Rick Shellenbarger
Member
So I was trouble shooting my Fuel Pressure Drive Module (FPDM) issues (still not solved) and I found another problem! The hits keep coming! Anyway, the VCPV (valve with two lines and a green screw on cap next to the battery) is leaking. I noticed that my idle slowly creeps up from around 750 up to 1000 rpms under idle, and right around 900rpm I could hear a hiss. I checked all the lines (and I've done multiple propane tests) but couldn't find it. Anyway, the hiss is coming from the actual valve/solenoid (through the top). I can place my fingers around the top and make the hiss stop, however I don't know if it's sucking or blowing. I assume this affects overall vacuum, including the vacuum that the fuel pressure regulator/sensor is controlled by. The solenoid is $35 on Rockauto. I'm hoping this is all connected and my idle/startup troubles (FPDM related I thought) will be fixed, or at least be easier to diagnose without the added trouble from this leak.
Anyone know how the VCPV works and how a leak should affect idle/performance? I know it has something to do with fuel vapors, and I know it has vacuum (one line going to the firewall, one going under the throttle body... It's dark out and Im working in the dark here, so that's all I could really see).
Anyway, I'm going to get the part and go from there, but like everything else I just like to know how things affect my truck when they break.
It's been a busy week replacing parts, TPS, FPDM, FPRS, Fuel Filter, and now the VCPV. The first four didn't help, and the new FPDM actually seemed to make things worse (after the install I've had vapor lock like symptoms at startup).
Another paycheck or two and I'll have the Trac running like new
:angry:
Anyone know how the VCPV works and how a leak should affect idle/performance? I know it has something to do with fuel vapors, and I know it has vacuum (one line going to the firewall, one going under the throttle body... It's dark out and Im working in the dark here, so that's all I could really see).
Anyway, I'm going to get the part and go from there, but like everything else I just like to know how things affect my truck when they break.
It's been a busy week replacing parts, TPS, FPDM, FPRS, Fuel Filter, and now the VCPV. The first four didn't help, and the new FPDM actually seemed to make things worse (after the install I've had vapor lock like symptoms at startup).
Another paycheck or two and I'll have the Trac running like new
:angry:
