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Jeep Wrangler YJ
YJ General Discussion
95 YJ crank, no start
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<blockquote data-quote="deadpool1" data-source="post: 440926" data-attributes="member: 21229"><p>on all cars that fail dead, we check all fuses first. (for sure F1) on new cars the PCM even tells me what fuse blew (of vast) not just F1</p><p>33 means A/C is missing (the factory only option, not aftermarket A/C) <strong><em><<< ignore this</em></strong></p><p>12 is a bingo? (maybe)</p><p>Fuse 1 is blown, or battery was removed, or battery was weak now or while cranking. (fusebox PDC, F1 blown)</p><p>PDC fuse 1 is it, not cab block Fuse 1 and fuse 5</p><p>okay?</p><p>I deleted all that so I can get you to focus on spark first. (and duration of the test)</p><p></p><p>the 3rd flow chart, decision is got spark. y/n so it has spark on all <strong>4 cylinders??</strong>, we do test fuel next.</p><p><strong>The spark must last longer than 3 seconds cranking if not ASD dropped off line (on purpose !)</strong></p><p>it will run on test<a href="https://youtu.be/064Ilsz8Fzg?t=35" target="_blank"> fuel every time tired, does it? </a>< watch him do it !</p><p>if spark did work then what?, and tests fuel too then what? well swap horn relay and fuel pump relay.</p><p>test for spark for say 5 full seconds cranking to get past the 3 second PCM/ASD rule.<< it's a jeep not a Chevy.</p><p></p><p>the terse words it the flow chart means MPI means EFI /MPI , check for injection multipoint and fuel pressure at spec cranking.</p><p>mpi = multipoint injection system (EFI)</p><p>fuse 1 PDC blows and ASD and fuel pump are dead</p><p>Fuse 1 blown means the PCM can not store codes. A14 power feed all things on it are dead.</p><p></p><p>if any device in the engine shorts out A142 feed, F1 blows. injector shorted, or o2 shorted and all things in the FSM , A14 and A142 must not be shorted.</p><p>and sure can;/</p><p>if F1 blows spark too is dead. as will be A142 power feed. A142 drives power to the spark coil (induction) and if the primary shorts F1 blows</p><p>or ASD +PCM shuts down ASD fast so fast F1 will not blow, toss a coin as overloads come in 2 forms, a hard 0 ohm dead short or is near 20 amps but not there yet.</p><p></p><p>the spark test is best done for 10 full seconds, ok? so we will see if the ASD stays energized for more than 3 seconds.</p><p>did you know the TPS stuck at 5v the PCm cuts fuel 100% dead . (if the ground wire is bad to the TPS bingo stuck in magic secret unflood mode.</p><p>the spark test is key to diagosing all cars.</p><p>most cars the rule is the crank shaft must spin a full 10 turns. to see all DTCs related to spark failing. CKP and CMP are 2 top contenders.</p><p></p><p>fuse 1 PDC makes must not be blown..</p><p></p><p>the fuel pump test must be doNe correctly</p><p>most cars made the pump only runs for 3 seconds at each key on, this is to prevent fires after a crash and by DOT laws.<<< SAFETY FIRST and all that.</p><p></p><p>the test is 2 man test, not just one person, hearing the pump spin is not a full test. one can use a voltmeter extended from the tank pump wires</p><p>to the cab and crank with 1man test.</p><p>knowing all this make the test valid, and not put the tech on an endless wild goose chase.</p><p>you now have new pump and pump relay.</p><p>but do you have 41psi pressure cranking, for 3 seconds or more. 10 is max so not to overheat the starter.</p><p>rule #1 after all fuses checked is keep the battery charged fully or as the battery gets weak at below 10vdc the PCM goes off line, making all test</p><p>totally useless. to fix cars we must own a battery charger, or use jumper cables to other car.</p><p>The pump can fail if either wire to it is rust (connections) the hot wire or the rear ground there.</p><p>G104 at the rear of car is the ground to the fuel pump. it too must not be bad as is so common on all cars. MPI.</p><p></p><p>The ASD must stay engerized all the time cranking this is a key test on all JEEPS (USA made, dodge ,etc)</p><p>or spark and fuel goes dead.</p><p>spark tests with test spark plug is best gapped correctly.</p><p></p><p>when the engine stall fast, just like turning the ign key off that is spark died, not fuel , fuel pressure falls slowly, for sure at idle (dies)</p><p>if it goes dead instantly and the TACH meter drops dead like hammer hit it, that is spark lost and is ASD drop out</p><p></p><p>a key set of evidence that,</p><p>and you do know all these related EFI parts can fail intermittently.</p><p>Even a car battery with 1 intermittent cell , goes shorted and not 10vdc is there, alternators does not like this short so it goes offline in a flash</p><p>and now the PCM is really angry, it now goes off line as its internal voltage reg goes dead at 10v or less. FSM warns if this, !</p><p>newer cars my go to 8v and die but this car is not a new car. with LDO regs inside the PCM,sorry this car is old with old regs there.</p><p>take away the battery must be good and fully charged for all tests and when driving the dash voltmeter as on 14 not 10.</p><p></p><p>we even see things like this.(fuse)</p><p>I am not saying at all I know what is wrong or bad and can be 1 rusty wire(conn).</p><p>or this.</p><p>Any fuse can do micro cracks or even rust(means corroded) in the salt belt? is it? BC is not I think but IDK.</p><p>even the alternator can short the A142 wire , random. o2 shorts and injectors shorts ASD drops like a hammer.(fast)</p><p></p><p>as seen in the rust belt</p><p>this.</p><p></p><p>IF code 12 fails after a DTC reset , the DTC 12 is relevant.</p><p> </p><p>[ATTACH=full]122427[/ATTACH]</p><p></p><p></p><p>take away 2 to 3</p><p></p><p>spark will last for 10 full seconds cranked, I can not see you do the test or how long done. using tests spark plug and all 4 spark full time>?</p><p>test fuel works, every time.?</p><p>fuel pressure 41 psi cranking of it will fail.</p><p>if pressure was say 20psi the FPR is dead.</p><p>pressure matters and the PCM on this car does not have any fuel pressure sensor like all new cars have.</p><p>To tests pump voltage at the tank takes 2 persons and I did not see how you did this, or if using the wrong ground to do so.</p><p>Ive seen cars with 6vdc going to the pump test correctly for 3+seconds (not less) and bingo bad wiring or relay(its new now)</p><p>the relay (FP) is closed full time cranking, it does not drop out, cranked ever. on any car. (unless battery is weak)</p><p></p><p>The PCM cuts spark when the ASD drops (PCM decision)</p><p>the PCM cuts fuel for many reasons. for sure ASD drops and the PCM DOES the drop. for A142<span style="color: rgb(184, 49, 47)"> overloads of ANY KIND</span></p><p>The PCM cuts fuel of TPS goes to 5vdc (output TSP pin) cranking</p><p>The PCM cuts spark if CMP fails or CKP</p><p></p><p></p><p>As you can see what the ASD does is SUPERKEY FACTOR in finding any kinds of stalls or no starts but cranks fast and robustly./</p><p>the PCM pin a142 the PCM has magic thing inside called a ADC, analog to digital converter. that is in EFFECT just a VOLTMETER.</p><p>this magic voltmeter measure voltage on the A142 bus. and if below spec voltage the PCm drop ASK like a hammer blow.</p><p>to prevent CRASH and BUN as seen on TV. </p><p>the PCM sees any kind of spark loss the PCM cuts the ASD dead (fuel ends) to save LIVES.</p><p>that is how it all works.</p><p>do the spark test and tell how it was done. do so for 10 full seconds. to be sure spark holds UP full time.</p><p>do the pump voltgage test and tell how it was down. do so CRANKING, WHEN CRANKING 11 VOLTS (PAR) MAKES IT TO THE PUMP FULL TIME CRANKED</p><p>AND IS A 2 MAN TEST , LACKING 12FOOT METER TEST LEADS ,LIKE i HAVE.</p></blockquote><p></p>
[QUOTE="deadpool1, post: 440926, member: 21229"] on all cars that fail dead, we check all fuses first. (for sure F1) on new cars the PCM even tells me what fuse blew (of vast) not just F1 33 means A/C is missing (the factory only option, not aftermarket A/C) [B][I]<<< ignore this[/I][/B] 12 is a bingo? (maybe) Fuse 1 is blown, or battery was removed, or battery was weak now or while cranking. (fusebox PDC, F1 blown) PDC fuse 1 is it, not cab block Fuse 1 and fuse 5 okay? I deleted all that so I can get you to focus on spark first. (and duration of the test) the 3rd flow chart, decision is got spark. y/n so it has spark on all [B]4 cylinders??[/B], we do test fuel next. [B]The spark must last longer than 3 seconds cranking if not ASD dropped off line (on purpose !)[/B] it will run on test[URL='https://youtu.be/064Ilsz8Fzg?t=35'] fuel every time tired, does it? [/URL]< watch him do it ! if spark did work then what?, and tests fuel too then what? well swap horn relay and fuel pump relay. test for spark for say 5 full seconds cranking to get past the 3 second PCM/ASD rule.<< it's a jeep not a Chevy. the terse words it the flow chart means MPI means EFI /MPI , check for injection multipoint and fuel pressure at spec cranking. mpi = multipoint injection system (EFI) fuse 1 PDC blows and ASD and fuel pump are dead Fuse 1 blown means the PCM can not store codes. A14 power feed all things on it are dead. if any device in the engine shorts out A142 feed, F1 blows. injector shorted, or o2 shorted and all things in the FSM , A14 and A142 must not be shorted. and sure can;/ if F1 blows spark too is dead. as will be A142 power feed. A142 drives power to the spark coil (induction) and if the primary shorts F1 blows or ASD +PCM shuts down ASD fast so fast F1 will not blow, toss a coin as overloads come in 2 forms, a hard 0 ohm dead short or is near 20 amps but not there yet. the spark test is best done for 10 full seconds, ok? so we will see if the ASD stays energized for more than 3 seconds. did you know the TPS stuck at 5v the PCm cuts fuel 100% dead . (if the ground wire is bad to the TPS bingo stuck in magic secret unflood mode. the spark test is key to diagosing all cars. most cars the rule is the crank shaft must spin a full 10 turns. to see all DTCs related to spark failing. CKP and CMP are 2 top contenders. fuse 1 PDC makes must not be blown.. the fuel pump test must be doNe correctly most cars made the pump only runs for 3 seconds at each key on, this is to prevent fires after a crash and by DOT laws.<<< SAFETY FIRST and all that. the test is 2 man test, not just one person, hearing the pump spin is not a full test. one can use a voltmeter extended from the tank pump wires to the cab and crank with 1man test. knowing all this make the test valid, and not put the tech on an endless wild goose chase. you now have new pump and pump relay. but do you have 41psi pressure cranking, for 3 seconds or more. 10 is max so not to overheat the starter. rule #1 after all fuses checked is keep the battery charged fully or as the battery gets weak at below 10vdc the PCM goes off line, making all test totally useless. to fix cars we must own a battery charger, or use jumper cables to other car. The pump can fail if either wire to it is rust (connections) the hot wire or the rear ground there. G104 at the rear of car is the ground to the fuel pump. it too must not be bad as is so common on all cars. MPI. The ASD must stay engerized all the time cranking this is a key test on all JEEPS (USA made, dodge ,etc) or spark and fuel goes dead. spark tests with test spark plug is best gapped correctly. when the engine stall fast, just like turning the ign key off that is spark died, not fuel , fuel pressure falls slowly, for sure at idle (dies) if it goes dead instantly and the TACH meter drops dead like hammer hit it, that is spark lost and is ASD drop out a key set of evidence that, and you do know all these related EFI parts can fail intermittently. Even a car battery with 1 intermittent cell , goes shorted and not 10vdc is there, alternators does not like this short so it goes offline in a flash and now the PCM is really angry, it now goes off line as its internal voltage reg goes dead at 10v or less. FSM warns if this, ! newer cars my go to 8v and die but this car is not a new car. with LDO regs inside the PCM,sorry this car is old with old regs there. take away the battery must be good and fully charged for all tests and when driving the dash voltmeter as on 14 not 10. we even see things like this.(fuse) I am not saying at all I know what is wrong or bad and can be 1 rusty wire(conn). or this. Any fuse can do micro cracks or even rust(means corroded) in the salt belt? is it? BC is not I think but IDK. even the alternator can short the A142 wire , random. o2 shorts and injectors shorts ASD drops like a hammer.(fast) as seen in the rust belt this. IF code 12 fails after a DTC reset , the DTC 12 is relevant. [ATTACH type="full" alt="fuse-is-first.JPG"]122427[/ATTACH] take away 2 to 3 spark will last for 10 full seconds cranked, I can not see you do the test or how long done. using tests spark plug and all 4 spark full time>? test fuel works, every time.? fuel pressure 41 psi cranking of it will fail. if pressure was say 20psi the FPR is dead. pressure matters and the PCM on this car does not have any fuel pressure sensor like all new cars have. To tests pump voltage at the tank takes 2 persons and I did not see how you did this, or if using the wrong ground to do so. Ive seen cars with 6vdc going to the pump test correctly for 3+seconds (not less) and bingo bad wiring or relay(its new now) the relay (FP) is closed full time cranking, it does not drop out, cranked ever. on any car. (unless battery is weak) The PCM cuts spark when the ASD drops (PCM decision) the PCM cuts fuel for many reasons. for sure ASD drops and the PCM DOES the drop. for A142[COLOR=rgb(184, 49, 47)] overloads of ANY KIND[/COLOR] The PCM cuts fuel of TPS goes to 5vdc (output TSP pin) cranking The PCM cuts spark if CMP fails or CKP As you can see what the ASD does is SUPERKEY FACTOR in finding any kinds of stalls or no starts but cranks fast and robustly./ the PCM pin a142 the PCM has magic thing inside called a ADC, analog to digital converter. that is in EFFECT just a VOLTMETER. this magic voltmeter measure voltage on the A142 bus. and if below spec voltage the PCm drop ASK like a hammer blow. to prevent CRASH and BUN as seen on TV. the PCM sees any kind of spark loss the PCM cuts the ASD dead (fuel ends) to save LIVES. that is how it all works. do the spark test and tell how it was done. do so for 10 full seconds. to be sure spark holds UP full time. do the pump voltgage test and tell how it was down. do so CRANKING, WHEN CRANKING 11 VOLTS (PAR) MAKES IT TO THE PUMP FULL TIME CRANKED AND IS A 2 MAN TEST , LACKING 12FOOT METER TEST LEADS ,LIKE i HAVE. [/QUOTE]
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Jeep Wrangler YJ
YJ General Discussion
95 YJ crank, no start
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