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[LC0112G]

Y reg 2000MY 3.0 V6 Elite Saloon Automatic.

Drove to the chip shop last night - about a mile. Then about half way home I had to stop at some lights. As I went to pull away, it stalled. Car is an Auto, so a bit of a faff to restart. Once restarted it ran for a few seconds before stalling again. Eventually I got it to run for long enough to left foot brake and use the accelerator to keep the revs up, crash it into gear and get home. It stalled again as I pulled onto the drive.

I then had to go out again about 2 hours later. Again it stalled as I pulled into where I was going, and was a struggle to re-start and keep going for the journey home.

Once I got home again I whipped off the IACV and gave it a good clean, not that it was very dirty.

Drove to work this morning (about 14 miles) and all was well until I pulled into the carpark when it stalled again.

It stalls whilst the car is still moving, so care with the power steering and brake servo assist is needed. The idle speed on overrun (60MPH downhill) seems to be very low too (350-400 RPM), as though it's trying to stall but the drag from the gearbox is keeping it turning over.

Never had a crank sensor go, and there don't appear to be any stored trouble codes. Of course I scrapped my spare engine last Thursday, so haven't got a spare!

Does this sound like a crank sensor fault?

Yes I know genuine dealer part only.

[biggriffin]

Shakeng has a new one in parts for sale section.. That be a real on too 

[LC0112G]

Shakeng has a new one in parts for sale section.. That be a real on too 

Yeah, but, does this actually sound like crank sensor failure symptoms, or possibly something else?

[Migv6 le Frog Fan]

How old is the fuel filter ?

[Doctor Gollum]

Fuel level?

[Shackeng]

Shakeng has a new one in parts for sale section.. That be a real on too 

Now sold, was for a 3.2.

[Enceladus]

Classic 2.5/3.0 V6 failure mode. Three possible sensors, yours is almost certainly the latest as used on 2.6/3.2. They're not interchangeable, they have different resistances in the sensor.

[LC0112G]

How old is the fuel filter ?

At least 2 years, may be as old as 5. I can remember cursing when trying to get those effing plastic clips undone, just can't rememeber when it was. However, its OK at high revs/power, just won't idle/low RPM, so doesn't smell like a fuel pressure problem to me.

Fuel level?

3/4 of a tank. As above, don't think its a fuel line/pressure problem.

Now sold, was for a 3.2.

Boooooo. Trousers at half mast down the dealers in the morning then.

Classic 2.5/3.0 V6 failure mode. Three possible sensors, yours is almost certainly the latest as used on 2.6/3.2. They're not interchangeable, they have different resistances in the sensor.

Hmm, Might be an issue deciding which one then. The engine in the car is an earlier one, but the ECU is the original. Had to change the engine when the oil pickup got blocked and wrecked the bottom end. The original engine was 08491727, which went to the scrap yard last Thursday. The replacement is 08247090. Any idea if the sensor goes with the ECU or with the engine?

[terry paget]

Might be MAF (mass air flow sensor). Happened to me on a 1999 3.0 V6 manual, spent 6 months finding it. easily checked by unplugging it and seeing if it cures the fault; doing so will bring on a fault light but engine will still run. It is found plugged into the air inlet tract after the air cleaner.

[Doctor Gollum]

Should go with the ECU/loom. Did you swap the sensors onto the new engine?

Also, what was the outcome of your wiring issues?

[Nick W]

Might be MAF (mass air flow sensor). Happened to me on a 1999 3.0 V6 manual, spent 6 months finding it. easily checked by unplugging it and seeing if it cures the fault; doing so will bring on a fault light but engine will still run. It is found plugged into the air inlet tract after the air cleaner.

Both are exactly the same symptoms as mine. Unplugging the MAF stopped the stalling and poor running at low rpm(mine started doing it during the M25 Friday evening rush hour).


Replacing it fixed the problem.


Quick easy test and fix to try before getting involved in wiring or more complicated diagnosis

[LC0112G]

Should go with the ECU/loom. Did you swap the sensors onto the new engine?

TBH I can't remember if I did or didn't. I know I thought about it, but don't know what I decided.

Also, what was the outcome of your wiring issues?

Fixed (well bodged) back in the spring - once I'd got access to the proper circuit diagrams. Turns out the front seat heating is run of F15 on the FL, and unplugging the switches on the dash does not isolate the them. So once I'd unplugged both front seats power feeds (under the cill trim) F15 stopped blowing. Dunno which seat - probably the one with the lardy @rse sat in it, but not had any problems since. Well except the Gearbox, and the Exhaust, and Bambi, and now the Engine 

[LC0112G]

Ok, so based on Nick and Terrys experience, I'll unplug the MAF next. Will go for a test drive tomorrow lunchtime and report back.

Have to say I'm doubtful that's it, but it's a cheap test.

Thing is, the output from a variable reluctance sensor increases with RPM, so if the crank sensor is variable reluctance, higher RPM will produce more signal and the ECU will see it easier. Low RPM is where the problems typically occur with variable reluctance due to the low output, and that's where I think my problems are.

Admittedly I may be fitting what I know about sensors to an apparent fault, but Crank sensor still smells like the likely fault to me.

[Shackeng]

Malc you have PM

[B52]

FWIW my recent crank sensor replacement was the first for KW02 (assisted by helpful responses on here)

It would start every time if cold - stall appeared after 10-15 minutes and was always at idle or no load.

[LC0112G]

Finally found the thread where I changed the engine.

http://www.omegaowners.com/forum/index.php?topic=122287.msg1570572#msg1570572

It appears that I did swap the original crank sensor from the old (wrecked) engine into the new/replacement one. However, it probably wouldn't of mattered because both the old and replacement engine are past the break point for the change in crank sensor, which according to EPC is VX90492002 up to engine no 08149313, and VX90540743 from engine number 08149313.

So I need VX90540743, which hopefully Shackeng is sorting for me.

[jb]

I have some of these new genuine GM if you need one

[Shackeng]

Malc, you have another PM

[LC0112G]

Malc, you have another PM

Have replied, unboxed is fine. Don't do social media though, so the WhatsFaceTweet thingy isn't gonna work.

[LC0112G]

Ok, sitrep....

I tried disconnecting the MAF, but when started it ran very very rough. I plugged it back in and from cold it started Ok. Unplugged it and very rough again. Decided I couldn't risk a test drive like that because I don't know what will happen if the ECU decides that both the Crank and MAF sensor are kaput.

The new sensor arrived sometime Friday (thanks Shack) so Saturday morning I fitted it. Not as easy a job as it should be, but there are worse ones. Drove it home (14 miles) and with trepidation approached the last roundabout...and...it was Ok. Haven't done many miles in it so far, but I did go to the chip shop again this evening, and then ran my Dad home 2 hours later and it hasn't stalled yet.

Idle isn't brilliant, but Ok. I'm reluctant to declare it 'cured' given the lack of driving so far, but it's looking promising.

[B52]

FWIW, I'm about 150 miles post crank-sensor replacement and still haven't relaxed.

[Doctor Gollum]

Being a cable throttled car, the ICV may well benefit from a good clean

[cam.in.head]

and also the throttle body/ butterflies. also making sure the stop screw hasnt been played with or worked loose causing a fully closed butterfly. if you squeeze the air pipe to the icv the idle speed should drop very low but not stall.

[Nick W]

Being a cable throttled car, the ICV may well benefit from a good clean

I've done that to dozens of cars, and some of the valves were really filthy.
It never made a difference to how the car ran.

[STEMO]

Being a cable throttled car, the ICV may well benefit from a good clean

I've done that to dozens of cars, and some of the valves were really filthy.
It never made a difference to how the car ran.

Well stop doing it then.

[Nick W]

Being a cable throttled car, the ICV may well benefit from a good clean

I've done that to dozens of cars, and some of the valves were really filthy.
It never made a difference to how the car ran.

Well stop doing it then.

I have

[Enceladus]

and also the throttle body/ butterflies. also making sure the stop screw hasnt been played with or worked loose causing a fully closed butterfly. if you squeeze the air pipe to the icv the idle speed should drop very low but not stall.

The main butterflies are fully closed at idle on X25XE and X30XE. The idle air intake bypasses the throttle butterflies via the Idle Air Valve.
A build-up of carbon in the throttle body throats will cause air to leak past the butterflies at idle. For that reason the throats need to be clean so they seal properly.
Please don't interfere with the TPS (throttle position sensor), it can't be easily reset.

[LC0112G]

Being a cable throttled car, the ICV may well benefit from a good clean

First thing I did - as mentioned in post #1.

[LC0112G]

FWIW, I'm about 150 miles post crank-sensor replacement and still haven't relaxed.

Well, I need the dead B52 currently sat at EGVA, and it's about a 150 mile round trip :-)

[cam.in.head]

and also the throttle body/ butterflies. also making sure the stop screw hasnt been played with or worked loose causing a fully closed butterfly. if you squeeze the air pipe to the icv the idle speed should drop very low but not stall.

The main butterflies are fully closed at idle on X25XE and X30XE. The idle air intake bypasses the throttle butterflies via the Idle Air Valve.
A build-up of carbon in the throttle body throats will cause air to leak past the butterflies at idle. For that reason the throats need to be clean so they seal properly.
Please don't interfere with the TPS (throttle position sensor), it can't be easily reset.

fully closed ? dont mean to contradict your answer but are you sure ? i always thought butterflies had to be slightly open to prevent jamming and let a little air through. the icv does the rest
 but i could be wrong. at least thats how it is on earlier jetronic injection cars

[B52]

FWIW, I'm about 150 miles post crank-sensor replacement and still haven't relaxed.

Well, I need the dead B52 currently sat at EGVA, and it's about a 150 mile round trip :-)

https://youtu.be/h5gAufVQEWM

One of these?

[LC0112G]

Yup. Diverted in last week with an engine failure. Very tricky landing with only 7 of the 8 engines running on one of the longest runways in the UK 

Likely to be there for a few weeks, till Santa brings it a new engine for Xmas.

[Shackeng]

I flew with an old timer years ago. One of his aphorisms was “When the Engineer tells me we’ve lost  number 4, my reply should be “Which side?” 

[B52]

Or in the case of the B-36, six turning and four burning:

https://youtu.be/sM1CZdppWrU

(Sometimes two turning, two burning, two smoking, two choking, and two more unaccounted for).

Sorry to derail the thread with aviation nonsense - how is the crank sensor?

[Doctor Gollum]

There's a plane that doesn't want to leave the ground if ever there was

[ronnyd]

They call it The Peacemaker, how apt.

[LC0112G]

Spoke too soon. Conked out again on leaving Tescos petrol station this morning. Eventually got it restarted (right foot on throttle, left on brake to keep the revs up), did the weekly shop and then got home. Just about to go out on a 1 hour 'test drive' - amongst other things to go fetch my Tech 1.

If it plays up again this afternoon I'll unplug the MAF to see what that does. DIS pack was replaced about 3 years ago, so shouldn't be that. Beginning to think it's electrical in nature - alternator, battery or wiring sort of thing. Rain Water in some connectors somewhere perhaps.

[cam.in.head]

does it play up whilst driving or with any throttle whatsoever or just stall when you have no throttle.
likewise if you just give it the tiniest of throttle whilst starting does it fire up immediately and run good.

[LC0112G]

I've found A fault, but don't know yet if it's THE fault. Haven't got enough time today to go looking further, and haven't got a spare of the part required anyway so until I get time for a bodge fix I'll leave you all guessing as to the cause  I'll try and get some photos tomorrow, and do a bodge fix.

does it play up whilst driving or with any throttle whatsoever or just stall when you have no throttle.
likewise if you just give it the tiniest of throttle whilst starting does it fire up immediately and run good.

It does (and has this afternoon several times) stalled whilst moving with the throttle closed. If you're going more than about 30MPH (for instance coasting down hill at 60MPH) then some throttle is enough to get it re-started again whilst moving. Below 20MPH then you can't get it to restart whilst still moving. I'm assuming that below 20MPH there isn't enough drag back through the TQ to turn the engine over to restart it.

It has started from cold every time so far. It starts to play up after perhaps 20 minutes once properly up to temperature. Once it's started stalling and you're stationary and in Park/Neutral it needs quite a lot of throttle (perhaps 30-50%) to get it to restart. Once restarted it'll stall again unless you keep above 1000RPM at idle. The amount of throttle to keep it running is variable whilst stationary - you just need to keep RPM >1000. Sometimes it will idle OK, if a little roughly, other times not. Once moving it doesn't seem to stall if you've got any throttle on.

Tech 1 is showing CTS and TPS working OK. MAF was showing 11kg/whatever at tickover. Only trouble code was TC19 whilst engine not running, which I think is just no crank sensor signal, which is fair enough whilst not running. Crank and Hall sensors show Ok with engine running.

[Doctor Gollum]

Which coolant temp sensor?

[Nick W]

Sounds even more like the MAF than it did when you started this post.
It's doing exactly what mine did.
Once the problem starts, disconnect  the MAF and see if it runs any better. Ignore the EML, it will go out when you reconnect the sensor.

[LC0112G]

Which coolant temp sensor?

Tech 1 only reads the ECU engine CTS. That's ok - if a little hot in the 85-92 range. Suspect it's running hoter than normal because I'm keeping the revs up, and Bambi does appear to have done for my Aircon, so the A/C fan isn't running. Main fans cut in correctly though just over 90.

Dash CTS agrees with the Tech 1 reading from t'other sensor.

[LC0112G]

Sounds even more like the MAF than it did when you started this post.
It's doing exactly what mine did.
Once the problem starts, disconnect  the MAF and see if it runs any better. Ignore the EML, it will go out when you reconnect the sensor.

The fault I've found isn't MAF, but is air related. Photos tomorrow.

[B52]

I'm curious how this turns out, KW02 being a lady of a certain age.

[Doctor Gollum]

If that's Kevin's old bus, you've not much to worry about 

[LC0112G]

Well, I promised some pictures. Story is...

I started the car in the garage seeing if it would stall. It didn't, but it wasn't running right. I popped the bonnet, and started waggling connectors and wires down the back of the Plenium, where the crank sensor connector lives. I then became aware of a hissing sound - like a vacuum air leak. I couldn't immediately locate it, but it was coming from here somewhere...


Then after a bit more poking I saw it...



And removed from the car...



The "funny" thing is I'd been aware for a while that the brakes were a but 'wooden' for the first few seconds after a cold start, and I was intending to replace all the pads last weekend. Now the reason is obvious - poor vacuum to the servo.

I think it probably explains the stalling too. It's not too little fuel/blocked fuel filter/low fuel pressure - it's too much air. The ECU won't be able to meter the air getting in through the hole , so it'll run very lean.

The hole was made by the pipe rubbing on the Air Con quick release connector. It's obviously not happened 'suddenly' and worn away over the years until eventually it rubbed through. It actually seals quite well on the A/C connector.

Anyway - haven't got a spare pipe, so a bodge fix required...



Several layers of glue filled heat shrink. Not very neat, but getting the lengths of heat shrink over the coupling nut and around the elbow is a bit of a game.

Has it cured it? - Dunno yet I managed to break one of the vacuum pipe couplings by the one way valve getting the wretched thing off, so need to fix that first. But I'm optimistic.

[B52]

Well, wouldn't have thought of that - my money was on something electronic.

Good detective work there.

[Shackeng]

Well done Malc. Something to check for others. 

[Nick W]

That would certainly explain your problem


It's very common on VAG cars, where the fix is to cut out the holed pipe and join it with vacuum hose. And to ensure it no longer rubs on whatever caused the hole....

[polilara]

Interesting case. Checked immediately mine but perhaps due to right side traffic slightly different design and there is a plastic clip to prevent those hoses to touch, too.

[Doctor Gollum]

Uk cars left the factory with the same spacer clips

Actually quite rare to find them still present, even on the best kept cars...

[Migv6 le Frog Fan]

I think mine still has them. Will try and remember to check tomorrow. 

[STEMO]

They look like one of those "Where the fick did that bit come from?" items that get chucked after a repair job.

[Nick W]

They look like one of those "Where the fick did that bit come from?" items that get chucked after a repair job.

More like a "It doesn't do anything, and it takes too long to get back under there, fit it in the bin" parts, that six months later makes you do another 3 hour job figuring out why the damn car doesn't work properly.

[STEMO]

I've always had the odd screw or bolt left, I'm still alive 

[LC0112G]

I've always had the odd screw or bolt left, I'm still alive 

But you've got a screw loose.

[STEMO]

I've always had the odd screw or bolt left, I'm still alive 

But you've got a screw loose.

But I'm still upright and breathing, which is all that's required 

[DrAndyB]

Just checked mine as got me paranoid and spacer still there, fitted a little before the other picture and looks like never been touched  , but I have had car from new 

I'll go and read her a story and tuck her blanket in 

[Lizzie Zoom]

Well done Malc. Something to check for others. 

Indeed!

I have now checked mine and all is ok.  Those pictures certainly gave me a scare, like my loose plenum servo pipe!!