Hello all. I've been a Cummins guy since I was 16 and dont know much about gas engines, but a recent job change is making me sell one of my cummins trucks. So, I bought a 01 1500 sport w/ 360. It has 98K miles. I got this cheap and after driving it until its hot now I know why.

When I drove it I didn't notice any smoke just a miss in the motor and noticed it didnt have as much as power as I thought it would (should of came here first and researched) Here is the list of problems I have noticed now.

Low idle miss in engine (probably misfire)
oil pressure goes to zero when hot then back up when throttle is applied
white smoke out exhaust smells like unburned fuel and oil
Oil is not milky
No oil in radiator
no signs of bubbling combustion gas when thermostat opens


I see many spots of oil when looking down throttle body, I am hoping this is the only thing wrong? He is original owner and did not replace plenum gasket and it has not been reflashed. Knowing my luck... heads are probably cracked, right?

 

I'd replace the plenum gasket and plate, with a Hughes. Along with the cat and both o2's. Also do a compression test first, with the motor as warm as possible, and see what you come up with.

 

Take a good look at all of the spark plugs. If it's not something you've done before you can easily find all kinds of references, most with photos, by searching the web. This can be done for free, so it's a good start that will give you useful information about what to look for next.

There's a vacuum/pressure test in the TSB for the plenum gasket that should tell you if you've got enough of a leaker to cause the symptoms you're seeing. Also do the compression test as zman suggested no matter what else you come up with. Note that a failed PCV valve can put lots of oil in the plenum, and will make the most exhaust smoke during times of high manifold vacuum (idling, cruising unloaded, decelerating). If the plenum gasket test doesn't indicate a problem, in fact even if it does, replace the PCV valve.

Oil pressure gauge falling to zero is probably a bad sending unit. Screw in a mechanical gauge to verify what's really there before acting on it.

The check for things crossing boundaries was a good one as it eliminates the more expensive kinds of problems.

As zman said, the catalytic converter and oxygen sensors should be on your shopping list. Whatever's throwing smoke has almost certainly eaten the cat and O2 sensors.

Welcome to the forum. I wish it were under better circumstances.

 

http://www.ngksparkplugs.com/tech_su...qs/faqread.asp

 

Going to pick up a pressure tester now.. I appreciate the quick replies.. I just hope its not a cracked head..

Just ordered the hughes kit

 

Also: http://www.4secondsflat.com/Spark_plug_reading.html which goes into more detail about what a functional plug is telling you about what's happening in the combustion chambers.

 

Well just did a block tester using the fluid.. re did it about 8 times when the motor was cold, warm, and hot, didnt turn colors... Next doing compression test i will check back. thanks

 

I had the same problem with my 99. The more I pushed the pedal the more power I lost. It was the plenum gasket.
Look down the throtle body with the butterflys open. If you see oil on the flat surface at the bottom the plenum gasket is bad.
Took me about 6 hours to replace including a broken bolt.

 

Passenger side compression from front to back

150
135
120
115

Im doing other side tomorrow.. I dont understand why its going down like that as you move towards back of motor

 

I'm guessing that it's very likely that you've got a fouled catalytic converter and it's been that way for quite a long time. When the cat plugs up, the rear cylinders see a lot more heat.