Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[GrpB Tom]

Hi All,

Just a quickie - car starts but doesn't run. Cuts out after a few seconds. Due to the amount of gizmos just wondering what I should check first.
The thermostat was stuck open so I decided to change that which meant taking off the plenum and inlet manifolds and uncoupling all sorts of connectors and hoses. Therefore my problem is more likely to originate from something I have fiddled with and failed to put back properly.
Any tips would be greatly appreciated.
regards

[GrpB Tom]

further to my last post I have go the engine to run but it's very lumpy and I can hear popping in the plenum. As the revs increase it smooth's out and sounds normal. Its idle that seems to be the issue.

[05omegav6]

Carry out the pedal trick...

http://www.omegaowners.com/forum/index.php?topic=90581.0

Decipher...

http://www.omegaowners.com/forum/index.php?topic=90594.0

And report back

[Diamond Black Geezer]

Have you had anything apart at all lately? Sounds very similar to mine a bit ago - and was a vac leak, due to an ill-tightened EGR.

[05omegav6]

Have you had anything apart at all lately? Sounds very similar to mine a bit ago - and was a vac leak, due to an ill-tightened EGR.

No egr on the 2.6/3.2

Pedal trick is a far more useful diagnostic tool than the earlier paperclip one as the dbw ecus are able to reveal alot more information

[Diamond Black Geezer]

No, very true - but what I meant was if there was a leak with anything that is associated with the vac / intake system - for instance if he'd had the plenum off, and it hadn't seated correctly, or any other kind of vac leak. Just sounded very similar symptoms to mine. Also not helping and stuffing up the idle was a badly adjusted throttle body butterfly - but I can't imagine that being the case here.

Other culprit could be ICV - give it a clean out, but make sure all rubber bits don't get carb cleaner on them, as these will corrode/go sticky and soft. 

[05omegav6]

Today's not your day...

No ICV on DBW cars either

[tigers_gonads]

Pull the plenum off and check that you have connected up the injector loom in the right order 


Ant bets that your codes will say "multiple misfires"

[05omegav6]

Pull the plenum off and check that you have connected up the injector loom in the right order 


Ant bets that your codes will say "multiple misfires"

That's not a bad shout thinking about it... I hadn't occurred to me as there shouldn't be a need to unplug the injectors individually

[tigers_gonads]

Pull the plenum off and check that you have connected up the injector loom in the right order 


Ant bets that your codes will say "multiple misfires"

That's not a bad shout thinking about it... I hadn't occurred to me as there shouldn't be a need to unplug the injectors individually

Made that cock up myself when I fitted the LPG 

[05omegav6]

Pull the plenum off and check that you have connected up the injector loom in the right order 


Ant bets that your codes will say "multiple misfires"

That's not a bad shout thinking about it... I hadn't occurred to me as there shouldn't be a need to unplug the injectors individually

Made that cock up myself when I fitted the LPG 

Ah... that would do it

[GrpB Tom]

HI All,
Thanks for your comments. I have been head scratching a lot over this one and replaying what I pulled off when I dismantled the plenum and intake manifold. I noticed the rather flimsy rubber gaskets on the plastic intake manifold were flat and thought I could bodge it with some sealant and an extra tweak of the spanner. I suspect this has not worked and I now have numerous air leaks around that manifold. I have ordered new gaskets which should be arriving today. Will do the pedal check once gaskets replaced. I'm comfortable with the injectors as I did not detach the injector rail completely - there was a cluster of wires that disappeared into the bulkhead that did not have a connector. I have also had trouble in the past with vacuum hoses, mainly the rubber right angles perishing. The latest one to go was on MAF ( I do get confused between MAF and MAS) its the box on the air intake pipe at the back of the rads. Therefore I'll check the rubbers at the back of the plenum for leaks. Have also noticed the switch over solenoid has been bodged a good 'un. Its been broken off as one securing lug is missing and a bit of plastic pipe from a WD40 can has been glued in place of one of the vacuum pipe couplings. Not sure if this would also contribute but is been there some time. Anyway, will report once the gaskets are changed but thanks again for your help.

[Diamond Black Geezer]

Today's not your day...

No ICV on DBW cars either

Oh, god, these blummin' swanky doo-dah 2.6 / 3.2s - you'll be telling me they have a poncy drive by wire throttle, not a proper cable next!!!! 

[Diamond Black Geezer]

HI All,
Thanks for your comments. I have been head scratching a lot over this one and replaying what I pulled off when I dismantled the plenum and intake manifold. I noticed the rather flimsy rubber gaskets on the plastic intake manifold were flat and thought I could bodge it with some sealant and an extra tweak of the spanner. I suspect this has not worked and I now have numerous air leaks around that manifold. I have ordered new gaskets which should be arriving today. Will do the pedal check once gaskets replaced. I'm comfortable with the injectors as I did not detach the injector rail completely - there was a cluster of wires that disappeared into the bulkhead that did not have a connector. I have also had trouble in the past with vacuum hoses, mainly the rubber right angles perishing. The latest one to go was on MAF ( I do get confused between MAF and MAS) its the box on the air intake pipe at the back of the rads. Therefore I'll check the rubbers at the back of the plenum for leaks. Have also noticed the switch over solenoid has been bodged a good 'un. Its been broken off as one securing lug is missing and a bit of plastic pipe from a WD40 can has been glued in place of one of the vacuum pipe couplings. Not sure if this would also contribute but is been there some time. Anyway, will report once the gaskets are changed but thanks again for your help.

Well I said symptoms suggested an air leak - so at least I got that right - even if every component I listed as suspect isn't ON the car!!! 

PS: My teeth have been cut on PFL V6s and BMW Diesels, never been up close and personal on the slower save-the-whales 2.6/3.2s 

[05omegav6]

HI All,
Thanks for your comments. I have been head scratching a lot over this one and replaying what I pulled off when I dismantled the plenum and intake manifold. I noticed the rather flimsy rubber gaskets on the plastic intake manifold were flat and thought I could bodge it with some sealant and an extra tweak of the spanner. I suspect this has not worked and I now have numerous air leaks around that manifold. I have ordered new gaskets which should be arriving today. Will do the pedal check once gaskets replaced. I'm comfortable with the injectors as I did not detach the injector rail completely - there was a cluster of wires that disappeared into the bulkhead that did not have a connector. I have also had trouble in the past with vacuum hoses, mainly the rubber right angles perishing. The latest one to go was on MAF ( I do get confused between MAF and MAS) its the box on the air intake pipe at the back of the rads. Therefore I'll check the rubbers at the back of the plenum for leaks. Have also noticed the switch over solenoid has been bodged a good 'un. Its been broken off as one securing lug is missing and a bit of plastic pipe from a WD40 can has been glued in place of one of the vacuum pipe couplings. Not sure if this would also contribute but is been there some time. Anyway, will report once the gaskets are changed but thanks again for your help.

Serious bodgery has taken place if there isn't a plug attached to the rear engine lifting point... just behind the 246 head.

The box you mention is a vacuum tank, as you say, it's common for the rubber connections to perish/split.

It would be churlish not to replace that solenoid while you're at it... a two minute job with the plenum off

[05omegav6]

Today's not your day...

No ICV on DBW cars either

Oh, god, these blummin' swanky doo-dah 2.6 / 3.2s - you'll be telling me they have a poncy drive by wire throttle, not a proper cable next!!!! 

Weelll, now that you mention it...

[Diamond Black Geezer]

 

[GrpB Tom]

Had a good afternoon stripping everything back down and checking for possible causes of air leaks.
First issue was a bit of plastic that had got caught on the O ring grooves on the plenum. Had deformed the new o ring slightly but nothing irrecoverable. I discovered why I cannot detach my inlet and injectors completely -  it's been hardwired into my LPG ecu. Should have realised that first time around. Next interesting discovery was the air vacuum valve at the back of the right hand bank had broken off - completely. Further investigation revealed this had been broken and then repaired with epoxy. The mix was a little heavy on hardener and it had become brittle. My fiddlings earlier had caused it to separate. I believe this was the root of unmetered air getting into the cycle and playing havoc with the other sensors. My bodge with the gaskets probably made no difference when compared to the open end of a vacuum pipe! One slight problem that I need help with - the valve is held in place by a rather curious fastener. Not sure how it works. There is a centre core which would suggest a push fit application. Certainly not enough room to weald a spanner or ratchet. Any ideas? Would download a photo but can't on this post.

[05omegav6]

The existence of lpg is an omission, as it double the list of potential issues... That said, it sounds like that valve is the source of your problem...

iirc it is held in by two Allen or female torx bolts... Remove the whole assembly then dismantle it

[GrpB Tom]

All good news! My second hand vacuum switchover valve and vacuum valve arrived this morning and I quickly fitted them and put everything back together. Turning the key with a freshly charged battery the engine burst into life. The idle held at about 700rpms and I couldn't hear any undue whistling sounds. The temp gauge got up to just shy of 90 deg before the thermostat opened and after a while the front fans kicked in. I took the car for a short spin to check everything was ok.
On return from my run I refilled the expansion tank as that had run down and double checked for leaks. I also put the heating on and felt a blast of hot air before it died down to a luke warm flow. I guess there must be an airlock in the system which I'll have to work out over time. therefore I think that's it - all sorted. Just goes to show what mischief an air leak can cause on these cars!
Many thanks for all your help. The anecdotes regarding air leaks was the break through and proved to be correct. That's all until next time!

[Diamond Black Geezer]

Great news!

Now can you fix mine?