Smoke at idle
09-11-2011, 03:40 PM
#16
Instructor
Join Date: Dec 2010
Location: Connecticut
Posts: 226
Likes: 0
Received 0 Likes
on
0 Posts
Add me to the list of ones doing exactly the same thing, did it before adding the catch can. never got oil in the can either. compression was a little down but not bad. turbo was recently rebuilt K26-8 4" exhaust , maf . went back to maf tree from aos and still smoked. Just completing a new engine build with new turbo so will report soon not back in car yet. The old cylinders had some wear at top and a few small scratches just doen't add up the way and times it smokes . This one could be run on the track with no smoke but consumed oil more than normal . Also no oil ever found in IC pipes and after pulling turbo no signs of oil in hot side , could it be burning it so fast that it never builds up there ? Think maybe they don't smoke until the pipes get hot enough ?
Clifton
Clifton
09-11-2011, 03:45 PM
#17
Addict
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Thread Starter
I went from an old turbo with some play and NO smoke to a freshly rebuilt turbo that felt nice and snug WITH smoke. Extremely frustrating, especially when the cylinders look good - I don't think the smoke is coming from the intake, compressor, or pistons... it's got to be coming from the hot side.
09-11-2011, 04:07 PM
#18
Instructor
Join Date: Dec 2010
Location: Connecticut
Posts: 226
Likes: 0
Received 0 Likes
on
0 Posts
Here is a link to my smoke video. Enjoy!
Notice how the smoke goes away when I give it some gas and then comes right back at the end of the movie when I get out of car.
Notice how the smoke goes away when I give it some gas and then comes right back at the end of the movie when I get out of car.
09-11-2011, 04:13 PM
#19
Addict
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Thread Starter
That looks pretty much exactly like what mine is doing. When the sun starts to go down tonight I'll see if I can't get a video.
09-11-2011, 04:15 PM
#20
Instructor
If you run the car (for a ride around home) for like 15min... and then park and let it idle, does it start to smoke again?
Typically, white smoke is just water vapor. Water vapor is normal when the engine is cold. Water is produced when gasoline is burned. When the exhaust line is cold, such as a cold morning, the exhaust is cooled quite a bit by the time it comes out the tailpipe, and the cooled water vapor in the exhaust turns to white "smoke" much the same as your breath is visible when it's cold out.
If your engine is loosing coolant when it idles, check your coolant temp, is it boiling?
I'd not be surprised if it was a coolant related issue, wether it's getting sucked somewhere in your engine or boiling in the rad, did you checked the PCV valve?
Typically, white smoke is just water vapor. Water vapor is normal when the engine is cold. Water is produced when gasoline is burned. When the exhaust line is cold, such as a cold morning, the exhaust is cooled quite a bit by the time it comes out the tailpipe, and the cooled water vapor in the exhaust turns to white "smoke" much the same as your breath is visible when it's cold out.
If your engine is loosing coolant when it idles, check your coolant temp, is it boiling?
I'd not be surprised if it was a coolant related issue, wether it's getting sucked somewhere in your engine or boiling in the rad, did you checked the PCV valve?
Last edited by Medski; 09-11-2011 at 04:31 PM.
09-11-2011, 08:59 PM
#22
Addict
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Thread Starter
Oil burning. Not water vapor, not fuel. These cars don't have a PCV valve.
I am trying to determine/monitor crankcase vacuum under various conditions, but so far I can't get a reading. I may be zeroing in to the cause on this path... even with the AOS routed back to the tree pipe, I don't get vacuum through the dipstick tube. I'd like to tap the tree pipe to get a reading somehow, but I already broke the little fuel vapor nipple off the tree pipe trying to get a vacuum line on to it.
I am trying to determine/monitor crankcase vacuum under various conditions, but so far I can't get a reading. I may be zeroing in to the cause on this path... even with the AOS routed back to the tree pipe, I don't get vacuum through the dipstick tube. I'd like to tap the tree pipe to get a reading somehow, but I already broke the little fuel vapor nipple off the tree pipe trying to get a vacuum line on to it.
Last edited by zerMATT951; 09-11-2011 at 09:23 PM.
09-11-2011, 11:07 PM
#23
Instructor
Join Date: Dec 2010
Location: Connecticut
Posts: 226
Likes: 0
Received 0 Likes
on
0 Posts
If you run the car (for a ride around home) for like 15min... and then park and let it idle, does it start to smoke again?
Typically, white smoke is just water vapor. Water vapor is normal when the engine is cold. Water is produced when gasoline is burned. When the exhaust line is cold, such as a cold morning, the exhaust is cooled quite a bit by the time it comes out the tailpipe, and the cooled water vapor in the exhaust turns to white "smoke" much the same as your breath is visible when it's cold out.
If your engine is loosing coolant when it idles, check your coolant temp, is it boiling?
I'd not be surprised if it was a coolant related issue, wether it's getting sucked somewhere in your engine or boiling in the rad, did you checked the PCV valve?
Typically, white smoke is just water vapor. Water vapor is normal when the engine is cold. Water is produced when gasoline is burned. When the exhaust line is cold, such as a cold morning, the exhaust is cooled quite a bit by the time it comes out the tailpipe, and the cooled water vapor in the exhaust turns to white "smoke" much the same as your breath is visible when it's cold out.
If your engine is loosing coolant when it idles, check your coolant temp, is it boiling?
I'd not be surprised if it was a coolant related issue, wether it's getting sucked somewhere in your engine or boiling in the rad, did you checked the PCV valve?
09-11-2011, 11:19 PM
#24
Addict
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Thread Starter
I have two things I want to eliminate, one is easy, one is more difficult and more likely the cause:
1. My cam tower bolts keep loosening. I've re-torqued them 3 times since the first start, and I've got under 200 miles on the car since reassembly. I've only re-torqued the lower bolts, not the upper/internal bolts. Could there be an internal leak allowing oil to seep into the wrong passage and burn? When the lower bolts are loose I got a slow oil drip on the header that smoked under the hood. I'm using the LR rubber coated aluminum gasket and new factory bolts.
2. The ONLY hose I didn't replace was the vacuum elbow from the turbo breather vent to the AOS. The ONLY reason I didn't replace it was because I didn't see it on the LR website, and I didn't think I could mess with that swivel fitting. Stupid me. It's hard as a rock and may not be holding vacuum... this seems like the most likely cause especially if I can't get a vacuum reading at the dipstick tube.
I have the replacement hose now, but cutting that fitting off with the turbo and heat shields installed is going to be a BITCH.
1. My cam tower bolts keep loosening. I've re-torqued them 3 times since the first start, and I've got under 200 miles on the car since reassembly. I've only re-torqued the lower bolts, not the upper/internal bolts. Could there be an internal leak allowing oil to seep into the wrong passage and burn? When the lower bolts are loose I got a slow oil drip on the header that smoked under the hood. I'm using the LR rubber coated aluminum gasket and new factory bolts.
2. The ONLY hose I didn't replace was the vacuum elbow from the turbo breather vent to the AOS. The ONLY reason I didn't replace it was because I didn't see it on the LR website, and I didn't think I could mess with that swivel fitting. Stupid me. It's hard as a rock and may not be holding vacuum... this seems like the most likely cause especially if I can't get a vacuum reading at the dipstick tube.
I have the replacement hose now, but cutting that fitting off with the turbo and heat shields installed is going to be a BITCH.
09-12-2011, 12:38 AM
#25
Racer
Join Date: Mar 2008
Location: MISSISSIPPI
Posts: 339
Likes: 0
Received 0 Likes
on
0 Posts
Guys I been chasing this problem for 3 years . Mine is oil for sure has never lost water uses oil at a great rate. I put the LR breather on to see how much blow by it had and to see how much oil it would catch, never got oil in the can. routed the top of the can back to the maf tree with out a vent on top of the can the AOS was opened up as well. Still no oil in the can but of course still smokes at idle. This one could be run on the track and nobody saw smoke. This one is a 86 still with the early OPRV and made more than average oil pressure I believe the OPRV may have been stuck and or a bad rebuild on the turbo. The car did not always smoke even after turbo was first built.
Going to be hard to deternine the cause on this one as have made to many changes now at one time.
used an 88 engine with really nice cylinders honed properly with hand fitted rings and will have a different turbo . Engine is ready to go in so won't be long .My other 2 cars you can't make them smoke .
Clifton Anderson
Going to be hard to deternine the cause on this one as have made to many changes now at one time.
used an 88 engine with really nice cylinders honed properly with hand fitted rings and will have a different turbo . Engine is ready to go in so won't be long .My other 2 cars you can't make them smoke .
Clifton Anderson
09-12-2011, 01:01 AM
#26
Burning Brakes
I have the exact same problem. I just post a thread about it 5 min. ago. I need to know! My car as been doing this for the last 4 months. And it just keep getting worse.
09-12-2011, 01:29 AM
#27
Instructor
Join Date: Dec 2010
Location: Connecticut
Posts: 226
Likes: 0
Received 0 Likes
on
0 Posts
Eric, I read your post. You talk about boost and then smoke. Does the car smoke when you start it cold and then let it warm up for about 5-10 minutes in driveway? Mine will smoke after a short drive about a mile or so and not getting into any boost just a real light drive down the street and then stop at light...smoke
Did you watch my video? Does you car put out more smoke or less? Does it look the same?
Did you watch my video? Does you car put out more smoke or less? Does it look the same?
09-12-2011, 03:05 AM
#28
Rennlist Member
Matt... have you tried pressurizing the whole intake system to see if you have a leak at the AOS/Turbo vent tube thingy area? I know that when I replaced my vent tube thingy, I could say for absolute certain that there was no chance the old one would hold vacuum... I really don't think it's supposed to swivel I think it just does once the rubber is deteriorated enough. The fitting on it looked just like a regular compression fitting.
09-12-2011, 08:28 AM
#29
Advanced
Join Date: May 2003
Location: Norway
Posts: 87
Likes: 0
Received 0 Likes
on
0 Posts
Hi.
I put on a new turbo and a MAF-system on my 951 last year. After this I immediately had one big problem, the same problem as described in this thread: Oil smoke from the exhaust on idle after the engine is warmed up.
I had no issues on stock setup before putting on new turbo/MAF.
After some testing on my car and on my friends completely stock 951, I found out that his stock 951 had a very slight vacuum in the cranckase at idle, while my car had a very slight positive pressure. It was very difficult for me to feal his vacuum / my positive pressure with my hands. But when I put a piece of a thin plastic bag over the oil filler hole at idle (cap off), I could see that it was slightly "sucked down" on my friends stock car and slightly "pushed up" on my car.
For testing, I put a vacuum cleaner near the oil filler hole (cap off) when my car was idling, creating a vacuum in the cranckase. This made the smoking stop!
This must be because the vacuum in the cranckase helps the turbo drain oil, not leak into the exhaust system. On my car with no vacuum in the cranckase (I think I have a slight postive pressure becuase of the "wind" created from the rotating parts, not leakdown), the sealings in the turbo was leaking - smoke on idle.
OK, so why did my friends car have a slight cranckase vacuum and I not?
I tested my leakdown and compression numbers, it was both very good.
The stock intake system is much more restrictive than the Maf-system I put on. This results in more vacuum just before the turbo on the stock system (where the cranckase breather connection is), again resulting in slight vacuum in the cranckase on the stock set up.
With my new Maf-system there is not enough vacuum before the turbo (because of the much less restrictive intake system) to create vacuum in the cranckase.
When I do not get vacuum from the intake, my turbo sealings leak and my car smokes...
At higher revs than idle, the vacuum before the turbo is higher (resulting in vacuum in the cranckse) and the turbo is spinning faster (oil draining better), resulting in no smoke.
Why do the turbo sealings on my new turbo leak on lack of vacuum when others with the same set up, and others driving with a "catch can" not connected to the intake (no vacuum) don't have the same problem? I do not know. Do I have a bad turbo? Do I have a restriction in the oil return line making draining "difficult" for the turbo?
After discussing with the place where I bought the turbo, I put in a restrictor on the oil fead line to the turbo to restrict the pressure / amount of oil. This did not help.
Because of this I made a PCV-system on my car like many other turbo-cars have. This is a valved connection between the intake manifold and the cranckase. The PCV-valve opens and lets some vacuum to the cranckase when there is vacuum in the manifold, and closes when there is pressure in the manifold (we do not want pressure in the crankase). I have driven with this about 3000 miles now, and I have not had any smoke at idle at all.
On normal driving I do not have any issues at all now. But I have been at a few trackdays, and sometimes I can see a bit of smoke in my mirrios when I change gears. A few have commented that my car smokes some too when I am on the track. My oil consumption is higher than it used to bee...
I am now about to check my leakdown and compression numbers again to be 100% sure I do not have any problems there. If (when) that turns up good, I am thinking of having the turbo rebuild to see if it helps..
I put on a new turbo and a MAF-system on my 951 last year. After this I immediately had one big problem, the same problem as described in this thread: Oil smoke from the exhaust on idle after the engine is warmed up.
I had no issues on stock setup before putting on new turbo/MAF.
After some testing on my car and on my friends completely stock 951, I found out that his stock 951 had a very slight vacuum in the cranckase at idle, while my car had a very slight positive pressure. It was very difficult for me to feal his vacuum / my positive pressure with my hands. But when I put a piece of a thin plastic bag over the oil filler hole at idle (cap off), I could see that it was slightly "sucked down" on my friends stock car and slightly "pushed up" on my car.
For testing, I put a vacuum cleaner near the oil filler hole (cap off) when my car was idling, creating a vacuum in the cranckase. This made the smoking stop!
This must be because the vacuum in the cranckase helps the turbo drain oil, not leak into the exhaust system. On my car with no vacuum in the cranckase (I think I have a slight postive pressure becuase of the "wind" created from the rotating parts, not leakdown), the sealings in the turbo was leaking - smoke on idle.
OK, so why did my friends car have a slight cranckase vacuum and I not?
I tested my leakdown and compression numbers, it was both very good.
The stock intake system is much more restrictive than the Maf-system I put on. This results in more vacuum just before the turbo on the stock system (where the cranckase breather connection is), again resulting in slight vacuum in the cranckase on the stock set up.
With my new Maf-system there is not enough vacuum before the turbo (because of the much less restrictive intake system) to create vacuum in the cranckase.
When I do not get vacuum from the intake, my turbo sealings leak and my car smokes...
At higher revs than idle, the vacuum before the turbo is higher (resulting in vacuum in the cranckse) and the turbo is spinning faster (oil draining better), resulting in no smoke.
Why do the turbo sealings on my new turbo leak on lack of vacuum when others with the same set up, and others driving with a "catch can" not connected to the intake (no vacuum) don't have the same problem? I do not know. Do I have a bad turbo? Do I have a restriction in the oil return line making draining "difficult" for the turbo?
After discussing with the place where I bought the turbo, I put in a restrictor on the oil fead line to the turbo to restrict the pressure / amount of oil. This did not help.
Because of this I made a PCV-system on my car like many other turbo-cars have. This is a valved connection between the intake manifold and the cranckase. The PCV-valve opens and lets some vacuum to the cranckase when there is vacuum in the manifold, and closes when there is pressure in the manifold (we do not want pressure in the crankase). I have driven with this about 3000 miles now, and I have not had any smoke at idle at all.
On normal driving I do not have any issues at all now. But I have been at a few trackdays, and sometimes I can see a bit of smoke in my mirrios when I change gears. A few have commented that my car smokes some too when I am on the track. My oil consumption is higher than it used to bee...
I am now about to check my leakdown and compression numbers again to be 100% sure I do not have any problems there. If (when) that turns up good, I am thinking of having the turbo rebuild to see if it helps..
09-12-2011, 08:41 AM
#30
Burning Brakes
Yes I agree we need to get to the bottom of this smoke at idle issue and keep this post alive !!!
I would like to see some video of your cars smoking to see if it looks similar to mine. I have some video of mine but need to post it on Youtube so I can give you guys a link. May be we could all post a short video. Also if you could rev the engine in the video to see how it changes the smoke under vacuum.
There are other threads in this forum with people who indicate similar problems but there never is an answer posted or a "I finally figured out why its smoking" post at the end...
I will try to post the video soon....
I would like to see some video of your cars smoking to see if it looks similar to mine. I have some video of mine but need to post it on Youtube so I can give you guys a link. May be we could all post a short video. Also if you could rev the engine in the video to see how it changes the smoke under vacuum.
There are other threads in this forum with people who indicate similar problems but there never is an answer posted or a "I finally figured out why its smoking" post at the end...
I will try to post the video soon....
Eric, I read your post. You talk about boost and then smoke. Does the car smoke when you start it cold and then let it warm up for about 5-10 minutes in driveway? No smoke at all when cold, or hot, only after going full boost Mine will smoke after a short drive about a mile or so and not getting into any boost just a real light drive down the street and then stop at light...smoke
Did you watch my video? Does you car put out more smoke or less? Does it look the same?
Did you watch my video? Does you car put out more smoke or less? Does it look the same?