12 Valve 2nd Gen Dodge Cummins 94-98 Discussion of 12 Valve 5.9 Liter Dodge Cummins Diesels with P7100 Injection Pumps

12V is suddenly way down on power. Need help...

  #1  
Old 04-18-2019, 08:46 PM
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Default 12V is suddenly way down on power. Need help...

Been a while since I've been around. My 98 2500 CTD with 235k miles has been running well...until recently. Suddenly it's way down on power. Way down. I'd been meaning to install a gauge cluster in preparation to turning up the boost a bit. Now that it's down on power, I installed a mechanical boost gauge. Here's what I'm dealing with:
  • 0 psi boost at idle.
  • 7 psi boost at wide open throttle
  • No black smoke
  • Engine runs very smoothly, just no power
  • No hard starting
  • Pinched off the line to the wastegate temporarily, no change to boost numbers.
  • Built a pressure tester and confirmed that the boost lines and intercooler hold 25 psi with no leaks
.
I still have the stock fuel pump and was not planning to install a fuel pressure gauge since it's a 12V.

I'm thinking the engine itself is healthy. Burns no oil and runs very smoothly. Based on what I've read, I'm thinking that I have a turbo problem, a wastegate problem or a fueling problem. Since pinching the wastegate line does not change the boost, wouldn't that point to a wastegate problem? Also, if my fuel system was functioning correctly, I thought I should have lots of black smoke if my boost is down. However, most folks who have fuel problems seem to have rough running too. My 12V is still very smooth.

If anyone has any ideas about where to start, I'd really appreciate it.

Thanks...Boatman1
 
  #2  
Old 04-19-2019, 11:16 PM
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Check the line from the head to the AFC housing on the injection pump. This line needs to be fully intact and free of obstructions. If it is broken, pinched, or clogged then your injection pump doesnít have a boost signal. This impacts fueling which would impact everything.

Thatís a possibility. There are dozens others. But itís the first that I would check based on whatís been said.

What work has been done to the truck so far?


Originally Posted by Boatman1 View Post
Been a while since I've been around. My 98 2500 CTD with 235k miles has been running well...until recently. Suddenly it's way down on power. Way down. I'd been meaning to install a gauge cluster in preparation to turning up the boost a bit. Now that it's down on power, I installed a mechanical boost gauge. Here's what I'm dealing with:
  • 0 psi boost at idle.
  • 7 psi boost at wide open throttle
  • No black smoke
  • Engine runs very smoothly, just no power
  • No hard starting
  • Pinched off the line to the wastegate temporarily, no change to boost numbers.
  • Built a pressure tester and confirmed that the boost lines and intercooler hold 25 psi with no leaks
.
I still have the stock fuel pump and was not planning to install a fuel pressure gauge since it's a 12V.

I'm thinking the engine itself is healthy. Burns no oil and runs very smoothly. Based on what I've read, I'm thinking that I have a turbo problem, a wastegate problem or a fueling problem. Since pinching the wastegate line does not change the boost, wouldn't that point to a wastegate problem? Also, if my fuel system was functioning correctly, I thought I should have lots of black smoke if my boost is down. However, most folks who have fuel problems seem to have rough running too. My 12V is still very smooth.

If anyone has any ideas about where to start, I'd really appreciate it.

Thanks...Boatman1
 
  #3  
Old 04-20-2019, 11:41 AM
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Crawler - Thanks for the reply. Will check that line first. No mods on the truck yet. Owned if for about 7 years and put 35K miles on it. Taken care of lots of maintenance items though. Will let you know what I find.

Bioatman1
 

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