1987 ford f150...

302 4spd 85,000 miles

so... last night went to start her up... she would crank but not start...

so i figured it was a fuel problem... the gas tanks were rusted so we replaced them a few months ago... figured the fuel filter was bad... so we replaced it and found that the filter was FULL OF RUST!

so then I figured that the fuel injectors were munged up...

So today me n my pops pull off the upper intake manifold...

heres what we find

1. bad gasket
2. Oil in the intake manifolds... upper and lower... lots of oil...

I can't figure out how if it was burning all this oil why it didnt smoke... the ammount of oil should have made it smoke like ****in hell...

Any idea on how it got there?

 

A small puddle of oil in the intake manifold is pretty common. Comes from oil getting sucked past the PCV valve. If your talking about a full cup or more of oil, then I would say the motor was blown....

 

lots of oil...

 

It's normal. Get an inline oil-seperator if you're nervous. It's caused by PCV blowby.

 

How do you figure that?

The way it gets sucked is from the vaccum of the motor pulling oil slug up onto the valve cover into the hose and then into the intake.

Maybe i dont get what your trying to say?

 

I know that the PCV valve puts oil in the intake...

THERE IS ALOT OF OIL...

ah... I'm gonna tear apart the top end anyhow I'll figure it out on my own...

 

Is there oil in the iside of the intake or in the itake ports?

My intake ports on my heads were full of oil and grease.

there could be something blown inside of your engine that is causng you to get oil blow back in your intake

 

All I'm saying is a little oil in the intake manifold is normal, sometimes the PCV system doesn't properly circulate everything, so just get an inline oil seperator.

 

But if it's a lot of oil, it's something more.

 

Being a 302 isn't the PVC in the back on the lower intake? I know for the mustangs, like the 95 i had, it is. IF it is like the stangs, did you check the little round mesh screen that's under the PVC, i would take that out and see how sludged up it is, and have you changed the PVC?

 

lots of oil in the intake suggests to me that you have a big blow by problem like a bad ring and it's causing pressure to build in the crank case. Oil is being kept in suspension in the air at the higher ambient pressures and is being sucked into the intake through the PCV system. As it enterst the intake the air pressure flips heavily over to vacuum and the oil falls out of suspension leaving great gooey gobs of it in the intake. No bwaynoh.

I'd, pull the intake (upper and lower) and replace the gaskets that mate them to the motor and to each other. Replace the PCV valve, then do a compression test and find the bad hole. Report back with your results and we'll take it from there.

 

pcv is fine... i checked that...

i thinks its a gasket...

not sure... its wierd cause the stupid thing was running... it was rebuilt once...

evidently my father changed the oil in it (years ago) with penzoil and the engine seized....

so he rebuilt it and ever since it has run ****ty... bad idel problems, idels at 2k or it stalls...

thanks redneck... thats perty dern helpfull... maybe thins extra info could help..

Its got me and my pops puzzled... he knows lots about cars... he used to build race cars n ****... so he knows his stuff and he is confused.. .ah

****

 

With you also saying it idles at 2K or stalls, i would definitely take off the intake and check that out. I know if the intake manifold isn't sealed to good it can cuase it to stall or idle high and puke up some oil into the intake.
if the PVC is good to go and not caked with oil, then it could be the lower intake gasket might have shifted during install awhile back, has it been low on oil? OR the valve guides/seals are bad, the compression check will be good to check out some cylinders, hopefully none are dead, but it would sound different and run like a$$. If you think you have a bad cylinder, unplug one fuel injector at a time, if it doens't stumble when you disconnect it, it's bad, if it stumbles it's good to go. also they are within +-15 of each cylinder
also check your TB/VC and see if it's caked with oil....

sometimes i can't think, then later i have to come back to voice my opinion again... Hope you find the problem and it's a easy fix for ya....good luck with it.

 

cool deal. let us know if we can point you anywhere. Having it run poorly post rebuild the way you describe (high idle ok, low idle dies) suggests that there's a possible vacuum leak. You can use my old redneck vacuum leak finder by taking a propane torch and hooking a rubber tube to the nozzle tip, set the idle to 850rpm or so and let it run, methodically run the propane around the engine and if the motor cleans up the idle all sudden like, note where you're pointing the gas as you've just found a vacuum leak.

 

Also WD40 is very flammable, if you spray it around the intake and the idle surges, that will point it out, just avoid spraying the rubber hoses, i heard WD40 can eat the rubber.

 

yah...

thats all good stuff to do when its running...

she aint running.. lol...

and the intake is already off...

such a pain in the ***...

 

well, you can still do a quick compression check, which I'd do anyway. It's a good way to see if other issues have caused internal issues that are more serious.

Carefully inspect the old gaskets for damage not related to their removal. Also look for places where sludge has built up more than others. Those are usually signs that are pretty easy to find. In any case, look inside the intake for the sludgiest spot, that's usually where oil is sitting and probably close to the point of entry.

If you can take some high resolution shots of the intake from various angles we might be able to spot something. Otherwise, tear it down and rebiuld it.

 

well yeh... its tricky...

I'll uddate ya'll with what i find...

thanks