Smoking Engine

502ADAMH

MEMBER
FORD F-250

I have a 96 2wd F-250 (212k miles) with an inline 6 cyl and at idle there is a substantial amount of smoke coming from the oil dipstick tube and the oil fill hole on the valve cover. I need to find out what is causing this and how to fix it. I don't understand why it would be coming from both when they are on opposite ends of the engine.

This truck is also running very rich you can smell it in the exhaust and it is lacking power. I did notice that a sensor on the intake manifold behind the alternator is broken. Does anyone know the name of this sensor or what it does so I can replace it? I am hoping that it might solve my air/fuel mixture problem.

I just recently bought this truck but have had ford trucks my whole driving career but these are new problems for me. Thanks in advance for any help.

7 Replies

JWALTH02

MEMBER
180 POSTS

The only reason it's coming from both is cause they both go to the same place, the oil pan. Can you see how much oil you have? Is it low? Have you changed the oil recently? Does it smell pretty burnt?

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Sunday, June 24th, 2007 AT 5:08 PM

502ADAMH

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4 POSTS

There is so much flow of smoke that it acually blows oil out from around the PCV, when you take the oil cap off it looks like a choo choo train. I havent changed the oil yet but so much is blown out and replaced it is probably changeing itself

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Sunday, June 24th, 2007 AT 5:40 PM

ASETEQ

MEMBER
5 POSTS

Hi there, it isn't easy to diagnose something like this without seeing the vehicle but it surely sounds like a problem with the Piston or piston rings and or badly worn or cracked cylinder wall. Cracked or broken either of the two could be it. What I would do is check the compression of all cylinders to come to a conclusion - Mechanical problem or not.

Here's more detail for you. A cracked piston would cause the engine not to burn fuel in that particular cylinder therefore unburnt fuel in the exhaust. Another symptom it would show is as you describe blow by gases in the bottom of the engine.

-Aseteq

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Sunday, June 24th, 2007 AT 6:06 PM

502ADAMH

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4 POSTS

Good idea that makes sense I will check the compression and let you know what I find out

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Sunday, June 24th, 2007 AT 6:36 PM

INDYUKE

MECHANIC
416 POSTS

Aseteq is right. Do a compression check. A cylinder leak down test will tell the the condition of the cylinders.

The sensor you are talking about is the intake air temp sensor. It is the primary sensor that gives the computer the info it needs to calculate fuel ratios.

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Monday, June 25th, 2007 AT 2:07 AM

502ADAMH

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4 POSTS

Well I finally did the compression test the first cylinder read 90, the second read 145, I figured with that difference there was not use going any farther. Does this mean I need to tear it down and replace the rings or could it be valves?

As far as the sensor goes I can not find the wire that hooks to it the sensor is still in the manifold but has been unhooked since I got the truck and yesterday I got on a stool with a drop light and still can't find it any where there is a wiring harness near it but no extra plugs that will fit on it

I was told when I bought the truck that the heads were replaced about a year ago with a new one, could improper installation cause this?

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Sunday, July 1st, 2007 AT 1:13 PM

INDYUKE

MECHANIC
416 POSTS

A good way to check whether or not the rings are bad is to do a compression test on all the cylinders, then squirt some oil into the ones that read lower than the others and test them again. If the compression reads higher than before or even as high as the others after doing that, then it's most likely your rings. The oil temporarily creates the seal the rings are supposed to.

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Sunday, July 1st, 2007 AT 5:59 PM