Poor idle and I've done everything! VR6

[Dox 22]

When the engine is running and you remove the filler cap can you see oil on the camshaft or does it appear quite dry?

 

Mine's rather dry............

[Jim 1]

Great news :) Stealth strikes again!

[Jon_vr6 1]

Collected the car from Stealth this morning and from cold it started and ran perfectly :dance: who would have thought the oil pump would have caused this kind of issue!

 

Vince has fitted new front wheel bearings and re-aligned the tracking and camber and with the four new tyres I have just fitted plus the new coil overs the handling is just as good as the modern stuff, well impressed for a car that's 22 years old.

 

I drove it the 40 odd miles home and really enjoyed the drive, glad it's all sorted now though as to this point it's taken weeks and weeks to solve the issue. Just a body work and re-spray to do in June and its all sorted.

Has he got his 4 wheel alignment system working now?

 

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[John Blount 11]

Has he got his 4 wheel alignment system working now?

 

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He has indeed..

[seanl82 23]

Glad to hear you've got to the bottom of it! Do you know where Vince sources the oil pumps from? There seem to have been a few cases where it has caused different running issues over the last 2 years, so its something I'd be quite tempted to replace myself. I'd imagine they cost the GDP of a medium sized South American Country from VW though!

[John Blount 11]

Glad to hear you've got to the bottom of it! Do you know where Vince sources the oil pumps from? There seem to have been a few cases where it has caused different running issues over the last 2 years, so its something I'd be quite tempted to replace myself. I'd imagine they cost the GDP of a medium sized South American Country from VW though!

 

Original VW around £160.00 worth I think it was, I know there are cheaper ones but I think he only fits VW branded ones for the quality which I'm perfectly happy with.

 

It's actually the pressure relief valve that fails in the pump rather than the pump won't pump. When the oils cold the pressure builds up to over 7 bar and this pressure relief valve should open to return the oil back to the sump but mine wouldn't open so there was too much oil in the cam lifters.

 

One way to test is start the car when stone cold and rev to around 4000 rpm then take your foot off the accelerator. If it cuts out/stalls try to start again immediately. If the engine spins really freely there's no compression which would mean in most cases the oil pump (relief valve) is knacked.

 

I did know that my car did this although it had only done this once to me before as I don't tend to rev it that hard when cold normally but I didn't mention it to Vince as I didn't really think that would point to what was wrong, it was only today when Vince mentioned it had done it to him and that's when he "twigged" what was wrong that the penny dropped with me.... Could have saved us all a lot of time if I had mentioned it.

[seanl82 23]

Thats not too bad actually. Think I'll try that test tomorrow to see what happens. I've never done anything like that before so worth trying it out, even if just for peace of mind. Thanks for the heads up, could well come in handy for others too! :thumbleft:

[dr_mat 0]

Much better handling than "modern stuff" since the steering actually feeds back what's happening under the wheels and there's not so much outright grip that the car is inert to speeds where you will not only lose your license but in fact die a horrific death if even the slightest thing goes wrong..

 

There's something to be said for the slightly sloppy chassis and rudimentary rear suspension design on these old cars in terms of creating a balanced, enjoyable drive. The ultimate in "fast"? No. But fun - yes.

[dr_mat 0]

Question:

 

If the pressure relief valve is seized shut I get how the engine oil system can go overpressure when the oil is cold. How does this cause a lack of compression?

[Dox 22]

Question:

 

If the pressure relief valve is seized shut I get how the engine oil system can go overpressure when the oil is cold. How does this cause a lack of compression?

 

Hydraulic "tappet jacking", the pressure is so high the tappets can't cope and hold too much oil to the point the valves don't close fully, hence Rev the engine to 4000 rpm when cold before allowing it to stall, attempt to restart and the engine will turn over faster than normal as there's little compression until the tappets have purged some of the oil.

[dr_mat 0]

Sounds dangerous..

 

I was under the impression that tappets normally fill quite slowly, particularly with thick oil, due to the very small inlet ducts - even if it's at high pressure.

 

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[Dox 22]

Sounds dangerous..

 

I was under the impression that tappets normally fill quite slowly, particularly with thick oil, due to the very small inlet ducts - even if it's at high pressure.

 

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If the over pressure relief valve is jammed then it possible the pressure seen at the tappets is huge - way beyond its preset 7 bar max, oil will force its way in to the tappet but can't get out hence the jacking and the valve not closing.

 

A stall is not a big deal in a manual car, but an auto where you have to select neutral or park and then crank the starter can be nasty in busy traffic.

[John Blount 11]

When the engine is running and you remove the filler cap can you see oil on the camshaft or does it appear quite dry?

 

Mine's rather dry............

 

Looked today and mine looks dry as well, certainly not flooded with oil..

[Dox 22]

Looked today and mine looks dry as well, certainly not flooded with oil..

 

Ta :)

[Cressa 44]

Just drove mine out the garage. Took the oil filter cap off and there is plenty of oil bouncing around in there.. Going on other people comments, should it be wet or dry?!!

Ha ha I prefer err wet

 

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[Dox 22]

Mines very tappety on cold starts up days, it had a genuine oil filter and oil change a week ago making no difference, I'm used to seeing the cam lobes flick a little oil around as they rotate like on other cars I've owned, not in this case.

[Cressa 44]

Mines definitely flicking oil around like all the cars I've previously had. Dox Are you thinking perhaps oil pump? After reading what's been found on this thread

 

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[Dox 22]

Mines definitely flicking oil around like all the cars I've previously had. Dox Are you thinking perhaps oil pump? After reading what's been found on this thread

 

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Its possible, maybe my over pressure valve is stuck open rather than shut? John Blount has a new pump fitted and says his is quite dry too, mines done 107K so not a huge mileage. The crank seal weeps a bit, clutch makes a strange whine at times and needs care to pull away smoothly, but even with its faults I'd rather drive it than spanner it.....

[Brunty's Dad 10]

I too have an idling problem but not quite the same. On starting idles at around 700, very briefly rises to 1500 and then settles down again. It is fine until it get up to temp and then drops to under 500 and hunts. I have tried the usual, ISV and throttle body. Any suggestions welcome. While cleaning contacts I checked the plug and socket in the pipe from the breather to the big air intake pipe. The wiring seems to go back to the branch of the loom which serves the ISV. The plug seems OK but there is nothing inside the socket to connect to. Can't tell if there was ever anything there. Should there be and what does it do? Curious :scratch:

[robrado974 1]

I too have an idling problem but not quite the same. On starting idles at around 700' date=' very briefly rises to 1500 and then settles down again. It is fine until it get up to temp and then drops to under 500 and hunts. I have tried the usual, ISV and throttle body. Any suggestions welcome. While cleaning contacts I checked the plug and socket in the pipe from the breather to the big air intake pipe. The wiring seems to go back to the branch of the loom which serves the ISV. The plug seems OK but there is nothing inside the socket to connect to. Can't tell if there was ever anything there. Should there be and what does it do? Curious :scratch:[/quote']

 

So the ISV is not connected?.

 

 

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[Brunty's Dad 10]

ISV is cleaned and working. The connection is on the left of the engine as seen from the front. I have fitted an oil catch can and cut the hose from the breather to the intake near the MAF so the connector in question

is in the small hose that would have connected the breather to the air intake. I tried to post a photograph without success.

Edited November 16, 2017 by Brunty's Dad
addition

[[email protected] 10]

Have you changed the lamda sendor on the exhaust ? Often forgotten cause you can't see it.

 

 

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[Brunty's Dad 10]

[ATTACH=CONFIG]90134[/ATTACH]

[Brunty's Dad 10]

The connector centre left has nothing in the socket.

[robrado974 1]

I can’t see the pic unfortunately.

 

 

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