97 5.0l weird starting issue

[MT-2500]

Originally Posted by |WYG|SS

anything?

Run the full test and post back pressure readings.

[|WYG|SS]

ok i am not trying to be mean here but that should be enough fricking information to tell me if their is eaither a problem with teh pump or the sending unit.

[MT-2500]

Originally Posted by |WYG|SS

ok i am not trying to be mean here but that should be enough fricking information to tell me if their is eaither a problem with teh pump or the sending unit.

To test pump you have to run the full test.

Post back all pressure readings and then we can help.

[|WYG|SS]

answers in bold
Check cold start fuel pressure.(i dont know what you mean by this but yeah the fuel pressure went up to 57 when priming and droped to about 53)
Check engine running fuel pressure.(53)
Check engine running on the road fuel pressure. 53
Then shut it off and watch for fast leak down. slow leak down
Pinch off at rubber part or block off return line and check full pressure.(have to do yet, which line is it i have to pinch off?)
If pump has full pressure with return line blocked and low pressure without it blocked most usually the fuel pressure regulator is leaking or not holding pressure.

-one question i got is when i pinched off both lines going to back of engine even if i got one of them partially pinched off with a pliers wouldnt you think i would see the pressure rise cause i didnt.

-and sorry for getting mad on the one post.
he is going to be replacing the fuel pump this weekend and im going to try and see if i can save him some money on it if it is just the FPR.

[MT-2500]

Originally Posted by |WYG|SS

answers in bold
Check cold start fuel pressure.(i dont know what you mean by this but yeah the fuel pressure went up to 57 when priming and droped to about 53)
Check engine running fuel pressure.(53)
Check engine running on the road fuel pressure. 53
Then shut it off and watch for fast leak down. slow leak down
Pinch off at rubber part or block off return line and check full pressure.(have to do yet, which line is it i have to pinch off?)
If pump has full pressure with return line blocked and low pressure without it blocked most usually the fuel pressure regulator is leaking or not holding pressure.

-one question i got is when i pinched off both lines going to back of engine even if i got one of them partially pinched off with a pliers wouldnt you think i would see the pressure rise cause i didnt.

-and sorry for getting mad on the one post.
he is going to be replacing the fuel pump this weekend and im going to try and see if i can save him some money on it if it is just the FPR.

Your fuel pressure readings is way to low.

Cold srart pressure is fuel pressure cranking engine cold.
You need 65 lbs on cold cranking.

If it does not have full pressure on a cold start the injectors will not squirt fuel to start.

The return is smaller than the tank to engine feed line.

Also check direct fuel pressure at fuel filter.
If not up to 95 -100 lbs.
Start looking for a new Delphi fuel pump.
Not a junk aftermarket airtex type pump.

Give us all of the fuel pressure readings.

[|WYG|SS]

now how would i test the pressure at the filter?

[MT-2500]

Originally Posted by |WYG|SS

now how would i test the pressure at the filter?

Remove the line going into fuel filter.
Hook the pressure gauge on the filter inline.
Or blocking return line should give same results if no leaks any place.
Post back what pressure you have.

[|WYG|SS]

Pinched off return line i got 62
when i did fuel filter i got about 38

[MT-2500]

Originally Posted by |WYG|SS

Pinched off return line i got 62
when i did fuel filter i got about 38

A good fuel pump should go to 100 lbs of pressure.

Time for a Delphi fuel pump.

No junk aftermarket type Airtex pumps.

Good luck and let us know how it goes.

[|WYG|SS]

well he has a buddy putting a new one in this weekend. i was told that when a fuel pump goes it goes(quits). my guage does leak a little bit but for a FP to put out only 30psi was stumping me also. well thanks for the reply's.

[MT-2500]

Originally Posted by |WYG|SS

well he has a buddy putting a new one in this weekend. i was told that when a fuel pump goes it goes(quits). my guage does leak a little bit but for a FP to put out only 30psi was stumping me also. well thanks for the reply's.

Fuel pumps go bad in many ways.
And do not forget to check for good power and grounds and wiring to pump.
Running low on fuel is a no no on fuel pumps.
Also dirty filters can over load a pump.

Good luck and let us know how it goes.

[|WYG|SS]

well everything is going fine, starts on one turn. and the guy who changed the pump did the spark plugs and was surprised that the truck even ran cause 4 or the plugs burnt off the ground.

thanks for all of the help

[MT-2500]

Originally Posted by |WYG|SS

well everything is going fine, starts on one turn. and the guy who changed the pump did the spark plugs and was surprised that the truck even ran cause 4 or the plugs burnt off the ground.

thanks for all of the help

You are welcome and thanks for posting back how it went.
Glad all is well.
Good luck