Barely runs, bad plenum and clogged cat
Hi Guys,
My friend has a 1999 Dodge 2500 5.9 4x4 auto truck. He was complaining when going down a hill the truck wants to stall. I looked at it and couldn't find anything wrong. No codes. Well a couple months go by and it wont run at all when it's hot. Now it has an o2 code. Replace the o2 and I knew it wasn't going to fix it and So I figured clogged cat. Did some things. remove o2 sensor sit runs like crap. Loosen both head pipes the same. Did some searching on the forum and found the "sticky" on the plenum kit (just ordered it) I understand about leaking oil in the cylinders but with the exhaust still open it barley runs. Plugs look good but #8 is a little fouled. With the truck on level ground and the pipes open the truck starts to smoke so bad that it looks like it's on fire.
1st I know it needs a plenum kit. Could this be all thats wrong along with the clogged cat? I will also do plugs and sea foam trick.
p.S. the truck has 125000 miles on it.
Thanks Mike
A little update. Ran a compression test 150 across the board. Fuel pressure is around 50psi. #8 SP was soaked with oil. The rest of the plugs looked ok but had a little soot around the base of the electrode.
My friend has a 1999 Dodge 2500 5.9 4x4 auto truck. He was complaining when going down a hill the truck wants to stall. I looked at it and couldn't find anything wrong. No codes. Well a couple months go by and it wont run at all when it's hot. Now it has an o2 code. Replace the o2 and I knew it wasn't going to fix it and So I figured clogged cat. Did some things. remove o2 sensor sit runs like crap. Loosen both head pipes the same. Did some searching on the forum and found the "sticky" on the plenum kit (just ordered it) I understand about leaking oil in the cylinders but with the exhaust still open it barley runs. Plugs look good but #8 is a little fouled. With the truck on level ground and the pipes open the truck starts to smoke so bad that it looks like it's on fire.
1st I know it needs a plenum kit. Could this be all thats wrong along with the clogged cat? I will also do plugs and sea foam trick.
p.S. the truck has 125000 miles on it.
Thanks Mike
A little update. Ran a compression test 150 across the board. Fuel pressure is around 50psi. #8 SP was soaked with oil. The rest of the plugs looked ok but had a little soot around the base of the electrode.
Last edited by mmzullo; Sep 17, 2012 at 03:48 PM.
Bad plenum & cat = #8 being fouled..misfires, bad o2's, bad plenum = kill the cat..If you removed the EM's from the heads, should run, probably like crap and loud of course...150 comp results sound good..would start with plenum, cat, both o2's & plugs and if he can afford it cap/rotor/wires...please update results
Thanks for the reply. I didn't remove the EM just the y pipe from the manifolds. I just thought it would run better with the y disconnected. I did plugs cap and rotor last year and what a pain it was to do a cap. I WILL replace the plugs and cap and rotor again.
I ordered the Hughes kit and wont get here until Thursday or Friday.
Thanks for your help
I ordered the Hughes kit and wont get here until Thursday or Friday.
Thanks for your help
Even after the Hughes Kit you'll have to address the cat and O2 sensor. You could gut the cat or just get rid of it completely, depending on local laws, nobody gives a damn about the feds....
Thanks for the reply. I didn't remove the EM just the y pipe from the manifolds. I just thought it would run better with the y disconnected. I did plugs cap and rotor last year and what a pain it was to do a cap. I WILL replace the plugs and cap and rotor again.
I ordered the Hughes kit and wont get here until Thursday or Friday.
Thanks for your help
I ordered the Hughes kit and wont get here until Thursday or Friday.
Thanks for your help
Also while your doing the work have your buddy take pics or the old belly pan (top/botton) and inside of the IM too..make it three, have him go to town on the TB with q-tips and 'TB cleaner'...tell him it should look like this B/A..ok 4, a new IAC wouldn't hurt too..


keep us updated and post them pics
Last edited by It's Me Patt; Sep 18, 2012 at 09:54 AM.
Well it's all apart down to the timimg chain. 1.5 hours not too bad. I did a water pump this past winter so everthing up front had antisieze put on the treads so most came off easy.
The belly pan was toast here are some pictures. Yes I was going to clean the TB.
I put a piece of paper to show how bad it was.
Thanks for all the help.
The belly pan was toast here are some pictures. Yes I was going to clean the TB.
I put a piece of paper to show how bad it was.
Thanks for all the help.
Last edited by mmzullo; Sep 19, 2012 at 09:24 AM.
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Well Im just waiting for the hughes kit to show up hopefully today. T Chain is on and the front of the engine is back together. Today I'll try to get the Y pipe out to gut the cat. $300 for a new y pipe w/cat. Every thing is cleaned and ready to go. Even the TB is cleaned. I have a few more picture of the manifold with a pool of oil in the bottom of it.



