Do these trucks have smog pumps on the engine? I was checking under the hood a lil bit ago after the check engine light came back on with the P0420 code(which is probably the catalytic converter) and I noticed what seemed to be no smog pump on the truck. Also if i take the cat off and put a piece of pipe in will the check engine light stay on all the time? Thanks in advance for the help!

 

No smog pump. Yes the check engine light will be on if you remove the cat, due to the post-cat o2 sensor. You could get an o2 simulator for the post-cat o2, but i would just buy a high flow cat and replace the stock one. If the cat is indeed bad, it's for a reason. Check your plenum, probably why the original cat is bad in the first place.

-JT

 

I will check the plenum! If it sets and idles for a lil bit and i rev it some it will smoke! Will a bad plenum cause this, or is that another problem that I have to figure out? Other than the occasional smoke and the check engine light it runs great! I just bought is last sunday and it wasnt doing all this crap when I drove it and checked it out. I wish it had of gave me some sigh before I bought it and then I wouldnt have.

 

The smoke could be a few things. What color is it? Could be the plenum, the engine running rich, or bad Valve stem seals. Rich is usually black smoke. Burning oil is usually a light bluish smoke, and burning coolant is typically white along with a ripe odor.

I would take your truck to the nearest parts store and have them scan it for free. Most all of them offer free code scanning, they'll just take a code scanner out to your truck and plug it in.

How many miles does it have?

-JT

 

It is a light bluish smoke and it smells like oil! I took it to have it hooked up and the only code it throwed was the P0420 catalyst emissions low. The truck has 170,000 miles with a new tranny that only has 23,000 miles on it. If the valve guide seals were bad it would smoke every time it cranks right? I am assuming the plenum has never been messed with and I am going to go ahead and change it. It only smokes if it sets and idles then I rev it up a little. I am new to the rams, I have been driving a 90 dakota for several years now. I know about that one and hopefully will know about this one before long lol.

 

that sounds like the vavle guide seals to me

 

It very well may be. I will be the first to admit that im no mechanic. Every vehicle that I have seen with bad valve guide seals smoked when you start it up. Mine dosnt do that and if I just drive it and not let it set and idle it dosnt smoke. when im going down the road or stop at a red light and take off it dosnt smoke. Who knows I will have to look into it more. Thanks for all the input. But it is losing oil somewhere and coolant somewhere. I think the heater core is leaking but thats not as important as the oil right now! One problem at a time right? LOL

 

Yep, valve stem seals primarily smoke on start up. If no smoke on startup, then you probably dont have bad valve stem seals. Read some of the plenum threads, they tell you how to check the plenum. Do a search for "Plenum" on this forum, make sure to search thread titles in the advanced search. Most likely, your plenum is leaking, it's common.

I would also check your PCV valve. Pull off the tube coming off of the PCV and check the hose for any oil inside. Some aftermarket pcv valves can suck oil from the valve covers. Replace it with an OEM valve.

Your check engine light could be due to bad o2 sensors also. With 170,000 miles, who know's how old the o2's are! I would change both sensors with NTK (NGK brand) o2 sensors. You'll at least gain some economy if the pre-cat sensor is bad, because it controls the Air/Fuel ratio.

-JT

 

Do you think the cat is bad also causing the P0420 code or could it be the plenum leaking and made the pre cat o2 bad causing the code? It still runs good and smooth and has tons of power! But on another note, If the plenum is leaking I most likely need to replace the cat and both o2 sensors in the process when I do the plenum correct?

 

A leaky plenum will clog up a good cat. I suppose it could also foul an o2 sensor too. A clogged cat will make the engine feel sluggish and underpowered. If you do install an aluminum plenum pan, then yes, I would pop in some new o2 sensors too. But if your plenum has been fixed in the past, your check engine light is probably just a bad o2 sensor. So i'd start by looking into whether your plenum is indeed bad or not.