VR6 ABV crank position sensor question - now fuel pressure issue

[fendervg 29]

Hi all - just fitted a replacement crank position sensor to my VR to see if it would help with intermittent starting/idling issues, I noticed that the old sensor that was in there had no plastic cover on it and the new one did? Does anyone know the difference or is it just one of those cosmetic things? Also there didn't seem to be a seal on the old one, which has me slightly worried - I wonder are these the same seal as used on the coolant sensors in the thermostat housing?

 

As an aside, even a simple job like this is a right pain on the VR due to the space restrictions in the engine bay - getting at the socket and plug was not fun, leading to scraped arms and wrists, and the allen key bolt is placed exactly in the wrong position for easy access! Car started fine, so I will see what it's like on a test drive.

Edited August 5, 2015 by fendervg

[seanl82 23]

You say there was no seal on the old one, but did you have a good dig around in the area it fits into!?

 

I'm not sure what you mean by plastic cover though. The main part of the sensor should be encased in plastic, with a bare metal probe that fits inside the crank area.

 

And yep, its an utter nightmare to do in situ! Hope it sorts your problems though mate. :thumbleft:

[fendervg 29]

Well the old one had no plastic casing on the sensor probe part, the replacement one had the probe encased with plastic with a hole in the middle where it faces the crank - and I've seen ones on ebay and spurious suppliers sites that don't have it either. I'll get hold of a seal to be on the safe side.

 

Should have taken a pic of the new one before it went on - not happening now anyway! I've had enough pain.

[fendervg 29]

[ATTACH]82078[/ATTACH]

 

This is what the old one looks like.

[fendervg 29]

Just took the car for a quick test drive and started on the button, reliable return to idle and some of that old VR6 urgency seemed to be back. Too early to tell though - we'll see what a cold start and a motorway trip to work brings in the morning.

 

May also do a full ECU reset once I get the time. We'll see.

[fendervg 29]

Well the plot thickens - same old cold start problem there this morning - cranks for about 10 seconds, then sputters to life slowly and catches, or will start on the button second try. I'm suspecting the fuel systems now - my fuel pressure regulator was replaced about 2 years ago, but will see if I can get a new one and replace that.

 

It also did a nasty cut-out when returning to idle when stopped in traffic on the motorway - started again after 10 seconds! Ah, the joys of Corrado ownership - or having one as an elderly dependent.

[Dox 22]

Well the plot thickens - same old cold start problem there this morning - cranks for about 10 seconds, then sputters to life slowly and catches, or will start on the button second try. I'm suspecting the fuel systems now - my fuel pressure regulator was replaced about 2 years ago, but will see if I can get a new one and replace that.

 

It also did a nasty cut-out when returning to idle when stopped in traffic on the motorway - started again after 10 seconds! Ah, the joys of Corrado ownership - or having one as an elderly dependent.

 

I've recently started to have similar issues, I suspect the cam sensor, the crank does 2 rotations for every one of the cams, the ecu uses the cam sensor to know which cylinder is on TDC on its firing stroke to determine timing of the spark, if the cam sensor is duff the ecu calculates the same thing via the crank sensor but it needs extra cranking to work this out.

 

Its just a guess though

[seanl82 23]

Your old crank sensor looks correct. I had a faulty cam sensor on the aqua too btw. It started and idled fine, and the only symptom I had was poor pickup. I really did struggle for power. Luckily I had a spare and its literally a 2 minute job to replace.

Is there anyone near you that could read the fault codes? Seems that even if you have to pay for it to be done, you'll save a few quid with the amount of parts your having to buy in the hope of fixing it.

[Dox 22]

Scanned mine

 

00537 Lambda regulation 11-10 control limit not reached - intermittent

 

00513 engine speed sensor 03 - 00 no signal (discounted as the engine wasn't running at the time so even a good sensor will show this code.

 

So looks like lambda or MAF as one is used to calculate the out of tolerance of the other.

 

I have a used MAF in unknown condition so may try that for a comparison and check the wiring to the lambda

[fendervg 29]

I'll scan it tonight - my only problem is it's a 93 VR so the cam sensor is part of the distributor (hall sender) and not a separate part, and as far as I know both the dizzy and the hall sender rebuild kit are no longer available.

[Dox 22]

I've swapped the maf and on first impression there's no difference with the starting, I've left it on and will monitor over the next few days if the situation is better or worse - I've read that hotwire mafs do a heating / cleaning process after turning the engine off so as the used maf has been sitting on a shelf for a couple of years its likely to be contaminated to some degree or other.

[fendervg 29]

I have two MAFs, one the original one that came with the car and another that was a new VAG replacement, but the symptoms are the same with both. They're expensive and hard to find as well if they are the earlier type.

[fendervg 29]

Anyone have any tips on troubleshooting the cam or hall sensor on a VR6 with distributor?

[fendervg 29]

I've pulled the codes - apart from the standard engine speed sensor error with the engine not running (which goes away), there's only a Lambda probe error:

 

00537 - Lambda (Oxygen Sensor) Regulation

08-10 - Control Limit Surpassed - Intermittent

 

Time for a new 02 sensor? I'll check again after a few days. As an aside VCDS v15 did not like talking to my ABS controller - lots of comms errors, has anyone seen this before?

 

I've also fitted a new fuel pressure regulator - but there seemed to be very little residual pressure in the system - when I undid the test socket on the left of the fuel rail, nothing came out! I'll check again tomorrow and then dig out a fuel pressure tester to follow up on this.

[Dox 22]

Scanned mine

 

00537 Lambda regulation 11-10 control limit not reached - intermittent

 

00513 engine speed sensor 03 - 00 no signal (discounted as the engine wasn't running at the time so even a good sensor will show this code.

 

So looks like lambda or MAF as one is used to calculate the out of tolerance of the other.

 

I have a used MAF in unknown condition so may try that for a comparison and check the wiring to the lambda

 

http://wiki.ross-tech.com/wiki/index.php/00537

[Dox 22]

I don't suppose your car cuts out on 1/4 tank of fuel or less when negotiating roundabouts?

[fendervg 29]

No - thank god. Don't fancy a fuel pump replacement either. The last time I did that on a MkII Golf GTI, the tank sender never worked properly afterwards!

 

VW Classic have what looks like the right Lambda:

http://shop.volkswagen-classic-parts.de/vwcp/scirocco-corrado/corrado/fuel-exhaust-system/lambda-sond-021906265e.html

Will get on to VW Heritage in the morning.

[Dox 22]

This is my pump assy

 

 

The rubbers that hold the pump central and off the bottom of the tank in the swirl pot have rotted away

 

 

I think the best thing for me is to swap the pump out with the one from my other car

[fendervg 29]

Not looking good there - at least you have another car to swap it over from, assuming it's in better condition of course.

[fendervg 29]

Well - another update. Replaced FPR with a new one last night. This morning the car took ages to start - it looks like there is no residual fuel pressure even with the replacement. My ideas now:

- fuel pump relay (replaced 2 years ago)

- ECU relay (replaced 2 years ago)

- Vacuum leak (all looks fine - will carry out a vac test)

- Fuel filter (replaced 1 year ago)

- injectors (have bought a set which I will get refurbished)

- Fuel pump?

 

Any more ideas? Thanks.

[Jim 1]

Wonder if it's worth getting a fuel pressure test done?

[fendervg 29]

That's my plan - I just need to find my pressure tester - I'm planning to use the test nipple/connector on the fuel rail - is this correct?

[Jon_vr6 1]

If you've got the yellow corrado manual it says in there how to do it.

[fendervg 29]

Yeah, have that - just have to find my pressure testing kit and take it from there.

[fendervg 29]

Lads, really need some help here. I can get a replacement for the whole fuel pump unit for €340, but don't want to spend that kind of money if I don't have to. The fuel pump relay will cost €10, but this was already replaced 2 years ago with a new VAG one, so not sure, but willing to try it because it's cheaper. Or I should I just take the risk and try to do a fuel pressure test tonight to see what's happening and what kind of results I get? My gut feeling says the last option, and I think it's not holding residual pressure somewhere, but I would have thought a new pressure regulator would have helped there...

 

Can I pull an injector to check the flow pattern without removing the intake manifold? It's my daily, so I am kind of stuck.

 

Any ideas appreciated.