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Thread: Help....My jeep has no power.

  1. #1
    Master Tech williambmac's Avatar
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    Default Help....My jeep has no power.

    In the past month my 4.0 has seemed to lose quite abit of power and it has me quite puzzled. My tj operates perfect around town and does quite well on the highway cruising at 65 mph. The problem is that when I start pulling a hill it falls flat on its face, most of the time I find myself downshifting into 4th gear. I can tell you up until a month ago I never had this problem, I could pull the same hills in 5th gear and keep excelerating. Here is what I have done so far with no luck:
    Scanned for codes, none present.
    Replaced spark plugs, gapped at .035
    Replaced the rear catalytic converter (was ratting but not plugged)
    Replaced all four oxygen sensors (ouch) upstream O2's were operating fine but both downstreams were lazy.
    Replaced the air filter
    Replaced the tps (voltage readings a little low on WOT)
    Performed a compression test and a cylinder leak down test, all within acceptable range.
    Checked fuel pressure
    Road test vehicle with scanner to observe system functions, all o.k.

    Like I said around town and cruising at 65mph on a flat stretch of road is no problem, as soon as the jeep hits any sort of incline it dogs right out. The only other thing I wanted to mention is under a load I get a strong ammonia smell coming from the exhaust. Anyone have any ideas? Larry feel free to chime in.

    Btw....it has 4.88 gears and 115k on the ticker.
    2005 Rubi LJ 35's 5.5 Clayton
    lots of extras

    2000 wrangler 35" Goodyears Rock-trac super 88 hp30 4.88Terminator trans 5.5" RE/Clayton lots of xtras. RIP
    2000 WJ 4.0 addco upcountry springs bilsteins
    2001 H-D Duece Black and Chrome (For Sale)
    1997 YZF1000 200mph Superbike (RIP)

  2. #2
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    Fuel filter clogged? Maybe it is only getting gas from a small source going uphill??? Just a guess.


    Trey

    What's the point? You don't read this crap anyway....

  3. #3
    Master Tech williambmac's Avatar
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    Quote Originally Posted by WildBlue View Post
    Fuel filter clogged? Maybe it is only getting gas from a small source going uphill??? Just a guess.


    Trey
    The fuel filter is part of the fuel pump module assembly which I replaced 6 months ago. fuel pressure and fuel volume are within factory spec. Thanks for the suggestion.
    2005 Rubi LJ 35's 5.5 Clayton
    lots of extras

    2000 wrangler 35" Goodyears Rock-trac super 88 hp30 4.88Terminator trans 5.5" RE/Clayton lots of xtras. RIP
    2000 WJ 4.0 addco upcountry springs bilsteins
    2001 H-D Duece Black and Chrome (For Sale)
    1997 YZF1000 200mph Superbike (RIP)

  4. #4
    Registered Knuckelhead's Avatar
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    Have you checked the exhaust pipe over/near the rear axle to see if it got crushed?...
    "Here's my strategy on the Cold War:
    We win, they lose."
    - Ronald Reagan-

  5. #5
    Master Tech williambmac's Avatar
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    Quote Originally Posted by Knuckelhead View Post
    Have you checked the exhaust pipe over/near the rear axle to see if it got crushed?...
    Exhaust is a nice custom job to clear my L/A suspension, no dings, dents or crushed pipes. The thing that is really baffling me is the ammonia smell coming from the tail pipe while the vehicle is under a load. I thought perhaps I had a slale tank of fuel so I dropped the tank and drained it, no help at all. In all my years of wrenching I have never run into anything like this.
    2005 Rubi LJ 35's 5.5 Clayton
    lots of extras

    2000 wrangler 35" Goodyears Rock-trac super 88 hp30 4.88Terminator trans 5.5" RE/Clayton lots of xtras. RIP
    2000 WJ 4.0 addco upcountry springs bilsteins
    2001 H-D Duece Black and Chrome (For Sale)
    1997 YZF1000 200mph Superbike (RIP)

  6. #6
    Registered Jodean's Avatar
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    QUIT RUNNING E85!!!! LOL
    99 TJ long arm 4.6L stroker

    Admin of http://dakotajeeps.com/index.htm

  7. #7
    Master Tech williambmac's Avatar
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    Quote Originally Posted by Jodean View Post
    QUIT RUNNING E85!!!! LOL

    I don't even think they have that crap in joisey!!! It is funny that you mention that though. GM has a voluntary recall to update the pcm for e85 fuel. I get about 5 people a day coming in to have the recall performed. When I ask why they want the recall performed most people say "because it is free"

    I am beginning to think that my pcm may actually have an internal driver problem though.
    2005 Rubi LJ 35's 5.5 Clayton
    lots of extras

    2000 wrangler 35" Goodyears Rock-trac super 88 hp30 4.88Terminator trans 5.5" RE/Clayton lots of xtras. RIP
    2000 WJ 4.0 addco upcountry springs bilsteins
    2001 H-D Duece Black and Chrome (For Sale)
    1997 YZF1000 200mph Superbike (RIP)

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    Senior Moderator Larry's Avatar
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    Quote Originally Posted by williambmac View Post
    The only other thing I wanted to mention is under a load I get a strong ammonia smell coming from the exhaust.
    This puzzles me. Sounds a bit like a bad coil aside from the smell.

  9. #9
    Master Tech williambmac's Avatar
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    Quote Originally Posted by Larry View Post
    This puzzles me. Sounds a bit like a bad coil aside from the smell.
    I swapped the coil from my wj just to see, no difference. The strange thing is the truck idles like a dream, no hesitation, no miss, plenty of power. Then you hit a hill or put it under a load and it falls flat on its face. When it happens it doesn't misfire or hesitate at all just a bad smell of ammonia coming from the tail pipe, but no smoke.
    There is a hill on route 80 in parsippany that I normally cruise up at 75 mph in 5th gear, now midway up I am at 55mph and have to downshift into 4th to keep with traffic. I am completely baffled on this one. The one thing that I can see on the scanner is that the air intake temp sensor is reading 190 degrees, which I believe is a little high.
    2005 Rubi LJ 35's 5.5 Clayton
    lots of extras

    2000 wrangler 35" Goodyears Rock-trac super 88 hp30 4.88Terminator trans 5.5" RE/Clayton lots of xtras. RIP
    2000 WJ 4.0 addco upcountry springs bilsteins
    2001 H-D Duece Black and Chrome (For Sale)
    1997 YZF1000 200mph Superbike (RIP)

  10. #10
    Senior Moderator Larry's Avatar
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    could the amonia smell be rotton egg smell?

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    I like where he is going with the rotten egg smell. You possibly got a cat stopped up!

  12. #12
    Master Tech williambmac's Avatar
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    Quote Originally Posted by Dmaxeter View Post
    I like where he is going with the rotten egg smell. You possibly got a cat stopped up!

    Cats are new. They were replaced because they were rattling, but they were not clogged. The ammonia smell was present prior to replacing the cats. Trust me it is an ammonia smell; not rotten eggs, if I have the rear window rolled up it can actually make your eyes water.
    2005 Rubi LJ 35's 5.5 Clayton
    lots of extras

    2000 wrangler 35" Goodyears Rock-trac super 88 hp30 4.88Terminator trans 5.5" RE/Clayton lots of xtras. RIP
    2000 WJ 4.0 addco upcountry springs bilsteins
    2001 H-D Duece Black and Chrome (For Sale)
    1997 YZF1000 200mph Superbike (RIP)

  13. #13
    Senior Moderator Larry's Avatar
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    Have you had the dealer scan it with their scan tool?

    I assume you've gone through a couple tanks of gas to eliminate the possibility of bad fuel. I'm stumped.....

  14. #14
    -DETOUR- Tim's Avatar
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    head gasket?
    There are no shortcuts to any place worth going.

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    ***** ****** 47cj2a's Avatar
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    could be wrong but have you checked your compression. could have worn out rings lowering your compression.
    98 tj


    '47 cj2a complete resto all stock 6 volt elec., no brakes, pto winch, warn overdrive
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    Jeep, available in Grand Cherokee trim for soccer moms

  16. #16

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    He said he did a compression test and cylinder leakdown test

  17. #17
    Registered jeepfourlife's Avatar
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    maybe this would be an excuse to install some nitrus!

    haha only kidding

    hope you figure it out, seems like a tricky problem.
    1999 tj 2.5l 4 banger, aem intake, magnaflow cat back, 4 inch pro comp short arm lift, 33 bfg ats, hi-lift, uniden 510 and 4 foot wilson antenna, custom front bumper, 2 day-lighters, and a poly performance rear bumper/tire carrier.

  18. #18
    ***** ****** 47cj2a's Avatar
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    Quote Originally Posted by GreenGeep View Post
    He said he did a compression test and cylinder leakdown test
    never mind then, helps if you read it all.

    how about the vavles/valve springs. if its loosing power during a load, it could be due to vavles not opening all the way.
    98 tj


    '47 cj2a complete resto all stock 6 volt elec., no brakes, pto winch, warn overdrive
    '62 M170 (CJ6) strewn about
    '68 M-416

    Jeep, available in Grand Cherokee trim for soccer moms

  19. #19

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    You said the cat rattled. By some chance did it break apart? You could have pieces in your muffler causing a restriction.

    You also may want to verify fuel pressure when it is acting up. If its loosing pressure it could be a lean smell you are sniffing.

  20. #20
    Master Tech williambmac's Avatar
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    Quote Originally Posted by baddapl1 View Post
    You said the cat rattled. By some chance did it break apart? You could have pieces in your muffler causing a restriction.

    You also may want to verify fuel pressure when it is acting up. If its loosing pressure it could be a lean smell you are sniffing.

    The rear cat was rattling so the whole y-pipe assembly (3 cats) were replaced. cats were not broken apart at all.
    Fuel pressure is @ 50psi at idle and 50psi while at cruising speeds. Also performed a fuel capacity test and it is dead nutz @ 1/4 litre @ 7 seconds.
    2005 Rubi LJ 35's 5.5 Clayton
    lots of extras

    2000 wrangler 35" Goodyears Rock-trac super 88 hp30 4.88Terminator trans 5.5" RE/Clayton lots of xtras. RIP
    2000 WJ 4.0 addco upcountry springs bilsteins
    2001 H-D Duece Black and Chrome (For Sale)
    1997 YZF1000 200mph Superbike (RIP)

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