[boyt911sc]

Originally Posted by ahh911

landyman,
I doubt both wur's have the same obscure problem unless the vw one has a different setup internally. The control pressure should not keep rising. As noted by others, is there a restriction on the fuel return side or backpressure for some reason that is heat dependent, not too probable either. You did check the primary pressure over temp too, right? Since you measure controlled pressure, you would have checked this too?


Anyhow, you can check the current flow through the wur when plugged in the car. The expected current flow for ~12 V would indicate a good power feed. Is there intermittent or heat sensitive contact issues or worn connectors, then your amps would be low. So measure the wur resistance (for the 090 they can fold into parallel as it warms up so be aware) and then I=v/r. So for the 090, when warmed up it was 10 Ohms roughly (by memory). So I expected was = 12.3v/10 A. If it was much lower then contact connector issue. I have extra connectors that i can add in series making this test easy. Otherwise check for additional resistance of the wur to the fuse box and local to the wur. The delta is the R drop. Be aware that one terminal of the wur for me was common. You can even bring the multimeter into the car and observe the current draw as you drive, but the setup has to be clean.
Phil

Phil,

The system pressure is not a function of temperature. The system fuel pressure remains the same when engine is cold or warm. Have you measured the SP at different operating temperatures and obtained different values? Keep us posted. Thanks.

Tony