FUEL PUMP...Whole asembly?

[J Browning]

So I took it to the dealer and they said one reason why I may be getting engine knock is that the fuel pump pressure is low creating a lean condition.



background: 01 Job 2, 4x4, fuel filter recently replaced, higher octance gas is not getting rid of knock that is audible between 2-3k, dealer says its not the timing rattle either because this happens every time after engine is warm, tried the 30w oil trick too.



The fuel pump whines constantly, as in its always on, it never goes off the entire time the truck is running. It starts fine and runs fine, but the pump always stay on. (trust me anyone can hear it clearly)





So the dealer tells me to replace the fuel pump becasue its not giving the system full pressure...but now i have questions. Could it be the fuel pressure regulator?



or how about this check valve i keep reading about...is that valve in the fuel pump itself or is it further up the line?



Do i need just the fuel pump or do i have to buy the entire assmebly? Reason being ofcourse cost...the fuel pump itself was about 150 BUT for the entire assembly (what ever that is)

listed for 650. thats a huge difference.



if anyone has some advice please let me know.



thank you

 

[shawn stonbraker 2]

Check your fuel shut off switch. I think it is on the passanger side kick panel. It could have been bumped but not completely. (doubt it but worth a shot) If they sell them seperately then you should be able to just replace the pump.

 

[EddieS'04]

My experiance with (stock OEM)" whining fuel pumps " has been they dont last long or pump well..I said it that way cause my stang pump whines but it is a highperformance pump 190 Lph...

Did the dealer actually do a pressure check ? Or they guessing ?

 

[J Browning]

Fuel shut off switch is good. the fuel pump wouldnt work at all if it was tripped.





he said he did a pressure check but never told me the readings. all he mentioned was that it was low.



to clarify my issue, the problem seems to be that the pump is constantly staying on, whether idleing or moving, so that it can try and maintain the fuel pressure needed to run the trac but yet that pressure is not enough when there is a high demand so then detonation occurs.





so i think...



if i turn the key and the fuel pump primes and then turns off before i start the truck then the fuel pump check valve and fuel pressure regulator should be ok correct?



if it continues to whine/hum while the ignition is on but the car is not started and it never shuts off then should i assume that the pump is fine but i have a pressure leak somewhere? or should i assume that the pump is defective and the check valve in the pump is not holding the pressure?



like possibly where the fuel filter is. considering one of the lines no longer connects directly to the filter anymore. it seems the old owner didnt know about the special tool to remove the line from the filter and he just cut it and used high pressure rubber fuel lines instead.



but i assume that if i dont see any fuel dripping then the lines should be in good shape right and not leaking pressure?



aggghhhh, frustrating

 

[Kevin Palmer]

First, the pump will run 100% of the time that the engine is running. It does not change speed or RPM. The fuel pump knows to pump at one speed and at one volume of fuel. The fuel pressure regulator is what determines the pressure/volume issue. It is controlled by vacuum. The more vacuum the less pressure.



So, if you turn the key on and wait a moment the pump should spin and then turn off after a few seconds. It has nothing to do with pressure though. It has to do with the ECM seeing that the engine is not running and then it shuts down the Fuel Pump Relay.



If it whines all the time it is probably bad or going bad. BUT, that does not mean that is your pressure issue. I have seen on many occasions where the relay does not allow full amperage to feed the pump. There a cheap item. Also, you will more than likely find that other relays on the Track are the same. If so, swap it with another and see what happens.



The best test is to take it to a garage that can/will hook it up to gauges and see what the pressure is at various times. For example, Key on engine off it should get fairly high before it kicks off, (like close to 80 psi or so). Running it will be slightly less, pedal pushed down it will increase due to less vacuum.



You need to see if these things are happening in order to properly diagnose the system.



Also, you mention there is a third line just hanging around due to the last owner not doing the filter right.



This needs to be fixed as well as you have some sort of a fuel issue right there.

 

[Casey B]

First dealer I went to about the timing chain rattle said it was engine knock. They offered a $100+ fuel system treatment and couldn't guarantee that it would go away. Went to another dealer who immediately said it was the timing chain and replaced it, Noise gone.

 

[J Browning]

now the question is do i need the whole assembly or can i just buy the pump?



and there is not a third line just that one out of the two is now connected by a small section of rubber hose near the filter.



thank you for all the replies.

 

[Kevin Palmer]

Pump only. From Ford you more than likely will HAVE to but it as part of a unit.



Auto parts stores will sell the pump alone.



As I mentioned. I STRONGLY suggest getting your Trac on a set of gauges to fully understand what the issue really is.



You will be plenty mad if you replace the pump inly too find out it whines to....



(Which can be caused by the vacuum hose falliing off the regulator for example).

 

[J Browning]

thanks coastie,



where do i hook up the guages?



does it go to that line you mentioned that connects to the FPR?



and am i even looking in the right direction. the Ford tech said he could confirm detonation with a tool he used but he only suggested that it was either the MAF sending out a bad signal or becaue it was not getting enough fuel due to slightly low pressure. do you think these would cause engine knock.



I recently did the IAC cleaning.

 

[Kevin Palmer]

Most Fords have a Shrader valve, it looks like a tire valve stem, that you thread the gauge tool onto.



However, Ford and others, have since made no provison to simply thread a tool on. You have to seperate the line, intsal an adapter, put the line on the end of the adapter, then put the gauge onto the adapter.



If your not familiar with it I suggest going to a loacl shop. You need the proper tools as well as a good guage and the data of what the pressure should be at what RPMs and or at what engine load.