Replaced te pump in my 99 f1 and fuel filter still won't start pump has power truk starts if u pour fuel in the intake. There is pressure at the motor. Has spark. Any ideas?

 

If your sure there is spark, check the cam position sensor and plug up.
The injection 'timing signal' and fire order comes from this sensor.
Good luck.

 

That's the weird thing. If u pour some fuel in the intake it'll fire up and die. Manual calls 55psi fuel pressure
. Were only gettin 10-35psi.
Brand new fuel pump and
filter.

 

With pressure gage in place, operate the key to run and check how much pressure you see then do it 3 or 4 more times to see how much pressure builds.
It should build to full pressure and remain for at least 5 min or more before beginning to bleed down.
It doesnot take real high pressure to start the motor and idle.
The vacuum line to the regulator knocks the pressure down at idle.
If you have no signs of starting, there is no fuel being injected.
May be the regulator has a fault.
Are the injectors being fired?

 

Some time it wil be 5psi and key on off back in forth can get it to about 40 psi max and still no start. We know it's gettin spark cuase it'll start with fuel thru the intake. How do you check the injectors?

 

Not sure if this is relevant here,but Ive heard alot about the Fuel Pump Control Module.Its supposedly located above the spare tire and attached to the rear axle(or close).From what I have read in past posts,these become corroded,and intermittent.Might be worth lookin into.

 

I'll and check it out as atthus point I'm lost. It's got fuel to the motor but won't run. It's got spark. Unless the injectors aren't firing. Like an above post suggested.

 

He suggested the regulator, which is my suggestion as well.

 

we did the key on and off several times and the most we get built is 40 manual calls 55psi..how much pressure does it take to start an idle?

 

Now that you can see fuel pressure it eliminates a lot of items for DC power.
The injectors get their power along with the fuel pump so they should all have 14 volts standing on all of them key on engine not running.
.
The PCM has to supply a ground in a fireorder to operate each injector.

How the PCM decides what injector to fire is determined by the Cam shaft sensor telling the PCM when it senses a certain position on the drivers side cam gear and the fireorder in the program.
.
Look at the CMP plug and sensor.

40 psi is plenty to allow the motor to at least fire up.
.
Ignition coils are powered from a different source "before the Pcm relay" but through the same 30 amp fuse and are 'not dependent' on the CMP sensor to operate because ignition has to be later than the injection and electronically adjustable for advance and retard..
See this reference in a Haynes book pages 12-18/19 for both coil pak and COP engines.

 

yeah im stumped..we tried and tried lastnight to get it going and just got shut down..my buddys uncle is dead set on it the pressure regulator hes betting money it is..im not so sure it is...if 40psi is enough to start up and idle then it should of fired unless the injectors arent firing fuel in..how exactly can you check and see if the injectors are firing? is there a way?

 

Put a voltmeter across the plug of one injector and look for the needle to move when ground is applied from the PCM, while cranking.
Put the plus or red lead to battery side and neg or black to the other side.
Set meter volt range just high enough to measure 14 volts +.
If reversed the needle will move to the left
This is a good time to test from either side of the connector to ground to see if there is supply voltage present.

 

my buddys dead set on the pressure regulator cuase thats what his dad said..becuase its only got like 5psi when u first turn the key on he said its not letting it build up pressure. but if you cycle the key a few times it steady builds up pressure to about 40psi so to me the pressure reg is holding pressure meaning truck should start..so im leaning tords pump not gettin full power or injectors not firing.

 

I know your trying to help.
For you, the reason it starts at low pressure is the pump only runs less than 2 seconds, not enough time to build full pressue unless the key is cycled several times.
When the crankshaft begins to rotate at cranking, the pump turns back on full time and raises the pressure to the full level. This happens due to the crank sensor detecting rotation and signals the PCM that turns the pump on full time.
In that time interval you never see a pressure issue unless there is a trouble.
Another hint. If the engine ran out of gas, key cycling is how you wold prime the fuel back to the motor again without longer cranking time.
Good luck with it.

 

Does 99s have chips in the keys? My buddy's dad said he started the truck up. But he had the original key. My buddy went to get the truck and it wouldn't start he had the spare key. Just wonderin cuase this is weird and is becoming a PITA!