Did 200 miles in a morning, no problems at all, parked car, 2 hours later started up again, sounded like a bag of nails.  Stopped.

This morning did error scan and have 542 Needle lift sensor intermittent error, and 550 SOI regulation (17-00-control difference).  Then started up, fired, idling rough, flags an immediate error 550 and 542.  542 actually comes up even without engine running.

Switching to measuring blocks in VCDS it is showing it is injecting at TDC, not advancing.

So, what are the opinions of people who are VP44 knowledgeable?

Likely VP44 ECU solder joint issue?

Or is my £400 special injector triggering all these issues?

I know there are companies who will fix the electronics in VP44 for peanuts.  Reckon pump we are looking at £1100+ excl fitting (I could DIY).

I was hoping the car would make it into high miles without these issues, but disappointing at 120k...

My guess is the needle lift sensor or wiring that is causing the problem. It's showing as short to ground or open circuit. You usually get 00550 when there is a problem with the needle lift sensor.

If you follow the wire for about 18", you will find the only connector between the injector and the ECU (it does not go to the IP). It is not uncommon for a problem to occur at this connector.

My VP44 failed at 121k - ran, but in limp mode. Recon cost around £1600 - and the cambelt had done about 50k miles so was also replaced. Not many cheap options............ and you have got to be good to DIY including the re-timing!

Re-timing does not bother me, I have the tools, but expensive to replace the pump.

I read on an audi forum of someone with the same problem being resolved with a new needle lift injector.

It's definitely not the pump. You wouldn't get 00542 - short to ground or open circuit.

If you unplug the needle lift sensor, you can measure the resistance. It should be between 80 and 130 ohms.

Resistance is infinity.  Cleaned the contacts and still open circuit.  I think that's the culprit.

Question is get a used one for under £190 (90 day warranty) or a new one for £393.73.

Resistance is infinity. Cleaned the contacts and still open circuit. I think that's the culprit.

Question is get a used one for under £190 (90 day warranty) or a new one for £393.73.

Contact a Bosch service centre and ask if the needle lift sensor can be replaced.

According to Audi forums it can't be replaced as there are many people who have asked the same question.

Im tempted to cut the plug and measure wire resistance independent of the plug.  Could be just the plug itself - been known to happen.

According to Audi forums it can't be replaced as there are many people who have asked the same question.

Im tempted to cut the plug and measure wire resistance independent of the plug. Could be just the plug itself - been known to happen.

It's very common for the flylead to be the problem - either at the connector or where it meets the injector body. With the meter connected bend and twist the cable at several points to see if you get a reading.

Yes, you can cut off the plug - you have nothing to lose.

IF YOU ARE NOT DOING AN INJECTOR EXCHANGE, then you can cut away the strain relief where the cable enters the injector to see if you can find unbroken wires there.

Of course, if the sensor is gone, nothing will help

Have not cut it off, just exposed the wires half way down the loom and this has shown that the plug is OK, but the discontinuity in the cabling is closer to the injector body or within the cam cover or injector itself. I have ordered the used one and see if that fixes it.  Any tips on injector change?  Cam cover gasket to be bought or use a generic sealant?  Torque settings?  Do I have to renew the injector copper washer?  I could anneal the existing one.

First thing to do is check the needle lift sensor before you install it

PM me the VIN/engine code/year and a real email address and I'll send you what you need.

Thanks @rwbaldwin for the PM and very useful information!

Just a further question - or two - I've now taken the cam cover off, exposed the injectors.

Is a slide hammer the only way to remove the injector?  Tried pulling by hand and some grips, but stuck in.  I suppose I need a slide hammer, need to buy one.  I also suppose it needs to be a specific 17mm thread injector removal slide hammer rather than a generic one.  I have never owned or used one.

The other thing is, what is the difference between 059130202F and G?  I ordered an F.  Are the nozzles different?

I've double checked. The 059130202F is the right one for injector 3 for an AYM.

059130202G is not as it's for the BDG.

If it has 201 instead of 202, then it's the ordinary injector without the needle lift sensor.

A slide hammer is the way to go and most have interchangeable adapters (usually M8, M12 and M14).

Don't try twisting the injector as there is a locating pin on the side.

Try making a slide hammer out of vise grips, a metal coat hanger, a weight with a hole in it and a piece of wood with a hole in it. Grab the injector with vise grips. Feed metal coat hanger between jaws and twist together. Thread a heavy weight onto coat hanger and secure the other end of the coat hanger to a piece of wood. Take up the tension and bash the weight against the piece of wood.

Good luck.

Another good way to make a slide hammer which will operate at an angle to the injector is to use a length of chain with a weight at the free end. If you choose the stoutest chain which the job will accomodate, it's very effective.

 

rotodiesel.

Thanks for the suggestions!!  I will try to improvise...

Does someone know the injector HP union thread?  Is it M14x1.0 pitch?

Update: the used injector arrived.  Resistance across the pins infinity 

Sending back.

Bought a new genuine Bosch injector.  Arriving tomorrow and fitting tomorrow - hopefully.  Treating the missus to the cinema tonight so I get a car tinkering free pass tomorrow night 

Any advice on getting rid of the air in the right bank high pressure lines?  Just crack off the unions a bit during cranking?  Is it a nightmare or does it purge the air quite easily as the other bank should be firing no problems?  Been cold these days and car not run for 7.5 days now.  Worried the battery might not tolerate a lot of cranking that's all.

Here we go: finally managed to get all the bits, new return line seals, new injector combustion chamber sealing washer, new injector (from Central Auto Supplies - genuine Bosch, though no VAG part number on it.

Checked the resistance across the terminals, around 93 Ohms, so went to fit it.

Didn't do any HP line bleeding, just went in, cranked over and fired, ran lumpy (I kept my foot in), then just completely cut out, injection pump light back on.

Another crank, fires up, letting go of the accelerator drops to idle and hunts between 1000 and 1500 rpm, lots of bad smell from the exhaust....

What are we thinking, injection pump?  Or would bleeding the HP lines possibly help?

VCDS laptop battery died so have not read error codes yet.  

I have no 2nd pair of hands assistance available (for HP line bleeding) at the moment but would really like to finish the job sooner rather than later.  Any advice is really welcome!

Loosen the injector 3 union nut, wrap a rag around it and crank. Even though the sensor is good, it won't send the correct signal until fuel is flowing through it.

If you have had the engine running, the injector you replaced will eventually self-bleed.

 

rotodiesel.

Three injector lines were disturbed as I had to take the cam cover off, but I suppose the biggest problem is the brand new one, number 3.

Will try cracking the unions off while cranking.  It's just so smoky it's embarrassing

Edited 6 December, 201312 yr by oh_superb

VCDS laptop got some charge in the battery so plugged it into the car, same error codes as before.

But now at least when I clear them, the G80 fault does not come back on at the next ignition ON cycle (it did with the old injector).

So, hopefully the fault is being triggered by air in the high pressure lines.  Will try bleeding, though the battery is getting tired as the car hasn't run properly for 9 days now, and not sure how old the battery is, but I have had the car for 4 years nearly and have not changed it.  Oops, that might be another £100...  I just want to get the car back on the road, I get a lot of nagging from my better half for using her Jap Favourite motor.

Edited 6 December, 201312 yr by oh_superb

OK, bled the system with the missus, took a few attempts, lots of white smoke, nasty. Then stabilised.  Was very happy.

Stopped.  Checked error codes, only 550 present. Cleared.  Re-started, idles smooth, no codes.

VCDS, however, says cold start valve at 100.2%, specified 0.2 BTDC actual 25 deg BTDC. Coolant temp 50 degC.

When I put into into R (reverse) and engine load goes up I get knocky diesel rasp. So injecting too soon. Chickened out of a test drive!

I'm thinking dodgy VP44. Or cold start valve stuck (that's also dodgy ECU I suppose). What do you think? Or jumped a tooth on injection pump drive ?  Does anyone know at what temp the cold start advance solenoid is meant to disengage? Not taken it past 50C. But sounded too knocky to be normal TBH, though not ridiculous, but felt not right.

How many teeth does the IP have?  

How can I check mechanical pump timing in sync with the rest of the engine?  The problem first occurred on a warm start, still wondering if it may have jumped a tooth.  If the IP has say 30 teeth, then 1 tooth jump is 12 cam degrees which is 24 crank degrees, and that's not far off where we seem to be sitting at the moment, but it beats me why it would have gone advanced and not retarded.

 

I really need some help here from someone who knows the VP44 system a bit more.

Obviously check the static timing of the pump before you jump in too far. If the last drive belt was fitted correctly, it's extremely unlikely to be a tooth out - the stresses on this belt are not high.

 

Unfortunately one of the VP44 party acts is wear in the advance servo bore which results in a stuck cam ring. If you can make a dynamic timing check with VCDS you could verify this. Regrettably, the cam ring advance servo is bored directly in the pump body making repair a complex procedure.

 

rotodiesel.