Fuel Pressure Test (Results)

[modelageek]

Please analyze my test results. I changed my filter this morning. It was very dirty. Then I went down to AZ and borrowed a fuel pressure tester. It took 8 cycles of the key to get the koeo pressure to 62. I then started it koer pressure 64. I turned it off pressure went back to 62. I let it sit 6 minutes pressure went down to 54( I had the gauge on finger tight with no teflon). So what do you think how long do I have on the pump?

 

[RangerSVT]

Sounds fine to me, the fuel system is not designed to sustain pressure after the pump is shut off. The system is designed to maintain an operating pressure of around 65 psi. The fuel pump may cycle off and on while the engine is running, this is normal as to not build up too much pressure. This off and on surging is controlled by the ECU
SVT

 

[modelageek]

thanks for the feedback. I was thinking that because it took so many times(8) to cycle up from 0 to 62 that the pump was fading out. on some other cars I have tested I thought i remember the pressure building right up on 1 or 2 cycles koeo. thnx again.

 

[RangerSVT]

It shouldn't take that many cycles to build it up, but it is building up, a weak or bad pump wont make it, as the higher the pressure is, the harder the pump has to work. When was the last time you changed your fuel filter?? This could cause a delay in attaining pressure, also, take a look under your truck and inside your framerail to see if you have any fuel leakage...
SVT

 

[modelageek]

I change the fuel filter right before I checked it( the filter was real bad) I don't think there is a leak but I will check. I tested for it to lose pressure it went from 62 to 54 over 6 minutes. I had the gauge on finger tight without any teflon tape. so I thought that was not to much of a lose of pressure

 

[RangerSVT]

When you did your initial test, did you test right after you installed the filter, or after the filter was installed and engine ran??
SVT

 

[modelageek]

When you did your initial test, did you test right after you installed the filter, or after the filter was installed and engine ran??
SVT

I changed the fuel filter and then drove at least 10 miles. I went and got the tester at AZ. The truck was running much better from the new FF. but there was still a little hesitation occasional. thats why I did the test.

 

[RangerSVT]

How old are the plugs?? Wires?? Miles??
SVT

 

[modelageek]

How old are the plugs?? Wires?? Miles??
SVT

I changed the plugs and wires about 8k miles ago. I installed bosch platinum plus( I should have put motrocraft dp's in). 113k on truck. about 1 week ago I was getting a misfire and my cel thru p0303. I added a large techron to half a tank and within 5 miles the truck was much better. I cleared the codes and it never came back.( I think the techron woked on the dirty filter a little). No codes now. Truck runs good except for a little occasional hesitation. in the last 8k miles i put in new, pcv, air filter, cleaned maf, cleaned iacv, cleaned tb.
.

 

[RangerSVT]

Bosch plugs are straight garbage plugs for a ford...FYI, I learned to go with the manufactures rated plugs, if it says platinum, run platinums, if they say double, run doubles...I ran reg platinums in mine and it calls for doubles, after about 8-10K miles, I started having a pretty bad miss at idle and poor fuel economy/power and couldn't figure it out, no codes...then I changed the plugs and went with the rated, solved everything...Also, fords like Autolite plugs best, so I think you need to run the doubles in yours...try that and see how she does...
SVT

 

[modelageek]

thx I think I am going to do that. the autolites dp's

 

[RangerSVT]

Glad I could help a fellow member
SVT

 

[modelageek]

fixed for now.I just tested it again and koeo 62. it went right up there with one cycle. koer 64. I guess the new filter, some injector cleaner and driving it cleaned it up. I bought a new strainer for the pump and i will put that on in a few months when i take the bed off for some other work...thanks for your input

 

[RangerSVT]

Glad you got it fixed...Try not to run less than 1/4 tank of fuel in the tank, fuel cools the pump down, and when less than 1/4 tank the pump has nothing but air to cool it, as well as sucking up the trash thats in the bottom of the tank...
SVT