raw fuel in intake manifold/rough start after sitting

Hello again, 2000 4.0 <1k

ever since i had the new motor swapped in ive been getting a very rough, short lived idle on start-up after its been sitting a long time. i origanlly suspected a leakin injector but through a few things couldnt find one(shoulda tried harder) and moved on, threw some money here tried replacing this yada yada. anyways so i decieded to throughly clean my tb by removing it. upon its removal I noticed a strong oder of gasoline and with futher inspection i noticed that not only was my intake damp inside, i could see small pools and also the underside of the butterfly was actually dripping with fuel... FINALLY i found an actual issue instead of just chasing maybes haha.

My first(and only really) thought is that it is a leaking injector like i first suspected, i plan to pull my still attached rail out and set the injectors on a slip of cardboard as sort of a broke ass leak down test and see if i can spot a leaker.

But as i stated thats really my only guess, if theres any other way my manifold could contain gas that ya'll know of id love to hear it. Or possibly you know that my "leak down test" is the dumbest thing uve ever heard, thatd be good to know too so i can try something else

thanks again

heres my lil ghetto set up


as soon as i pulled it a puddle came out with the rear one
whereas all the others were dry... ill be watching that one

so i ended up yanking that rear one out and... not sure how well u can see it in the pic but ya got one half silver hole and three black ones... gotcha!

put her back together and fired her up, ODDLY smooth. like I thought something was wrong at first but i think thats just how its supposed to do it and ive been used to an aggressive(rich) start. Not holding to high of hopes cause it wouldnt be the first time i thought i fixed it but none the less.

oh and now i have cel from turning the key to on while all my tb sensors were disconnected haha well thats easy enough to clear

oh cool the code cleared itself

What is under the tin foil? What is the history on those injectors?

As for the smell, its normal to smell gas in the intake manifold.

under the "tin foil", which is that cool tape stuff, is heat wrap. under that is my fuel rail. got the injectors offa a cherokeeforum guy that cleans and rebuilds em. just contacted him about buying a replacement one and he said he'd toss me one for the price of shipping. A smell yes but visable puddles of gas are not, correct? and the underside of the tb dripping with fuel?

MrAnderson said:

A smell yes but visable puddles of gas are not, correct? and the underside of the tb dripping with fuel?

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Wow... thats not good.

actually it is good ha, well no its bad but as i stated in the first post at least ive found an issue and dont have to chase ghosts and possibles anymore.

that oddly smooth was bugging me. like, id start her and it wouldnt rev at all. itd just pop up to tad under a grand and sit there. ive since flashed the system and now she fires up over the grand then falls back down. ah much better hahaha

so after two days i got my hopes up, threw away the old injector and guess what happens this morning. F my life

Shop says the precats are plugged. 4-600 bucks to fix

the fuel on the bottom of the TB is just condensation from the raw fuel evaporating. there isnt any fuel in the TB for it to leak.
plugged pre-cats? dont think i've ever heard that one. how long have you been running those new injectors? not sure how long it would take for raw fuel to kill a cat......

probably a year now on the injectors. its only been doing this since the motor swap. ive read up on a plugged cat issues, none really sound like this. i dont bog out, theres no rattling from the cats but just today, and i mean ive been watching my temp lika hawk all the time so no joke as of today, on my way to work she was getting hot crusing down the highway. nothing crazy, just slowly made its way up to 210 but normally it stays a hair above the tick mark to the left of 210(195? i dunno those tick marks are oddly numbered to me, 100-210 on the left 210-260 on the right). gonna bring it by a different place for a second opinion on friday.

210 is not hot. Its normal.

you are absolutely correct, its just not "typical" for me. altho it was 97 at that time and it didnt do it again later that night so i would assume that thats all it was.

The shop said that the computer majigger was giving a reading of a bad O2 sensor and lean fuel mixture. I informed him that the upstream are brand new but been reading up on O2 sensors, the ones i put in are Bosch and apparently thats a No No a faulted one would throw a cel but would a bad preforming one not? also the downstream are far from new but from what i read the downs just monitor how your cats doing and dont affect fuel/air input? a false reading here would seem like a bad cat, but would it cause a rough start scenario?

so many questions

I just called the local jeep dealership(numerous thread recommended doing so) to see how much some mopar O2's would be... GOOD LORD, the front ones 133 and the rears 145:shocked::shocked:

this option "seems" alot better

NTK is fine. IIRC they are OE.

Talyn said:

NTK is fine. IIRC they are OE.

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from what ive read yes, they are made by ngk and it states it the description that its OE.

MrAnderson said:

The shop said that the computer majigger was giving a reading of a bad O2 sensor and lean fuel mixture. I informed him that the upstream are brand new but been reading up on O2 sensors, the ones i put in are Bosch and apparently thats a No No a faulted one would throw a cel but would a bad preforming one not? also the downstream are far from new but from what i read the downs just monitor how your cats doing and dont affect fuel/air input? a false reading here would seem like a bad cat, but would it cause a rough start scenario?

so many questions

Click to expand...

could i request ur opinion on this?

the NTK ones are good stuff. Bosch seems ot be the same china crap everyone else is selling marked up with a fancy box.

I'd suspect that you've got an injector that's leaking if you've got puddles after it sits.