Originally Posted by candymancan

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

Originally Posted by candymancan

what would a normal fuel pressure be ?

Originally Posted by HeyYou

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.

Originally Posted by bosanci28

hi,HeyYou,

i have posted my problem here

https://dodgeforum.com/forum/2nd-gen...ml#post2726758

and i was pointed here to read,and found this post ,to check if i have maybe the plenum gasket blown , now, i did exactly how you said,
but when testing
""You should feel a breeze blowing OUT of the fill hole."" is little hard to hear ,to feel maybe little ,because the fan makes a lot of wind,but i decide to keep my hand tight at the oil fill hole and after about 10 sec when i let it go ,a pop of air comes up,pressure,

what this mean ,do i have a blown plenum gasket?

thanks and i appreciate your advice!.

regards,
bosanci28

Originally Posted by HeyYou

If it builds pressure, your plenum either isn't blown, or, if it is, it ain't very bad. Pull the throttle body, and have a look around. Pooling oil is a sure sign of a blown plenum. (along with excessive oil consumption.) If its clean, you are good to go. Note: There will be some oil in there from the pcv port. But, it shouldn't be pooling anywhere.

Originally Posted by HeyYou

Oil pooling in the intake is a bad sign. If there is just some residue, not a big deal, as it is more than likely from PCV system.

If you are getting oil on the underside of the air filter, (where the PCV systems DRAWS air from....) probably be a good idea to replace he PCV valve. Get one from the dealer, they are actually the correct flow rate, whereas, the aftermarket fellers aren't always.....

Also might be a good idea to do a dry/wet compression test, to check condition of the piston rings....... there is a real possibility it will take you things you really didn't want to know there.... (main reason I haven't done one yet..... 175K miles on mine....)