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04.5 runs bad then runs normal

1252 Views 12 Replies 2 Participants Last post by  DODGEOUTLAW, 
DODGEOUTLAW
this started Thursday of last week on my way home from work, i went to pass someone on the highway and my truck was a slug. it acted like it didn't have any power at all. my fuel rail gauge would drop to 3-5000 when i get on it, and then shoot up to 25000+ when i let off. Also getting the code p0148(fuel delivery error). This is easily controllable with driving technique though, and i made it home.

i did my research, and on Friday morning went through the basics with a sluggish symptom - first with replacing my fuel filter(old one was still clean) and blew out my air filter. - that wasn't it.

Saturday, i returned my bullydog to stock(usually keep it on tow and performance) and after that my truck ran fine, like nothing ever was wrong.

I didn't drive yesterday at all, i got up this morning to make a trip from Amarillo to KC - as i was getting on the highway my truck had the same symptoms from before, sluggish and no power. So i dont think it was the bullydog causing it. I unplugged my gauges(specifically my fuel rail pres) and also unhooked and hooked back up my batteries and my truck is running fine again. What the heck!!

So i just drove from amarillo to my shop at work(hour drive) and my truck ran fine the whole way. im just spooked to start an 8 hour drive to kansas knowing that my truck has been running goofy.

From my research, everyone says to replace the FCA, high pressure rail valve and/or rail pressure sensor. But if one of these was bad wouldnt my truck run bad continuously until i replaced it? I just hate to replace all those expensive parts and that not be it.

Do yall think i may just have bad fuel?

Also, running an airdog 150 that was installed may of this year.

thanks in advance
chad
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motormilitia
Do you have a lift pump pressure gauge? If so what's that look like?
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DODGEOUTLAW
motormilitia said:
Do you have a lift pump pressure gauge? If so what's that look like?
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No I don't, just fuel rail.
I didn't think it would be my lift pump if it doesn't do it all the time.

Thinking possible fuel gelling? It's been in the teens and snowing the past few days.
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DODGEOUTLAW
Update, I plugged my gauges back in and the truck runs normal with them.

So unplugging then earlier was not the mystery fix.
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motormilitia
If it's gelling, It should clear up some as fuel heats up unless it clogs filter. If your filter looks good I'd rule out gelling. Electrical sensor or wiring gremlin sounds likely. FCA would be my start since your pressure is going whacky. Try unplugging it and checking rail perssure?
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DODGEOUTLAW
motormilitia said:
FCA would be my start since your pressure is going whacky. Try unplugging it and checking rail perssure?
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With my truck running?
When I unplug it what should my rail pressure read?
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motormilitia
Should max out when unplugged. Few good threads on this too, like this one:
http://www.cumminsforum.com/forum/3rd-gen-powertrain/322599-unplug-fca.html
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DODGEOUTLAW
Max out if its bad or still good?


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motormilitia
Unplug it, start truck and watch gauge. Should make somewhere around 20k if it's good. Shut it off once pressure levels out.
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DODGEOUTLAW
motormilitia said:
Unplug it, start truck and watch gauge. Should make somewhere around 20k if it's good. Shut it off once pressure levels out.
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It went straight to 30k...new FCA?
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motormilitia
Not necessarily. I'm not sure there's a way to definitively rule an FCA good or bad. Sounds like its regulating pressure at idle (pressure only spikes with it unplugged), which it's supposed to do. You can try taking it out and shaking it to see if it "rattles". replacing it is about the only way to make sure you have a good one as far as I know. You can also try checking all electrical connections.
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motormilitia
Rattle = good BTW if you try that test.
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DODGEOUTLAW
motormilitia said:
Not necessarily. I'm not sure there's a way to definitively rule an FCA good or bad. Sounds like its regulating pressure at idle (pressure only spikes with it unplugged), which it's supposed to do. You can try taking it out and shaking it to see if it "rattles". replacing it is about the only way to make sure you have a good one as far as I know. You can also try checking all electrical connections.
Click to expand...
Well I've gone all over town and couldn't find anyone who keeps an FCA in stock, dodge house said it would be until Wednesday so I'm borrowing a vehicle from a family member for my trip and just deal with that after the holiday.

My truck did continue to run fine the rest of today, but I just don't want to chance it on a long trip.

Thanks for your help though, I really appreciate it!

Chad


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