TJ won't start after cleaning throttle body and changing spark plugs

Krischick33

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Joined
May 10, 2020
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67
Location
06825
2001 2.5 5 sp 108k.

My problem - jeep will not start. I doest not sound good/normal while turning over. Its like the timing is off. It turns then seems like its struggle to turn over. I now see small puddle of oil in the intake manifold looking through the TB.
The weird thing is she was running "fine" except for a rough idle. I was just trying to make it smooth. All I did was removed the TB and all attached sensors and cleaned thoroughly with carb cleaner then reinstalled. I also changed the plugs from Autolie AP 985 to XP985. I'm sure all plug wires are where the should be.

First attempt to start was good it started but would not idle. I thought maybe I sleeve on the TPS was hung up. Removed checked and reinstalled. Tried starting...difficult turning over...turns...then struggles. I pull the plugs and they are covered in black. I tried to put the old plugs back in. I've checked the firing order. Not sure what to heck I did but hoping someone have some suggestions. THANKS
 
You might have carb cleaner in one of the sensors like the MAP and it's not happy. If you don't have time to let them dry on their own you could pull each sensor you removed and make sure it's dry. You might also have yanked something from the distributor cap, I'm not too familiar with the 2.5 ignition setup that year.
 
Thanks for the suggestions. Yesterday towed the jeep to the to of a long hill...got rolling...and put into 3rd gear to jump it. After a little while she caught and started to run. I kept the idle up a ran around the block a few time. CEL came on. Seems to run fine. Came back to the driveway and parked. Idle may be a little better...less surging...but my idle is lower than before. Put the traded on this am and getting p0505 for IAC. Would this cause the initial starting issue. It happen again this morning. It sounds terrible.
 
Something wrong with the IAC could definitely cause not wanting to start issues which is why I asked if it started when you held the throttle open with your foot.
 
Sorry I didn't respond to that question. I'm not sure if I pushed the pedal all the way down while cranking. It seems to start normal after its warmed up. I'm on my way to get an IAC now. I'll report back later today.
 
Sorry I didn't respond to that question. I'm not sure if I pushed the pedal all the way down while cranking. It seems to start normal after its warmed up. I'm on my way to get an IAC now. I'll report back later today.
Hold on, there's usually no need for a new IAC. They normally just get dirty which causes starting/idling issues but they can be easily cleaned without even removing them by using an aerosol throttle body cleaner.

With the engine running at IDLE rpms spray the cleaner into the TB. The engine will die which is normal, just restart the engine and spray some more cleaner into the TB. Don't raise the engine rpms up away from idle or the cleaner won't go through the IAC. Spraying into the TB at idle rpms will thoroughly clean the IAC and its orifice in the TB its plunger fits into. I'd try for around 1/3 of the can of TB cleaner through the IAC, then use the last 2/3 of the can to finish cleaning the rest of the inside of the TB.

Not to mention I'd MUCH rather have the OE Mopar IAC and clean it than install a new aftermarket IAC. Especially a store brand like a Duralast from Autozone.

And if you already bought it, don't install it yet. Try the above first and only if it doesn't work then replace it. Odds are that cleaning it, if it's dirty, will restore it to good operating condition and you can return the new IAC.
 
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I didn't see the last 2 replies before I installed the new IAC. I started the jeep and I fired quickly. The idle wwas higher than normal and was slow to return below 1k after a rev up. I drove a few laps around the neighborhood and eventually everything returned to normal. BTW brand of IAC was BWD.
I've thoroughly cleaned the IAC numerous times over the past few months. In my case it doesn't seem to have any impact on my rough idle. The new IAC seems to make her start easiler but didn't help the rough idle. I may just have to live with it or take to a mechanic with proper diagnostic equipment.
The only thing I probably didn't mention is the smell of fuel after ini cold start. Possibly too much fuel.
I've already changed every sensor on the TB. NTK O2 sensors. New XP plugs, wires, cap , rotor and ignition coil. Pretty sure no vacuum leaks and current no CEL lights after changing the IAC. Not sure what else to check.
Would the plug wire length matter. Although the wires I have are for the 2.5 I may not have the right length one on the correct plug.