No power to fuel pump
- Thread starter glenn
- Start date
greg92jeepxj
Official Supporter
Hitting the books now , your thinking what I'm thinking , check all concerned until we find something broken , which is good thinking . Hope it's not , unless you like changing them . On the 4.0 , it's FUN to reach , but not impossible. On the 2.5 , we're granted serenity . Speaking of , I never asked , does your YJ have the four or the six cylinder ? Crazy me , didn't ask !
you check a CPS by unplugging the harness connector by the firewall and probing the sensor plug terminals A and B ( should be marked on plug) , meter set to ohm scale , 200 on my meter.
book says 200 + or - (plus or minus) 75 ohms. But that's warm engine. Lol. I know , thanks a lot. No wonder they hate HAYNES. Well , anything close to that cold will make us feel better.
oh ! Use the search engine on our forum and search 1995 jeep wrangler wiring diagrams , Terry Mason posted one some time back . Forgot to tell you . I'm checking everything I can get my hands on , from auto shutdown relay to fuel pump relay on how to check circuits schematically.
glad you said your getting current from terminals 30 & 87 to light up the fuel pump.
makes me feel good too ! I HATE PULLING TANKS , but gotta do what ya gotta do . Hoping pressure is good too . Will thank you for checking spark , we need to know what shape your PCM is in. PCM lights up your ignition coil , so if your getting spark , that's a better sign the PCM is working , but we can't assume every PCM controlled circuit is working just because one is found to be. We must always check the one in question . But if we got spark , we can start an engine , just need fuel . Ok , back to the books , leaving by 2:00 PM , got to get all I can . Will post back .
getting psyched yet ? Another member just got his jeep running , yours is next . Not patting myself on the back, I just hate when engines don't start . One of my biggest annoyances next to flat tires . Kind of making it a mission . Stay tuned ! More to come !
you check a CPS by unplugging the harness connector by the firewall and probing the sensor plug terminals A and B ( should be marked on plug) , meter set to ohm scale , 200 on my meter.
book says 200 + or - (plus or minus) 75 ohms. But that's warm engine. Lol. I know , thanks a lot. No wonder they hate HAYNES. Well , anything close to that cold will make us feel better.
oh ! Use the search engine on our forum and search 1995 jeep wrangler wiring diagrams , Terry Mason posted one some time back . Forgot to tell you . I'm checking everything I can get my hands on , from auto shutdown relay to fuel pump relay on how to check circuits schematically.
glad you said your getting current from terminals 30 & 87 to light up the fuel pump.
makes me feel good too ! I HATE PULLING TANKS , but gotta do what ya gotta do . Hoping pressure is good too . Will thank you for checking spark , we need to know what shape your PCM is in. PCM lights up your ignition coil , so if your getting spark , that's a better sign the PCM is working , but we can't assume every PCM controlled circuit is working just because one is found to be. We must always check the one in question . But if we got spark , we can start an engine , just need fuel . Ok , back to the books , leaving by 2:00 PM , got to get all I can . Will post back .
getting psyched yet ? Another member just got his jeep running , yours is next . Not patting myself on the back, I just hate when engines don't start . One of my biggest annoyances next to flat tires . Kind of making it a mission . Stay tuned ! More to come !
greg92jeepxj
Official Supporter
Had trouble finding post , google "1995 jeep wrangler wiring diagrams" and look for the Jeepz.com post . Dated 7/72012
greg92jeepxj
Official Supporter
Your welcome brother . Well , at least the 2.5 CID is a little easier to get your hands on .
my blasted desktop (windows XP) is gripping and cannot read or print a '95 diagram , but trying to compare from my iPad the 95 diagram and my 1992 Chrysler factory shop manual for YJ,XJ ,MJ so I can view a nice diagram . My air printer is jacked , so I can't even print for it. Ever have one of those day ? Fear not , I'm not letting the small stuff I timid ate me, if I did , I wouldn't have A/C in my 92 XJ right now. Hey , if you find you got spark and getting hot to try to start 'er up for a couple seconds, disconnect pump harness and jump the orange wire .
my blasted desktop (windows XP) is gripping and cannot read or print a '95 diagram , but trying to compare from my iPad the 95 diagram and my 1992 Chrysler factory shop manual for YJ,XJ ,MJ so I can view a nice diagram . My air printer is jacked , so I can't even print for it. Ever have one of those day ? Fear not , I'm not letting the small stuff I timid ate me, if I did , I wouldn't have A/C in my 92 XJ right now. Hey , if you find you got spark and getting hot to try to start 'er up for a couple seconds, disconnect pump harness and jump the orange wire .
greg92jeepxj
Official Supporter
Hey , if you got a computer safe test light , you can check terminal 9 on the PCM (if they're marked) . It's a 18 gauge white w/ yellow stripe wire . This is the power supply to the PCM. ONLY use a computer safe test light , they're inexpensive and good to have. Pre tell , like for these kind of occasions. A good thing to do is to clean the computer and O2 ground wires . Should find them with the battery ground on the engine block. This can help anyone , anytime.
greg92jeepxj
Official Supporter
Ok , rather than check power at terminal 9 , check terminal 3 for power. That powers the auto shutdown relay , which in turn , the fuel pump relay. I cannot emphasize enough , please try to obtain a computer safe test light for this work or anytime you will work with computer feedback wiring. Ask me how I know. Beg, borrow, steal or kill (just kidding) , you really will benefit now, and future times. F1 fuse for fuel pump (I think you checked this?) and terminal 51 (not area , lol)of PCM powers relay coil (terminal 85) of the fuel pump relay. Terminal 86 of both , fuel pump and auto shutdown relays go to ground. The computer safe test light checks grounds to :shades:.
it will also check , by touching wire terminals on connectors ( do not pierce wires , not cool) the fuel injectors to verify they fire on crank . Days of looking down carburetor throat gone. Wasn't safe either . Can you say , backfire ? NOT cool ! Ok , this may be a bit daunting , but accomplishable. Take you time , we need to know what works , what dosen't . Post back when you can , please use care , and a computer safe test light . Mine was $15 when I got it , 10 yrs. ago ? No tool box complete without. Best of luck , will continue to research ASAP if I can think of any more checks. This should be a good start. I'm using a 1992 manual , but there should be little , if any difference . It's chrysler , not AMC. More consistency . Hoping you may find what problem is . I won't condemn the PCM until we are sure . For fun , you know anyone who might have a spare PCM to swap in ? Ok , almost go time for you , hope the rain holds out to let you work . Best luck and take careful , thoughtful steps. The life you save my be your PCM's .
it will also check , by touching wire terminals on connectors ( do not pierce wires , not cool) the fuel injectors to verify they fire on crank . Days of looking down carburetor throat gone. Wasn't safe either . Can you say , backfire ? NOT cool ! Ok , this may be a bit daunting , but accomplishable. Take you time , we need to know what works , what dosen't . Post back when you can , please use care , and a computer safe test light . Mine was $15 when I got it , 10 yrs. ago ? No tool box complete without. Best of luck , will continue to research ASAP if I can think of any more checks. This should be a good start. I'm using a 1992 manual , but there should be little , if any difference . It's chrysler , not AMC. More consistency . Hoping you may find what problem is . I won't condemn the PCM until we are sure . For fun , you know anyone who might have a spare PCM to swap in ? Ok , almost go time for you , hope the rain holds out to let you work . Best luck and take careful , thoughtful steps. The life you save my be your PCM's .
greg92jeepxj
Official Supporter
Crank sensor B C ; this is the position of the harness plug to the crank sensor.
A
Incidentally , speaking of computer safe , hope your DMM , VOM meter is 10 mega ohm impedance rated ? That means it is safe to use on computer controlled vehicles.
Yeah I know , everything is money. I love tools , hate buying them. Improvise when I can , and when safe .
P.S. - the "A" indented , is supposed to be in between the B and C on second line , in a triangle form . A is sensor + , B is sensor - , C is ground .
A
Incidentally , speaking of computer safe , hope your DMM , VOM meter is 10 mega ohm impedance rated ? That means it is safe to use on computer controlled vehicles.
Yeah I know , everything is money. I love tools , hate buying them. Improvise when I can , and when safe .
P.S. - the "A" indented , is supposed to be in between the B and C on second line , in a triangle form . A is sensor + , B is sensor - , C is ground .
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greg92jeepxj
Official Supporter
Hey , no problem buddy . Tomorrow is another day . Sometimes it's better to have more time to think . When we rush , we forget things or just don't consider all the possibilities and potentially miss something . One thing I forgot to mention or ask , do you know if any trouble codes exist ? The wiring diagram has the o2 sensor connected with the engine shutdown relay , just wondering will it play a part in this no start. We want to cover all our options , but attack each item one at a time. We want to be sure that we find all the faults and correct them to get the jeep to work right. Let also think about how it ran before this problem . Was it running fine and just died or was it slowly developing a drivability problem ? Things like that may help narrow down and find the problem . But ultimately , you want to correct all the problems.
greg92jeepxj
Official Supporter
Ok , if no troubles are logged , then we must continue as planned . Happy that fuel pump is working , making testing and drivability checks possible. Right now , as you know your interest is to find why the current stopped to the electric fuel pump. Hoping there is no issue with ignition and the PCM , but we will address each or any issues as always , post any questions as well as findings to keep up with your progress . Will continue research . Member contribution always welcome.
greg92jeepxj
Official Supporter
Wait a minute , hold on , stop the presses , did you say , IT'S RUNNING ? You were screaming ? Really ? No , I didn't hear you , I was working . Wow ! , ok , damn ! A 15A fuse ? Don't you hate that ? I once had a 25A fuse to the PCM stop me , DEAD ! And that was in a bus . An MCI. Avenue C and 17 th street , jammed the whole left lane to the FDR drive south . Total bummer.
But great ! , I'm happy you got it running ! See , and you were ready to throw in the towel the first day . See that , now you just earned all those braggin' rights ! Who's the man ? And to the ladies , who's your daddy ? LOL . Ok , I'm a little confused , you got a five speed , right ?
do you mean when your letting off the clutch ? If so , maybe a broken transmission mount ?
Universal joints will clunk and followed by a little quick jump , or do you mean the clutch linkage itself ? Wonder if the bell crank ( or cross shaft ?) is dry and needs to be greased ? Sometimes they have a zero fitting on the bell crank . Check too the adjusting rod to the clutch fork .
did it just start doing this ? Did not before the no start ?
But great ! , I'm happy you got it running ! See , and you were ready to throw in the towel the first day . See that , now you just earned all those braggin' rights ! Who's the man ? And to the ladies , who's your daddy ? LOL . Ok , I'm a little confused , you got a five speed , right ?
do you mean when your letting off the clutch ? If so , maybe a broken transmission mount ?
Universal joints will clunk and followed by a little quick jump , or do you mean the clutch linkage itself ? Wonder if the bell crank ( or cross shaft ?) is dry and needs to be greased ? Sometimes they have a zero fitting on the bell crank . Check too the adjusting rod to the clutch fork .
did it just start doing this ? Did not before the no start ?
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greg92jeepxj
Official Supporter
Yeah , sorry , I forgot to ask you about the drive shaft if you can twist it and the joint moves without the axle flange moving. Yeah , the u - joint is ready to throw the drive shaft . Glad you found it now , not when you were driving . Gets ugly sometimes , especially when your friends are watching , then they yell out " LOSER" , well , they did that to me once.
Manual trans are rough on u -joints , when the shaft is off , good idea to change the front to because the new strong one will stress the old weak one . I know you really don't want to do this twice , just got it running , you want to drive it . I always scream when I get something working or an engine started , you have to , no one can hear you over the engine !
Manual trans are rough on u -joints , when the shaft is off , good idea to change the front to because the new strong one will stress the old weak one . I know you really don't want to do this twice , just got it running , you want to drive it . I always scream when I get something working or an engine started , you have to , no one can hear you over the engine !
greg92jeepxj
Official Supporter
Hey , now that I think of it , wonder how the clutch adjustment is , wonder how the clutch disc is too , is the clutch grabbing hard when the pedal is almost up ? My '78 cherokee got like that until I took some play out of the linkage to clutch fork . Disc was good , Borg & Beck pressure plate.
AMC 360 t-18 4speed . I don't know what clutch they used in the 2.5 , if there is an inspection cover near bottom ? , see if you can get any kind of measurement of the disc .
AMC 360 t-18 4speed . I don't know what clutch they used in the 2.5 , if there is an inspection cover near bottom ? , see if you can get any kind of measurement of the disc .
