Hi there, I have posted on this before, have a 2.5 tdi that initially (cold) fires on a couple of cylinders then dies, then fires on second crank, but lumpy for a few seconds and smoke overtakes the car, smells bad (diesely, not oily smell).

Thought I had a dodgy glowplug or two. Even bought a set. Then read on the internet that glowplugs can get seized in the head, so decided to test them all for continuity before removing and replace only the ones that need doing. Soaked them all in PlusGas too, in case of removal, to maximise chances of trouble free removal.

Then invested in a cheap Maplins multimeter. Must say a cracking piece of kit for £7!

Checked them all, they are ALL fine!

BUT, two of them were disconnected. Reattached the loom, but no change to start characteristics.

Also noticed that some of them looked a bit shiny, like they were new. I suspect the previous owner had these starting difficulties then gave it to some monkey who played with it for a while then forgot to reconnect the difficult to reach plugs.

It is strange that it starts equally badly with those two plugs now connected up.

I plan on checking next if power is fed to them at all, maybe I have a blown fuse or damaged loom.

Pretty new to this car, so don't even know where the fuse box is!

I don't want to be a prophet of doom, but this could be the beginnings of the dreaded Bosch VP44 syndrome. These electronically controlled rotary pumps were not the best idea - putting loads of electronics inside a diesel pump on an engine is asking for trouble - and most end up giving it. One great advantage of the PD system is that there are no electronics other than transducers on the engine.

Your best bet would be to have a diagnostic check made at a Bosch repair centre - I suspect the timing actuator or ring has packed up. Don't waste any time with VAG unless the vehicle has a warranty - but even if it has, it's worth getting a Bosch report first. This is because these pumps are expensive and the VAG denial machine will go into overdrive at the first sniff of trouble.

If you are checking the supply to the glowplugs, on PD engines, it's PWM controlled to 7V so a Maplins meter won't give you a true picture. Being older technology, the V6 may have glowplugs running at system voltage (11V) so see what the marked voltage is on the plugs if you take one out.

Hope you get it fixed without too much trouble.

rotodiesel.

Edited 23 April, 201016 yr by rotodiesel

I don't want to be a prophet of doom, but this could be the beginnings of the dreaded Bosch VP44 syndrome. These electronically controlled rotary pumps were not the best idea - putting loads of electronics inside a diesel pump on an engine is asking for trouble - and most end up giving it. One great advantage of the PD system is that there are no electronics other than transducers on the engine.

Your best bet would be to have a diagnostic check made at a Bosch repair centre - I suspect the timing actuator or ring has packed up. Don't waste any time with VAG unless the vehicle has a warranty - but even if it has, it's worth getting a Bosch report first. This is because these pumps are expensive and the VAG denial machine will go into overdrive at the first sniff of trouble.

If you are checking the supply to the glowplugs, on PD engines, it's PWM controlled to 7V so a Maplins meter won't give you a true picture. Being older technology, the V6 may have glowplugs running at system voltage (11V) so see what the marked voltage is on the plugs if you take one out.

Hope you get it fixed without too much trouble.

rotodiesel.

Thanks Rotodiesel, I'll carry out a voltage check, doubt they will be PWM controlled on the V6 lump for extended burn on cold starts, but good comment, will keep it in mind.

Luckily I have a Bosch centre 1 mile from me!

Looks like a shed though. Will give them a call.

If it is the pump, will the timing belt etc etc have to be removed, or is there a secondary belt for the inj pump so the front end can all stay intact? I don't mind paying for a new pump, but dreading the thought of 5 hours labour charge (or whatever it is).

Just rang my local Bosch service centre, explained the symptoms to the guy on the phone who seemed quite knowledgeable, he said it sounded like an air leak, porous pipe or connection on the feed to the pump or the diesel filter. They plan on doing a vacuum test on the system initially, so I've booked it in for 4th May!

Let's hope it's just a silly pipe or jubilee clip.

Just rang my local Bosch service centre, explained the symptoms to the guy on the phone who seemed quite knowledgeable, he said it sounded like an air leak, porous pipe or connection on the feed to the pump or the diesel filter. They plan on doing a vacuum test on the system initially, so I've booked it in for 4th May!

Let's hope it's just a silly pipe or jubilee clip.

Lets hope so, but if it doesn't, get some good quality inj cleaner in half a tank and go for a nice high speed ride.

Update:

Took car to Bosch service centre, apparently only one out of 5 glow plugs worked, the 6th one broke in the head! They have checked the diesel pump and it was OK.

So I now need a head removal, thread repair job: bill £1000!

I have asked them to renew the belt (though it was done 4000 miels ago, and a new water pump too, as this was not done at the time when belt/tensioners were done by main dealer. False economy in my opinion, so we will use the opportunity to fix that.

But didnt really anticipate all this when I woke up this morning!

Very careless of them to break it off in the head. If there is still a compression seal, why not leave it - the engine will start perfectly well with 5 working glowplugs. You can avoid a CEL by wiring a good plug externally to the engine and connecting it to the lead of the broken one. Find a safe place for it.

It's just not worth spending £1000 on an old Superb - if it can be run as it is, leave it alone. Beware, money pits start like this.... (fuel pump next month).

rotodiesel.

Very careless of them to break it off in the head. If there is still a compression seal, why not leave it - the engine will start perfectly well with 5 working glowplugs. You can avoid a CEL by wiring a good plug externally to the engine and connecting it to the lead of the broken one. Find a safe place for it.

It's just not worth spending £1000 on an old Superb - if it can be run as it is, leave it alone. Beware, money pits start like this.... (fuel pump next month).

rotodiesel.

They say the glow plug that broke off could fire-out like a projectile at some point. If I understood correctly it started coming off the seat and then broke.

I know it will fire perfectly with 5 g/plugs but nervous about the above statement. What do you think? I will pop into the workshop this morning to see with my own eyes whats going on.

They broke it; it's down to them to get it out and fix it at their expense. I presume you're "happy" to replace the cambelt and waterpump at your expense if the head's coming off and the belt being disturbed anyway.

If "it started coming off the seat" then broke - they're incompetent. There is also a fair chance that somebody with some skill could get the plug remains out with an extractor - if it moved once, there's a good chance. The "projectile" story sounds like scaremongering - as perfected by VAG and 4 year cambelt changes. It it's stuck to the point where it broke off and is mostly screwed in, it won't fly out. Getting it out is the problem...

Do you want people like this dismantling your engine?

rotodiesel.

If "it started coming off the seat" then broke - they're incompetent. There is also a fair chance that somebody with some skill could get the plug remains out with an extractor - if it moved once, there's a good chance. The "projectile" story sounds like scaremongering - as perfected by VAG and 4 year cambelt changes. It it's stuck to the point where it broke off and is mostly screwed in, it won't fly out. Getting it out is the problem...

Do you want people like this dismantling your engine?

rotodiesel.

Good points rotodiesel.

I rang up a couple of places specialising in cylinder heads and they did not want to touch it while fitted to the engine.

Just need the car back on the road asap.

In hindsight I could have tried to drive it with those 5 plugs working and one broken one remaining in the head. But taking the car to conti europe in a fortnight so need to make sure it is good.

It's an official Bosch place, so considering writing to the HQ and complaining and asking for a percentage contribution to costs as they screwed up after all.

Not sure what grounds I stand on, considering the car is 8 years old though. But you could argue I never gace them permission to remove glow plugs, I only took the car in for a diesel system diagnostics as I genuine thought something was wrong with this, either air in system or pump timing, then 3 hours later they ring me to say they busted the glow plug! They screwed up, they are gonna fix it, then I complain to Bosch. Not sure what sort of customer service to expect really. If it was a main dealer maybe it would be a different story.

Popped into garage today. saw my engine block sitting down there, still waiting for cylinder head to come back from m/c shop, had a chat with the supervisor. Good news is that the bores look lovely, no real sign of wear, but you can see that one of the injectors had rotated a bit due to the carbon marks on piston crown. The garage supervisor said it was a bit loose, so they will realign and secure. Apparently there was evidence of previous attempts to remove the glow plugs and they were all leaking past the seals. I think I might have found the reason for the sale of the car! At some cost.

The timing belt was replaced by Marlborough Skoda last summer, and you may recall from one of my previous posts the poor headlight alignment with the fenders/bonnet etc, and a couple of loose hex screws I found, which made me suspicious of the standard of the whole workmanship... Well - the garage supervisor is now telling me that there were a lot of loose bolts all over the place, sprockets, tensioners, pulleys, you name it! Shocking. All that, plus the fact the water pump was not renewed when the belt was replaced with the tensioners etc, considering the overall job cost, (£700) not replacing the water pump was just daft. So we'll rectify that this time. Plus 6 lovely glow plugs, and hopefully she will be as god as new. I will also ask them to put some copper slip on the glow plug threads and reduce the torque a couple of Nm.