4bangerjp.com
General Forums => The Mess Hall => Topic started by: calvinh on November 10, 2011, 02:19:24 AM
-
On my 100 mile drive home from college tonight, I started getting a nasty hesitation and the engine started cutting out. After a few seconds, it cleared up, but it came back a few more times, enough to make me pull over. I poured a half bottle of fuel system cleaner in just to see if it would help, and surprisingly, I made it the rest of the way home.
I've noticed a few things about the problem:
When it starts hesitating, if I hit the rumble strip on the side of the highway for a few seconds, it clears up.
No check engine light
No odd engine noises
fuel pump sounds fine when it primes up when I turn the key
I think it could be either a) a loose wire on the fuel pump or b) clogged fuel filter.
Is it possible it could just be a clogged filter? I got the car 2 months ago, and before I had it it had been sitting in a barn for 2 years. I've run a couple bottles of seafoam through the tank, so could I have dislodged some crap on the bottom that blocked the filter?
I'm hoping its that, because I don't feel like dropping the tank anytime soon because it's already started snowing here.
I'd appreciate any advice.
Thanks!
-
A fuel filter is a good place to start and checking your electrical connections. Who know what kind of crap is in that filter or if it had ever been changed.
-
I think I found my problem... the fuel filter that was on there had to be the original one, it was so rusted that there wasn't any paint left on it. I replaced it today, hopefully that took care of the problem
-
Could have also been bad gas.
-
Replaced the fuel filter, still have the same problem. It seems to only happen in 4th or 5th gear, I'll be driving and then it starts bucking and slowing down no matter how much gas I give it. If I let off the throttle completely, it idles normally.
Could it actually be the fuel pump? It primes up fine when I turn the key, and I'm not getting any check engine lights.
parts I've recently replaced: dist cap, wires, plugs, fuel pressure regulator, fuel filter, o2 sensor
-
Last time mine did that it was a clogged cat. Jeep even had a recall on their cats.
-
fuel pump or clogged cat like he ^ said
-
Exhaust flow seems fine, but there is a O2 too rich code being thrown even though I just changed the sensor, and a persistent occasional misfire once the engine is warmed up. I just had the exhaust looked at a few weeks ago and he didn't say anything about the cat looking bad.
Drove it 150 miles today, for the first 100 miles of interstate driving there was no problem at all, but then I stopped for a half hour and when I got back on the interstate it started hesitating again. It cleared up though and I was able to finish the trip.
There really seems to be no rhyme or reason to when the problem shows up, but since it really isn't throwing any codes that are meaningful to the symptoms, I think the TPS and most sensors can be ruled out.
One however, is the CPS (crank position sensor). Has anyone had one of these go bad? if so, did you have similar symptoms? (hesitating and stumbling seemingly randomly on the highway)
-
I had a cat break apart and clog the muffler in another vehicle a number of years ago. It would drive fine until I put the engine under load. So is the O2 code intermitent?
-
Exhaust flow seems fine, but there is a O2 too rich code being thrown even though I just changed the sensor, and a persistent occasional misfire once the engine is warmed up. I just had the exhaust looked at a few weeks ago and he didn't say anything about the cat looking bad.
Drove it 150 miles today, for the first 100 miles of interstate driving there was no problem at all, but then I stopped for a half hour and when I got back on the interstate it started hesitating again. It cleared up though and I was able to finish the trip.
There really seems to be no rhyme or reason to when the problem shows up, but since it really isn't throwing any codes that are meaningful to the symptoms, I think the TPS and most sensors can be ruled out.
One however, is the CPS (crank position sensor). Has anyone had one of these go bad? if so, did you have similar symptoms? (hesitating and stumbling seemingly randomly on the highway)
I've helped a friend diagnose his CPS. It's completely random at times. Although his was worse enough that the engine would die and not start. Then he'd have to wait and it would start eventually, sometimes. CPS is hard to pinpoint.
-
I had a cat break apart and clog the muffler in another vehicle a number of years ago. It would drive fine until I put the engine under load. So is the O2 code intermitent?
Exactly what happened to mine, did not find out till later there was a recall from the Factory to replace the cats. I also did not notice a flow difference. But when I was under the Jeep I could find nothing wrong, But for some reason I kicked the cat and it rattled. The guts had broken free and would turn Sideways from time to time completely blocking the Exhaust. Pull over and that piece would fall out and it would run fine again.
But it was doing one other really weird thing, Oil was coming out of the Dipstick from Back Pressure in the Motor.
-
Mine did something similiar years ago but it was my own fault. I had replaced the fuel pump earlier in the year and used some red rtv around the gasket. It had deteriorated and got into the tank clogging the pump. I replaced the pump and used some Indian head to seal it. Live and learn. If it's been sitting a couple years in a barn the old gas in the return could've got deposits and brought them to the pump. Just a thought.
-
problem is back, still haven't figured it out. It seemingly comes and goes at will.
I'm thinking it could be the exhaust at this point, just because theres no codes, and only occurs when you drive at higher speeds for 5-10 minutes.
I kicked the muffler a few times, and you can definitely hear stuff rattling around in there. I have no idea if mufflers are supposed to rattle.
-
problem is back, still haven't figured it out. It seemingly comes and goes at will.
I'm thinking it could be the exhaust at this point, just because theres no codes, and only occurs when you drive at higher speeds for 5-10 minutes.
I kicked the muffler a few times, and you can definitely hear stuff rattling around in there. I have no idea if mufflers are supposed to rattle.
mufflers aren't supposed to rattle and neither are catalytic converters - could be that you have broken honeycomp in the cat that moves around and when it finds it's way to block the output would bog down the engine, could be the same in the muffler if it's rusted inside. this is an assumption so don't take it as a certainty, you can actually hear a hissing sound when that happens (exhaust gasses escaping under pressure).
-
mufflers aren't supposed to rattle and neither are catalytic converters - could be that you have broken honeycomp in the cat that moves around and when it finds it's way to block the output would bog down the engine, could be the same in the muffler if it's rusted inside. this is an assumption so don't take it as a certainty, you can actually hear a hissing sound when that happens (exhaust gasses escaping under pressure).
Well its between that and a pinched fuel return line (testing the pressure sometime in the next few days) so I might try to get the exhaust off this weekend, temporarily gut the cat and muffler, and put them back on and see if that helps at all.
-
Well its between that and a pinched fuel return line (testing the pressure sometime in the next few days) so I might try to get the exhaust off this weekend, temporarily gut the cat and muffler, and put them back on and see if that helps at all.
if you take them off i would just replace with new, probably not worth the effort to do it twice, something like $40 each for generic ones or even less if you shop around.
-
My jeep started cutting out randomly last year, it turned out to be the filter screen on the fuel pump was clogged and the tank had shrunk with age and was pressing too hard on the pump pinching the inlet.
Replaced the pump and screen (200K miles on the pump what the heck...) while I was at it I shortened the pump bracket about 3/8 inch so it would not hit the bottom of the tank as hard. Problem seems gone now... It was worse on hot days than cool days and seldom happened with a full tank, had to be down to about 1/2 tank.
Dave
-
Went under the jeep today to check out the condition of the fuel lines, everything looks fine under there. Fuel lines are still pliable and don't appear to be pinched.
The gas tank is plastic and looks to be in good condition
Although it sounds like theres a loose baffle somewhere in the muffler, I wasn't able to replicate the problem by kicking the muffler while it was running.
I think the poster above me might be right about the clogged fuel pump inlet.. Since the fuel pump still seems to be priming/working, can I just drop the tank, clean the inlet/screen out and put it back together?
-
Went under the jeep today to check out the condition of the fuel lines, everything looks fine under there. Fuel lines are still pliable and don't appear to be pinched.
The gas tank is plastic and looks to be in good condition
Although it sounds like theres a loose baffle somewhere in the muffler, I wasn't able to replicate the problem by kicking the muffler while it was running.
I think the poster above me might be right about the clogged fuel pump inlet.. Since the fuel pump still seems to be priming/working, can I just drop the tank, clean the inlet/screen out and put it back together?
it's a lot easier to measure the fuel pressure than to drop the tank, i would start there just so you don't do unneccessary work
-
it's a lot easier to measure the fuel pressure than to drop the tank, i would start there just so you don't do unneccessary work
Autozone wants a $150 deposit to rent their fuel pressure gauges, is there a cheaper place to rent from?
-
Harbor Freight and buy them.
-
Autozone wants a $150 deposit to rent their fuel pressure gauges, is there a cheaper place to rent from?
you get it back when you return it, or like he ^ said. You need a long hose one though to monitor while driving and you experience the problem, otherwise won't be relevant
-
This weekend I took apart the entire throttle body, air control valve, fuel rail and injectors and cleaned everything out and replaced all the o rings and gaskets to see if the problem was something in there... still not fixed. I was impressed at how simple these cars are to work on though. Only took 2 hours to take everything apart and replace everything, and this was without any manuals or instructions. Anyways...
I'm 99.9999999% sure the problem is somewhere in the fuel tank. Since the pump still sounds healthy when it primes, could I just clean out the pump inlet and strainer and put everything back together? If you haven't been able to tell so far, I'm kinda strapped for cash. Just dropped over 2 grand on college tuition for this semester, as well as over $500 in parts for the jeep already so my bank account balance is pitiful. So I'm hoping to do this job for free and just reuse old parts.
I tried taking off the fuel tank, but the bolts above the real axle are rusted on. REALLY rusted on. So I have to cut them off somehow. I have a sawzall, angle grinder, and a drill, but I don't think that any of those tools will fit in there. I'm also concerned about sparks, considering the gas tank is a few inches away. Would a dremel with a cutoff wheel do the trick?
-
Calvin,
before you do this make sure it is the fuel tank and/or the pump, it's a big job to take the tank out if you never done it before - like i said, check the pressure first, that might not be it and if it is fine then the tank job is redundant - unless the bottom of the skid is bent I doubt that's your problem but you never know. Fuel pressure should be 31 at idle with the vac line connected, 39 at wide open throttle or with the vac line disconnected, when you drive it should not go lower than 31 unless you're engine braking, when it starts to do the problem you're having floor it (and i mean literally, pedal all the way to the floor) and read the pressure, if it's not 39 or close by then your problem is fuel pump, tank, filter, lines in that order. Could also be electrical fuel related (relay, wiring) so keep that in mind as well, less likely but still possible.