I was reading an article in the diesel power mag on a 98 12 valve, It said the valet switch cuts the air off to the pump. Just wondering what they are talking about.

 

Cuts the air out? I know next to nothing about 12v, but come on! Less air to the pump?

 

There is a line that runs into the AFC housing on the pump. When your motor starts making boost, it pushes a little rubber diaphram in the pump forward, and lets your injection pump start fueling harder to keep it from smoking like crazy right off of idle. The valet switch blocks off that line so that the boost doesent get to the pump, therfore it wont fuel near as hard as what is possible. Flip the switch, it lets the boost go through, and you are back to full power. I have a valet switch on my truck. Kinda fun to play with. When you loosen the starwheel on a 12 valve it makes that rubber diaphram easier for the boost to push forward, which gives you more fuel and smoke on the bottom end.

Eric

 

probably the only "flip of the switch" us 12V guys can have.

 

Its as close to electronics on a truck as I ever want to get again.

 

What about the lock-up switch for the autos?