Andyman

Hi! I hope everybody has a good holiday season! As for me, I've got a sick 4runner. On a recent trip of 250 miles, I found that I was 4 quarts down on oil. So I refilled and halfway home I had to add another two quarts. In short, I'm burning about one quart of oil over 70 - 100 miles... I haven't been driving it much with summer and all, but with winter coming I have to have it running okay. When I rev the engine I get a big cloud of black smoke. Not white or blue, but kinda like I was burning charcoal... I checked the coolant and there isn't any oil in it, so I'm thinking it isn't the head gasket. But what else can it be and how do i check for it? What tests can i do? btw - it's a '97 4runner ltd. 3.4L Auto.

Thanks!
Andy

nunsa

Happy Holidays!
Black smoke is a sign that your engine is running way to rich! Your afm might be the cause, most likely, a clogged air filter will give you the same!
Your also burning way too much oil, possibility of rings and/or valve seals!
Good Luck!

Toytech

You might want to check your pcv to see if it is cloged, if not you will need to
do a compression test to check the rings

Fahrenheit 451

Had you checked the oil before the trip? Running rich will increase your oil consumption considerably, but not that dramatically unless you are just pouring gas into the cylinders.
I'd say figure out what is causing the rich condition first then see how things go.

Andyman

Hey, thanks for the replies!

I had replaced the air filter before the trip actually, so that should have been okay. How do I check the valve seals?

I'll check the pcv and do a compression test.

I did check the oil before the trip and found that I was low about 3 quarts.. I brought it up to full before the 250 miles... What can cause the rich condition?

Thanks!

MTL_4runner

Do you have a check engine light?

Does the truck leak oil at all when idling in the driveway? if so, how much and where?

Any number of things can cause a rich condition (MAF, O2 sensor, coolant temp sensor, leaking injector, etc). You need to basically start going through the truck methodically to find the answer.

Mad Chemist

For burning that much oil, you'd think a CEL would come on. Good luck, hope you figure it out!

Andyman

Nope, no check engine light. It doesn't leak at all, its nice and clean. I took it to a friends shop and we had it up on a lift to check it out. It doesn't leave puddles anywhere either.. mystery to me..

MTL_4runner

If so then definately do a compression check because it does leak oil somewhere (perhaps internally).
Also you might pull the plugs to see what they look like too.

Did you ever do the headgasket?...or has it ever been done?
How many miles are on the truck?