Let me begin by saying that I know it can be next to impossible to accurately "internet diagnose/troubleshoot" an issue, so by no means am I looking for or expecting someone with the wave of a computer mouse to fix my issue. Just looking for some alternative insight, experiences, and ideas.
I'll try to provide all possibly relative information, this may be a bit lengthy.
The truck has been perfectly good for the last couple years. Randomly however over the last couple of years the radio would just turn off for no reason. Sometimes it would come back on in a minute or two, sometimes it would take a lot longer, or not until the next day. This only happened maybe 3-4 times over the last 2-3 years, so admittedly I never made it much of a priority to pursue. Now, also possibly relative, from time to time after a hard rain I would notice a "wet" smell inside the cab, occasionally have condensation on the inside of the windshield, and a few times found a little water on the passenger side in the "track" under the rubber door molding. Again, it didn't happen every time it rained, and since there were no other obvious issues, I didn't make it a big priority.
Now, about two weeks ago a buddy of mine needed to borrow the truck to use so that he could tear into his '05 6.0 to do some fixes and mods, so he's been using my truck.
His driveway is at an incline, and he's been backing it in, so the front of the truck has been pointing down hill. I mention this because I think it may be relative.
So, a few days ago he started the truck to move it around in the driveway and it started fine, but then after a minute or two he says the RPM's started dropping and then it shut off. Since then, it won't start. It cranks but won't start. Oil level is full.
First thought was CPS, so I swapped that with a new spare I keep in the truck. No change.
Next thought was maybe the IPR. Disconnected the IPR which I understand will cause the truck to default to a 700psi reading. No change, still cranks but no start.
Next thought was the ICP. Now, ICP is "somewhat" new. About two years ago I had a HPOP failure, which I replaced/upgraded with a T500. When I installed the T500 I also installed a new ICP sensor. However, to test, disconnected the ICP, no change.
Since this was an easy/quick thing to try, next I swapped the starter and glow plug relays with each other. Now, here's where it gets a little more weird. Both are NAPA GPR 109 or 110 relays. After swapping them, still crank but no start situation. But, this time, the relay installed at the glow plug relay position get's REALLY hot, to the point of even starting to smell it a little. Even turning the key off doesn't stop it from heating up. Key off, key completely out the ignition and the truck is acting like the key is on. Relays buzzing, etc. So, I disconnect the batteries, remove both relays. Unfortunately, by this time in the evening NAPA was closed, so I go to Advance Auto and get two new relays. I know, not the best choice/quality part, but I'll address that once the truck is firing again. So, put the two new relays on, reconnect the batteries, same thing, cranks but no start.
Next thought is maybe a bad chip. Truck has a DP Tuner F5 installed. So I pull the chip out the PCM and then try to start. Again, no change. So I put the chip back in.
Admittedly this should have been one of the first steps, but at this point we grab my buddies top of the line Matco scanner and hook it up to the OBD port. Interestingly it can't establish a connection to the PCM. So, I grab my el cheapo eBay Bluetooth OBD adapter that I use with the Torque app on my phone that I know for sure has worked on my truck before....same thing, can't establish a connection to the PCM. Now, during all this the WTS (Wait To Start) light has been coming on when turning the key on to the run position. I've read that if the PCM is bad or not getting power, there will be no WTS light, but if there is a WTS light, the PCM is at least getting power. Doesn't mean it couldn't still be bad I suppose though. Also, during all this the RPM's have been between 500 and 750 when cranking, but the oil pressure gauge has not moved. Full tank of fuel, no smoke at all when cranking.
Now, this is where we left it Friday night as we ran out of daylight. We had hooked jumper cables up to the battery from another vehicle in between all of these multiple crank attempts, so when we stopped Friday night the batteries still were adequately charged and would turn the truck over fine. I couldn't get over there today (Saturday) to mess with it further, but when my buddy got back home this evening he had to grab something out of the truck and he said the batteries were almost completely dead. The dome light would barely illuminate when he opened the door. So, something has been drawing on the system with the ignition off to almost kill the batteries.
Bad PCM - The fact that neither scan tool can see/connect to the PCM makes me kind of think perhaps that could be the problem? But, the presence of the WTS light makes me wonder. Again, I suppose not impossible the PCM could be energizing, but still have a problem. My questions is this, since I'm essentially overwriting any programming in the PCM with the DP Tuner F5, if I pick up a used/replacement PCM to swap in, does it have to been the exact same PCM code, or as long as it's from the same year or close to the same year and not a CA "low emissions"? Is there anything I could check or do to rule out the PCM, or make it the less likely cause?
Bad GEM - Now, there are a few things that make this seem like a likely cause. The water in the cab in the past, the radio randomly turning off a few times, and then that my buddy has been parking the truck with the front down hill which would have allowed any recent rain that was leaking into the cab (either from a bad windshield seal or the roof clearance lights) to run down the A-pillar and drip onto the GEM. But, I've read that the GEM has nothing to do with the starting of the truck, just control of lots of various accessories and systems. Again, if I replace the GEM, does it have to be the exact same part, or is there some interchangeability there? Also, does it have to be coded or programmed in any way to the truck? Is there any way to rule it out without actually replacing?
I'm going to try to get back over to his place tomorrow to just spend some time looking the truck over good. I'm going to really examine the fuse box/GEM areas for any obvious signs of water. I'm also going to pull the top plug out of the HPOP and crank the truck. As I understand I should get a stream of oil out if the LPOP is working. However unlikely that may be considering all the other little odd things going on pointing clearly to electrical, it's an easy/quick way to rule out the LPOP from being the problem.
Well, I believe that's pretty much all the info I have at this point and gets the situation up to current.
Again, I'm not expecting someone to definitively tell me exactly what my problem is or what certainly is the failed part. Just wanting to get some ideas, thoughts, or suggestions on where to go from here.
Thanks in advance for taking the time to read and for any responses.
I'll try to provide all possibly relative information, this may be a bit lengthy.
The truck has been perfectly good for the last couple years. Randomly however over the last couple of years the radio would just turn off for no reason. Sometimes it would come back on in a minute or two, sometimes it would take a lot longer, or not until the next day. This only happened maybe 3-4 times over the last 2-3 years, so admittedly I never made it much of a priority to pursue. Now, also possibly relative, from time to time after a hard rain I would notice a "wet" smell inside the cab, occasionally have condensation on the inside of the windshield, and a few times found a little water on the passenger side in the "track" under the rubber door molding. Again, it didn't happen every time it rained, and since there were no other obvious issues, I didn't make it a big priority.
Now, about two weeks ago a buddy of mine needed to borrow the truck to use so that he could tear into his '05 6.0 to do some fixes and mods, so he's been using my truck.
His driveway is at an incline, and he's been backing it in, so the front of the truck has been pointing down hill. I mention this because I think it may be relative.
So, a few days ago he started the truck to move it around in the driveway and it started fine, but then after a minute or two he says the RPM's started dropping and then it shut off. Since then, it won't start. It cranks but won't start. Oil level is full.
First thought was CPS, so I swapped that with a new spare I keep in the truck. No change.
Next thought was maybe the IPR. Disconnected the IPR which I understand will cause the truck to default to a 700psi reading. No change, still cranks but no start.
Next thought was the ICP. Now, ICP is "somewhat" new. About two years ago I had a HPOP failure, which I replaced/upgraded with a T500. When I installed the T500 I also installed a new ICP sensor. However, to test, disconnected the ICP, no change.
Since this was an easy/quick thing to try, next I swapped the starter and glow plug relays with each other. Now, here's where it gets a little more weird. Both are NAPA GPR 109 or 110 relays. After swapping them, still crank but no start situation. But, this time, the relay installed at the glow plug relay position get's REALLY hot, to the point of even starting to smell it a little. Even turning the key off doesn't stop it from heating up. Key off, key completely out the ignition and the truck is acting like the key is on. Relays buzzing, etc. So, I disconnect the batteries, remove both relays. Unfortunately, by this time in the evening NAPA was closed, so I go to Advance Auto and get two new relays. I know, not the best choice/quality part, but I'll address that once the truck is firing again. So, put the two new relays on, reconnect the batteries, same thing, cranks but no start.
Next thought is maybe a bad chip. Truck has a DP Tuner F5 installed. So I pull the chip out the PCM and then try to start. Again, no change. So I put the chip back in.
Admittedly this should have been one of the first steps, but at this point we grab my buddies top of the line Matco scanner and hook it up to the OBD port. Interestingly it can't establish a connection to the PCM. So, I grab my el cheapo eBay Bluetooth OBD adapter that I use with the Torque app on my phone that I know for sure has worked on my truck before....same thing, can't establish a connection to the PCM. Now, during all this the WTS (Wait To Start) light has been coming on when turning the key on to the run position. I've read that if the PCM is bad or not getting power, there will be no WTS light, but if there is a WTS light, the PCM is at least getting power. Doesn't mean it couldn't still be bad I suppose though. Also, during all this the RPM's have been between 500 and 750 when cranking, but the oil pressure gauge has not moved. Full tank of fuel, no smoke at all when cranking.
Now, this is where we left it Friday night as we ran out of daylight. We had hooked jumper cables up to the battery from another vehicle in between all of these multiple crank attempts, so when we stopped Friday night the batteries still were adequately charged and would turn the truck over fine. I couldn't get over there today (Saturday) to mess with it further, but when my buddy got back home this evening he had to grab something out of the truck and he said the batteries were almost completely dead. The dome light would barely illuminate when he opened the door. So, something has been drawing on the system with the ignition off to almost kill the batteries.
Bad PCM - The fact that neither scan tool can see/connect to the PCM makes me kind of think perhaps that could be the problem? But, the presence of the WTS light makes me wonder. Again, I suppose not impossible the PCM could be energizing, but still have a problem. My questions is this, since I'm essentially overwriting any programming in the PCM with the DP Tuner F5, if I pick up a used/replacement PCM to swap in, does it have to been the exact same PCM code, or as long as it's from the same year or close to the same year and not a CA "low emissions"? Is there anything I could check or do to rule out the PCM, or make it the less likely cause?
Bad GEM - Now, there are a few things that make this seem like a likely cause. The water in the cab in the past, the radio randomly turning off a few times, and then that my buddy has been parking the truck with the front down hill which would have allowed any recent rain that was leaking into the cab (either from a bad windshield seal or the roof clearance lights) to run down the A-pillar and drip onto the GEM. But, I've read that the GEM has nothing to do with the starting of the truck, just control of lots of various accessories and systems. Again, if I replace the GEM, does it have to be the exact same part, or is there some interchangeability there? Also, does it have to be coded or programmed in any way to the truck? Is there any way to rule it out without actually replacing?
I'm going to try to get back over to his place tomorrow to just spend some time looking the truck over good. I'm going to really examine the fuse box/GEM areas for any obvious signs of water. I'm also going to pull the top plug out of the HPOP and crank the truck. As I understand I should get a stream of oil out if the LPOP is working. However unlikely that may be considering all the other little odd things going on pointing clearly to electrical, it's an easy/quick way to rule out the LPOP from being the problem.
Well, I believe that's pretty much all the info I have at this point and gets the situation up to current.
Again, I'm not expecting someone to definitively tell me exactly what my problem is or what certainly is the failed part. Just wanting to get some ideas, thoughts, or suggestions on where to go from here.
Thanks in advance for taking the time to read and for any responses.