VR6 ABV crank position sensor question - now fuel pressure issue

[Jon_vr6 1]

Id get a fuel pressure test done. Cheapest option first.

[Jim 2]

No way of getting any injectors out without taking the manifold off from what I can see :( Though removing the manifold isn't too bad a chore to be honest!

[seanl82 23]

It won't be the relay if its getting some fuel. Remember a relay is effectively just a switch, so it'll either be on or off.

[Dox 23]

I'm going to try and swap my pump tomorrow if I get chance and they are compatible.

[fendervg 33]

Ok - I found two fuel pressure testers - one I can't make head nor tail of the dial on, and I'm not sure it's working properly, and the other for K-Jet systems - this measured 3.5 bar with the engine running, but it leaks very slightly, so I won't get a proper residual reading. From my reading of the Bentley I should be seeing 4 bar? Anyone know what the pressure with the engine off should be, or will it just drop to 0 gradually over time?

 

The Pierburg replacement fuel pump I am looking at is rated at 3 bar.

Edited August 5, 2015 by fendervg

[Jon_vr6 1]

Surely yours being a VR6 the fuel pump should match the FPR at 4bar?

[fendervg 33]

Found this:

http://www.corrado-club.ca/mods/vr6_fp_test.html

and it says 3.5 bar running and 4.0 with the FPR vacuum hose disconnected. Gonna do a few more tests.

[fendervg 33]

Ok - so here are the results of some more testing this morning.

 

With the engine running at idle from cold start - constant 3.5 bar, this agrees with VAG specs and the Canadian source in the link above

 

With throttle variations, the pressure varies slightly up or down. The behaviour is the same when warmed up and running the standard cycle

 

With the vac hose on the fuel pressure regulator disconnected, pressure rises to 4 bar, also seems normal and as expected.

 

When I turn off the engine, pressure drops to just above 3 bar, but then gradually rises to just below 4 bar? Strange. Will leave it sitting for half an hour and then see.

 

Will also do a vacuum test - does anyone know what values I should be getting on the vac test?

[fendervg 33]

Vacuum test shows 46 hg vac at idle, which converts to 22 PSI or 1.5 bar - at least I think I have that right - what should I be seeing?

 

The engine seems to be flooding and not starting from warm as well - so I'm thinking injectors, fuel lines, fuel filter and is there a valve somewhere else in the fuel system?

[fendervg 33]

Anyone? Am really stuck here.

[Dox 23]

Poor starting when hot can be ecus coolant temp sensor

[fendervg 33]

They've all been replaced, so should be fine. The cars seems to cut out when idling and then won't start for a good while - there's no error codes in VCDS - I can pull all the values from it if anyone thinks it would be helpful or could assist in interpreting them.

Edited August 6, 2015 by fendervg

[robrado974 1]

Wish I could help mate , my manual is not with me ATM . I know it says all the pressures in it .

[fendervg 33]

Thanks Rob - no worries. From what I've been reading:

OBD1 2.8 AAA cars have a 3 bar regulator (Golf, SLC etc.)

OBD1 2.9 ABV have a 4 bar regulator and run at 3.5 bar, 4 with the vac hose disconnected, this is what I get

I've double checked ETKA and cross-referenced the Bosch part numbers and I have the correct FPR.

What I don't know is if the vacuum pressure reading is correct.

[fendervg 33]

The mystery deepens in relation to parts - ETKA lists a Pierburg fuel delivery unit for a VR, but with a VDO 4 bar pump inside it. The FPR is definitely supposed to be 4 bar, there don't seem to be any other options. The replacement Pierburg unit I was assured is for my year/chassis number is listed as 3 bar! Looks like I will need to pull the pump unit and get some part numbers - or does anyone have any out to confirm? To make matters worse, I found an old fuel rail lying around, and this had a 3 bar FPR in it, but I'm not sure if that was from a 2.8 VR6 off a Golf or the like.

[fendervg 33]

Even the various suppliers don't seem to know the answer. My suspicion is that the 2.8 AAA engine is 3 bar pressure, and the 2.9 ABV is 4 bar, at least that seems to be confirmed by ETKA. The only 4 bar pump I can source is a VDO one, http://www.ottocarparts.com/shop/parts/13693-vdo-fuel-pump-e22-041-060z.html, part#E22-041-060Z, which is a direct replacement for VAG#1H0 919 651 Q, and only that part number.

 

Now the crazy thing is that the Pierburg fuel delivery unit which is rated at 3 bar is also listed as a replacement for 1H0 919 651 Q - but also some other ones, which correspond to Golf VR6s and Passats etc. with the 2.8 engine. Surely the same one can't do for both, or there is an error with parts listings.

 

There's also a Bosch one, but I've read on here that the fuel gauge sender won't work with this one as the part has changed.

Edited August 8, 2015 by fendervg

[Jon_vr6 1]

I think the pierburg ones have been discontinued now thus meaning there is only VDO - 1H0 919 651Q available. So when people needed to change their fuel pump they had to order a new vdo pump plus the level sender. When i needed a pump i got mine from VW.

[fendervg 33]

Ok - will give VAG a ring on Monday - but my old trusty dealer that I had built up a good relationship with is gone now, and VW distribution in Dublin has been taken over by a faceless entity only interested in selling new cars called, ironically enough, Karmann Volkswagen! Ask them for a Corrado part and you will be lucky to get an acknowledgement that it was even made by VW in the dark distant past, and then this is usually followed by "part no longer available here". But I'll try anyway...getting angry and depressed now.

[fendervg 33]

Going over everything again today - have both spare relays 109 and 67/167 to hand, a new fuel filter, and will pull and test the pump as well.

 

Getting 3.5 bar pressure at the rail with engine running, 3 bar residual with ignition turned off, even after 30 minutes

 

VCDS shows no faults.

 

If left to idle for a while, engine just cuts out - no fault codes in VCDS. This time it started again straight away.

Left it running at idle once up to temp for a good while - twice it has cut out and started again, the third time it won't start from hot. If I leave it for a while now, I reckon it will start again.

Edited August 9, 2015 by fendervg

[fendervg 33]

On a good note, I just replaced my sunroof motor with a spare I had, and I have a working sunroof again - afraid to use it though in case it breaks again or it starts raining!!!

[fendervg 33]

Ok - 10 volts at the pump, so all good there. Replaced the fuel filter, no difference in pressure. Swapped out relays 109 and 67/167, same issue as before.

Pulled the fuel pump to verify part numbers - we've got a unit (the complete fuel delivery unit) with lid, sender for fuel gauge, pump and swirl pot with Pierburg on it and the part number 535919051A on the lid. This part number is obsolete, but was comprised of:

- fuel pump191919651

- fuel gauge sender 535919673B

- flange 535919679

 

The replacement pump appears to be 1H0919651Q, 4 bar VDO unit, but needs a new sender for the fuel gauge, 5359191673C.

 

Will check this out with VW tomorrow.

[fendervg 33]

This is the pump unit I have. Must be the original one. [ATTACH]82115[/ATTACH][ATTACH]82116[/ATTACH]

[fla 9]

When it cuts out does it sound like its run out of fuel ie does.it sound'dry'? Now that you have access to the pump apply power to it directly and see what happens.

If the crank sensor is not properly earthed to the block it can caue issues. Remove and clean the block surface.

Maybe someone can advise on using vcds to monitor live data so you can see what happens when it cuts out. From the symptoms it doesn't sound like the pump more an electrical fault somewhere, which can be a nightmare! But hopefully we'll help you bottom this one out.

[fendervg 33]

I've replaced the crank sensor with a second hand replacement - waiting on a new one to arrive to be on the safe side. I'd love it if someone could put a pressure tester on their fuel rail to confirm if it should be 3.5 bar or 4. The pressure does not drop when the engine cuts out - it's more like the engine is flooding - I'm beginning to suspect the injectors, and am waiting on a set to arrive that I can send off to be tested and refurbished. Only problem is I have no car now for at least a week, maybe 2.

Edited August 10, 2015 by fendervg

[GreenRado 10]

Have you checked the continuity of the wiring behind the fuse box, like my issue turned out to be from?

 

Really does sound like injectors are last on the list, but from re-reading your thread it sounds a lot like my issue, especially given the seemingly random nature of the stalling and no-starts.

 

I'll check my pressure either tonight or tomorrow morning and let you know the values I have :)