Engine/Transmission (1994 - 1998) fuel pressure readings?

[jeepit]

Email me at -- email address removed -- for my write up on the 12 valve fuel supply system, how it works and how to fix it. It has how to deal with the fuel heater with pictures.

Joe, I emailed you for the info. My buddy has a 97 12 valver that has a gauge bouncing around only after long hauls and it seems to lose some pressure also. After truck sits it will be ok again till he makes another run.

I am a 24 valve guy so what pressures should he be seeing? what is optimal? is there a difference in pressure at launch or taking loads up hillls?

 

[Joe G.]

The specs are idle at 18 PSI and run on the road about 25 PSI. Pressure does not work like it does with an electric pump. Full throttle at low RPM will drop pressure some, but as the engine speeds up pressure will increase in spite of high demand. Power mods will affect that behavior somewhat. If you lift at high RPM pressure will go up. The overflow valve limits pressure so some extent, but the high flow rate (about 55 GPH) can push pressure above what the overflow valve is rated for. However, the engine will run fine at pretty low pressure. Not nearly as critical as later fuel systems with electric pumps. When my OF valve failed my engine ran ok at 6 PSI. The P7100 pump will forgive quite a few of fuel pressure problems.

 

[jeepit]

Buddy is taking the pressure reading off the filter? Is this the correct place to read it from? He said the it came from Geno's.

 

[Joe G.]

The fuel fuel outlet or the banjo fitting into the P7100 will have the same reading. I prefer the banjo fitting because the sensor is more out of the way there.

 

[CEdwards]

moparsean, did you get it figured out?