick metal and not too much paint on them.

[barlidge]

@ using HDD covers to get a handy little metal sheet for fabrication into an EGR blanking plate.

I usually end up cannibalising things like baking trays for that purpose. I find that the Ã,£2.99 ones from Tescos are best - nice thick metal and not too much paint on them.

Needs must lol - I have to say while it might have temporarily fixed the problem of leaking exhaust gases it has accentuated the hunting problem, it feels and sounds like an angry beast, quite growly and not nice to drive over 2k revs now  Have just changed N75 so will do another run shortly, finger crossed.

It'll be tricky, but can you see the part number on the turbo?

Yep it was tricky and that involved getting in some funny angles to get and in focus shot of the numbers 

03G 235 010 E which according to essex turbos is hopefully correct?

Pics

[johnnyroper]

If the n75 donââ,¬â,,¢t fix it next step is vac gauge on it and check amount of vac,if vnt actuator holds vac correctly and at what pressure it operates. 3-5hg it should start to move and at 17-19 reach its max position. One would hope the turbo if itââ,¬â,,¢s recon was set up correctly on a bench tester but you never know.

[SirDavidAlhambra]

Agreed, reconditioned turbos can be a bit iffy. My own experience of recon turbos is that theyââ,¬â,,¢re rarely set up properly. Despite all the BS about having the latest equipment and calibration devices, I think they usually just leave the adjustment screws where they are when they get the old unit in and give the thing a clean before selling it on to someone else. Often itââ,¬â,,¢s not a problem because usually the fault which resulted in them receiving an old turbo isnââ,¬â,,¢t related to a faulty adjustment, but on the occasion it is indeed a problem (like it always is for me for some reason), they just give u some BS about not having cleaned the manifold ports properly before u fitted it hence there is ââ,¬Å"obviouslyââ,¬Â carbon damage and the warranty is invalid. I would always recommend a genuine brand new turbo from a proper manufacturer for that reason, not a sandblasted/cleaned up unit from a ââ,¬Ëœmom and popââ,¬â,,¢ shop despite generally preferring to support small independent businesses. Once u have experienced the inconvenience of spending hours diagnosing a fault which shouldnââ,¬â,,¢t exist because u have already put on a ââ,¬Å"newââ,¬Â turbo, getting shouted at by the wife because the car keeps conking out at 65mph, doing a turbo replacement in the freezing rain a second time just because the reconditioned replacement one was dodgy, and shelling out for new pipes and seals again, and spending hours on the phone arguing with some shirty geezer who is well versed in the art of fobbing people off because he no doubt has had so much experience of doing that, u eventually swear never to use them again

[barlidge]

Well it hasn't cured it but it is remarkably better than it was this morning, much smoother and only noticeable at certain points when accelerating, which  the attached graphs would seem to confirm.  I do have a hand vacuum pump/gauge but I'm not sure I would rely on it, will have a play with it and see what the readings are.

I have no idea if its a recon, I only referenced Essex turbos to look up the part number for the car - I have had one from them before though on my old Galaxy, to be fair I fitted that in 2010 at 124k miles and it was still running on there until about 3 weeks ago when the big ends went at 226k miles.  I have also heard some horror stories though 

[johnnyroper]

Looks like it is turbo related now then as you have eliminated the other stuff. A vac pump is next step as said above,also see if you can see what stop screw is set like. From memory basic set up is back off until not in contact with the arm then wind back in until it just touches and then go 1.5 turns. Vane gap should be approx 1.5mm and with full vac on the actuator at 2000rpm you want boost pressure between 2-4psi. Just link the 2 pipes on n75 to get max vac on turbo while checking.

[SirDavidAlhambra]

Just thought I should add that my comment about reconditioned turbos was about my own personal experiences with them generally (and not about any particular company)... I am sure there are good companies out there that do an excellent job of reconditioning them, I personally just havenââ,¬â,,¢t used one yet (including the one u mention which may well be great for all I know!)... knowing my luck I have just been using the less reputable ones so far Hehe

I have a hunch that the root cause of this problem will end up being the turbo, they really do start causing all sorts of weird problems when they start going wrong, itââ,¬â,,¢s just a shame there arenââ,¬â,,¢t any codes to go with yet

[barlidge]

Looks like it is turbo related now then as you have eliminated the other stuff. A vac pump is next step as said above,also see if you can see what stop screw is set like. From memory basic set up is back off until not in contact with the arm then wind back in until it just touches and then go 1.5 turns. Vane gap should be approx 1.5mm and with full vac on the actuator at 2000rpm you want boost pressure between 2-4psi. Just link the 2 pipes on n75 to get max vac on turbo while checking.

Thanks, going to have another look this morning, whereabouts is the 1.5mm vane gap measured?

[johnnyroper]

You need the exhaust housing off to do that, thatââ,¬â,,¢s why I said the pressure you should be seeing on live data aswell to try and save you splitting the turbo.

When I had my head off I set vane gap and then tweaked it with stop screw once back up and running, with gap set it was pretty much where it should be

[barlidge]

The vanes don't seem to be sticking at all (see vid), will adjust it up as Johnnyroper suggested:

https://youtu.be/vL5WRRdqkbk

[barlidge]

Ignore this image, cant seem to delete it.

[johnnyroper]

That is a lot of adjustment when I did mine it was a small grub screw locked with a nut that is in the body and not a rod.
Canââ,¬â,,¢t make out in picture what that rod is, does it operate the VNT from the actuator?