ok I've got a new vac advance on the dizzy, to replace the one that was shot (91 efi auto)
the new one came with a rubber cap fitted to the little pipe at the back of the diaphragm housing, where as the old one just had the pipe venting to atmosphere. Now I assumed that venting to atmosphere would prevent the diaphragm from having to create a negative pressure, when the engine is 'sucking' in the other side of it.
This is my firs rr, but I have never seen this before with the numerous other cars I have worked on.
Anyone know which way to go: cap on or cap off?? is it just a shipping cap?
cheers
tom