328 Fuel Pressures Correct

Hi JRV et al!

Had a moment to install my fuel pressure gauge. Attached between line from fuel distributor leading to warm-up regulator (disconnected line @ WUR & input into one end of tester connected other end to WUR). Ran fuel pump and bled air from line. System pressure about 40psi. Started car & pressure increased to 50-52psi, no difference when cold/warm or when turning small valve to isolate control pressure.

Is this correct behavior?

Thanks once again,

Carl

PS: Will write this up as "How-To" once figure out if testing properly.

Hi Carl,

for sure "control pressure" & "system pressure" are different.

Can you convert into Bars?

Control Pressure will be 2.8-2.9 Bar Cold, rising to 3.4 Bar Warm. This only takes about 2 minutes running time to occur.

System Pressure of 50-52 sounds right.

System pressure is almost certianly higher than control pressure. Also I did some math, 14.7 x 3.4 = 49.98lbs...so it appears the System Pressure is lower on your car than I would have suspected. Based on that I would suspect System Pressure readings in the 55-60lbs range would be expected. It's possible but rare that System Pressure is ever the issue. If after confirming the results again the system pressure is in fact to low, there is an adjustment valve w/shims on the side of the FD. The sealing o-ring can leak due to old age.

Regards, JRV

Goodness JRV you respond rapidly!

To read control pressure when gauges attached in this manner I turn in-line valve to close off line from fuel distributor to WUR, correct? When I did this the engine speed would noticeably slow during warm up.

Let's see my caculator says 51psi = 3.46 bar. Which sounds like control pressure. Do I have low system pressure (fuel pump?)

Thanks as always, wish I still ived in Houston...

Carl

PS. Sorry I missed you & Mr. Lawrence on last visit; lots of West U "house restoration". Returning again late next month.

Carl,

I added to my reply above.

also it is customary to read system pressure with the engine off, FP running. It is normal when switching the tester valve to see a difference in engine speed as the two pressures are different and affect the Air Flow Plate resistance.

HTH's

Too bad we missed meeting, next time for sure.

Regards, JRV