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Jeep Wrangler YJ
YJ General Discussion
Sputtering / hesitating / stalling after lifter replacement (out of ideas and desperate for help)
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<blockquote data-quote="JeepDawg25" data-source="post: 436321" data-attributes="member: 20649"><p>This might be a long one - I appreciate your patience in advance because I am mentally at rock bottom right now. 1995 Wrangler 2.5L manual with extremely rough/shuddering idle and no power on acceleration.</p><p></p><p>I have been dealing with a ticking lifter since buying this Jeep and got that god forsaken itch to finally do something about it. Ordered some Sealed Power lifters and Enginetech pushrods/rockers/pivots from RockAuto and it was surprisingly easy. Steps taken:</p><ol> <li data-xf-list-type="ol">Added ZDDP additive to the 10W-30 still in the crankcase (about 500 miles or so since last change). Aimed for 3000ppm for the break in since I kept the old cam.</li> <li data-xf-list-type="ol">Applied assembly lube to all mating surfaces. Made sure to torque the rockers evenly at 21 ft/lb</li> <li data-xf-list-type="ol">Turned the crank by hand a few rotations to make sure all the pushrods moved as expected</li> <li data-xf-list-type="ol">Broke in the lifters for 15 minutes cycling between 1800-2500 RPMs.</li> </ol><p>The end result was a wonderfully quiet engine - after the break-in I sat for a few minutes listening to that lovely idle and the n shut it down for the night.</p><p></p><p>The next day, drove 2 miles down the road with everything normal. On the 2 miles trip back, I started noticing a hesitation/power loss around 2200 RPMs that did not exist on the trip out. Accelerating in that RPM range would cause it to hesitate with no power and almost sound/feel like a semi-truck engine braking. By the time I got home, any throttle over 1400 RPMs would cause the same hesitation. After sitting in the garage poking around the engine bay for 5 minutes or so, the idle got super choppy. At its worst, it would almost "pulse" 4 times a second or so, the entire engine block shaking and the entire Jeep shuddering. After doing this for about a minute, it stalled out.</p><p></p><p>Here are observations over the last week:</p><ul> <li data-xf-list-type="ul">Starts right away but it immediately shudders at idle (I wouldn't dream of trying to drive it anywhere)</li> <li data-xf-list-type="ul">It inevitably stalls out eventually - sometimes after a minute, sometimes after 20.</li> <li data-xf-list-type="ul">I can give it throttle in neutral and it will sound normal up until 2k RPMs when it hesitates/misfires.</li> <li data-xf-list-type="ul">Sometimes it will idle roughly and then out of nowhere, smooth out and idle basically like normal. Almost like she is waking up from a dream or something. But minutes later it always returns to the rough idle.</li> <li data-xf-list-type="ul">Smells strongly of fuel and will spit black soot out the tailpipe.</li> <li data-xf-list-type="ul">Issues do not seem to clear up once operating temp is reached</li> <li data-xf-list-type="ul">After shutting her down, I will hear a single metallic sound from the muffler area after 5-10 seconds - think two pieces of sheet metal hitting together.</li> </ul><p>Here is the troubleshooting I have done:</p><ul> <li data-xf-list-type="ul">Compression is good - ~145-150 in all 4 cylinders. Oil pressure good at ~55-60 (consistent with pressure reading pre-lifter replacement).</li> <li data-xf-list-type="ul">Fuel pressure has always been a little high (~45psi) and this number has stayed consistent during my troubleshooting. I suspect a pinched return and thus tried running the engine bypassing the return to the tank - no change.</li> <li data-xf-list-type="ul">All 4 plugs are getting spark (confirmed with inline tester)</li> <li data-xf-list-type="ul">Diligent throttle body cleaner spraying cannot identify any vacuum leaks</li> <li data-xf-list-type="ul">Replaced spark plugs/wires, IAC, TPS, and MAP sensors. Cleaned throttle body. Changed oil.</li> <li data-xf-list-type="ul">Confirmed consistent injector operation via stethoscope</li> <li data-xf-list-type="ul">Removing the valve cover and observing the rockers at idle shows consistent lift and good oil throw.</li> </ul><p>Based on my steps so far, I have done what I can to check spark, air, fuel, and compression...what the heck am I missing? My next thought is vacuum gauge to test for back pressure - maybe the exhaust is clogged (no catalytic converter on the vehicle as far as I can tell). Or perhaps a timing issue even though I didn't touch the distributor or timing chain - does turning the crank by hand affect timing in any way? Would an O2 sensor problem cause this much headache (even though it shouldn't even come into play until up to temp)?</p><p></p><p>I am struggling to tie the actual lifter replacement to all these issues. There is no ticking, oil throw/pressure is good, and rockers appear to be getting consistent lift height across all cylinders. No rockers are misaligned on the springs, pushrods still appear straight, and there is no play in the valvetrain at all.</p><p></p><p>I know this is a beast of a post but I would sincerely appreciate any help - I have spent so much time troubleshooting on my own that I am seriously contemplating listing for basically scrap price and being done with it.</p></blockquote><p></p>
[QUOTE="JeepDawg25, post: 436321, member: 20649"] This might be a long one - I appreciate your patience in advance because I am mentally at rock bottom right now. 1995 Wrangler 2.5L manual with extremely rough/shuddering idle and no power on acceleration. I have been dealing with a ticking lifter since buying this Jeep and got that god forsaken itch to finally do something about it. Ordered some Sealed Power lifters and Enginetech pushrods/rockers/pivots from RockAuto and it was surprisingly easy. Steps taken: [LIST=1] [*]Added ZDDP additive to the 10W-30 still in the crankcase (about 500 miles or so since last change). Aimed for 3000ppm for the break in since I kept the old cam. [*]Applied assembly lube to all mating surfaces. Made sure to torque the rockers evenly at 21 ft/lb [*]Turned the crank by hand a few rotations to make sure all the pushrods moved as expected [*]Broke in the lifters for 15 minutes cycling between 1800-2500 RPMs. [/LIST] The end result was a wonderfully quiet engine - after the break-in I sat for a few minutes listening to that lovely idle and the n shut it down for the night. The next day, drove 2 miles down the road with everything normal. On the 2 miles trip back, I started noticing a hesitation/power loss around 2200 RPMs that did not exist on the trip out. Accelerating in that RPM range would cause it to hesitate with no power and almost sound/feel like a semi-truck engine braking. By the time I got home, any throttle over 1400 RPMs would cause the same hesitation. After sitting in the garage poking around the engine bay for 5 minutes or so, the idle got super choppy. At its worst, it would almost "pulse" 4 times a second or so, the entire engine block shaking and the entire Jeep shuddering. After doing this for about a minute, it stalled out. Here are observations over the last week: [LIST] [*]Starts right away but it immediately shudders at idle (I wouldn't dream of trying to drive it anywhere) [*]It inevitably stalls out eventually - sometimes after a minute, sometimes after 20. [*]I can give it throttle in neutral and it will sound normal up until 2k RPMs when it hesitates/misfires. [*]Sometimes it will idle roughly and then out of nowhere, smooth out and idle basically like normal. Almost like she is waking up from a dream or something. But minutes later it always returns to the rough idle. [*]Smells strongly of fuel and will spit black soot out the tailpipe. [*]Issues do not seem to clear up once operating temp is reached [*]After shutting her down, I will hear a single metallic sound from the muffler area after 5-10 seconds - think two pieces of sheet metal hitting together. [/LIST] Here is the troubleshooting I have done: [LIST] [*]Compression is good - ~145-150 in all 4 cylinders. Oil pressure good at ~55-60 (consistent with pressure reading pre-lifter replacement). [*]Fuel pressure has always been a little high (~45psi) and this number has stayed consistent during my troubleshooting. I suspect a pinched return and thus tried running the engine bypassing the return to the tank - no change. [*]All 4 plugs are getting spark (confirmed with inline tester) [*]Diligent throttle body cleaner spraying cannot identify any vacuum leaks [*]Replaced spark plugs/wires, IAC, TPS, and MAP sensors. Cleaned throttle body. Changed oil. [*]Confirmed consistent injector operation via stethoscope [*]Removing the valve cover and observing the rockers at idle shows consistent lift and good oil throw. [/LIST] Based on my steps so far, I have done what I can to check spark, air, fuel, and compression...what the heck am I missing? My next thought is vacuum gauge to test for back pressure - maybe the exhaust is clogged (no catalytic converter on the vehicle as far as I can tell). Or perhaps a timing issue even though I didn't touch the distributor or timing chain - does turning the crank by hand affect timing in any way? Would an O2 sensor problem cause this much headache (even though it shouldn't even come into play until up to temp)? I am struggling to tie the actual lifter replacement to all these issues. There is no ticking, oil throw/pressure is good, and rockers appear to be getting consistent lift height across all cylinders. No rockers are misaligned on the springs, pushrods still appear straight, and there is no play in the valvetrain at all. I know this is a beast of a post but I would sincerely appreciate any help - I have spent so much time troubleshooting on my own that I am seriously contemplating listing for basically scrap price and being done with it. [/QUOTE]
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Jeep Wrangler YJ
YJ General Discussion
Sputtering / hesitating / stalling after lifter replacement (out of ideas and desperate for help)
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