blue smoke out tail pipe after down hill run

[subarurage]

I live up in the mountians and today I drove 13 kilometers down hill so I did give it gas for 13 km's and then came to a stop at a stop light. While at stop light blue smoke start pouring into the car coming from the exhaust. I drive a block leaving a trial of blue smoke behind me and come to another stop light and it is still smoking. :mad:Then take off from that stop light and drive for about 4 blocks leaving trail of blue smoke and then smoke goes away. It normal doesn't smoke except when I coast or let off the gas in gear and then give it gas like mentioned above. Usually the time coasting (in gear) is short so I only get a little smoke. It seems the longer I coast (in gear) the more smoke I get.

 

Any guess on what my issue is?

 

I do get a check engine light after I drive a few blocks from start up. Supposedly PO said it was O2 sensor but replaced that and still get the light. Not sure if there is a short in the 02 sensor wire somewhere.

 

I have tried to do the light flash self diagnoses but can't find the wires under my dash board that they show in the haynes manual. Furthermore there is something at looks wired into the my wiring harness and it not stock (little back box).

 

Thanks for the help! I hate leaving a blue smoke everywhere:mad:

[renob123]

What kind of car do you drive? The diagnosis may vary depending on that.

 

Jacob

[eulogious]

Is this the same car that's in your other thread?

 

http://www.ultimatesubaru.org/forum/showthread.php?t=111519

 

If so, then I would do what I said in my last post there. There is obviously something going on with your car, you need to get a code to see what's going on...*edit* See here: http://www.ultimatesubaru.org/forum/showthread.php?t=105472&highlight=ecu*+codes

 

I am confused on which thread I should respond to at this point...

 

As for the blue smoke, maybe your PCV valve is going out...

Edited July 17, 2010 by eulogious

[naru]

No need to guess about the smoke.Your engine is old and worn.

 

Coasting downhill w/closed throttle at highish RPMs creates a high vacuum which pulls oil past the valve guides/rings.Short of a rebuild,new valve seals may help.

[subarurage]

Sorry 1992 Loyal EA 82 Single port fuel injection.

 

Sorry for confusion I didn't want to line up to many problems under one thread so thought I would spread it out a little. Thanks for your responses!!

 

Engine has 240k kilometres (150K miles) on it. It seems to be strong but maybe the piston rings are still good but not value guide/seats

[skishop69]

Pulling oil past the guides is a common misconception for blue smoke on a coast down. Worn guides will (90% of the time) cause valve seating issues and an unstable idle. You can have bad valve seals that can cause the problem in combination with slightly worn guides, but this usually results in only a small amount of smoke for a short time. I would tend to agree with the worn rings. Only the oil rings need to be worn (excessively) for this to happen. They wear down, the oil then bypasses the 'scraper' portion of the oil ring and finds its way around the compression rings. Matter of fact, they don't even need to be worn. If you let it sit for long periods, they can stick and cause the same problem. I have the same thing going on with my Brat. I have down a leakdown and compression test. The compression test was a little low but not unexpected as she's pushing 200K. I checked the stem fit and replaced the seals as well, but to no avail. The more I drive it, the less it does it.

 

As far as your SES light, the most probable answer is that the burning oil is creating a rich condition that is setting the O2 code. You did say it comes on after the coast down and a little driving. JMTC

[subarurage]

How do I check my PCV valve. Haynes says I can just take it off the hose and shake it but my valve is screwed into the the engine block.

 

1992 Loyal EA 82 SPFI

 

Thanks

[renob123]

How do I check my PCV valve. Haynes says I can just take it off the hose and shake it but my valve is screwed into the the engine block.

 

1992 Loyal EA 82 SPFI

 

Thanks

 

Heh, yeah, you have to unscrew it:) Also look at the hose attached to it for heavy buildup.

 

Jacob

[subarurage]

I pulled the PCV value and it does rattle so I guess it is working fine. There was no heavy build up in the hoses anywhere.

 

I am getting a CEL light saying that I have an issue with my Purge control solenoid valve. Would this cause the blue smoke system?

 

The more I read the more it looks like the purge control solenoid valve has to do with the fuel system.

Edited August 24, 2010 by subarurage

[archebald23]

done with it? exactly same problem im experiencing with my tail pipe. well, i guess we should just learn how to replace a tail pipie anyway...

Edited October 12, 2010 by archebald23

[subarurage]

Yes it still does it so I am going to sell the car. That will fix MY problem.

[Yo'J]

You can throw money at anything to fix it. Most cars do that past a certain age. Have you seafoamed your engine? That can fix a variety of age related problems if done right. My 82 wagon does the same thing after a long downhill run, sometimes sips a little bit of oil too. Bad maintenance by a previous owner, the engine only has just over 140k. Its not gonna kill me or itself so I'm gonna drive it till it dies. If your worried about looks.....give it a hair of gas on the way down hill so it wont create that oil sucking engine pressure.