Hey all - having a tough time with my throttle positioner and not getting vacuum from VSV port 1 at idle. Truck is a 10/76 build 1977 California 2F. I bought a "new" VSV thinking this might be it, as the '77 emissions control manual pointed to that as the issue, but to no avail. I've also reflowed solder on all of the joints on the back of the emissions computer circuit board, replaced all hoses, and checked for other vacuum leaks. Additionally checked that the VSV is receiving power (it is) and checked all of the pins as per the emissions control manual. I have not tried the speed test, as I don't know if there's a point in doing so if there's no vacuum at idle; i.e., no way to see if it's switching off if doesn't turn on to begin with.
I've also checked all fuses and they look fine, however I've only looked at the fuses under the dash (if there are others I don't know about them?). Last thing this points to is a wiring problem, potentially. Any other ideas / thoughts?
TIA!
I've also checked all fuses and they look fine, however I've only looked at the fuses under the dash (if there are others I don't know about them?). Last thing this points to is a wiring problem, potentially. Any other ideas / thoughts?
TIA!