Fuel pump question
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Senior Member
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From: White Bear, MN
Fuel pump question
My fuel pump doesn't seem to run when I turn the key to the "on" position. I changed my fuel filter and couldn't prime the fuel rail by turning the key on and off a few times before hitting the starter.
Does the SRT6 only start the fuel pump when the starter motor cranks the engine?
The car runs well but can be a hard starter when it sits overnight (loss of leftover fuel pressure).
Does the SRT6 only start the fuel pump when the starter motor cranks the engine?
The car runs well but can be a hard starter when it sits overnight (loss of leftover fuel pressure).
THREE 6S
Joined: Aug 2007
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From: From North TX..To SoCAL..Now Cnt Philly
Re: Fuel pump question
Originally Posted by tunaglove
My fuel pump doesn't seem to run when I turn the key to the "on" position. I changed my fuel filter and couldn't prime the fuel rail by turning the key on and off a few times before hitting the starter.
Does the SRT6 only start the fuel pump when the starter motor cranks the engine?
The car runs well but can be a hard starter when it sits overnight (loss of leftover fuel pressure).
Does the SRT6 only start the fuel pump when the starter motor cranks the engine?
The car runs well but can be a hard starter when it sits overnight (loss of leftover fuel pressure).
If you are having hard starts, it maybe pinpointing another problem, since our fuel system is under continuous pressure.
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From: Michigan
Re: Fuel pump question
the srt6 pump will start running as soon as the key is in the on position (before the car cranks), it will run for 3-5 seconds assuming you dont start the car
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From: White Bear, MN
Re: Fuel pump question
HMMMM.. These are two conflicting views. I will add this: when I went to replace the filter, I thought I would relieve pressure at the schrader valve at the end of the fuel rail. The car had been sitting for about one hour. There was no pressure or fuel spray. Is there a check valve to keep pressure in the rail? Also when you guys turn your key to "on" can you hear the fuel pump cycle when sitting in the driver's seat?
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From: Chicago
Re: Fuel pump question
If you see a puff of white smoke when you start, you have a fuel injector that is leaking fuel into your engine when it sits. This is a common problem on older GM cars.
Also, if your fuel pump is going, you will have hard starts for a while then it will cease to run at all; learned that from experience.
Also, if your fuel pump is going, you will have hard starts for a while then it will cease to run at all; learned that from experience.
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From: White Bear, MN
Re: Fuel pump question
Found this in the manual.
Looks like Rob was right.
"The PCM controls the Fuel Pump Relay by switching the ground path for the coil side of the relay on and off. The
PCM turns the ground path off when the ignition switch is in the OFF position. When the ignition switch is in the ON
position, the PCM energizes the Fuel Pump. If the Crankshaft Position Sensor does not detect engine rotation, the
PCM de-energizes the relay."PCM turns the ground path off when the ignition switch is in the OFF position. When the ignition switch is in the ON
position, the PCM energizes the Fuel Pump. If the Crankshaft Position Sensor does not detect engine rotation, the
Looks like Rob was right.
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From: White Bear, MN
Re: Fuel pump question
Ok, I can't hear it either Gang, but im going to take a long piece of tube and stethiscope it today after work. Looks like there is a check valve in the fuel pump and in the fuel filter/regulator. I do see white smoke on start up so maybe I have a leaky injector.
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From: St. Louis, MO
Re: Fuel pump question
There are check valves that keep the fuel pressurized, this will cause long cranking times if the line is losing pressure when off.
when the car does start does it run fine? if it does then the valve is your culprit
when the car does start does it run fine? if it does then the valve is your culprit
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From: Atlanta, GA
Re: Fuel pump question
theres not a valve in the rail, there might be one in the fuel line somewhere but not in the rail itself
and the fuel pump is supposed to run when the key is turned to on, thats how it is on mine
and the fuel pump is supposed to run when the key is turned to on, thats how it is on mine
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From: IN
Re: Fuel pump question
what do you call a hard start? do you crank for sometime or just a few seconds? if a long time, then yes, you have a fuel problem...Rob is correct as noted....did it still do this after you have driven it for awhile?
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From: Ontario
Re: Fuel pump question
You can hear the fuel pump easier when the car door is open and you turn the key.
From the shop Manual;
The pressure regulator is a mechanical device that is calibrated to maintain fuel system operating pressure of between 3.7 - 4.2 bar (54 - 61 psi) at the fuel injectors. Fuel is supplied to the fuel filter/fuel pressure regulator by the electric fuel pump directly.
The fuel pump assembly contains a check valve to maintain some fuel pressure in the system when the engine is not operating.
If fuel pressure at the pressure regulator exceeds a set amount, an internal diaphragm closes and excess fuel pressure is routed back into the tank through the pressure regulator. The diaphragm pressure regulator (2) regulates the fuel pressure by means of the return flow (10) quantity to the fuel tank. If the pressure rises above the set pressure, the diaphragm (6) is pressed further against the compression spring (4). The valve (7) attached to the diaphragm opens the passage for the return flow further. If the pressure drops below the set pressure, the valve is closed again by the compression spring (4).
From the shop Manual;
The pressure regulator is a mechanical device that is calibrated to maintain fuel system operating pressure of between 3.7 - 4.2 bar (54 - 61 psi) at the fuel injectors. Fuel is supplied to the fuel filter/fuel pressure regulator by the electric fuel pump directly.
The fuel pump assembly contains a check valve to maintain some fuel pressure in the system when the engine is not operating.
If fuel pressure at the pressure regulator exceeds a set amount, an internal diaphragm closes and excess fuel pressure is routed back into the tank through the pressure regulator. The diaphragm pressure regulator (2) regulates the fuel pressure by means of the return flow (10) quantity to the fuel tank. If the pressure rises above the set pressure, the diaphragm (6) is pressed further against the compression spring (4). The valve (7) attached to the diaphragm opens the passage for the return flow further. If the pressure drops below the set pressure, the valve is closed again by the compression spring (4).
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From: White Bear, MN
Re: Fuel pump question
Either the check valve in the pump or a leaky injector. Rob, no if I try to prime first then crank it still cranks too long, sometimes it will time out. BUT, THIS TRICK WORKS EVERY TIME: If I crank for one second then turn of the key then hit it again, it lights up perfectly. I'm going to get a pressure tester from Harbor Freight ($19 woot) and try the proceedure in the manual. Otherwise the car runs great and no CELs.
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From: Los Angeles
Re: Fuel pump question
As somebody already posted, I too believe that puff says the pressure is dribbling out an injector (or two?). Now I'm not believer in any 'miracles in a can' but doggone if I haven't gotten some amazing results from "SeaFoam" in a can on higher milage injected motors
Two cans of that stuff in a full tank has cured two rough idle motors I've had and restored some some snap to off throttle/on throttle transitions. I just bought my 32K mile SRT6 on Tuesday of this week but I stopped at an auto parts store for a couple cans of SeaFoam for the 350 mile drive home. Now it *will* smoke a bit with the double shot but I've never plugged a catalytic convertor or detected any rattle/ping running the stuff. Just the same, I drove it mello for the trip home (mostly, there were a few passing points on the 46 highway from Monterey
) *If* this is a leaky injector due to grungy deposits, Seafoam will fix it or I will give you any $$ back that you've paid for my input
First post BTW looking forward to learning a bit about the Six and building a solid 12 second performer that turns too
Mike
Two cans of that stuff in a full tank has cured two rough idle motors I've had and restored some some snap to off throttle/on throttle transitions. I just bought my 32K mile SRT6 on Tuesday of this week but I stopped at an auto parts store for a couple cans of SeaFoam for the 350 mile drive home. Now it *will* smoke a bit with the double shot but I've never plugged a catalytic convertor or detected any rattle/ping running the stuff. Just the same, I drove it mello for the trip home (mostly, there were a few passing points on the 46 highway from Monterey ) *If* this is a leaky injector due to grungy deposits, Seafoam will fix it or I will give you any $$ back that you've paid for my input First post BTW looking forward to learning a bit about the Six and building a solid 12 second performer that turns too
Mike
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From: White Bear, MN
Re: Fuel pump question
Ok, tests reveal.......
55 PSI when key is turned on. The pump is just very quiet. After the initial prime fuel pressure drops to 0 PSI in a few seconds. Moved gauge to fuel line with same results. So the problem is either check valve in filter/reg or check valve in fuel pump. Filter/reg are brand new so I'm going with fuel pump. 70K miles on it. With the car running I get a steady 55PSI at idle. Once I get a new pump in I'll post results to help others. Oh yeah, SeaFoam was the first thing I did when I bought the car. Good stuff.
55 PSI when key is turned on. The pump is just very quiet. After the initial prime fuel pressure drops to 0 PSI in a few seconds. Moved gauge to fuel line with same results. So the problem is either check valve in filter/reg or check valve in fuel pump. Filter/reg are brand new so I'm going with fuel pump. 70K miles on it. With the car running I get a steady 55PSI at idle. Once I get a new pump in I'll post results to help others. Oh yeah, SeaFoam was the first thing I did when I bought the car. Good stuff.
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Joined: Apr 2010
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From: Nashville, TN
Re: Fuel pump question
Originally Posted by MrSix
As somebody already posted, I too believe that puff says the pressure is dribbling out an injector (or two?). Now I'm not believer in any 'miracles in a can' but doggone if I haven't gotten some amazing results from "SeaFoam" in a can on higher milage injected motors Two cans of that stuff in a full tank has cured two rough idle motors I've had and restored some some snap to off throttle/on throttle transitions. I just bought my 32K mile SRT6 on Tuesday of this week but I stopped at an auto parts store for a couple cans of SeaFoam for the 350 mile drive home. Now it *will* smoke a bit with the double shot but I've never plugged a catalytic convertor or detected any rattle/ping running the stuff. Just the same, I drove it mello for the trip home (mostly, there were a few passing points on the 46 highway from Monterey ) *If* this is a leaky injector due to grungy deposits, Seafoam will fix it or I will give you any $$ back that you've paid for my input
First post BTW looking forward to learning a bit about the Six and building a solid 12 second performer that turns too
Mike
Two cans of that stuff in a full tank has cured two rough idle motors I've had and restored some some snap to off throttle/on throttle transitions. I just bought my 32K mile SRT6 on Tuesday of this week but I stopped at an auto parts store for a couple cans of SeaFoam for the 350 mile drive home. Now it *will* smoke a bit with the double shot but I've never plugged a catalytic convertor or detected any rattle/ping running the stuff. Just the same, I drove it mello for the trip home (mostly, there were a few passing points on the 46 highway from Monterey ) *If* this is a leaky injector due to grungy deposits, Seafoam will fix it or I will give you any $$ back that you've paid for my input First post BTW looking forward to learning a bit about the Six and building a solid 12 second performer that turns too
Mike
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From: White Bear, MN
Re: Fuel pump question
After looking around I think the Needswings Walbro kit is the best deal. The SL55 is too expensive. Fittings, pump everything ready to go for $119. Done deal.
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Re: Fuel pump question
Originally Posted by onehundred80
You can hear the fuel pump easier when the car door is open and you turn the key.
From the shop Manual;
The pressure regulator is a mechanical device that is calibrated to maintain fuel system operating pressure of between 3.7 - 4.2 bar (54 - 61 psi) at the fuel injectors. Fuel is supplied to the fuel filter/fuel pressure regulator by the electric fuel pump directly.
The fuel pump assembly contains a check valve to maintain some fuel pressure in the system when the engine is not operating.
If fuel pressure at the pressure regulator exceeds a set amount, an internal diaphragm closes and excess fuel pressure is routed back into the tank through the pressure regulator. The diaphragm pressure regulator (2) regulates the fuel pressure by means of the return flow (10) quantity to the fuel tank. If the pressure rises above the set pressure, the diaphragm (6) is pressed further against the compression spring (4). The valve (7) attached to the diaphragm opens the passage for the return flow further. If the pressure drops below the set pressure, the valve is closed again by the compression spring (4).
From the shop Manual;
The pressure regulator is a mechanical device that is calibrated to maintain fuel system operating pressure of between 3.7 - 4.2 bar (54 - 61 psi) at the fuel injectors. Fuel is supplied to the fuel filter/fuel pressure regulator by the electric fuel pump directly.
The fuel pump assembly contains a check valve to maintain some fuel pressure in the system when the engine is not operating.
If fuel pressure at the pressure regulator exceeds a set amount, an internal diaphragm closes and excess fuel pressure is routed back into the tank through the pressure regulator. The diaphragm pressure regulator (2) regulates the fuel pressure by means of the return flow (10) quantity to the fuel tank. If the pressure rises above the set pressure, the diaphragm (6) is pressed further against the compression spring (4). The valve (7) attached to the diaphragm opens the passage for the return flow further. If the pressure drops below the set pressure, the valve is closed again by the compression spring (4).
Last edited by firemen; May 31, 2010 at 10:06 PM.