The VP44 is the spawn of Satan (and Dodge). I expected the 00550 to go away when the faulty needle lift sensor was replaced. If I had to guess, something has been driven to it's limit in a vain attempt to maintain timing when the NLS failed and has stuck. The last time I saw this specific problem it was fixed with a mallet and a block of wood. A few gentle taps all around and I heard a clunk. All was well after that.

Well, there was a lot of speed and injection advance timing hunting while it sat on the driveway, during fault-finding, and post NLS injector replacement while bleeding the system, but I did not drive it with the NLS fault except on day 1, probably 200 meters.

How do I check static timing?  Do I need to buy all the pegs, peg it up, and see it that way?

What about the cold advance valve 100% position at 50 deg C?  Is this normal?

Anything I can do with VCDS, like spanning from "early" to "late"injection?

Mallet approach... I love it!     

Is the cold advance valve what moves the timing from early to late during the Basic settings procedure in VCDS?  I suppose if it is stuck then it won't move.  Or are we saying something else may have got stuck advanced and now cannot compensate for it.

Edited 8 December, 201312 yr by oh_superb

From memory, I just tapped the pump body on all sides with the engine off. I was just starting to think that someone was yanking my chain, when I heard a clunk.

Check fuse 28 and that the lift pump is running. The VP44 EDC does the all the pump control - not the ECU. The ECU talks to the VP44 EDC via CAN-Bus.

Disconnect the battery and wait 10 minutes.

Let it idle up to temperature and run it for 20 minutes. The pump can be a pig to get all the air out.

I don't think you have a timing issue but you asked...

As you know there are two toothed belts. One drives the two camshafts from the crankshaft and the other drives the VP44 from one of the camshafts. You can check the pump timing using VCDS. There are slots on the camshaft drive gear that can be used to adjust the pump timing.

The cam-crank-cam timing is adjusted with a cranklock screw and two camlock brackets. The screw is inserted at TDC and the brackets are inserted into the cam slots. The cam slots are under covers that break when you remove them.

From memory, I just tapped the pump body on all sides with the engine off. I was just starting to think that someone was yanking my chain, when I heard a clunk.

Check fuse 28 and that the lift pump is running. The VP44 EDC does the all the pump control - not the ECU. The ECU talks to the VP44 EDC via CAN-Bus.

Disconnect the battery and wait 10 minutes.

Let it idle up to temperature and run it for 20 minutes. The pump can be a pig to get all the air out.

I don't think you have a timing issue but you asked...

As you know there are two toothed belts. One drives the two camshafts from the crankshaft and the other drives the VP44 from one of the camshafts. You can check the pump timing using VCDS. There are slots on the camshaft drive gear that can be used to adjust the pump timing.

The cam-crank-cam timing is adjusted with a cranklock screw and two camlock brackets. The screw is inserted at TDC and the brackets are inserted into the cam slots. The cam slots are under covers that break when you remove them.

 

You mean the VP44 is a pig to get all the air out?

Could some air still be giving me the issues I am experiencing?

While the engine was running erratically (bleeding injectors on the RH bank) I did see air going through the clear line into the injection pump, I thought this was due to the injector spill lines containing air and engine/fuel being cold so recirculating the aerated fuel around the engine bay rather than sending back to the tank.  Anyway, that cleared up after a few minutes.

Why would a dysfunctional / dead lift pump cause the IP to run too advanced?  Cavitating and out of control?

Will try the mallet treatment tomorrow, worth a try, and will also check Fuse 28 beforehand.  What if fuel filter is giving too high a depression?  Not been changed for 25000 miles, but the last thing I want is to introduce another variable into the system, but if it is considered to be another possibility then why not.

Under what condition does the lift pump operate once ignition is ON?

 

But just to re-iterate: car ran perfectly, filled up with fuel (Asda - used the pump many times before), then did another 50 miles, engine off, 2 hours later engine on, and bang, noisy and no power. S0 it was a step-change in behaviour, like heat soak related, or warm re-start shake related, or something like that.

I am starting to think stuck advance ring or whatever it's called inside the pump, but will give the lift pump a try, I suppose if i get the missus to turn ignition on with me in the boot, I should be able to hear it run for a few seconds, right?

Edited 8 December, 201312 yr by oh_superb

IIRC, the advance cam ring is controlled by fuel pressure. I usually bleed all six injectors. 25000 miles is OK for the fuel filter. If you run the engine at idle you should hear the pump run. At idle, the VP44 can suck enough fuel to run but at higher loads the feed is insufficient.

In theory, replacing injector 3 and bleeding the line is all that is required, but I've seen a few cases where fuse 28 has blown (not sure why) and a few VP44s that have required rebuild/replacement.

The cam ring advance servo is operated by the incoming fuel pressure fed to the VP44 rather than transfer pressure generated by a self-contained pump. This is one of its downfalls. If the VP44 feed pressure is insufficient, the servo plunger frets in the bore due to the reaction forces on the cam ring generated by the HP plungers, and eventually wears it to the point of stiction. Bosch failed to realise that feed pressure is applications dependent and will also depend on fuel filter pressure drop. Making such a critically dependent operating parameter for the VP44 reliant on these external factors is just plain stupid.

 

The VP44 was probably born as a result of the expiry of the Hartridge patent originally held by CAV. Bosch should have considered the working principles of radial piston pumps more carefully before designing one. The CAV pumps always had the cam advance actuated by transfer pressure and did not fail in this way.

 

The lift pump on the Superb will only run very briefly on "switch on" - fold down the rear seat and remove the (rusty) access lid to check. Unless you have filled with some dirty fuel, 25k miles is OK - I change my fuel filter (PD) every 30k. Use Mann & Hummel or Bosch filters only.

 

rotodiesel.

Thanks Roto, that info is useful.

So if the lift pump is not working, could that mean that I may only need a new lift pump?  What sort of pressure is required on the pump feed side to activate the cam ring advance servo?  

Does the lift pump operate continuously once the engine is "idling" in order to generate a slightly positive pressure feed to the IP?

Again this morning on cold start the idle speed was hunting.  Yesterday when it was warm (50 deg C) it idled smoothly and too advanced.

I'm close to giving up on this car, and either handing it over to a garage or ebaying as is and getting a trustworthy French alternative.  I ran French diesels for years and they never gave me problems.  For a start they had priming pumps built in.

IP will be around £700 for a recon unit, plus fitting.  I'm making some enquiries now, as I have the morning off work.

I suppose I could fit myself, but the requirement to re-program the ECM is outside of my DIY scope.  Plus the re-priming of 6 HP lines frankly scares me, 3 was bad enough yesterday.

The other concern is that even if I did fit a new one (or had one fitted by a company) I am not certain how long it is likely to last, as it largely depends on factors outside my influence, and these things are like Swiss watches, far too complex and tight tolerances.

The lift pump in the tank runs continuously as long as the engine is running or being cranked. It stops when it sees a "no speed signal" from the ECU, such as at key on without a crank.

 

I don't know what the spec for the VP44 feed pressure is, but some of our American friends have fitted bigger lift pumps to some vehcles (?Dodge) to overcome this problem. One problem may be that the PD cars will actually operate without a lift pump - the tandem pump will happily pull the fuel out of the tank, so the spec for feeding the VP44 with the same lift pump may be marginal.

 

I would not give up too soon - and above all don't necessarily go for a French diesel. There are frying pans and fires and the diesel world has moved on since the XUD engines were designed. Thanks to our politicians, any diesel you buy now will be stuffed full of electronics (+ a DPF) which will not generally last as long as well designed mechanical parts.

 

The French are not to be trusted with electricity. I have been working on a Citroen HDi van which has the ECU under the bonnet in the front RH corner - the first thing to mangle in a minor prang. It also suffers under-bonnet temperature cycling and rain water ingress into the connectors - merde! The VAG CR diesels are not bad, as long as the HP pump survives and the DPF pressure sensors don't fail. At least the ECU is in a protected location. The CR engines require high and consistent fuel lubricity.

 

I have no personal user experience of the VP44 - I just study the drawings and examine failed parts. Your best bet is to find a good honest independent Bosch specialist. He will have seen this sort of problem a thousand times and will give you a fair judgement. I'm pretty sure you are now at the stage where detailed interrogation of the pump is needed.

 

rotodiesel.

Edited 9 December, 201312 yr by rotodiesel

I did not take the lift pump cover off, like you say three rusty screws there, but lifting the carpet and sticking my head in there I certainly can't hear any pump noises.  Are they very quiet, or should I be able to hear it through the hatch?

Absolutely silent on key-on.

Is there a possibility that all these issues are caused by the lift pump, and that the damage is (1) irreversible (on the IP), or (2) no permanent damage and once I have changed the lift pump all will be good?

 

BTW, checked fuse 28 (lift pump, as suggested above) and it's OK.

Edited 9 December, 201312 yr by oh_superb

It depends on how much fuel there is in the tank. If it's above 1/2 full, the lift pump is difficult to hear, but you should hear it close to with the carpet up. If the tank is below about 3/8 full, the lift pump noise is very evident - I can hear it from the driver's seat with all trim/seating in position at key "on".

 

I always make it a policy to run the tank generally between 1/2 and full, letting it go low only occasionally on a journey. These crappy electric pumps run hot and are better fully immersed in fuel to lengthen their life. Although they run in a "pot" of fuel, unless they are surrounded by cold fuel sloshing around, they get far too hot for my liking.

 

A bad lift pump could be the cause of your problems - consider powering it up separately and doing a flow test at the filter inlet. You would have to shift that rusty lid and have a fight with the connector. The VP44 will not welcome feed pump failure...

 

rotodiesel.

Edited 9 December, 201312 yr by rotodiesel

 

I'm close to giving up on this car, 

 

While I empathise, I've also got to say no-ooo  , hang on in there Oh S, its all part of the journey.  The thread's way too technical for me, but I'm still reading with interest and hoping you get it sorted okay.

 

Gaz

So if the lift pump is not working on power ON ignition for 3 seconds, and I get in there and disconnect the connector and try jumping straight from the battery and it turns out it's dead (or relay failed) then do you think it's initially worth trying to replace the lift pump and / or replace its relay (whatever is causing it not to work) as it may make my car a runner again with the current VP44?  You mentioned above that the IP relies on positive feed pressure to make it work OK.

My tank is nearly brimmed, I only did 50 miles post re-fuel - but I should be able to hear it, our street is traffic-free, quiet, and I was buried in the boot with my head stuck to the floor but could hear nothing.  In fact I don't remember ever hearing it to be honest.  I know on some cars it's obvious, but on mine I've never heard it since I acquired the beast 4 years ago.

I wonder if the VP44 would have survived all this time with a non-working lift pump.

 

One more question: if I did get another VP44 off a scrappy, identical part number that came off a Superb automatic, would the Bosch ECM need programming to my car or is it likely to work straightaway.  For me this is an important consideration if I do embark on this DIY adventure, as relying on garages is not something I frequent.

Edited 9 December, 201312 yr by oh_superb

The other issue I now have is, if I were to fit a used pump (off of another SUperb with the same engine and transmission), it would appear based on some Googling action that the engine may not fire-up until I have adapted the ECM on the Bosch pump to the Immobiliser/ECU?

Is this something that is possible on a used pump and can it simply be done via VCDS?  Do I need any information from the seller of the used pump, like does he need to provide a PIN code or something from the donor vehicle?

This is getting a bigger pain in the proverbial by the day.  Quick replies are really welcome.

 

Also what sort of feed pressure into the VP44 is expected on the Superb? I'd like to test this.

Edited 10 December, 201312 yr by oh_superb

Don't know all the answers but am really interested in the results of your quest .... for obvious reasons.

 

Regarding the lift pump, have read around a bit and it seems like the function of the lift pump is to supply way more fuel than the VP44 needs for the engine, the theory being that it not only supplies the fuel, but also recirculates fuel back to the tank, thus cooling the VP44 and generally keeping the fuel cool.

 

There are lots of American truck forums where owners have fitted booster pumps to give a better pressure at inlet of the VP44 and if you google "tapped banjo" there are even companies over there that sell a banjo bolt with a thread for a pressure gauge or switch to be connected to so that they can keep an eye on it. Seems that 15 PSI (1 bar at the VP44 is the generally accepted OK figure for the modifiers.)

 

Regarding the pressure at the inlet of the VP44 on the standard pump, that seems a little more difficult to find, but effectively any pressure after switching on should show that it's working.

 

If the lift pump has failed, then the VP44 is working in the worst possible way. It's essentially a positive displacement pump, so it will suck fuel into itself, but having to suck fuel through the defunct lift pump and the fuel filter will mean big pressure losses and as there is no fuel recirculation, that fuel will get hot and as it started life with only the head pressure of the fuel in the tank, then the odds are that the VP44 will be pulling a vacuum at the inlet.

 

Lower pressure and hot fuel could possibly equal cavitation in the pump as the fuel valorises in the low pressure at the inlet and the bubbles collapse in the high pressure at the outlet. Cavitation will erode anything over time .... it's horrible and sounds like sand being pump when a centrifugal pump is cavitating when pumping water with a high friction loss hose on the inlet.

 

I'm tempted to try and get hold of one of those banjo bolts - apparently they fit on the "test port" of the VP44, but I haven't lifted the bonnet yet to have a look at what they mean.

 

Good luck ... hope you resolve it.

Thanks mate. I've also been thinking about installing some sort of pressure monitoring kit!

The car is in a garage now. Gave them the symptoms and have also told them lift pump may not be working. Pump is off to a diesel specialist who will run it on a test rig. Hope they get it fixed soon.

OK, good news, the car is back in action, purring along!

A diesel specialist has rebuilt my injection pump.  Apparently, the advance servo part of the electronic control unit was broken.  A rig test has shown this.

They then took the pump apart and gave it a new lease of life.

In combination with the new injector number 3, now the engine is idling so smoothly, it's never been that good in my ownership.  Last night when I got home I had to leave it idling for a minute just admiring the smoothness!

I could swear the car is also more responsive.  

If I had a logical head screwed on these shoulders, spending £1600 of a car worth £2-3k was not going to be an option, but I know at 120k miles she has many more miles in her, I do not have any corrosion problems, new tyres, those Bilstein shocks are working a treat, no rattles, pinch bolt has been addressed (reminding myself to take them out again and re-lube before winter sets it!), so I thought let's bring her back to life - life goes on...

I was just thinking possibly about changing the other 5 injector nozzles, no particular reason, it's just when I took number 3 out, the nozzle seemed not to have all the holes working correctly, and the others may have a similar state of affairs, although the car is working "purrfectly"... what do people think, how many miles are these nozzles good for?  And does someone have the correct Bosch part number for the 2002 AYM engine (155PS)?

Good news that you got it fixed, but a shame the failure of the NLS in injector #3 probably caused the failure of the advance servo.

Bosch have told me several times that there should be no loss of performance to 80k for the injectors on the 1.9 v4 VEP and 95k for the 2.5 v6 VEP. From experience, the injectors on your car should be rebuilt at 140-150k miles.

Nice one, glad you are back on the road now

Good news that you got it fixed, but a shame the failure of the NLS in injector #3 probably caused the failure of the advance servo.

Bosch have told me several times that there should be no loss of performance to 80k for the injectors on the 1.9 v4 VEP and 95k for the 2.5 v6 VEP. From experience, the injectors on your car should be rebuilt at 140-150k miles.

Interesting comment about the NLS causing failure.  Definitely plausible.

Would an injector rebuild only encompass re-nozzling?

Do you happen to have the nozzle part numbers, or any other part numbers I may need, or do you think this is a specialist job only?

Interesting comment about the NLS causing failure. Definitely plausible.

Would an injector rebuild only encompass re-nozzling?

Do you happen to have the nozzle part numbers, or any other part numbers I may need, or do you think this is a specialist job only?

I would use a specialist. At the very least they would need cleaning, new nozzles and checking the break pressures/spray patterns. Sometimes they also need re-shimming.

I'm pleased to hear it's now fixed - so much better than scrapping an otherwise perfectly good car. £1600 was not a bad price for the considerable work involved - I wonder what sort of a pig's ear a VAG dealer would have made of it - and at what cost?

 

In my experience the Bosch nozzles are good for very high mileages as long as fuel quality is reasonable (eg. any EN590 including Tesco, but not chip fat). I have here a TUD5 on its original undistubed nozzles at 180k miles - EN590 fuel only, Bosch/M & H filters and no fuel additives. If you get reasonable smoke readings at MOT time, leave the nozzles well alone.

 

I'd like to get my hands on the idiots that decided that the VP44 would be a good place to house electronics....

 

rotodiesel.

...I'd like to get my hands on the idiots that decided that the VP44 would be a good place to house electronics...

You can blame Dodge for that and many other poor design changes to what started life as a blatent knock off a Hartridge CAV.

Guess who I used to work for...

 

rotodiesel.

The car starts perfectly and runs very sweetly, so I will leave the nozzles alone.  If I develop a leaky cam cover and the cover has to come off anyway, then may reconsider...

This was done by a trusty Bosch garage in Northampton... I have used them before, they are very familiar with the 2.5.

By the way, the pump was £1100, labour to change, including belt, and fuel filter another £180, and I sourced a Bosch NLS injector for £290 and fitted myself - dealer wanted £388 for one.  So total cost under £1600, would have been probably a £200- £300 more if I had not fitted the injector myself.

Edited 22 December, 201312 yr by oh_superb

Car starts perfectly when left overnight.  I have noticed, however, when left standing for 2-4 hours in this cold-ish weather, the glow plugs do not stay on and prolonged cranking is required for a fire-up, maybe 5-8 seconds.

I have checked the static timing and it's sitting on 1.2 ATDC when idling.

I have also noticed a discrepancy between dash temperature reading an what was read by VCDS (90 deg C and 75 deg C respectively).  I'm on my 3rd CTS in the last 12 months by the way.  The last one just read 50 deg on the dash at all times so I thought I needed a new stat.  The CTS I currently have installed is made by Hand Pries Germany, which I think is a reputable brand.

Q: is it worth advancing the SOI to 0.8 deg ATDC, though I doubt it would make that much difference

Q: perhaps the CTS is reading too low when the water is hot and too warm when it's cold hence glow plugs are not getting re-energised and it actually needs them to work. What are other people's experiences with the 2.5 these days, left standing 2-4 hrs do the glow plugs come on?

Q: I was thinking that perhaps because by NLS injector is new, the actual cracking pressures are different from the other 5 injectors leading to a different actual injection timing?

Q: perhaps the injection pump re-con job wasn't perfect and fuel pressures at cranking speeds are too low?  I think unlikely, as it comes from a reputable approved Bosch garage.

I've done around 500 miles since the work was done on the car.

 

Apart from this the car is perfect, idle is smooth, pulls really well at speed, particularly noticeable in top gear on the motorway, very linear from 60 - 90, but these lukewarm starts are annoying.