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A. Penland
A. Penland, Ford Senior Master Technician, ASE
Category: Ford
Satisfied Customers: 6577
Experience:  ASE Master Certified, ASE Advanced Gasoline Engine Performance
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05 freestar 4.2l codes p2196 and p2198 car running. Frp

Customer Question

05 freestar 4.2l codes p2196 and p2198 car running rich. Frp sensor reads 34psi when running. When i hook up a guage to the fuel rail it reads 90psi. O2 sensors read above 900mv when running. I replaced the fuel pump,frp sensor, maf sensor couldn't find any vacuum leaks check grounds
Submitted: 1 year ago.
Category: Ford
Expert:  A. Penland replied 1 year ago.

Does the FRP read the same and the fuel pressure still at 90 PSI after the FRP and pump were replaced or before?

Customer: replied 1 year ago.
they read the same before and after
Expert:  A. Penland replied 1 year ago.

Actual fuel pressure tested with a manual fuel pressure gauge should be reading the same as the FRP while the engine is either running or the key is turned on. The PCM uses the FRP to monitor the fuel pressure and then regulates the power to the fuel pump to control the fuel pressure through the fuel pump driver module.

Let me do a little digging, I'll be right back.

Customer: replied 1 year ago.
Have any luck?
Expert:  A. Penland replied 1 year ago.

Do you have a scan tool that can monitor the Long fuel trims and short fuel trims?

Customer: replied 1 year ago.
I can get some numbers for you tomorrow
Expert:  A. Penland replied 1 year ago.

Actually, monitor the trims and then disconnect the line from the vapor management valve to the intake and plug it off to stop any vacuum leaks and see if the short fuel trims return to around 0.

Customer: replied 1 year ago.
Sorry couldn't get back to you yesterday. When car is warmed up short and long trim values are 0. With line disconnected and plugged same values
Expert:  A. Penland replied 1 year ago.

What were the short fuel trims?
The long are the learned/adjusted.

The short are actual at that moment.