2 Month And Couldn't Fix My Problem, Can Someone Help Please

[monana]

First i am in Beirut/Lebanon i have GT 2005 with 117k on it that was shipped from the US. I have a major problem on acceleration and on WOT with the fuel delivery as shown in the video here:


I shipped a new FP and installed it but the problem remains the exact same one.
I sat in the back of the car with a friend driving it and tested the voltage coming to the pump on load, it reached maximum 9V (thats a problem) .

I did some pids logs :
Fuel rail pressure on WOT: fluctuating severely between 0 and 60psi
Fuel pump voltage: between 5-9V maximum (problem)

VOM tests with key on:
TPS showed 5v
FRPS showed 5v
FPDM 12v (i read that it should be 10.5v)
Fuel Pump showed 4v
Battery 13v
ALT 14v (on idle)

Ground test:
12v (no leaks)

Vacuum test:
no leaks

Inertia switch test passed (i connected the 2 wires and car runs)

MAF cleaned also.

I logged battery voltage pid and it goes down to 10-11V on load, something is sucking power (here is the problem)

Does the PCM gives voltage directly to the pump or it has to pass by the FPDM first? How does electricity goes to the pump so i can check more things.

How can i check the PCM fuel pump wire that goes to the pump and FPDM?

Any ideas what else should i check please?

Thank you.

 

[bigb427]

I watched that video and can't make any determination from it at all. Was the check engine lamp on? Do you have any codes? What specifically makes you think that there is something wrong with the car? Checking voltage at the fuel pump on a vehicle with this type of fuel system is not an accurate method to diagnose a concern. Let me know on the questions I asked, and we'll go from there.

 

[monana]

I watched that video and can't make any determination from it at all. Was the check engine lamp on? Do you have any codes? What specifically makes you think that there is something wrong with the car? Checking voltage at the fuel pump on a vehicle with this type of fuel system is not an accurate method to diagnose a concern. Let me know on the questions I asked, and we'll go from there.

The car is stalling hesitating bogging. On accelration and on WOT. No normal fuel delivery and pids I logged were very low and jumping up and down. Installed new pump with no success then I made those voltage tests which showed low voltage at the same time when the car generate the problem.
No codes, no cel, no lights. The car is stock no mods.
Tests I did lead me that the PCM is not getting enough voltage to send it to the pump.
Anything else that I should check?

 

[bigb427]

I am not sure what you basing the diagnosis of "no normal fuel delivery" off of, and you haven't mentioned specifically what PID's you were monitoring.

What you want to do if you suspect a fuel delivery problem is install a mechanical fuel pressure gauge and compare it's reading to the FRP (measured fuel rail pressure) in PSI PID at idle and after a couple seconds at WOT while accelerating. It's normal for the FRP to read about 8 PSI higher than the mechanical gauge.

You will also want to monitor at idle and at WOT on a road test the FP% (commanded fuel pump duty cycle) and FRP_DSD (desired fuel rail pressure). The FRP_DSD might not be available on your car. Along with those also monitor long and short fuel trims for both banks at idle and at WOT.

Report back with those items and I will tell you if you have a fuel delivery problem or if you should be looking for another problem.

 

[monana]

I have the pids log you asked me for , i dont have a fuel pressure gauge and garage people her are not familiar with a stang, not even the dealer who broke 8 spark plugs in the engine while trying to remove them and i fixed it by myself with a lisle tool, im telling you this info so you can have an idea about mechanic people in my country.

If the logged FRPS PID drops down to even 5psi (i have this low pressure on WOT) it means the mechanical FRPS will read less pressure (am i wrong here?)

I did a road test with my VOM , sat in the back and monitored FP voltage, on full open TB it didnt reach more than 9V and 5000rpm then and car falls on its face. In the pid log FP_V_TA its 8.8V

I have FPDC dunno if its the one ur taking about 0.50 at 5000 rpm

I have FRP 7.42 on 5000 rpm (also dunno if its the one u mentioned)

I have battery 10-11v on 5000 rpm, this is my concern here that made me look for electricity problems from the PCM.

i also noticed a kicking sound at a non stable interval from the fuel pump and not a continuous spinning, tested with my fingers too, its kicking fuel.

If you need some pids to see pleas let me know so i can log them for you, and by the way today i got P0140-P1000 but no light on the cluster, SCT found them when i checked for codes.

 

[bigb427]

I am not familiar with any of the aftermarket scan tools out there including the SCT. I would have to imagine that the SCT scan tool will give you a definition of the available PID's somewhere - either through the tool itself in some manner or in a manual that came with it possibly. Maybe check SCT's website or call them if you have to?

You absolutely must find a PID that shows you the duty cycle that the PCM is commanding the fuel pump to properly diagnose a fuel delivery concern. This PID on Ford's diagnostic tools is simply labeled "FP" and is displayed as a percentage. At idle the commanded fuel pump duty cycle should be around 18-24%. At WOT the duty cycle should be around 36-38%. If it's higher than that, then you have a fuel delivery problem. Typically when there is a fuel delivery problem the FP commanded at WOT will be 44-50% and the fuel pressure will fall well below 30PSI.

Testing the voltage at the fuel pump is not an accurate method of testing for a concern due to the design of the electronic returnless fuel system it is equipped with in which voltage is constantly varying. Ford does not publish any specification for what a "normal" voltage reading at the fuel pump connector should be.

You may have a problem with your alternator if you are reading voltages as low as you stated. The battery voltage with the engine running should always be at least 13.5 volts. 14.1 to 14.3 volts would be considered normal at RPM's of 2000 and higher.

A code P0140 is not a valid code. I don't know what to tell you about that. A code P1000 only occurs after the PCM has lost it's memory for some reason such as disconnecting the battery, clearing codes, removing fuses, or disconnecting the PCM. Driving the car in a set predetermined manner for a a period of time is the only way to get rid of the P1000.

 

[SpartaPerformance]

When did this problem start? If it started after your first tank of gas that may be it, I'm not certain of middle east but in most European countries the lowest octane is 95, if that's the case their you may have simple combustion issues

 

[monana]

When did this problem start? If it started after your first tank of gas that may be it, I'm not certain of middle east but in most European countries the lowest octane is 95, if that's the case their you may have simple combustion issues

The problem starts after exceeding of wots and hard driving of the car (race)
I always fill 98 octane in it since 2 years without problems untill now.
I had an accident on the right fender and i changed it and fix but the problem started after a month of that accident.