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Unbelievable fuel pressure question?

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Old 04-18-2007, 05:39 PM
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Unbelievable fuel pressure question?

ok here goes, my brother in-law has an 06 and he has been having some issues with it. when I asked what was his fuel pressure was he told me that the mechanic told him it was between 140 and 150 psi , I said no way that is not right, in tank pump at most 10 -15psi he would not believe me no matter what I said, including that the FASS and walboro pump are tuned to put out less then 50psi for our trucks, I'm I wrong? He got the flywheel fix a couple days ago and he inquired about the fuel pressure and again they told him it's at 140 -150 psi and was told thats what 06 and up run at. I call bull. So have they change the pump or are they pulling his leg?
Old 04-18-2007, 06:06 PM
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From the tank to the CP3 anything from 0 to 15 is normal, not necessarily good but normal. Usually they run 5-15 depending on load. Now on the high pressure side it goes from 10000 lbs up to 26000 or so. That is on the common rail engine, that is why on the newer common rails you "DO NOT WANT TO CRACK A LINE AS IT CAN BE EXTREMELY DANGERIOUS OR A THREAT TO LIFE AND LIMB". So it depends on where you want to know what the pressure is and where it is, before the CP3 or after.
Old 04-18-2007, 06:17 PM
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agreed, but he(the mechanic not bilw) is claiming the pressure from the lift pump before cp3 is between 140 to 150psi and get this they are saying it is failing.
Old 04-18-2007, 06:27 PM
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That's why I avoid the dealership like the plague. Not all, but alot of the mechanics are braindead...
Old 04-18-2007, 07:05 PM
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Who wants to bet it's 14-15psi and the guy can't read a gauge?
Old 04-18-2007, 07:15 PM
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Originally Posted by jrussell
Who wants to bet it's 14-15psi and the guy can't read a gauge?
Yep the decimal point does matter some times.
Old 04-18-2007, 11:32 PM
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On an 06 it shouldn't even be at 14-15 if stock. These intake pumps have a hard time putting out 10psi.
Old 04-19-2007, 09:13 AM
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Originally Posted by 95ram
On an 06 it shouldn't even be at 14-15 if stock. These intake pumps have a hard time putting out 10psi.
Yup. My 06 has put out 10psi or less since i first put the gauges on at around 10k miles.
Old 04-19-2007, 10:04 AM
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Originally Posted by jrussell
Who wants to bet it's 14-15psi and the guy can't read a gauge?
I asked about that and I still got the answer 140 -150psi. and converting it to kpa doesn't help either. So either the mechanic has no clue on how to operate the testing equipment or does not know how to read the numbers(scale). even if it's ditigal .

thanks for the replies now I have more ammo in trying to tell my brother inlaw someone is feeding him a good plate of bul.....
Old 04-19-2007, 10:40 AM
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The only place that has those types of pressures are some pre-chambers in the cp3 before it's squeezed to higher pressures. And I don't believe there's any way to measure that location....?
Old 04-19-2007, 01:10 PM
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Originally Posted by GreyTD
I asked about that and I still got the answer 140 -150psi. and converting it to kpa doesn't help either. So either the mechanic has no clue on how to operate the testing equipment or does not know how to read the numbers(scale). even if it's ditigal .

thanks for the replies now I have more ammo in trying to tell my brother inlaw someone is feeding him a good plate of bul.....
Dude, he abviously knows NADA/ZILCH/NOTHING about a diesel, he is talking about a HEMI..........................................YEAH !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Old 04-19-2007, 02:48 PM
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My 2006 is right at 10-11psi fuel pressure. I would go to the repair manual and print the mechanic out the couple pages that are associated to testing both the in-tank pump (pre-cp3) and the cp3 itself. You could even print out the test for the common rail itelf. I alo would highlight the pressures so that this mechanic gets it. In fact, I would go to the dealership owner and ask him/her if they wanted to have a good laugh at the expense of their mechanic - then hold the conversation again regarding pressures, then explain why it is you are having problems having any confidence in the work you are having done. When this idiot spewed out the 140-150 numbers I would challeng that with the correct info I was holing in my hand. I would bet one of two things will happen, either they will start getting things correct or on track OR you will be moving on to another dealership.

CD
Old 04-19-2007, 02:53 PM
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Originally Posted by PEAKSTRYDE
Dude, he abviously knows NADA/ZILCH/NOTHING about a diesel, he is talking about a HEMI..........................................YEAH !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Does the Hemi really run that high?

I guess the mechanic is busted if that's the case. Probably never checked it and then just lied when asked.
Old 04-19-2007, 05:45 PM
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Originally Posted by GreyTD
I asked about that and I still got the answer 140 -150psi. and converting it to kpa doesn't help either. So either the mechanic has no clue on how to operate the testing equipment or does not know how to read the numbers(scale). even if it's ditigal .

thanks for the replies now I have more ammo in trying to tell my brother inlaw someone is feeding him a good plate of bul.....
Don't feel bad, the head diesel mech at my local dealership told me the return line from the hydrobooster was actually a "vacuum" line. He said "you gots vacuum all over this motah" (2004 5.9 HO)...sigh. I wouldn't let a dealer mech touch my truck (now I know they aren't all this dumb, but enough of them are to make you not sure who's working on your truck).



140-150 psi of fuel pressure? I'm sorry but that idiot should be fired, because he is either a liar AND stupid, or he is just plain stupid, either way he sounds like a liability to the dealership.
Old 04-20-2007, 12:34 AM
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Originally Posted by CD in NM
My 2006 is right at 10-11psi fuel pressure. I would go to the repair manual and print the mechanic out the couple pages that are associated to testing both the in-tank pump (pre-cp3) and the cp3 itself. You could even print out the test for the common rail itelf. I alo would highlight the pressures so that this mechanic gets it. In fact, I would go to the dealership owner and ask him/her if they wanted to have a good laugh at the expense of their mechanic - then hold the conversation again regarding pressures, then explain why it is you are having problems having any confidence in the work you are having done. When this idiot spewed out the 140-150 numbers I would challeng that with the correct info I was holing in my hand. I would bet one of two things will happen, either they will start getting things correct or on track OR you will be moving on to another dealership.

CD

What are your cruising numbers. My guages have been on since 1800 miles and I've never seen anyting over 8psi. It may not seem like a lot, but in reality 2psi is. I want the extra 2 psi.
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