Bucking, skipping, popping Ram...

From : steve w

Q: vehicle - 2001 ram 2500 standard cab 5.9 magnum automatic trans 70k problem - engine starts and runs ok. take it for a test drive and once it warms up it will act like the timing goes way off and it runs out of fuel. you can hear it backfiring through the exhaust engines dies down for a couple seconds then it will catch and act like you have the throttle floored for a second then it does it a couple more times. after about 10-30 seconds depends on ambient temperature it will suddenly run fine. it wont do it again until you shut it down and let it set for a few minutes like filling the tank. no current or pending codes. watching the life data showed nothing while it was bucking except the timing looked to be dancing a lot. once it settled down the timing followed suit. it has new plugs wires and cap&rotor also a new fuel pump old one failed. will be throwing the scope on it to see what the ignition is doing. im leaning toward a faulty coil. ideas -- steve w. .

Replies:

From : john selph

did you ever find out what was causing the problems john vehicle - 2001 ram 2500 standard cab 5.9 magnum automatic trans 70k problem - engine starts and runs ok. take it for a test drive and once it warms up it will act like the timing goes way off and it runs out of fuel. you can hear it backfiring through the exhaust engines dies down for a couple seconds then it will catch and act like you have the throttle floored for a second then it does it a couple more times. after about 10-30 seconds depends on ambient temperature it will suddenly run fine. it wont do it again until you shut it down and let it set for a few minutes like filling the tank. no current or pending codes. watching the life data showed nothing while it was bucking except the timing looked to be dancing a lot. once it settled down the timing followed suit. it has new plugs wires and cap&rotor also a new fuel pump old one failed. will be throwing the scope on it to see what the ignition is doing. im leaning toward a faulty coil. ideas -- steve w. .

From : steve w

john selph wrote did you ever find out what was causing the problems john went through every connection on it along with a bunch of cleaning and testing. flushed the fuel system and cleaned the injectors. i also reflashed the pcm. it seems to be ok now but i dont trust it yet. steve w. .

From : steve w

maxpower wrote vehicle - 2001 ram 2500 standard cab 5.9 magnum automatic trans 70k problem - engine starts and runs ok. take it for a test drive and once it warms up it will act like the timing goes way off and it runs out of fuel. you can hear it backfiring through the exhaust engines dies down for a couple seconds then it will catch and act like you have the throttle floored for a second then it does it a couple more times. after about 10-30 seconds depends on ambient temperature it will suddenly run fine. it wont do it again until you shut it down and let it set for a few minutes like filling the tank. no current or pending codes. watching the life data showed nothing while it was bucking except the timing looked to be dancing a lot. once it settled down the timing followed suit. it has new plugs wires and cap&rotor also a new fuel pump old one failed. will be throwing the scope on it to see what the ignition is doing. im leaning toward a faulty coil. ideas -- steve w. just because you put a fuel pump on it means nothing especially if it was an after market one. what is the fuel pressure reading glenn beasley chrysler tech 50 psi. holds that while running and is delivering almost 1/2 liter in 10 seconds. i pulled and cleaned the injectors and checked the spray patterns. also flushed the rail and the tank line. -- cam and crank in sync steve w. yep. i am wondering if it isnt related to the p1606 buss failure code. except an intermittent failure that isnt setting a code. i would expect that to show up on a data capture but dont see it. scope showed good spark sync and it didnt drop out. -- steve w. .

From : maxpower

maxpower wrote vehicle - 2001 ram 2500 standard cab 5.9 magnum automatic trans 70k problem - engine starts and runs ok. take it for a test drive and once it warms up it will act like the timing goes way off and it runs out of fuel. you can hear it backfiring through the exhaust engines dies down for a couple seconds then it will catch and act like you have the throttle floored for a second then it does it a couple more times. after about 10-30 seconds depends on ambient temperature it will suddenly run fine. it wont do it again until you shut it down and let it set for a few minutes like filling the tank. no current or pending codes. watching the life data showed nothingwhile it was bucking except the timing looked to be dancing a lot. once it settled down the timing followed suit. it has new plugs wires and cap&rotor also a new fuel pump old one failed. will be throwing the scope on it to see what the ignition is doing. im leaning toward a faulty coil. ideas -- steve w. just because you put a fuel pump on it means nothing especially if it was an after market one. what is the fuel pressure reading glenn beasley chrysler tech 50 psi. holds that while running and is delivering almost 1/2 liter in 10 seconds. i pulled and cleaned the injectors and checked the spray patterns. also flushed the rail and the tank line. -- cam and crank in sync steve w. .

From : steve w

john selph wrote the only other things i can think that may cause something like that would be the computer getting faulty input. how is the o2 sensor oh and also check all ground connections. john o2 reads good. so does the post cat sensor. also did a back pressure test and found nothing wrong there. i started going through all the connections today. fun... i figure ill bench test all the sensors as i come to them. since its a minimal pay job fil owns the truck i just work on it in spare time. it is one of the times i wish i had a full parts room in the back... -- steve w. .

From : steve w

maxpower wrote vehicle - 2001 ram 2500 standard cab 5.9 magnum automatic trans 70k problem - engine starts and runs ok. take it for a test drive and once it warms up it will act like the timing goes way off and it runs out of fuel. you can hear it backfiring through the exhaust engines dies down for a couple seconds then it will catch and act like you have the throttle floored for a second then it does it a couple more times. after about 10-30 seconds depends on ambient temperature it will suddenly run fine. it wont do it again until you shut it down and let it set for a few minutes like filling the tank. no current or pending codes. watching the life data showed nothing while it was bucking except the timing looked to be dancing a lot. once it settled down the timing followed suit. it has new plugs wires and cap&rotor also a new fuel pump old one failed. will be throwing the scope on it to see what the ignition is doing. im leaning toward a faulty coil. ideas -- steve w. just because you put a fuel pump on it means nothing especially if it was an after market one. what is the fuel pressure reading glenn beasley chrysler tech 50 psi. holds that while running and is delivering almost 1/2 liter in 10 seconds. i pulled and cleaned the injectors and checked the spray patterns. also flushed the rail and the tank line. -- steve w. .

From : john selph

the only other things i can think that may cause something like that would be the computer getting faulty input. how is the o2 sensor oh and also check all ground connections. john john selph wrote was it acting this way before the parts were changed out does the rotor have a resistor in it - if so put the old one back in and see if that solves the problem. john yes. it was acting up and the owner changed out the plugs and such. the fuel pump was changed out when he bought it died on the lot! ill have to see if he has the old parts. the current rotor doesnt have a resistor that i can see. vehicle - 2001 ram 2500 standard cab 5.9 magnum automatic trans 70k problem - engine starts and runs ok. take it for a test drive and once it warms up it will act like the timing goes way off and it runs out of fuel. you can hear it backfiring through the exhaust engines dies down for a couple seconds then it will catch and act like you have the throttle floored for a second then it does it a couple more times. after about 10-30 seconds depends on ambient temperature it will suddenly run fine. it wont do it again until you shut it down and let it set for a few minutes like filling the tank. no current or pending codes. watching the life data showed nothing while it was bucking except the timing looked to be dancing a lot. once it settled down the timing followed suit. it has new plugs wires and cap&rotor also a new fuel pump old one failed. will be throwing the scope on it to see what the ignition is doing. im leaning toward a faulty coil. ideas -- steve w. .

From : maxpower

vehicle - 2001 ram 2500 standard cab 5.9 magnum automatic trans 70k problem - engine starts and runs ok. take it for a test drive and once it warms up it will act like the timing goes way off and it runs out of fuel. you can hear it backfiring through the exhaust engines dies down for a couple seconds then it will catch and act like you have the throttle floored for a second then it does it a couple more times. after about 10-30 seconds depends on ambient temperature it will suddenly run fine. it wont do it again until you shut it down and let it set for a few minutes like filling the tank. no current or pending codes. watching the life data showed nothing while it was bucking except the timing looked to be dancing a lot. once it settled down the timing followed suit. it has new plugs wires and cap&rotor also a new fuel pump old one failed. will be throwing the scope on it to see what the ignition is doing. im leaning toward a faulty coil. ideas -- steve w. just because you put a fuel pump on it means nothing especially if it was an after market one. what is the fuel pressure reading glenn beasley chrysler tech .

From : steve w

john selph wrote was it acting this way before the parts were changed out does the rotor have a resistor in it - if so put the old one back in and see if that solves the problem. john yes. it was acting up and the owner changed out the plugs and such. the fuel pump was changed out when he bought it died on the lot! ill have to see if he has the old parts. the current rotor doesnt have a resistor that i can see. vehicle - 2001 ram 2500 standard cab 5.9 magnum automatic trans 70k problem - engine starts and runs ok. take it for a test drive and once it warms up it will act like the timing goes way off and it runs out of fuel. you can hear it backfiring through the exhaust engines dies down for a couple seconds then it will catch and act like you have the throttle floored for a second then it does it a couple more times. after about 10-30 seconds depends on ambient temperature it will suddenly run fine. it wont do it again until you shut it down and let it set for a few minutes like filling the tank. no current or pending codes. watching the life data showed nothing while it was bucking except the timing looked to be dancing a lot. once it settled down the timing followed suit. it has new plugs wires and cap&rotor also a new fuel pump old one failed. will be throwing the scope on it to see what the ignition is doing. im leaning toward a faulty coil. ideas -- steve w. .

From : john selph

was it acting this way before the parts were changed out does the rotor have a resistor in it - if so put the old one back in and see if that solves the problem. john vehicle - 2001 ram 2500 standard cab 5.9 magnum automatic trans 70k problem - engine starts and runs ok. take it for a test drive and once it warms up it will act like the timing goes way off and it runs out of fuel. you can hear it backfiring through the exhaust engines dies down for a couple seconds then it will catch and act like you have the throttle floored for a second then it does it a couple more times. after about 10-30 seconds depends on ambient temperature it will suddenly run fine. it wont do it again until you shut it down and let it set for a few minutes like filling the tank. no current or pending codes. watching the life data showed nothing while it was bucking except the timing looked to be dancing a lot. once it settled down the timing followed suit. it has new plugs wires and cap&rotor also a new fuel pump old one failed. will be throwing the scope on it to see what the ignition is doing. im leaning toward a faulty coil. ideas -- steve w. .