[Glueballs]

About a month ago I started the truck ran inside and when I came back out it had died. Tried to restart and no go. After getting off work I started the no start checklist and determined it was FICM voltage when cranking was droping to 30-32V. Ordered up a bulletproof 6phase and installed the next week. No start issue was fixed but the next issue was Battery voltage was dropping too low when cold and resulting in no start and periodic stalls until at operating temp above 150F when FICM cold run program shuts off. I Replaced the batteries with a pair of new Odyssey's and intial voltage issue was gone but just had a stall this morning when temp was 130F. Thinking now maybe alternator belt is sliping. Runs 13.5-14V most of the time now but it had droped to ~12 right before it stalled. I was off throttle approaching a light. Has anyone had anyting simmilar. Would like to figure this out before throwing more money at the issue.

EDIT: No Codes KOEO and KOER are both good. Doesn't sputter or surge just shuts off with battery light on dash engine voltage was ~12V until cranking then droped to 11.5/6

 

[twoicebergs]

The only time you should see less than 13.5v engine running is when the glow-plugs are still on after start (about 12v or greater with good batteries), for about another minute or 2, depending on the temperature. It is time to look at your wiring connectors for corrosion and charge circuit from the alternator. It would not be uncommon for the alternator/regulator to be in need of replacement. Less common would be a GPCM that is staying on.

 

[Glueballs]

The only time you should see less than 13.5v engine running is when the glow-plugs are still on after start (about 12v or greater with good batteries), for about another minute or 2, depending on the temperature. It is time to look at your wiring connectors for corrosion and charge circuit from the alternator. It would not be uncommon for the alternator/regulator to be in need of replacement. Less common would be a GPCM that is staying on.

Thanks for the quick response. I agree that I should not be dropping below 13.5V. Let me know if any of the info below changes your opinion.

My Normal starting sequence voltage wise when cold is. KOEO ~12V with GPCM circuit active. ~11.8V cranking. Once running returns to ~12-12.5V for a minute or two then bumps to 13.5-14V. The issue I'm experiencing is a random voltage drop. It was occurring on my weak batteries and I was assuming it was due to the extra load of the alternator due to the weak batteries. They have now been replaced with Odyssey 65-PC1750's and all connectors were cleaned. (I didn't due neutral grounds on frame will do next when I'm on days off) The Voltage at the alternator is the same as at batteries with engine running. Belt is starting to show age but appears to be in good shape and tension is good. What I was wondering is what is the common failure mode of the alternators. Do the voltage regulators cause an intermittent issue like this one? I have normal voltage 99% of the time so I do not think I lost a pole etc. It does not seem to occur at any specific RPM if we include the instances that occurred prior to replacing the batteries. The only times I've seen something similar were on vehicles with belt slippage under high load but they were gassers and you would only lose accessories. (Radio etc.)

 

[twoicebergs]

If it is randomly dropping out, it is probably the regulator circuit in the alternator. It a could be number of different reason, but in most cases it means buy a new alternator before you get left stranded somewhere.

 

[Glueballs]

That was what I was affraid of. Well I guess I now have the excuse to by the high output one so that I can convert to electic fans eventually.

 

[Glueballs]

Ok truck was Hot was coming down the last straight before the house on the way back from work. Punched it. Everything was looking good on my IPad then when I get off the throttle the voltage starts dropping and she stalls out. This time while trying to restart ICP pressure was really low. Only 1-2MPa while cranking. Unplugged the sensor and it fired up second crank. Just wondering now if a failing ICP sensor could cause a stall condition under these circumstances. I plugged it back in when I was back home and it and the IPR are responding again. Wish the stupid thing would replicate issues.

 

[twoicebergs]

The question is was the lower voltage a result of the IPR/ICP or the ICP dropping as a result of a lost CKP due to PCM dropping out due to low voltage or a short? However, if no short, the batteries should be able to keep the PCM working. What was the IPR doing when it was dying (ICP dropping)? If it is opening then it is electrical of some sort. If it is closing, then the IPR, HPO may be more at fault. Of course, there are lots of things to check in the no start sticky.

 

[Glueballs]

The question is was the lower voltage a result of the IPR/ICP or the ICP dropping as a result of a lost CKP due to PCM dropping out due to low voltage or a short? However, if no short, the batteries should be able to keep the PCM working. What was the IPR doing when it was dying (ICP dropping)? If it is opening then it is electrical of some sort. If it is closing, then the IPR, HPO may be more at fault. Of course, there are lots of things to check in the no start sticky.

Hard to diagnose and drive. But from what I remember ICP/IPR was normal. The engine just quits. I would think it would surge or get injector symptoms if it was HPO system real or fake. I never lose communication to the PCM so it is not failing. The batteries never drop below 11.8 even cranking cold. So I should not be losing the FICM. I didn't have it on the display at the time. But I have my BPD FICM set to 58V and it is always pinned high on the iTSX so I stopped monitoring. One thing I have noticed is shouldn’t PCM voltage and FICM supply voltage be the same? I may start monitoring it as well it was 13.5v and steady last I looked with PCM 13.8-14 fluctuating. I wish it would warm up. No room in the garage and don't want to do the oil cooler until it's +10-15C out. I know how to get it started and how the systems interconnect. I just don't think it is a short based on what I'm seeing. At >11V the engine should stay running I think. I'll try and replicate it some more and see what I can figure out.

EDIT: What do you mean by CKP? Crank Postion Sensor

EDIT2: Update looks like it is HPO system related. Had a simillar situation occur without the truck stalling. IPR was hunting all over the place then lined out. Tonight the Truck stalled out in the same spot(Gremlins?) 2 min from the house. I pulled the ICP sensor and drove in to work. Engine ran fine but I took it easy. Will do some troubleshooting on the sensor tomorrow morning. The injector pressure that the PCM sees when the sensor is unplugged is that strictly calculated. If so it is awfull precise. Other than bottoming out at 6MPa it is pretty close to normal values and IPR output.