Gen 3 Coyote break up at about 2500 RPM and 25% throttle
I am new to the tuning world, but I want to learn more. I have a Ford Performance Gen 3 Coyote engine package with the manual transmission and the Ford ECU. I have this in a Factory Five Type 65 Coupe. My understanding is due to the aftermarket MAF sensor housing a tune is needed. I followed the forum suggestions on tuning the MAF. Based on my results in STFT and LTFT in the attached files, I believe I did good. The two files attached show a test I ran to look at the GDI high pressure fuel pump. In the first file, you will see times when the desired fuel pump pressure was 900 PSI plus and the actual pressure was under 50 PSI. Based on this, my feeling was the GDI pump/ controller combo was bad. I purchased a new one from Ford and the second file shows the results. I am having the same or worse problem.With the stock tune I had the same dead spot but I had not tracked the GDI fuel pressure. I did check my supply fuel pump pressure which is recommended to be a minimum of 65 PSI. I set it at 70 and I drove the car with a camera watching my regulator fuel pressure gauge and it did not go below 65 PSI. I have 150 miles on this motor and probably an additional 2 hours of run time. As long as the computer is requesting a higher pressure and I don not have it, I don't beleive any fuel cutouts are happening. Ford Performance recommended a kit from Power by the Hour that has an OEM diameter MAF housing and they claim no tuning is needed. I have doubts that will solve this problem. You the forum, are the experts so I will ask for your opinion. Thank you in advance for your time and responses.
I wanted to let everyone know that the problem is fixed. I want to thank "engineermike" for looking at my data and discussing some options. It turns out that the supply hose going from the Port fuel injection rail to the GDI pump has a check valve/ restrictor in it. I disconnected it from the GDI pump and did a key cycle volume test on the line with low output. A straight fuel line flowed fine. When I recevived the new crate motor package, I added the billet crankshaft timing gear and the billet oil pump gears. I would have had the GDI pump off at that time. I must have installed the line backwards backwards during reassembly. Ford Performace tech department sent me this Ford Manual note:
This note is for the fuel line from fuel rail to mechanical high pressure pump. NOTICE: The high-pressure fuel pump supply tube must be installed with the Oetiker? clamp end installed to the port fuel rail; if it is installed backwards a check valve will prevent the engine from running properly.
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