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Jeep Wrangler YJ
YJ General Discussion
Any performance advice for 2.5 4-cylinder?
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<blockquote data-quote="deadpool1" data-source="post: 441032" data-attributes="member: 21229"><p>redux 1</p><p>causes or upgrades.??? is it normal or not now? not told, I will make it more like a physics class answer. ( i can name 50+ causes so I won't)</p><ol> <li data-xf-list-type="ol">Engine is<strong> bad</strong>, compression at 100psi and is a very sick and old tired engine, as many are this old. (bad as in worn out but still runs)</li> <li data-xf-list-type="ol">EFI not <strong>happy</strong>, inputs to it dead wrong ( the PCM is a computer for sure and wrong inputs to any computer gets you lies outputted.</li> <li data-xf-list-type="ol">Fuel pressure <strong>dead wrong </strong>Wot. 41psi is correct. (sealevel) (hand meter gauge it)</li> <li data-xf-list-type="ol"><strong>ACTUATOR</strong>S BAD. these are PCM computer outputs. and if injectors are clogged there will be no full power, 1/2 clogged. or fuel filter clogged?</li> <li data-xf-list-type="ol">drive train<strong> excess friction</strong> from flywheel to <strong>tires </strong>hitting the ground, including bad brakes dragging. or huge wide tires.</li> <li data-xf-list-type="ol">the hill is just too steep for 80 HP or forgot to down shift it?, with tall tires even 4th gear acts like OVER DRIVE slug mode. 33 tires are tall !</li> <li data-xf-list-type="ol">the PCm never sees ever fuel pressure is wrong and power is weak unless you get DTC for lean burn. code 21/22 maybe. 02 dead.</li> </ol><p>the 1996 up cars have codes for <strong>fuel trim</strong> 100% dead or stuck max lean. not ours.</p><p>newer cars have fuel <strong>pressure tests</strong>, failing, but not ours. we use a hand gauge to find it. easy.(OBD1 ways and means)</p><p>the car does not have <strong>misfire detection</strong> as newer do, OBD2 all have it by law USA< 1998 Canada next.</p><p>the PCm has <strong>no CAT test</strong>s so if the CAT is <strong>1/2 melted</strong> inside the power can be 1/2 power so unbolt the cat and test. (remove it and test) or?????</p><p>there are 3+ cat tests one is vacuum test @manifold,, that shows vacuum needle acting<strong> backwards </strong>at WOT.(or gunned)</p><p>the 2nd test is using pressure gauge, 1-5psi put in the place of the pulled O2 sensor, and back pressure is say 1 to 2psi at WOT.</p><p>if higher the cat is melted, and blocking the exh. path huge.</p><p>many shops uses this data 2.8 psi max 2500 RPM, back pressure, finding this out is not in the shop manual. but all shops know what to do.</p><p>there is thermal test that shows front to rear CAT temps increase greatly (hot engine) the output is 100f more degrees than front of cat. if both the same on this CAT the CAT is dead, ( many of them in side now are gone blow out long ago)</p><p>test 4?</p><p>run with no cat, (or buy a new one your call) if bumping the cat gently makes it rattle inside it is bad. omg I posted 4 tests</p><p></p><p>not told 50mph limited in what gear and what RPM and if on flat ground or not not told. (just 50 told)</p><p>the car really is too heavy for any 80HP, engine. (corrected HP this is)</p><p>[ATTACH=full]122481[/ATTACH]</p><p>it will be more power on a cold foggy day,</p></blockquote><p></p>
[QUOTE="deadpool1, post: 441032, member: 21229"] redux 1 causes or upgrades.??? is it normal or not now? not told, I will make it more like a physics class answer. ( i can name 50+ causes so I won't) [LIST=1] [*]Engine is[B] bad[/B], compression at 100psi and is a very sick and old tired engine, as many are this old. (bad as in worn out but still runs) [*]EFI not [B]happy[/B], inputs to it dead wrong ( the PCM is a computer for sure and wrong inputs to any computer gets you lies outputted. [*]Fuel pressure [B]dead wrong [/B]Wot. 41psi is correct. (sealevel) (hand meter gauge it) [*][B]ACTUATOR[/B]S BAD. these are PCM computer outputs. and if injectors are clogged there will be no full power, 1/2 clogged. or fuel filter clogged? [*]drive train[B] excess friction[/B] from flywheel to [B]tires [/B]hitting the ground, including bad brakes dragging. or huge wide tires. [*]the hill is just too steep for 80 HP or forgot to down shift it?, with tall tires even 4th gear acts like OVER DRIVE slug mode. 33 tires are tall ! [*]the PCm never sees ever fuel pressure is wrong and power is weak unless you get DTC for lean burn. code 21/22 maybe. 02 dead. [/LIST] the 1996 up cars have codes for [B]fuel trim[/B] 100% dead or stuck max lean. not ours. newer cars have fuel [B]pressure tests[/B], failing, but not ours. we use a hand gauge to find it. easy.(OBD1 ways and means) the car does not have [B]misfire detection[/B] as newer do, OBD2 all have it by law USA< 1998 Canada next. the PCm has [B]no CAT test[/B]s so if the CAT is [B]1/2 melted[/B] inside the power can be 1/2 power so unbolt the cat and test. (remove it and test) or????? there are 3+ cat tests one is vacuum test @manifold,, that shows vacuum needle acting[B] backwards [/B]at WOT.(or gunned) the 2nd test is using pressure gauge, 1-5psi put in the place of the pulled O2 sensor, and back pressure is say 1 to 2psi at WOT. if higher the cat is melted, and blocking the exh. path huge. many shops uses this data 2.8 psi max 2500 RPM, back pressure, finding this out is not in the shop manual. but all shops know what to do. there is thermal test that shows front to rear CAT temps increase greatly (hot engine) the output is 100f more degrees than front of cat. if both the same on this CAT the CAT is dead, ( many of them in side now are gone blow out long ago) test 4? run with no cat, (or buy a new one your call) if bumping the cat gently makes it rattle inside it is bad. omg I posted 4 tests not told 50mph limited in what gear and what RPM and if on flat ground or not not told. (just 50 told) the car really is too heavy for any 80HP, engine. (corrected HP this is) [ATTACH type="full" alt="HP.jpg"]122481[/ATTACH] it will be more power on a cold foggy day, [/QUOTE]
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Jeep Wrangler YJ
YJ General Discussion
Any performance advice for 2.5 4-cylinder?
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