Hey guys. Thanks in advance for the help. In March of this year, I put together a 1994 F250 with the 5.8L. It used to be a plow truck and sat for a couple of years before I started on it. I've put about 10k miles on it so far and have only had these 2 issues.

1) Low RPM bogging. If I start out in 2nd or try to lug in a higher gear, the truck seriously bogs down to the point of moving me forward in my seat. It acts as if it's getting too much fuel. I would expect it to lug, but not bog down. I can give it slight gas and it'll lug just fine. Once the rpm's climb a bit, it picks up and goes great. I don't lug often, I know it's not good for the motor, but if I slow down for a light, I won't bother shifting.

2) Within the last 2 weeks, I've been getting a lot of oil smoke at idle and decel. That tells me it's a valve/valve seal problem. I replaced the seals and the pcv, but no change. The motor doesn't seem to start or run as if the compression was low. Would the oil be sucked in from valve guides? maybe an air intake gasket? I'm going to do a compression test today, as well as a vacuum and leak test for the intake gasket.

I can't think of anything else that would cause either of these problems. The truck has 4.10 gears, 2.5" exhuast with a gutted cat and glass pack muffler. New air filter as well.

Thanks again.

 

Forgot to mention...

The only cylinder burning oil is #8, driver side rear. This is the only plug getting oil fouled. All others appear to be normal. The #8 plug comes out dripping in oil. I know this was common with older 5.8's with the pcv routed to the rear of the intake runner, but mine is routed in the middle.

 

sounds like it needs new rings I had that proublem with my 5.0

 

I'm really hoping it's not rings. The compression test will answer that later today. If I understand correctly, if the rings are bad and I'm getting blow-by, I should see smoke on acceleration too. Is this accurate? I'm only seeing the smoke at idle and decel...

Thanks.

 

my mechanic friend says that is not true

 

Have you done the PCV Relocation yet? There are stories that the PCV valve (which dumps into the #8 runner) can kill cyl. 8 with all the miles of dumping oil into only that one cylinder. I see your running a compression test, that will tell you for sure.

-Mike

 

Guess you missed post #2...

 

Thanks for the replies. #8 failed the compression test at 55psi. The other 7 were near 150psi. Time for rings.

 

Thats cheeper then a new engine good luck man

 

Did you try squirting some oil in there and running the test again? If the compression comes up when you do that, it will prove it's the rings and not something else like burnt valves or head gasket blown,,, It might be worth doing just for the heck of it.....

 

Yep missed it completely. Looks like it was done too late, that's a bad stroke of luck. Good Luck.

-Mike

 

Agreed. Tablespoon of oil. If its the rings, the compression should go up.