Cleaned PCV, now only smoking at idle RESOLVED, plugged hose

ramilio · Post by **ramilio** » 14 Jul 2013, 16:57

After reading endless posts, I decided to tackle the job of cleaning/replacing my PCV system (including the flametrap) on my 1998 Volvo v70 2.5l. For the most part, my system was pretty clean with only a bit of crud in the pipes (the bulk of it being in the oil return)

After I finished up, I re-did the glove test. Under acceleration, the glove gets sucked in - however it expands when the engine is returned to idle. I believe that the vacuum line from the intake manifold is supposed to assist with pulling the emissions through the PCV system via the flametrap - but I'm unsure how such a small vacuum line can do this? Just wondering if anyone can explain?

Also, has anyone discovered any workarounds introduce more vacuum into the flame trap? and provide a more efficient method of venting the PCV emissions?

Also, if anyone could assist with the following PCV related questions, it would be greatly appreciated.
1. Where is the PTC valve located? I've heard that this can contribute the problem, but i'm not sure my car has one. My car is a 2.5l non-turbo, the only thing I can see on the intake is the flame trap.
2. Where does the vacuum port on the intake manifold get its vacuum from? Is the vacuum generated by the intake of air? It doesn't appear to be connected to the vacuum system

Thanks,
Paul

Post by **xHeart** » 14 Jul 2013, 18:17

Did you look here viewtopic.php?f=1&t=28487

...this too PTC Nipple removal and cleaning

sidharrell · Post by **sidharrell** » 14 Jul 2013, 22:30

I believe the ptc is only on turbo cars. The line going from the oil seperator to the ptc on turbo cars goes to the flame trap on non-turbo cars.

Post by **jblackburn** » 15 Jul 2013, 06:00

Vacuum comes from the intake stroke of pistons. Same as it does at the vacuum tree; that dedicated vacuum port just provides more of it.

So all hoses were replaced? Find a larger inner diameter vacuum hose (just buy some at an auto parts store - try 6 or 8 mm with a clamp on both ends) and run it from the vacuum port to the flame trap vacuum port. Long as its connected, you shouldn't have any air metering issues.

To avoid taking the whole intake off again, just run the vacuum hose around the front of the motor for now to see if it helps.

ramilio · Post by **ramilio** » 15 Jul 2013, 22:06

Hi all,
Thanks for the replies. My car definitely doesn’t have a PTC on the intake, just a flametrap.

Jblackburn, does this mean I can plug the flame trap into the vacuum tree rather than intake manifold? I was scared to this as I thought it might contaminate my vacuum system - my other car that I do maintenance on (an old Merc) has a dedicated vacuum pump, I assumed that my Volvo had one too…

If I put a Y connector on the flame trap vacuum line and fed two vacuum lines into it, would this increase vacuum in the flame trap? Or is this against the laws of physics? - Or maybe the laws of common sense?

Thanks,
Paul

Post by **jblackburn** » 15 Jul 2013, 22:11

Volvo does not have a vacuum pump. You could try the vacuum tree, but the intake manifold port on the end provides a stronger vacuum source which is what it sounds like you need along with a slightly larger hose.

"Y" idea could work, but be careful not to create a vacuum leak.

ramilio · Post by **ramilio** » 19 Jul 2013, 23:19

Hi All,

Success!

I reinspected by Flametrap and noticed that the vacuum line still had some crap in it. After cleaning it out and re conducting the glove test, I have negative crankcase pressure! Woo!

Anyone that has a smoking dipstick on idle should definitely check the vacuum line on the flametrap.