- Sep 9, 2013
- 106
This problem started as a no start out of the blue one day last year. I'm going to copy and paste what I wrote on the other board that I didn't get any response to.
this is from 6/30/12
went into the store today. it was running fine. came out and hit the key. she fired up ran for MAYBE 2 seconds started running really rough and died. tried starting again and did the same thing. didn't have any tools with me so there wasn't a whole lot i could do. luckily a friend of mine was there to give me a ride home. planning on going back tomorrow with my manual and some tools to start trouble shooting. check engine light never came on. kinda seems like it's starving for fuel but it starts for those 1-2 seconds every time. never could really hear the fuel pump come on before starting it before this happened. tried switching the fuel pump relay with another relay but it didn't change anything. my first thought was something fuel related (maybe pressure regulator?) and my friend thinks it might be the crank sensor. he said he's had similar problems before and it turned out to be a bad crank sensor. any ideas? thanks in advance for any help or suggestions...
7/2/12
update:
i went back about 6hrs later and she fired up and ran like she normally does. drove it home no problem. get to the house shut it off and tried to start it again, nothing happens. now it just cranks, cranks, cranks... no more running for a few seconds and dying. now back at the house i can hear the fuel pump cycling on and off with the key. i also hear it when i stop cranking. it sounds like it's building pressure and cutting off like it should. still haven't checked fuel pressure but that's not the problem at this point in time.
the crank sensor was cheap enough that i went ahead and changed it. got a duralast from the zone. no change...checked for spark, had spark at first then it didn't. unplugged coil, tested for ignition voltage, got voltage, tested for ground, got ground, tested for signal from pcm, nothing. all fuses have been checked, rechecked and checked again. all good there.
according to my manual the only thing left is the pcm. just so happens that i have a pcm that i bought from pcm for less last year that i still hadn't installed due to the case relearn issue that i refused to pay the stealer over 100 bucks to do. now that i messed with the crank sensor i figured the case relearn is inevitable so i installed the new pcm. went through the security relearn process and it took after the third cycle of leaving the key on for 11 minutes and off for 30 seconds. STILL NO SPARK OR SIGNAL TO THE COILS!!!! WTF do i do now???? what's left? according to my manual i've covered everything that's involved in the ignition system. is there an ignition module somewhere that isn't mentioned in the manual? is there a way to test the crank sensor? the only thing the manual covers is replacing it. i'm at a loss as to what to do next. any ideas or suggestions would be MUCH appreciated.
tia, tom
7/4/12
still no love... tried doing the security relearn process a few more times after rereading the instructions that came with the pcm from pcm for less. even though the security relearn seemed to be completed (security light went out with the rest of the lights on the dash shortly after the key was switched to "run") on the third cycle of crank, leaving key on "run" for 11 minutes and "off" for 30 seconds, the instructions say to do the process for four times OR until the engine starts. it's not going to start b/c i've got it all apart but i'm testing for spark AND ignition signal to the coil and still have neither...
wiring schematics in my repair manual SUCK and don't really have any for the engine controls. i found some online that show the crank sensor with a purple and a yellow wire coming from the pcm. purple is the low reference and yellow is the crank signal back to the pcm. i've found some other low reference voltages for other sensors are 5 volts. never found a voltage called out for the crank sensor. i unplugged the crank sensor, checked for low voltage reference on the purple wire with the key on and got 2.4 volts. not sure if it should be higher or not but i am getting something. i'd like to plug the crank sensor back in and check for voltage coming back on the signal wire but i'm worried i might damage the pcm if i do. anyone have any thoughts on that?
anyone have a way to test the crank sensor off the vehicle? the manual doesn't give any info. i tried to test the resistance of the old one but not really sure what i'm looking for. iirc, i had my ohm meter set at 20k. when i test across the two pins on the sensor it reads 0.73 ohms. when i touch it to a piece of metal i see it drop some for a split second and go right back to 0.73. seems to me it should be reading 0.00 or at least drop to something lower and stay there while i have it on the metal but i don't know. i'm planning on pulling the new one back out and test it the same way to compare the two.
next plan is to find the yellow and purple wires where they come into the pcm and check them for continuity from the plug at the crank sensor to the plug at the pcm. if that all checks out i'm considering trying the original crank sensor or returning the new one for another one and/or bring both pcm's to the dealer and see if they can test them for me.
beyond that i don't know what else i can do. i guess no one else has had this problem or the folks with all the answers around here have taken an extended weekend to celebrate independence day.
i guess i should try calling pcm for less to see if they've ever run across something like this or maybe they can help get me pointed in the right direction. this truck has been pretty much problem free until now with 12x,xxx miles on her. never thought twice about driving it anywhere. now not so much, IF i can even get it running again...lol
9/8/13
back from the dead...lol... finally got the truck running last year but it still isn't right. wiring for ckp checked out from sensor to pcm. i finally decided to just put it all back together and it started. still not sure how it started... sometimes it starts first try, sometimes it takes a while but i've been able to get it started every time.
over the past year i've had a bunch of random codes pop up here and there, i have them all written down somewhere but i can't seem to find them right now. i've also had the reduced power light come on along with the traction control light. boy, the engine running in reduced power mode is FRIGHTENING...sounds like a bad running diesel engine. only way to get going again after the reduced power situation was to clear all codes with my scanner and she'd run fine again. that only happened a few times and it hasn't happened for a while now. knocking on wood.
check engine light comes and goes but one thing is always there whether the light is on or not. po335 crankshaft position sensor A circuit malfunction. right now it reads the same code three times. 1- history/current
2- confirmed and 3- pending.
these all came up yesterday, along with p0336 crankshaft position sensor A circuit range/performance. never saw this one before.
also got co327 encoder circuit (4 wheel drive seems to work fine) reads as history.
p0171 bank 1 system too lean, reads as intermittent. this is the first time i've seen these come up.
these came up a while back but i haven't seen them lately.
p2431
p0068 twice, one was pending
p0014
the really strange thing is if i don't go past half throttle it seems to run fine most of the time. if i try to put my foot into it, it'll fall on its face. usually when it falls on its face the tach drops to zero. sometimes it kicks the check engine light at this point but sometimes it doesn't. sometimes when it's acting up and won't start right away, the tach stays at zero when it finally starts. what's even stranger (if that's even possible at this point) is when the tach isn't working it runs like a raped ape!!!
since all this started over a year ago, i've replaced the crank sensor, pcm, had the case relearn done and the cam sensor. starter also went out a while back (most likely from all the excessive cranking) and that really seemed to improve the initial start ups but not the drivability issues i've been experiencing.
i've been starting to wonder if maybe the tach has something to do with all of this but i'm not so sure after reading all the threads about the stepper motors in the cluster. when the tach works, it's spot on with the scanner. if the tach drops out while the engine is running, the scanner stays at the last recorded rpm. if the tach reads zero on start up, the scanner reads zero also.
one thing i noticed in the data i recorded with the scanner yesterday was that the fuel injection system switched from closed loop to open loop a few different times WELL after the truck was warm. it's always been my understanding that it's only in open loop when it's cold at start up to richen the mixture.
sorry for the long winded post. i feel like i'm all over the place but i'm just trying to include all the info that i have. this thing has got me at my wits end. i really love this truck but i just feel like i can't depend on it anymore. any help would be much appreciated.
this is from 6/30/12
went into the store today. it was running fine. came out and hit the key. she fired up ran for MAYBE 2 seconds started running really rough and died. tried starting again and did the same thing. didn't have any tools with me so there wasn't a whole lot i could do. luckily a friend of mine was there to give me a ride home. planning on going back tomorrow with my manual and some tools to start trouble shooting. check engine light never came on. kinda seems like it's starving for fuel but it starts for those 1-2 seconds every time. never could really hear the fuel pump come on before starting it before this happened. tried switching the fuel pump relay with another relay but it didn't change anything. my first thought was something fuel related (maybe pressure regulator?) and my friend thinks it might be the crank sensor. he said he's had similar problems before and it turned out to be a bad crank sensor. any ideas? thanks in advance for any help or suggestions...
7/2/12
update:
i went back about 6hrs later and she fired up and ran like she normally does. drove it home no problem. get to the house shut it off and tried to start it again, nothing happens. now it just cranks, cranks, cranks... no more running for a few seconds and dying. now back at the house i can hear the fuel pump cycling on and off with the key. i also hear it when i stop cranking. it sounds like it's building pressure and cutting off like it should. still haven't checked fuel pressure but that's not the problem at this point in time.
the crank sensor was cheap enough that i went ahead and changed it. got a duralast from the zone. no change...checked for spark, had spark at first then it didn't. unplugged coil, tested for ignition voltage, got voltage, tested for ground, got ground, tested for signal from pcm, nothing. all fuses have been checked, rechecked and checked again. all good there.
according to my manual the only thing left is the pcm. just so happens that i have a pcm that i bought from pcm for less last year that i still hadn't installed due to the case relearn issue that i refused to pay the stealer over 100 bucks to do. now that i messed with the crank sensor i figured the case relearn is inevitable so i installed the new pcm. went through the security relearn process and it took after the third cycle of leaving the key on for 11 minutes and off for 30 seconds. STILL NO SPARK OR SIGNAL TO THE COILS!!!! WTF do i do now???? what's left? according to my manual i've covered everything that's involved in the ignition system. is there an ignition module somewhere that isn't mentioned in the manual? is there a way to test the crank sensor? the only thing the manual covers is replacing it. i'm at a loss as to what to do next. any ideas or suggestions would be MUCH appreciated.
tia, tom
7/4/12
still no love... tried doing the security relearn process a few more times after rereading the instructions that came with the pcm from pcm for less. even though the security relearn seemed to be completed (security light went out with the rest of the lights on the dash shortly after the key was switched to "run") on the third cycle of crank, leaving key on "run" for 11 minutes and "off" for 30 seconds, the instructions say to do the process for four times OR until the engine starts. it's not going to start b/c i've got it all apart but i'm testing for spark AND ignition signal to the coil and still have neither...
wiring schematics in my repair manual SUCK and don't really have any for the engine controls. i found some online that show the crank sensor with a purple and a yellow wire coming from the pcm. purple is the low reference and yellow is the crank signal back to the pcm. i've found some other low reference voltages for other sensors are 5 volts. never found a voltage called out for the crank sensor. i unplugged the crank sensor, checked for low voltage reference on the purple wire with the key on and got 2.4 volts. not sure if it should be higher or not but i am getting something. i'd like to plug the crank sensor back in and check for voltage coming back on the signal wire but i'm worried i might damage the pcm if i do. anyone have any thoughts on that?
anyone have a way to test the crank sensor off the vehicle? the manual doesn't give any info. i tried to test the resistance of the old one but not really sure what i'm looking for. iirc, i had my ohm meter set at 20k. when i test across the two pins on the sensor it reads 0.73 ohms. when i touch it to a piece of metal i see it drop some for a split second and go right back to 0.73. seems to me it should be reading 0.00 or at least drop to something lower and stay there while i have it on the metal but i don't know. i'm planning on pulling the new one back out and test it the same way to compare the two.
next plan is to find the yellow and purple wires where they come into the pcm and check them for continuity from the plug at the crank sensor to the plug at the pcm. if that all checks out i'm considering trying the original crank sensor or returning the new one for another one and/or bring both pcm's to the dealer and see if they can test them for me.
beyond that i don't know what else i can do. i guess no one else has had this problem or the folks with all the answers around here have taken an extended weekend to celebrate independence day.
i guess i should try calling pcm for less to see if they've ever run across something like this or maybe they can help get me pointed in the right direction. this truck has been pretty much problem free until now with 12x,xxx miles on her. never thought twice about driving it anywhere. now not so much, IF i can even get it running again...lol
9/8/13
back from the dead...lol... finally got the truck running last year but it still isn't right. wiring for ckp checked out from sensor to pcm. i finally decided to just put it all back together and it started. still not sure how it started... sometimes it starts first try, sometimes it takes a while but i've been able to get it started every time.
over the past year i've had a bunch of random codes pop up here and there, i have them all written down somewhere but i can't seem to find them right now. i've also had the reduced power light come on along with the traction control light. boy, the engine running in reduced power mode is FRIGHTENING...sounds like a bad running diesel engine. only way to get going again after the reduced power situation was to clear all codes with my scanner and she'd run fine again. that only happened a few times and it hasn't happened for a while now. knocking on wood.
check engine light comes and goes but one thing is always there whether the light is on or not. po335 crankshaft position sensor A circuit malfunction. right now it reads the same code three times. 1- history/current
2- confirmed and 3- pending.
these all came up yesterday, along with p0336 crankshaft position sensor A circuit range/performance. never saw this one before.
also got co327 encoder circuit (4 wheel drive seems to work fine) reads as history.
p0171 bank 1 system too lean, reads as intermittent. this is the first time i've seen these come up.
these came up a while back but i haven't seen them lately.
p2431
p0068 twice, one was pending
p0014
the really strange thing is if i don't go past half throttle it seems to run fine most of the time. if i try to put my foot into it, it'll fall on its face. usually when it falls on its face the tach drops to zero. sometimes it kicks the check engine light at this point but sometimes it doesn't. sometimes when it's acting up and won't start right away, the tach stays at zero when it finally starts. what's even stranger (if that's even possible at this point) is when the tach isn't working it runs like a raped ape!!!
since all this started over a year ago, i've replaced the crank sensor, pcm, had the case relearn done and the cam sensor. starter also went out a while back (most likely from all the excessive cranking) and that really seemed to improve the initial start ups but not the drivability issues i've been experiencing.
i've been starting to wonder if maybe the tach has something to do with all of this but i'm not so sure after reading all the threads about the stepper motors in the cluster. when the tach works, it's spot on with the scanner. if the tach drops out while the engine is running, the scanner stays at the last recorded rpm. if the tach reads zero on start up, the scanner reads zero also.
one thing i noticed in the data i recorded with the scanner yesterday was that the fuel injection system switched from closed loop to open loop a few different times WELL after the truck was warm. it's always been my understanding that it's only in open loop when it's cold at start up to richen the mixture.
sorry for the long winded post. i feel like i'm all over the place but i'm just trying to include all the info that i have. this thing has got me at my wits end. i really love this truck but i just feel like i can't depend on it anymore. any help would be much appreciated.
