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General Forums => The Mess Hall => Topic started by: sirchesshire on December 23, 2009, 01:27:30 AM
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Okay, first let me state that I've already read the other posts and changing my crankshaft position sensor did the trick...or so I thought. I bought a new set of wheels and tires (that went into the back of my Jeep, not on yet... set of 5 AR 15x8 with 31" Cooper HT's) and almost as soon as I drove out of the guy's driveway, she started hiccuping again. Got home, unloaded the tires and bam...good to go again. I know my little squirrels weren't exactly designed for 31's but they were on it when I bought the jeep and haven't had a need to replace them yet. With this newer set of 31" HT's I'm still in the green for tires. Btw, 65 is a good speed for me as I drive back roads all the way to and from work.
I've checked or replaced many components over the last year trying to fix this problem and thought I finally had with the cps. Now it doesn't make sense anymore.
Plugs, wires, fuel pressure, vacuum hoses...all good. Had the injectors and fuel rail cleaned by a local shop. I'm out of ideas now.
My main reason for concern is that if I decided to go off road and start putting a heavy load (crawling up a mountain or such), I don't want her to start acting up on me. That would be a very poor time for such behavior.
Any ideas???? :brick:
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tps is also known to cause hiccups, but that is just one case in many. could also be MAP sensor and also you could have some fuel delivery issues. does it throw any codes (i assume not since you didn't mention it, but who knows) - tps and/or map usually throw a code, if you lack fuel flow under load that can be w/o a code so imo i would start by monitoring the fuel pressure when that happens and go from there (not at idle or revving the engine while the vehicle is not moving, that won't require as much fuel as you would need under load - best to find a place when you can drive uphill at full throttle for a bit and see if the pressure drops). Since you mentioned that all the ignition items are sound i will leave that out, but hiccups can also be caused by spark issues so i wouldn't rule that out completely just yet. If you have a vac leak that would only cause your idle to increase but not loss of power unless it's the line that goes to the MAP sensor (i am talking at full throttle or close to that which i understand is your case since you mentioned under load).
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Under load, as I meant it, is...driving my jeep with nothing but the seats and me inside...no problems. Add about 500 pounds (the wheels and tires I bought), it started acting up. Take out the new shoes and it is fine again. I had the exact same problem (without the added weight) before replacing my cps. It acts like it is missing on 1 cyl randomly. Sometimes only once a min, sometimes much more often. Power is lost and the tac drops about 1000 rpm for a brief second. Then the power is back until it happens again. I tried revving the motor as soon as I got home that day, and she purred just fine. It was only happening when I was trying to drive down the road, more so on grades and flat ground.
I probably have the same issues as someone else, but I've yet to be able to pin point the problem from the other questions in this forum and jeepforum.com. And I have been reading for quite some time.
Hope that clears up any questions I left last time. :smile:
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Under load, as I meant it, is...driving my jeep with nothing but the seats and me inside...no problems. Add about 500 pounds (the wheels and tires I bought), it started acting up. Take out the new shoes and it is fine again. I had the exact same problem (without the added weight) before replacing my cps. It acts like it is missing on 1 cyl randomly. Sometimes only once a min, sometimes much more often. Power is lost and the tac drops about 1000 rpm for a brief second. Then the power is back until it happens again. I tried revving the motor as soon as I got home that day, and she purred just fine. It was only happening when I was trying to drive down the road, more so on grades and flat ground.
I probably have the same issues as someone else, but I've yet to be able to pin point the problem from the other questions in this forum and jeepforum.com. And I have been reading for quite some time.
Hope that clears up any questions I left last time. :smile:
this sounds familiar with couple of other threads i've seen here (tach rpm dropping) - the tach dropping points towards something electrical rather than fuel, read this thread (to the end), maybe you find your answer there http://4bangerjp.com/forums/index.php/topic,7178.0.html
there were a few things that were mentioned by some other folks: tps, cam and map sensors were mentioned in there to cause the rpm drop (although i cannot confirm that would be the case with any of them it's something to look at).
there is another thread where the guy had a issue with a bad wire that was causing somewhat the same issue, but none of these ones were related to the load (weight in vehicle) and in your case by simple logic would point to tps or map sensors (just b/c you would open the throttle more) - hope this helps and if you find the problem post an update please. good luck
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Ok....so now I'm just ticked off. Nothing you guys did of course.
While checking the TPS, I realize one of my vacuum lines was unplugged. Plugged it in and the idle drops a little, but everything is still working ok.
I figure...I'll put her in low 4, trug through my backyard in 1st at around 3k rpm and pull into my brother's yard. Everything seems ok until I let off the gas to change back to 2...then she dies. Can't crank back up. (I've already done the stuff below, just figured I'd see if she was still acting up before replacing the TPS). On to todays story...
I tested the TPS as the manual says....5 volts on the supply, 1 volt going up to 3.2 volts on the signal (a little low), and whoa and behold...when I check the resistance across the supply and signal (with the ign off of course) I go from .8 volts up to 1.3 at about 1/8 throttle, back down to .8 through the rest of the throttle range. I figure....BINGO....bad tps. So I go get another from the zone and pop it it...she's running...then she's stuttering...then she's stalling. Check all the vacuum lines and I have one of the connectors cracked. Gank one from my brother's 4banger (as he's putting in a V8....btw this is the same tube I found unplugged earlier) and I figure, good to go. WRONG. Doesn't help at all.
Just to recap....running fine...troll along in 4 low...cuts off and won't crank...replace TPS and she cranks...runs fine about 10 min...then dies and won't crank again.
One would think...maybe a fuel issue, but when she cranked back up and ran good for 10 min, there were no problems until just before she died. Problems being that she started stumbling when the accel was pressed, started stumbling until she died. I'm willing to bet that if I hadn't already been up 18 hours and have to be back at work in 5, she'd crank back up a little later tonight.
Any ideas?????
On a positive side...I had a productive trip to the local junkyard, getting a 4.0 TB out of a TJ, along with the air tube (which I plan on cutting to adapt a K&N cone onto), got a very nice Cougar fan which looks to be the perfect size...and a few odd and end parts that I just felt like buying because they were in better shape than mine.
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how's the fuel press when it dies?
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Sent you a pm "sharp"
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Since you have a spare engine sitting around, why not swap the CPS?
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Have replaced Cps and tps.
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Have replaced Cps and tps.
Can you recreate the problem by adding weight to the Jeep every time?
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I can't find it now, but I've been fighting a similar problem, that I've found documented on a couple other web sites.
There seems to be some gas tanks that don't play well with Alcohol and the plastic tank actually shrinks, causing the tank to push up on the fuel pickup and occasionally blocking it off. Its aggravated when you get weight in the rig and it flexes the body and skid plate.
I'm hoping to get the tank out in a week or so and check it on mine.
Dave
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Igit a new tank, pump, and filter about a year ago when my last pump melted the wires INSIDE my tank. Talk about some pucker power when I found out how close I was to being a pile of ash.
So the tank should be the problem either. :brick:
When the tank was replaced, all injectors were checked and cleaned, fuel rail was cleaned and fuel system was checked with no probs. Just this annoying little problem.
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Sorry about the typo in the last message....Supposed to be "I got".
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let's do a recap
1. CPS and TPS replaced
2. gas tank replaced
3. fuel pump & filter replaced
3. connector replaced (dunno which one)
4. vac line reconnected (dunno which one)
Still, i would just try to identify why is dying and go with the basics to try and narrow it down
1. I would begin by having a pressure gauge on the fuel rail - it can also be too much pressure as well that can cause the problem (like a bad fuel pressure return valve or a plugged return line) and it makes me think of the melted wires you mentioned.
2. If that checks out ok next i would look at the spark plugs (or you can start with this one first) and see if they're wet when it fails to start - if they are wet then you'd get too much fuel or no spark. You mentioned that it starts back up if you let it sit for a while, that could be a symptom
of flooding the engine
3. Check the spark
4. check the MAP output (since you already replaced the CPS and TPS)
5. do the Camshaft position sensor test as described in the FSM
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If the CPS fixed it temporarily and the problem is intermittent, I suspect the CPS wiring or connector. It's pretty common for the connector to have problems.
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also don't account on new parts being still Known good especially after a year is gone by or umm more depending if you look at your receipts and go shit that was 4 years ago+.
being a tech I have heard that story a lot. wouldn't hurt to check the basics. spark like coil output/ cap & rotor condition/ fuel pressure during problem/ electrical aka wiring & fuses & relays, even battery volts say you let it sit for a bit battery gains enough voltage to start then volts go to high or to low causing things to shut down for the period of time.
Do you have oil leaks causing oil on the crank sensor?
sometimes the most obvious thing you already know about can be a cause of the problem.
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Ok. Thanks for more great ideas!!!!! Got her running again, :stupid: , once I figured out the problem with it not staying cranked was due to a fuel issue....the tank was empty. (Go ahead and say it...I deserve it for not looking at my trip meter and realizing I'd driven that far. That is what I get for driving too many cars.)
In answer to the last 2 posts... 1) I think I tracked it down to the TPS, especially since my PCM finally decided to show the codes (below) and that was one of them. 2) No oil leaks, sparks/wires/rotor good.
Back to the issues at hand. I FINALLY got the codes to show up on my dash. Codes were 24 (TPS), 21 (O2 Circuit), 51 (02 sensor). Went out and bought the 02 sensor and going to drive for a while to see how it goes.
Replaced so far in the last month...battery, CPS, TPS, O2 sensor. Will drive her for a few days to allow the PCM to learn the new components and then load her up with weight to see if the problem is fixed.
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Ok. Thanks for more great ideas!!!!! Got her running again, :stupid: , once I figured out the problem with it not staying cranked was due to a fuel issue....the tank was empty. (Go ahead and say it...I deserve it for not looking at my trip meter and realizing I'd driven that far. That is what I get for driving too many cars.)
In answer to the last 2 posts... 1) I think I tracked it down to the TPS, especially since my PCM finally decided to show the codes (below) and that was one of them. 2) No oil leaks, sparks/wires/rotor good.
Back to the issues at hand. I FINALLY got the codes to show up on my dash. Codes were 24 (TPS), 21 (O2 Circuit), 51 (02 sensor). Went out and bought the 02 sensor and going to drive for a while to see how it goes.
Replaced so far in the last month...battery, CPS, TPS, O2 sensor. Will drive her for a few days to allow the PCM to learn the new components and then load her up with weight to see if the problem is fixed.
:roflol:
:guns:
but to be honest it happened to me once to call the tow truck for the same reason :lol:
my guess is it will run fine now since you replaced those 2 and had those codes - when my tps went south was running Jell-O mid throttle.
EDIT: for the record i didn't say jell-o, i didn't know that crappy spelled with an S is a restricted word :)
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Something I learned the hard way was to Always disconnect the battery to clear the computer for at least 30 seconds when you change the TPS or it won't make much difference - you might just want to do the same thing rather than racking up the miles and posing a threat to the cat
I think I am having problems with my CPS: runs like poop, cannot take a hard acceleration, dosen't want to start on the first try, has no power from takeoff when warm, minor backfires in the intake.... Does this sound familiar?
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New to the forum, Have you tried replacing your Cat. I had an 02 with similar issues replaced the cat and it solved it and got a lot better gas mileage.
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New to the forum, Have you tried replacing your Cat. I had an 02 with similar issues replaced the cat and it solved it and got a lot better gas mileage.
actually that is a great suggestion, could be related - mine plugged so bad once i had to punch a hole in the cat as i could not drive it otherwise, so yeah, that can be a reason if it's semi-plugged and would explain why is more obvious under load.
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where is the test port for fuel pressure? was going to put a gauge on mine, and did not see it??
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where is the test port for fuel pressure? was going to put a gauge on mine, and did not see it??
it's usually on the fuel rail in the middle, some TJs had it and some didn't. if you don't have one you'll need an adapter for the line.
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I've given it time and miles....to no avail. The hiccup is still here. Call my mechanic, he does all the work on all my vehicles, so he's willing to troubleshoot any time I call because he understands that I like to wrench on my Jeep. Lets go back 2 years (I did check the receipts) and he is the same mechanic I took it to at that time....with the same problem. He and I thought it was fixed at the time, then I changed jobs and didn't drive it for about a year because I was doing 150 miles a day and my Kia gets a lot better mileage. Moved closer to home recently (same company) and now I can drive my Yj to and from when I get the urge (every time I walk out the door).
After saying all that...I troubleshot with him over the past couple of weeks, replaced all the tps, cps, o2 sensors and still actin the same (to repeat my last paragraph only shorter). Asked him about the cat, and he gave me the steps to check it myself...did so...no problems found without actually drilling a hole and putting a gauge on it. His recommendation was for me to bring it in and he'd put one of his fancy new computers on it and drive it around for a few days for me. $75-100. That way I'm not just throwing money at my jeep (his words) instead of fixing the problem. Sounds good to me at this point because I'm :brick:!!!
Will give updates when I take her in and get her back.
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Ok, so the mechanic couldn't find anything deffinate either. He had to put 50 miles on her just to get something to show up. The final decision was that one of my wires is broken internally and not giving adequate voltage. So I guess I'll do ANOTHER plug/wire refit.
He did say that the Bosch wires I was running have been causing a lot of problems with many vehicles over the last few years. That could have been the problem in itself. Guess I'll go to NAPA and get a "better" set of wires.
We'll know in a week or so, and I'll update again. :brick: :brick: :brick: :brick:
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I've always had good luck with the Echlin NAPA brand as well as Taylor.
Not flashy but really well made.
Dave
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The problem (I think) been solved. Originally it WAS the cps. Once that was fixed, there was a problem with the tps. Then I went ahead and replaced a bad O2 sensor (wasn't actually causing a problem, but it was bad so why not right?). FINALLY, the issue came down to a plug wire that was broken on the inside. When I checked them, they all showed good...but the problem was occurring as I was driving down the road. The mechanic drove about 50 miles and could only find the problem with a diagnostic computer attached that showed that one of the cylinders would occasionally not fire. This was due to the plug wire literally being "barely wiggled" by the wind blowing through the engine compartment. ($80 labor solution)
So I've replaced the wires, plugs, dizzy and button....and voila...no more hiccups. (Saved money of course by changing them myself instead of letting the mech do it. His bill for the putting on the $45 in parts? :rtfm: $200 ..... :roflol: ..... :ban:)
Now on to the projects...elec fan, 4.0 tb, wire my light switch into my ign swith...lots more tinkering to do now that I have resolution of the hiccuping.
Thanks for the brainstorming guys. I'll return the favor whenever possible.