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Discussion Starter · #1 ·
I was going to make this video myself, but since it is already made ...

youtube .... watch?time_continue=2&v=8AcvKPYFeDI

My car threw a 2187 ( lean air mixture ) error after a local garage removed and replaced the valve cover as part of a timing chain tensioner replacement. The car threw the error the morning after the repair and had a very rough idle, especially when cold. After my local mechanic did a smoke test and checked the vacuum lines he suggested that the issue might be the PCV valve in the cover. He verified this by doing the above linked test which showed no crankcase vacuum at idle. Not wanting to replace the cover I ordered the PCV valve replacement from ECS. The morning I went out to replace the PCV valve in the cover the rough idle at cold start was not there, but the code was there and I could not delete it with my Scan Gauge, so I warmed up the car, checked the vacuum (none), and proceeded to replace the PCV in the cover. When I opened the PCV cover the original PCV plastic looked brand new, but I replaced it, put the new cover back on and when everything was put back together..... still no vacuum. I bought a mini specific comm (I put a link up to that here on the forum $49 on amazon) which was able to clear the code and after driving a total of about 400 miles, the code did not come back, despite no vacuum in the crankcase.

A fellow board member put the car on his very impressive computer and did not pull any codes.

In the 400 miles the car only struggled at idle once or twice. It does Idle around 870 RPM and throws, a "little" more white smoke than it should for a fully warmed up car ( not a lot, but noticeably more than other cars I'm idling nearby.

Another thing that I don't get, If there is no vacuum, then why does the idle change so much when I remove the cap? Isn't no vacuum, no vacuum?
Good advice is usually, if it ain't broke don't fix it, but this is buggin' me.
 

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I was going to make this video myself, but since it is already made ...

youtube .... watch?time_continue=2&v=8AcvKPYFeDI

My car threw a 2187 ( lean air mixture ) error after a local garage removed and replaced the valve cover as part of a timing chain tensioner replacement. The car threw the error the morning after the repair and had a very rough idle, especially when cold. After my local mechanic did a smoke test and checked the vacuum lines he suggested that the issue might be the PCV valve in the cover. He verified this by doing the above linked test which showed no crankcase vacuum at idle. Not wanting to replace the cover I ordered the PCV valve replacement from ECS. The morning I went out to replace the PCV valve in the cover the rough idle at cold start was not there, but the code was there and I could not delete it with my Scan Gauge, so I warmed up the car, checked the vacuum (none), and proceeded to replace the PCV in the cover. When I opened the PCV cover the original PCV plastic looked brand new, but I replaced it, put the new cover back on and when everything was put back together..... still no vacuum. I bought a mini specific comm (I put a link up to that here on the forum $49 on amazon) which was able to clear the code and after driving a total of about 400 miles, the code did not come back, despite no vacuum in the crankcase.

A fellow board member put the car on his very impressive computer and did not pull any codes.

In the 400 miles the car only struggled at idle once or twice. It does Idle around 870 RPM and throws, a "little" more white smoke than it should for a fully warmed up car ( not a lot, but noticeably more than other cars I'm idling nearby.

Another thing that I don't get, If there is no vacuum, then why does the idle change so much when I remove the cap? Isn't no vacuum, no vacuum?
Good advice is usually, if it ain't broke don't fix it, but this is buggin' me.
there is a difference between vacum and crankcase pressure, crankcase pressure gasses are very carefully designed in to how a new engine needs to be ie to meet emission laws and targets. and it live a knife edge,, where a very slight change will effect it, ie cracked pipe, piston ring wear. leaking injector O-rings on non direct injection engines, even engine oil can effect it.. this is before the other stuff like cat failure and 02 sensors or crap fuel even a air filter can effect it,, this is why these tyres of fault are so hard to sort out,, and the only way to begin with them is to ensure its serviced and very important on these prince engines timing chains are all good as this will effect it as well, so start with the very best base to start with,
this all said i have had cars that just do not play well then others that had a dam good hiding from a customer for them to report back it cured it,, in those cases i would guess extra heat and pressure must of cleared some carbon from some where,, on turbo cars the inlet valves get carbon on rears cause it to run all to hell.. i get a feel to them these days and know form listening and driving them sort of where things need improving... i always compression test, oil pressure test. and timing chain check, before doing much else
 

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Discussion Starter · #3 ·
there is a difference between vacum and crankcase pressure, crankcase pressure gasses are very carefully designed in to how a new engine needs to be ie to meet emission laws and targets. and it live a knife edge,, where a very slight change will effect it, ie cracked pipe, piston ring wear. leaking injector O-rings on non direct injection engines, even engine oil can effect it.. this is before the other stuff like cat failure and 02 sensors or crap fuel even a air filter can effect it,, this is why these tyres of fault are so hard to sort out,, and the only way to begin with them is to ensure its serviced and very important on these prince engines timing chains are all good as this will effect it as well, so start with the very best base to start with,
this all said i have had cars that just do not play well then others that had a dam good hiding from a customer for them to report back it cured it,, in those cases i would guess extra heat and pressure must of cleared some carbon from some where,, on turbo cars the inlet valves get carbon on rears cause it to run all to hell.. i get a feel to them these days and know form listening and driving them sort of where things need improving... i always compression test, oil pressure test. and timing chain check, before doing much else
If you look at the video, he puts a vacuum gauge on the oil cap and check the vacuum at warm idle. There is a chart at the end showing what the correct vacuum should be for different models. I was questioning this, since I don't get a vacuum on mine.
 

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If you look at the video, he puts a vacuum gauge on the oil cap and check the vacuum at warm idle. There is a chart at the end showing what the correct vacuum should be for different models. I was questioning this, since I don't get a vacuum on mine.
chances are the black 22mm plastic pipe that runs from pcv valve to the bottom on the inlet manifold has split or cracked lost count the amount i have replaced
 

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Discussion Starter · #5 ·
chances are the black 22mm plastic pipe that runs from pcv valve to the bottom on the inlet manifold has split or cracked lost count the amount i have replaced
That would not be fun to replace. On the N12 engine the intake manifold needs to be removed to get at it. Gonna have to wait for warmer weather before I'll try and tackle inspecting that bit.
 

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That would not be fun to replace. On the N12 engine the intake manifold needs to be removed to get at it. Gonna have to wait for warmer weather before I'll try and tackle inspecting that bit.
yep it does pretty much, you can get at the end of the plastic pipe by undoing it it the undo the 13mm nuts that are easy to get at with top filter box off and 3 inch socket extension form the top,, ie use 1/4 drive set its so much easier, under the car theres a single 10 mm bolt on very bottom edge of inlet lower box section.. it looks worse than it is.. dont have to remove it just loosen it enough to get hand in a release the plastic clip. the pipe has a heat resistant sheaf on it this covers the cracks so need removing totally and blow through the pipe seal one end up and see if holds pressure..
 
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Discussion Starter · #7 ·
yep it does pretty much, you can get at the end of the plastic pipe by undoing it it the undo the 13mm nuts that are easy to get at with top filter box off and 3 inch socket extension form the top,, ie use 1/4 drive set its so much easier, under the car theres a single 10 mm bolt on very bottom edge of inlet lower box section.. it looks worse than it is.. dont have to remove it just loosen it enough to get hand in a release the plastic clip. the pipe has a heat resistant sheaf on it this covers the cracks so need removing totally and blow through the pipe seal one end up and see if holds pressure..
It's $50 Bucks to replace, if I'm going to go through that, I might as well just replace then darn thing while I'm in there if it's good I'll just keep the old one as a spare, from what I understand it's not that uncommon for them to crack. Here's hoping for some 50 degree days. It was 11 coming into work today.
 

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It's $50 Bucks to replace, if I'm going to go through that, I might as well just replace then darn thing while I'm in there if it's good I'll just keep the old one as a spare, from what I understand it's not that uncommon for them to crack. Here's hoping for some 50 degree days. It was 11 coming into work today.
we.ve had nothing but rain since 3pm today southwest of uk 50 degrees would be nice lol. i bought a roll f the same plastic corrugated plastic pipe off ebay for £8 for 1 metre 22mm diameter and can cut the clip ends off and glue the pipe on.
 
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