Fuel Pressure Loss Woes
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Professional
Joined: Sep 2010
Posts: 167
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From: New Brunswick Canada
Fuel Pressure Loss Woes
Hopefully I can sum this up without writing a book. This has been going on for 2 years - since I bought the truck.
- Shortly after buying the truck, I started having long crank times to start the truck.
-upon firing up, it kind of stumbles bought does not stall - sounds like it is starving for fuel
- The PO put a new fuel pump in shortly before selling
- CEL all along with evac leak - PO442
- Replaced many hoses, gas cap, o2 sensors. the code kept coming back.
- in November of 2011, Removed gas tank and forced air into it and found the air escaping around the the grommet that the fuel pump fits into. Removed pump and applied a sealent around the fuel pump nut
- Cleared the code and the code has not come back since.
- Shortly after, the truck began starting normally and consistently started normally throughout the winter
- In early summer, truck was once again starting hard
- I recently put a fuel pressure guage on - hear are the findings:
- Started the truck and it idled consistently at about 50lbs
- turn the truck off and the pressure immediately dropped to 40lbs and then quickly bled down to 0
- if I cycle the pump without starting truck, pressure would go to 50lbs but with running, immediaetley drops to 40lbs and then bled down.
- Installed 2 ball valves on either side of the pressure guage (1 on rail side and 1 on tank side).
- I brought the pressure up to 50lbs (key on, not running). closed rail side valve. pressure bled down with 1 minute. Re opened valve.
-I brought the pressure up to 50lbs (key on, not running). closed tank side valve and pressure dropped to 40lbs but maintained at 40 for 5 minutes.
So it seems that my bleed down is occuring on the tank side... but where?
- Many will say it's the checkvalve in the pump but the pump was new when this began.
- could there be some type of voltage issue causing the pump/ fuel pressure regulator to not function properly?
- could there be something that is causing the check valve not to function properly?
- if bad check valve, is it possible to install an inline check valve on the fuel line rather than buying a complete pump?
- Since it seemed to work fine in the winter, is it possible that there is a sensor causing an issue? There is a temperature sensor for the coolant that tells the PCM what temp the engine is at. Is it possible that if the sensor is bad the PCM is calling for the wrong fuel amount?
- Shortly after buying the truck, I started having long crank times to start the truck.
-upon firing up, it kind of stumbles bought does not stall - sounds like it is starving for fuel
- The PO put a new fuel pump in shortly before selling
- CEL all along with evac leak - PO442
- Replaced many hoses, gas cap, o2 sensors. the code kept coming back.
- in November of 2011, Removed gas tank and forced air into it and found the air escaping around the the grommet that the fuel pump fits into. Removed pump and applied a sealent around the fuel pump nut
- Cleared the code and the code has not come back since.
- Shortly after, the truck began starting normally and consistently started normally throughout the winter
- In early summer, truck was once again starting hard
- I recently put a fuel pressure guage on - hear are the findings:
- Started the truck and it idled consistently at about 50lbs
- turn the truck off and the pressure immediately dropped to 40lbs and then quickly bled down to 0
- if I cycle the pump without starting truck, pressure would go to 50lbs but with running, immediaetley drops to 40lbs and then bled down.
- Installed 2 ball valves on either side of the pressure guage (1 on rail side and 1 on tank side).
- I brought the pressure up to 50lbs (key on, not running). closed rail side valve. pressure bled down with 1 minute. Re opened valve.
-I brought the pressure up to 50lbs (key on, not running). closed tank side valve and pressure dropped to 40lbs but maintained at 40 for 5 minutes.
So it seems that my bleed down is occuring on the tank side... but where?
- Many will say it's the checkvalve in the pump but the pump was new when this began.
- could there be some type of voltage issue causing the pump/ fuel pressure regulator to not function properly?
- could there be something that is causing the check valve not to function properly?
- if bad check valve, is it possible to install an inline check valve on the fuel line rather than buying a complete pump?
- Since it seemed to work fine in the winter, is it possible that there is a sensor causing an issue? There is a temperature sensor for the coolant that tells the PCM what temp the engine is at. Is it possible that if the sensor is bad the PCM is calling for the wrong fuel amount?
Professional
Joined: Jan 2012
Posts: 213
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sounds like the previous owner had some major issue putting the new pump in so who knows what he did to it as for the bleed down it would indicate that the pressure regulator witch is part of the pump is taking a crap. now it can be replaced separately but it still involves removing the tank and pump so you might want to replace the whole unit
Thread Starter
|
Professional
Joined: Sep 2010
Posts: 167
Likes: 0
From: New Brunswick Canada
sounds like the previous owner had some major issue putting the new pump in so who knows what he did to it as for the bleed down it would indicate that the pressure regulator witch is part of the pump is taking a crap. now it can be replaced separately but it still involves removing the tank and pump so you might want to replace the whole unit