98 tj 4.0 major power loss and major sputter

creepytj98

Member
Joined
Mar 25, 2010
Location
Clemmons, NC
ok i have a 98 tj 4.0... ran great forever then i got a hole in my gas tank and it caught on fire. no wires got burned. i checked the compression all cyl are about 130 psi. ( dont know exactly how to check it right but i got a guage and tured the motor over a couple turned and it would hit 90 then 125-130) took the fuel line off the rail and its pumping plenty of gas. checked all the injectors and there all getting fuel. spark pulgs all pretty new and all fireing. so im lost.... it runs great at about 1/2 throttle but wide open it sputters likes crazy and has almost no power. when i turn hard or get it leaning hard four wheeling it will barley run. fuel lines are clear. i got a gas tank out of a 4cyl and had a hard time getting the plastic locking ring on but i got it tight. ive had alotr of electrical problems. (brake lights, turn signals, horn, all kinds of electronics) the previous owner put a radio system in and wired all kinds of stuff together. i have put a new exhast valve, head gasket, alternator, plugs, wires, distributor cap starter and rotor button.(all that over about a year or so) seems likes it sucking air somewhere but it dosent leak gas. i am missing my jeep and four wheeling really bad. if anyone has any ideas on how to get it running good again i would really REALLY appriciate it. i do all my work on my jeep and hate takeing to a shop and letting some one mess with it. i miss wheeling so bad and its summer thanks its like its not getting enough gas and smells like its sucking air. so come on guys give me some advise ANYTHING HELP

i live in clemmons and i can still drive it so if anyone could take a look at it for me and let me stay around and help i would have no problem paying someone 20 bucks or something to help me diagnose my problem that would be great thanks for any advise
 
Has it run like this since the fire?

My first thought was a plugged cat, but with the fire, who knows.
 
well it had a sputter with the old tank that had a hole in it but no where near as bad as now. but i guess so. it ran decent right after i put the new tank in but i had alot of trouble getting the locking ring on. i had my valve cover gasket in wrong and it was leaking a good bit of oil. i read something that if the o2 sensor gets clogged up wth oil that can cause problems and i tryed to check it but i couldent get it off. what should i do about the cat? pull it off and see how it rund with just the header? i tends to pretty much die when i turn sharp so donughts are impossible. i mean i have lesss than 1/2 power than stock o and my air bag light just came on dont know if that has anything to do with it but thought id throw it in there
 
Gut the cat if needed. Sounds like your gas tank maybe some how has blockage or is starving it of fuel since you had I hole in the last tank maybe the fuel pump sucked up some trash. I'm not sure if the fuel pump is in the tank or not or block drivin.
 
well i pulled the fuel line off the rail and turned the motor over a few time and it seemed to be pumping put a good bit of fuel. but right after i put the new tank in the the locking ring wasent very tight and i sank it in a mud hole and it had to sit in the mud hole for abut 5 min so it have got some water in the tank..... also after i ran it tonight i looked under it and the inside of the muffler was glowing red.
 
creepytj98 said:
well i pulled the fuel line off the rail and turned the motor over a few time and it seemed to be pumping put a good bit of fuel. but right after i put the new tank in the the locking ring wasent very tight and i sank it in a mud hole and it had to sit in the mud hole for abut 5 min so it have got some water in the tank..... also after i ran it tonight i looked under it and the inside of the muffler was glowing red.
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Still thinking cat. The muffler shouldn't get THAT hot. The cat should be taking that heat. Ok, here's my theory. You have a cat that has come apart inside. Under say 1/2 throttle, the junk in the cat stays put in the bottom not obstructing the outlet (imagine a hollow can). Switch to full throttle or turning or off camber and that chunk of cat guts flops over to the cat outlet and plugs it up, thus losing power. I actually have seen it happen exactly like that before on a cherokee.
 
ok i pulled the muffler off and looked inside the cat. everything seemed to look fine but it still runs the same (slightly better). my cat is welded on so i cant pull it off..... would you recomend i gut the cat? i dont want to inless i have to and im gunna get a fule pressure guage today and check that first before i smash the cat. the back side of it look fine if anything is messed up in it it must be up front
 
ok so i didnt want to gut the cat just yet so i took off the exhaust pipe and shook it around and beat on the cat and nothing came out... i took it down the road with just the header on (sounds beast) but runs the exact same. i cant even give it 1/2 throttle. below 1/2 throttle it runs perfect no sputter good power everything fine but any extra gas make it sputter and lose a ton of power. (has more power at 1/4 throttle than full) and both o2 sensors looked fine. like i said before i put a 4 cyl gas tank in it with the old sending unit so im thinking thats the problem. im gunna get a 4.0 tank and new sending unit tomorrow maby that will fix it. anyone know how i can clean the sending unit and filter? ive heard that you cant change the filter but idk for sure.... im open to any suggestions ive tryed everything i can think of an sat over my engine and stared and checked everything i can... anything helps thanks
 
one other thing.. its been a pain in the as* to get it to crank up i have to barley turn it over a couple times to let the injectors spray some fuel in and it will hit on like 2 cly for a fraction of a sec and die. i have to do that over and over and finally when it cranks i have to rev it real easy for a few min.... it has got to be a fuel issue i just dont know what kind.
 
couple of things did you replace the tank with the same size ?? 98 tj's by my chrysler parts book had 2 diffrent tanks and pumps 15 gallon vs 19 gallon. Could it be pick up is bottomed out against the tank and is flowing enough for low speed but can't keep up under high flow ?? Also the fule filter on the truck is the silver canister on top of the pump could be clogged with mud. You said you had trouble sealing the lock ring is the top seal in place ???

Chris
 
fuel? x2

Silver91Hatch said:
Fuel pressure? Check it at idle and under load.
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sounds like low pressure to me. maybe line on pump assy is damaged. had a s10 with a pin hole in the supply line inside of the tank and when 1/2 empty would run like crap. if there is water in the tank it needs to come out anyway.
 
i replaced it with a 15 gal and im sure i had the 19 before. i think that is my problem, i had atleast 7 gal in it today and when i was wheeling i got it laying hard on the left side it died and wouldent crank. ive rolled it before and pretty much had it laying upside down and it kept running with the stock tank. if its low on gas it will sputter alot more espically on a left turn and i never had that problem with the stock tank. it has seemed like its not getting enough fuel. ive messed wth the tank a couple times and got the lock ring on good but the 15 and 19 gal tanks are pretty different. im getting a 19 gal tank and new sending unit tomorrow. but i also have some serious wireing issues that may have something to do with it. ill have the tank in tomorow evening but i really appriciate the help everyone!!! i try the new tank and keep my fingers!!!
 
Update? I'm curious if the tank actually made a difference. I'm betting no, but who knows at this point. If it doesn't I'd go the route of checking the TPS next.
 
Sounds like fuel delivery for sure an this is a shot go the dark but are the spark plugs gapped correctly has a 350sb Chevy an didn't gap the plugs right an it would idle an run but didn't have any power. Hope it helps
 
ok so i figured out what it was. the gasket between the sending unit and the tank was installed wrong (my fualt) but i put the new tank and sending unit in with the gasket right this time. but it was still a bit*h to get started. it ran MUCH MUCH better had tons more power and almost no sputter. but lastnight it wouldent crank w/o dumping a some gas in the throttle body. then today my sputter came back (pretty much the same) and it would just die after about 3 min of driving. i had to run the piss out of it to keep it going and i mean like bouncing off the tac hard. i was under it one time when it died and it sounded like gas was running back into the tank. i checked the fuel pressure while someone hit the starter and it was getting fuel but still would not crank. since i put the new tank on its had a high idle too it idle's at about 1500 rpm all the time. i disconned the middle sensor on the throttle body (think its the tps) and it would idle normal (about 750rpm). i think the fuel is getting there right but i think its a sensor problem. the check engine light came on but i havent been able to check it yet and i havent been able to get the codes to come up on the dash since i got it. the tps is pretty new but im gunna go by a shop and get someone to check the codes. ill post what codes its throwing when i find out what they are. im alos gunna pull the tank again and make sure the locking ring it plenty tight thank for the help everyone
 
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