need help: 6.5 problems
#11
04-22-2012, 01:24 PM
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no codes at this time. still getting sts light when in on position.
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No go on disconnecting sensors. about to try checking connector voltage of fsd.
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I'm a plagiarizer. I got this from a friend of a friend (I have 6.5 problems also) but fits your symptoms. It is a real similar theory to the large industrial engines I work on daily. Hope it helps. I think you tried almost everything.
The following comes from CarQuest:
This tip applies to the 1994 and newer version that has the computer controlled diesel fuel injection system. Thankfully,this system is not nearly as complicated as some other systems being used. This means that there are a few quick checks that any technician can perform in order to determine why there's a no-start condition.The computer in this system uses two
sensors to determine engine rotation.
These sensors are in two locations. The first sensor is an optical sensor which is located inside of the injection pump. This sensor produces two signals which are identical to the signals generated by an optical distributor in gasoline powered engines. One signal is relatively slow, producing eight signal pulses per revolution of the pump shaft, or, one for each cylinder.
One of these signal pulses is longer than the other seven in order for the computer to identify cylinder #1. The second signal is a much faster signal, producing512 signal pulses per pump shaft revolution. This sensor also contains a fuel temperature sensor.
The second sensor, the crankshaft position sensor, is a Hall effect type
sensor mounted through the front timing cover which produces four signal
pulses per turn of the crankshaft, or, eight pulses per turn of the pump shaft.
If you run across one of these vehicles that is a "no-start", before you
do any testing, make sure the batteries are fully charged and are in good
condition. The engine must be mechanically sound. The starting
system should be fully operational.
Also, make sure the "Service Engine Soon" light is operational. No light
indicates a power problem to the computer that must be resolved before
going any further. Once you have verified that the light is operational,
make sure there are no trouble codes.
Now that the preliminary steps are out of the way, the first quick check is to
disconnect the optical pickup at the pump. Turn the key on, wait for the
"wait" light to go off. Now crank the engine for approximately 30 seconds. If
the engine starts, the most likely cause of the no start is probably an erratic optical sensor signal, as the computer was able to run the engine based solely on the input of the crankshaft position sensor.
If it does not start, reconnect the optical sensor and disconnect the crankshaft sensor. Repeat the starting procedure as before. If the vehicle starts, the problem again is an erratic crank signal. Keep in mind that a signal that is completely missing from one of the sensors will not cause a no start condition,simply because it relies upon input from the other sensor.
When this happens, it operates in "back up" strategy. In a situation where
an erratic signal is present, the computer becomes confused, resulting in a no
start. If disconnecting the sensors does not yield any result, make sure there's available fuel at the pump. Also, check to see if there's an injection command from the fuel solenoid driver (this will usually trip a fault code 35 or 36). If not, make sure there is a command from the computer to the driver. You can do this by making sure there's at least 1.2 volts DC at terminal "A" of the fuel solenoid driver while cranking. If not, check for battery voltage at terminal C of the driver harness connector with the key "on". If all checks are good, the pump itself needs to be checked. If you determine that the computer requires replacement, you must program the "TDC offset" into the new computer. This process electronically compensates for minor timing differences between the injection pump and the crankshaft. The vehicle must be at operating temperature and at idle.
The following comes from CarQuest:
This tip applies to the 1994 and newer version that has the computer controlled diesel fuel injection system. Thankfully,this system is not nearly as complicated as some other systems being used. This means that there are a few quick checks that any technician can perform in order to determine why there's a no-start condition.The computer in this system uses two
sensors to determine engine rotation.
These sensors are in two locations. The first sensor is an optical sensor which is located inside of the injection pump. This sensor produces two signals which are identical to the signals generated by an optical distributor in gasoline powered engines. One signal is relatively slow, producing eight signal pulses per revolution of the pump shaft, or, one for each cylinder.
One of these signal pulses is longer than the other seven in order for the computer to identify cylinder #1. The second signal is a much faster signal, producing512 signal pulses per pump shaft revolution. This sensor also contains a fuel temperature sensor.
The second sensor, the crankshaft position sensor, is a Hall effect type
sensor mounted through the front timing cover which produces four signal
pulses per turn of the crankshaft, or, eight pulses per turn of the pump shaft.
If you run across one of these vehicles that is a "no-start", before you
do any testing, make sure the batteries are fully charged and are in good
condition. The engine must be mechanically sound. The starting
system should be fully operational.
Also, make sure the "Service Engine Soon" light is operational. No light
indicates a power problem to the computer that must be resolved before
going any further. Once you have verified that the light is operational,
make sure there are no trouble codes.
Now that the preliminary steps are out of the way, the first quick check is to
disconnect the optical pickup at the pump. Turn the key on, wait for the
"wait" light to go off. Now crank the engine for approximately 30 seconds. If
the engine starts, the most likely cause of the no start is probably an erratic optical sensor signal, as the computer was able to run the engine based solely on the input of the crankshaft position sensor.
If it does not start, reconnect the optical sensor and disconnect the crankshaft sensor. Repeat the starting procedure as before. If the vehicle starts, the problem again is an erratic crank signal. Keep in mind that a signal that is completely missing from one of the sensors will not cause a no start condition,simply because it relies upon input from the other sensor.
When this happens, it operates in "back up" strategy. In a situation where
an erratic signal is present, the computer becomes confused, resulting in a no
start. If disconnecting the sensors does not yield any result, make sure there's available fuel at the pump. Also, check to see if there's an injection command from the fuel solenoid driver (this will usually trip a fault code 35 or 36). If not, make sure there is a command from the computer to the driver. You can do this by making sure there's at least 1.2 volts DC at terminal "A" of the fuel solenoid driver while cranking. If not, check for battery voltage at terminal C of the driver harness connector with the key "on". If all checks are good, the pump itself needs to be checked. If you determine that the computer requires replacement, you must program the "TDC offset" into the new computer. This process electronically compensates for minor timing differences between the injection pump and the crankshaft. The vehicle must be at operating temperature and at idle.
Last edited by leverguy3030; 04-22-2012 at 01:24 PM. Reason: Automerged Doublepost
#12
04-22-2012, 03:10 PM
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I'm not totally familiar with this system so I might be talking out of my rear end here.
No codes and the service light on is troublesome. if you unplugged the optical sensor and tried with a no start then hooked it back up and unplugged the crank sensor tried again with a no start. You should have logged code 17, and/or 36 or some other code.
I looked back in the thread and don't see anything about the oil pressure switch. I have read that it can cause issues resembling a bad PMD by not allowing the LP to turn on or causing it to run intermittently. I have seen a lot of that in other brand engines. It might be worth bypassing and trying again.
If I was in your shoes I would start over put on your lab coat. Break the system down into sections and verify everything again. Ask "What did I change just before it quit running?" If you have any smoke at all go old school and break lose an injector line and see if you get fuel at the injector when you crank the engine. bubbles=fuel supply. nothing=pump/pump control, fuel supply, good fuel flow=
possible engine damage.
Fuel supply-spec 4 PSI checked at water drain valve with LP on. What about fuel quality?
Electrical-power and grounds does everything have what it needs? Remember you have been abusing the snot out of your starter and batteries whit this no start condition. Most 12V components go to sleep about 10V so if your starter is drawing high amps the system might be off when you need it the most.
Components- new used reconditioned a working component yesterday might not today. swapping a known good or just a different one may help. Do the symptoms change?
Wiring-This is where the work begins. You can have a bad connection on the plugs you have been working with and back-probing. Remember that blue flash and click when you were standing on your head? Check fuses. Wiring rarely gets rubbed where you can see it or feel it. Did the last guy tie down the harness after the trans swap or whatever. Probably not. check and recheck.
MECHANICAL- We have to go here now. If I read correctly the last time this engine ran it was in a overspeed condition followed by rough idle and now throttle response. Did you look at the tachometer? I'm not sure how high a 6.5 will rev and survive if it was much more than 4250 I would worry. What about smoke? Gray thick smoke may indicate timing or lack of compression due to real pump or engine damage. Black smoke in this case would indicate over fueling due to pump/electronics assuming air system is good. No smoke is back to fuel supply, pump, electronics.
These are basic trouble shooting tips I use every day. Just remember you engine is a mechanical device under that electronic gizmo. good luck
No codes and the service light on is troublesome. if you unplugged the optical sensor and tried with a no start then hooked it back up and unplugged the crank sensor tried again with a no start. You should have logged code 17, and/or 36 or some other code.
I looked back in the thread and don't see anything about the oil pressure switch. I have read that it can cause issues resembling a bad PMD by not allowing the LP to turn on or causing it to run intermittently. I have seen a lot of that in other brand engines. It might be worth bypassing and trying again.
If I was in your shoes I would start over put on your lab coat. Break the system down into sections and verify everything again. Ask "What did I change just before it quit running?" If you have any smoke at all go old school and break lose an injector line and see if you get fuel at the injector when you crank the engine. bubbles=fuel supply. nothing=pump/pump control, fuel supply, good fuel flow=
possible engine damage. Fuel supply-spec 4 PSI checked at water drain valve with LP on. What about fuel quality?
Electrical-power and grounds does everything have what it needs? Remember you have been abusing the snot out of your starter and batteries whit this no start condition. Most 12V components go to sleep about 10V so if your starter is drawing high amps the system might be off when you need it the most.
Components- new used reconditioned a working component yesterday might not today. swapping a known good or just a different one may help. Do the symptoms change?
Wiring-This is where the work begins. You can have a bad connection on the plugs you have been working with and back-probing. Remember that blue flash and click when you were standing on your head? Check fuses. Wiring rarely gets rubbed where you can see it or feel it. Did the last guy tie down the harness after the trans swap or whatever. Probably not. check and recheck.
MECHANICAL- We have to go here now. If I read correctly the last time this engine ran it was in a overspeed condition followed by rough idle and now throttle response. Did you look at the tachometer? I'm not sure how high a 6.5 will rev and survive if it was much more than 4250 I would worry. What about smoke? Gray thick smoke may indicate timing or lack of compression due to real pump or engine damage. Black smoke in this case would indicate over fueling due to pump/electronics assuming air system is good. No smoke is back to fuel supply, pump, electronics.
These are basic trouble shooting tips I use every day. Just remember you engine is a mechanical device under that electronic gizmo. good luck
#13
04-22-2012, 03:52 PM
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#14
04-22-2012, 04:05 PM
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I'm not absolutely sure but it should be in the valley under the fuel filter. you should be able to unbolt the filter with the hoses still connected to reach it. I'm not close to my rig or I would check. I believe this is a normally closed switch so you will have to use a jumper wire. with the key on the pump under the truck should turn on with it bypassed.
#15
04-22-2012, 06:21 PM
#16
04-22-2012, 06:30 PM
Diesel Enthusiast
OPS is in the rear of the valley on my truck, and of course it had a problem, so I wired the LP so it runs with ignition on. I've heard rumor this may cause hard starting, hence the reason it went through an OPS from the factory. Interestingly enough, I've had no trouble at all with mine being bypassed.
#18
04-23-2012, 11:19 AM
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haven't gotten to test ops yet. gotta deal with this crazy thing called 'working for a living'. in the mean time though, i was wondering about the tps. to my knowledge, this truck does not have a traditional tps, because of the apps. is this correct? also, i have heard that if the apps fails, it fails into idol. if so, does it have to be this way 100% of the time. is it POSSIBLE to fail, and have a runaway condition like mine had, and then cause 'no start'.
also, i am an electrician, and so i tend to think about things that i see in the AC world, although i know there are some differences. i was wondering, if when i ran the truck for so long with out an alternator, if because of the current increase, that maybe i fried some part of the pcm? if resistance stays constant, and voltage goes down, then current goes up. also, if i did manage to do that, SHOULD i get a trouble code? every time? or only in certain instances?
oh yeah, another thing - anyone ever heard of a faulty pmd causing a runaway condtion? then no start? not just yes in theory, but actually heard someone talk about having it happen, or happened to your self?
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i don't believe i ever reached that high of rpm. it all happened so fast, but i'm thinkin mid 3's.
also, i am an electrician, and so i tend to think about things that i see in the AC world, although i know there are some differences. i was wondering, if when i ran the truck for so long with out an alternator, if because of the current increase, that maybe i fried some part of the pcm? if resistance stays constant, and voltage goes down, then current goes up. also, if i did manage to do that, SHOULD i get a trouble code? every time? or only in certain instances?
oh yeah, another thing - anyone ever heard of a faulty pmd causing a runaway condtion? then no start? not just yes in theory, but actually heard someone talk about having it happen, or happened to your self?
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MECHANICAL- We have to go here now. If I read correctly the last time this engine ran it was in a overspeed condition followed by rough idle and now throttle response. Did you look at the tachometer? I'm not sure how high a 6.5 will rev and survive if it was much more than 4250 I would worry. What about smoke? Gray thick smoke may indicate timing or lack of compression due to real pump or engine damage. Black smoke in this case would indicate over fueling due to pump/electronics assuming air system is good. No smoke is back to fuel supply, pump, electronics.
These are basic trouble shooting tips I use every day. Just remember you engine is a mechanical device under that electronic gizmo. good luck
These are basic trouble shooting tips I use every day. Just remember you engine is a mechanical device under that electronic gizmo. good luck
Last edited by leverguy3030; 04-23-2012 at 11:23 AM. Reason: Automerged Doublepost
#19
04-23-2012, 10:46 PM
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The main reason for the OPS in the fuel pump power feed is a safety to shut off fuel flow in an accident/rollover and secondary to shut engine down if oil pressure is lost thus protecting the engine from lack of lube damage. Unfortunately the OPS is the week link in just about every brand engine I've worked on. I'm not sure why it would cause a hard starting problem.
As far as electric theory. All laws of electricity apply.... But there is a certain amount of FM (friggin magic) involved in this system. Remember you have digital and analogue inputs/outputs to several processors. This system is old and dumb with limited self diagnostics compared to today's control systems. I agree the engine should start and idle with a open TPS. I guess we overlooked the possibility of a bad kill solenoid also with all the other symptoms.
As far as electric theory. All laws of electricity apply.... But there is a certain amount of FM (friggin magic) involved in this system. Remember you have digital and analogue inputs/outputs to several processors. This system is old and dumb with limited self diagnostics compared to today's control systems. I agree the engine should start and idle with a open TPS. I guess we overlooked the possibility of a bad kill solenoid also with all the other symptoms.
Last edited by wyowrench; 04-23-2012 at 11:12 PM. Reason: missed leverguys3030s update.
#20
04-24-2012, 08:03 AM
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