End-all Be-all plenum thread
Hopefully you are reading instructions from either one of the free FSM downloads in the FAQ/DIY section or a Haynes (and not just relying on info you get in your threads here). Because if you are reading one of the manuals , you will see that both say to put a small amount of rtv on both sides of the intake gaskets around the coolant ports only.
Question could ap lenum be blown but show no oil on the plenum pan ? My plenum pan viewing down the throttle body is litterally so clean i cant even get anything on tissue paper when i wipe it using a long tool to get down there..
I also just bought a adjustable mirror to see the front and the rear, and the pan is the same way in the front and the rear is extremely clean I followed the gasket side to side rear to rear and it looks good.. The only things i noticed that were a tad dirty was the top of the intake manifold, and 1 of the front intake vents where the air goes to the engine is a little brown, and 1 of the rear ones are a little brown as well.
The gasket tho i can see all around the pan and it looks uniform meaning not poping out or anything. It does look a little shreded on a few spots where the bolts go meaning a couple tiny peices were hanging off..
However compared to the pictures i have seen of blown plenums my pan looks 99% better then all of them.. In fact mine looks like the pans after people clean them..
Im wondering could my engine pinging be from something else instead ? Like this picture is what my pan looks like and no im not lying.. I looked at it inch by inch for about 45 minutes with my mirror.. I did notice a few deposits of something on some parts of the gasket area tho

and my half keg looks clean as well except a few spots on the top, and 2 of the little vents look like they are caked on brown
I also just bought a adjustable mirror to see the front and the rear, and the pan is the same way in the front and the rear is extremely clean I followed the gasket side to side rear to rear and it looks good.. The only things i noticed that were a tad dirty was the top of the intake manifold, and 1 of the front intake vents where the air goes to the engine is a little brown, and 1 of the rear ones are a little brown as well.
The gasket tho i can see all around the pan and it looks uniform meaning not poping out or anything. It does look a little shreded on a few spots where the bolts go meaning a couple tiny peices were hanging off..
However compared to the pictures i have seen of blown plenums my pan looks 99% better then all of them.. In fact mine looks like the pans after people clean them..
Im wondering could my engine pinging be from something else instead ? Like this picture is what my pan looks like and no im not lying.. I looked at it inch by inch for about 45 minutes with my mirror.. I did notice a few deposits of something on some parts of the gasket area tho

and my half keg looks clean as well except a few spots on the top, and 2 of the little vents look like they are caked on brown
It there isn't any oil, it probably isn't blown. Quick test would be pull the PCV valve out, and plug the hole in the valve cover. Take the hose off the air box, that goes to the vent on the other side valve cover, and plug that as well. Take off the oil fill cap, and start the engine. You should feel a breeze blowing OUT of the fill hole. If you have vacuum there, plenum gasket is blown, or, intake gaskets are leaking.
Pinging is usually caused by running lean, and/or carbon deposits in the chambers. You could try running some seafoam thru the brake booster line, and see if it doesn't help clear it up some.
Pinging is usually caused by running lean, and/or carbon deposits in the chambers. You could try running some seafoam thru the brake booster line, and see if it doesn't help clear it up some.
I have done the seafoam in the past, and i ran techron through the gas once, and a few other cleaners in the gas, none of it helped. I have done that pressure test before and no i had no sucktion on the oil cap hole. I did feal a ever so slight breeze but it was so slight only my arm hairs could feal it. Meaning i also have little blowby which that test also checks for. The heads on the pistons when i look through the spark plug holes are a dry black but i think thats normal for a 14 year old engine. The spark plugs the old ones i replaced were so clean that the only reason to replace them was they were so worn out that the gap on them was .50 vs the .40 its suppose to be.
Also if i block the PCV hose, and put my thumb on the intake hose on the air tube i have positive pressure coming out of that. not alot but it will go pssh when i let my thumb off.
I mean the intake manifold itself was shiny, like it had a film of something on it, but IMO thats most likely just oil blowby from the PCV.. Put the pan itself is bone dry from what i could see back to front. The manifold also smells of gasoline and not oil.
How would i check if the engine is running lean ? Because thats the only explanation i can think of... Also the engine pinging seems random, sometimes it wont do it, sometimes it does everytime i rev to 2500 rpm or above.. It seems to only do that when its been driving for awhile. I replaced the spark plug wires and plugs, did the TSB on the wire routing to avoid spark crossover. I even changed to cooler plugs auto 3923's vs the longer tip champion coppers which are RC12LC4 for my Jeep 5.9. I also got a new mopar PCV and grommet, and replaced the rubber tube because it was cracked
Im using 93 octane as well, since i have to use 91 or higher anyway on this engine and all they sell is 93 around here. Should I just bring it to the dealership and see what they say would they be able to check the timing and see if its running lean
Also if i block the PCV hose, and put my thumb on the intake hose on the air tube i have positive pressure coming out of that. not alot but it will go pssh when i let my thumb off.
I mean the intake manifold itself was shiny, like it had a film of something on it, but IMO thats most likely just oil blowby from the PCV.. Put the pan itself is bone dry from what i could see back to front. The manifold also smells of gasoline and not oil.
How would i check if the engine is running lean ? Because thats the only explanation i can think of... Also the engine pinging seems random, sometimes it wont do it, sometimes it does everytime i rev to 2500 rpm or above.. It seems to only do that when its been driving for awhile. I replaced the spark plug wires and plugs, did the TSB on the wire routing to avoid spark crossover. I even changed to cooler plugs auto 3923's vs the longer tip champion coppers which are RC12LC4 for my Jeep 5.9. I also got a new mopar PCV and grommet, and replaced the rubber tube because it was cracked
Im using 93 octane as well, since i have to use 91 or higher anyway on this engine and all they sell is 93 around here. Should I just bring it to the dealership and see what they say would they be able to check the timing and see if its running lean
Repaired and all put back together, now I notice my gear shift indicator only displays in park or neutral. When I shift they aren't outlined. The only other thing I did was replace the o2 sensors. Any thoughts??







