Fuel Pump or Fuel Leak..?
#1
Fuel Pump or Fuel Leak..?
My truck has had problems starting for over a year now and I've thought that it has been my fuel pump going bad and not pressurizing. I'd always have to turn my key over 2-3 times before actually trying to start it, if I didn't the engine would just turn and turn until it finally started. I just bought a fuel pump today and went to go change it but when I went to release the pressure from the fuel rail nothing came out.. I turned my truck on for a second and turned it off and got a minor release of pressure. Every time I turn the key before starting it I can hear the fuel pump whining (turning on). Does this sound like it's my fuel pump still or maybe I have a leak somewhere between point A and B..
I'd rather not spend the time putting in this fuel pump to find out it's not the problem before checking for a leak if this sounds like the problem (or the money, $220).
Thanks a lot guys, members on DodgeForum have always been helpful and saving me from spending money on labor!
I'd rather not spend the time putting in this fuel pump to find out it's not the problem before checking for a leak if this sounds like the problem (or the money, $220).
Thanks a lot guys, members on DodgeForum have always been helpful and saving me from spending money on labor!
Last edited by Jvello15; 10-06-2009 at 06:36 PM.
#5
you might want to check the fuel pressure at the rail with a gauge. i don't know if you can rent/borrow a gauge or not. even if you do have to buy one, it shouldn't be too much. pressure should be around 49 psi. if you're not getting this, it might be the pump. also think through how the fuel shutdown works, to see if there might be a malfunction there. i've read through it in the past, but don't remember all the pieces. its likely described in the service manual in the merry christmas thread. maybe somebody can describe it.
a leak should be pretty obvious with wet area and smell of gas.
a leak should be pretty obvious with wet area and smell of gas.
#6
Join Date: Jul 2009
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The normal mode of operation of the fuel system is to bleed off pressure after a period of non-use. However, at time of hitting the key to <ON>, the pump will pressurize the system and, it will drop two or more lbs when <OFF> and hold that pressure for a given amount of time while, over longer periods of time of non-use, it will drop to zero psi.
After pressurizing the system, if one were to open the pressure relief valve on the fuel rail (Schrader valve), normal event is to expel gas under pressure. If this is not happening- the pump is not working and should be replaced.
You can check for leaks in the following flow:
-there's a quick disconnect at the pump that attaches to the fuel supply line.
- this line runs along the frame and terminates with another quick disconnect, male end.
- this end mates to a female quick disconnect that is part of the SS braided flex line, just ahead of the frame rail
- from there this flex line goes up into the engine bay terminated with a quick disconnect fitting which mates to the fuel rail inlet.
IF there's a leak, you will find it at any of those points in the above flow. As DHV stated, clearly you would smell it and see it.
After pressurizing the system, if one were to open the pressure relief valve on the fuel rail (Schrader valve), normal event is to expel gas under pressure. If this is not happening- the pump is not working and should be replaced.
You can check for leaks in the following flow:
-there's a quick disconnect at the pump that attaches to the fuel supply line.
- this line runs along the frame and terminates with another quick disconnect, male end.
- this end mates to a female quick disconnect that is part of the SS braided flex line, just ahead of the frame rail
- from there this flex line goes up into the engine bay terminated with a quick disconnect fitting which mates to the fuel rail inlet.
IF there's a leak, you will find it at any of those points in the above flow. As DHV stated, clearly you would smell it and see it.
#7
Well I don't recall ever smelling gas while I've been under my truck.. I know in the past that my service engine light would come on and when I got the codes checked they basically said it was from the gas cap not being on all the way, etc.
Last edited by Jvello15; 10-07-2009 at 09:18 AM.
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#8
The pump will prime until the pressure is detected at the normally required PSI by the regulator , then it shuts off . If thats happening , it could be a simple filter being clogged issue . I'd test the fuel pressure at the rail as suggested above . Easy DIY test with the guage .
Similar slow start issues have been solved by cleaning the connection at the PCM as well .
Similar slow start issues have been solved by cleaning the connection at the PCM as well .