Car smoking...

'94ChickStang · Jul 5, 2007

ok my car is blowing what looks to be like blue smoke out the pipes while under WOT starting @ about 4k and higher. There is no smoke at all while driving normally (or none that I can see).

I've been driving it for about 4 days after my HCI switch and it just started smoking yesterday. The low oil indicator just came on in the evening...the car has a 12:1 AFR so I thought initially it could be excess fuel due to richness but wouldn't that be black smoke???

What might this be, I'm going to call the shop soon...

BlackVert · Jul 5, 2007

sounds like it might be blow by.

is there any evidence of oil leaks anywhere? check the headers. i had oil coming out through one of the valve cover gasgets and dripping on a header. that caused alot of smoke

'94ChickStang · Jul 5, 2007

I haven't seen any leaks but I was looking in the dark last night, I'll check later.

I know there's no oil on the floor of the garage and the collector for my oil separator is not completely full.

Stanger007 · Jul 5, 2007

Blue smoke is oil.

Did you check the oil level when you put oil in? How is the level now?

How's the oil pressure looking?

Is the stuff in your sig what you put on?

Wes

TheDamned · Jul 5, 2007

Don't worry I have the same problem... except my oil light never came on... I have to re-fill my oil every 1months and a half or so.

Badazgt. · Jul 5, 2007

^^ there is a reason to worry... ur rings are wearing out

chuck943 · Jul 5, 2007

if only smoking under wot could be valve stem seals

BlackVert · Jul 5, 2007

chuck943 said:
if only smoking under wot could be valve stem seals

i don't think so, when you have that problem you see it in a big cloud at startup after it has been sitting a while

reddy351 · Jul 5, 2007

chuck943 said:
if only smoking under wot could be valve stem seals

I agree completely. There might be a puff, or two, on startup and a "noticable amount" at WOT. The reason is because there is enough vacuum at WOT to pull oil past the valve seals. The seals might still be good enough to actually seal, when there is no pressure (vacuum) on them.

The "cloud of smoke on startup" would be badly worn/brittle seals letting oil drip down the valve, into the combustion chamber, when the engine has been static for a few days.

"Rings" would smoke all the time.

chuck943 · Jul 5, 2007

BlackVert said:
i don't think so, when you have that problem you see it in a big cloud at startup after it has been sitting a while

Yeah vert u are right but, they will also give you a burst of smoke at wot also. Think about that for a minute,you have oil trying to leak past a seal and down the valve stem. When you go wot and get a quick big suction in combustion chamber it will pull any oil hanging there on in the cylinder.

Now I know he didn't say he was smoking at start up but maybe he is in the beginning stages and it maybe not bad enough that he has noticed it yet?

compression test and leakage test would tell him for sure.

'94ChickStang · Jul 5, 2007

the oil pressure seems just fine and my signature is up to date

There's no smoke upon startup or after it's been running awhile, it only smokes under WOT @ higher RPMs and it smokes quite a bit...

Yeah I think it's going to be filled up more than once a month due to the fact I've driven it about 400 miles since the HCI swap and it's already low...it must be burning a bunch!! I don't know how low the oil must be to trigger the sensor

BlackVert · Jul 5, 2007

um, wouldn't there be less vacuum at wot, not more?

cjones · Jul 5, 2007

run a compression check then run a wet compression check and compare.

then possibly run a leakdown test.

chuck943 · Jul 6, 2007

BlackVert said:
um, wouldn't there be less vacuum at wot, not more?

yes there would be less vacuum in intake manifold at wot, but inside the combustion chamber it would be alot(like turning your vacuum cleaner from low to high speed). engine is nothing but a big air pump sucking air in pushing air out. when u go wot the pistons are pulling alot more air into the chambers. any oil film left on the valves would be pulled right off them into the chamber.

'94ChickStang · Jul 7, 2007

I also noticed yesterday a small amount of oil had sprayed out my tailpipes on the garage floor!! I hope my car doesn't blow up just from a top end swap

Dino Dino Bambino · Jul 8, 2007

Worn valve stem oil seals (on new AFR heads???) would cause a puff of blue smoke from the exhaust when the vacuum in the intake manifold is high, and that's after you snap the throttle shut.
WOT is a low vacuum/high load situation so if you get blue smoke in that situation, it's more likely to be oil leaking from the crankcase into the combustion chambers past worn piston rings.
I suggest you have a compression check done on all cylinders, first dry, and then repeated after putting a teaspoon of oil down each spark plug hole. If the "wet" numbers are significantly higher than the "dry" numbers, it's worn rings.

'94ChickStang · Jul 8, 2007

I'm going to bring it back to the shop this week. Ive noticed after the last few days it will smoke on startup sometimes and generally when I get on it.

I also have noticed that my oil separator will only fill up to about 1/3 of the way, and will fill up again almost immediately when I empty it so I must be sucking it all up through the intake??? My compression was 180 on all cylinders (supposedly as thats what the tech told me)...dunno what the difference is wet & dry.

My low oil light hasn't come on since the first time I noticed it & added a quart, so I checked my oil after a drive today and it's dry as a bone!!

I really hope it didn't cause any perminant damage , it has seemed to run fine through this.

Thanks for all the help y'all

cjones · Jul 9, 2007

a dry compression test is the normal test a WET test is where you add a small amount of oil into the cylinders to seal the rings.

was the tech that told you 180 on all cylinders at the same shop that did the work?? have them rerun the check and run a leak down test.

you can still have about 3 quarts of oil in the engine when the dipstick is dry(the stick doesn't go to the bottom of the pan)

'94ChickStang · Jul 9, 2007

cjones said:
you can still have about 3 quarts of oil in the engine when the dipstick is dry(the stick doesn't go to the bottom of the pan)

whew!

I will have them check those things and yes it was the same tech that did the work from the shop that's put me through the ringer already....

chuck943 · Jul 9, 2007

Bullitt95 said:
Worn valve stem oil seals (on new AFR heads???) would cause a puff of blue smoke from the exhaust when the vacuum in the intake manifold is high, and that's after you snap the throttle shut.
WOT is a low vacuum/high load situation so if you get blue smoke in that situation, it's more likely to be oil leaking from the crankcase into the combustion chambers past worn piston rings.
I suggest you have a compression check done on all cylinders, first dry, and then repeated after putting a teaspoon of oil down each spark plug hole. If the "wet" numbers are significantly higher than the "dry" numbers, it's worn rings.

They may have not been have been snapped all the way into place and after valve opened they could have stuck at the top of the valve stem. I would pull spark plugs and see if there is any oil on the end of any of them and if so then pull valve cover and look thru valve spring and see if one may be stuck at top of the valve.

Please explain what intake manifold vacuum would have to do with this? Valve stem seals are not subject to much if any intake manifold vacuum.

Car smoking...

'94ChickStang

Member

BlackVert

'94ChickStang

Member

Stanger007

TheDamned

"I am Canadian and Damned for it!"

Badazgt.

New Member

chuck943

New Member

BlackVert

reddy351

chuck943

New Member

'94ChickStang

Member

BlackVert

cjones

chuck943

New Member

'94ChickStang

Member

Dino Dino Bambino

'94ChickStang

Member

cjones

'94ChickStang

Member

chuck943

New Member

Similar threads

Car smoking...

Member

Member

"I am Canadian and Damned for it!"

New Member

New Member

New Member

Member

New Member

Member

Member

Member

New Member

Similar threads

Privacy & Transparency

Privacy & Transparency