hey guys...
i bought an autometer electrical fuel pressure gauge and air/fuel ratio gauge for my truck in order to tune the adjustable fuel pressure regulator. i have a question for those who have installed them. where does the "sender" go? in the instructions it only says "install sender", but theyre not clear as to where it goes. i was going to have a shop install the gauges for me, but i figured id give it a shot first and see if i can save money on the installation. someone help me out please, thanks!

 

The fuel pressure gauge mounts where the schrader valve is on the fuel rail, just before the regulator. You may need to buy an adapter. The air/fuel gauge mounts inside the exhaust near the collector. Some people wire them into the O2 sensor, but this usually alters the sensors output voltage, which fools the ECM into thinking you are running rich, and leans out your mixture. The correct way to install it is to drill a new hole into the exhaust, near the O2 sensor, and have a boss welded to the hole that can be drilled and tapped to match the sending unit diameter and thread pitch.

Take care,
-Chris

 

thanks a lot for the info! one more question, my shrader valve has external threads and so does the sender, so i guess i will need an adapter. i did a search and someone said that the adapter needed is one with one male and one emale end, but wouldnt i need one with 2 female ends? also, how can i find out the size of the schrader valve? thanks!

 

The schrader valve is a universal size. It's the same size as the ones on your tires. Take the sender with you to a hardware store, and ask for help. Tell them you need a double female brass adapter for connecting the sender with a schrader valve. You can always go out to the parking lot to verify that it fits the schrader valve. I don't know the diameter or thread pitch of the schrader valve off the top of my head (although I probably should), so you're going to have to hope they do. The other thing you could do is go to your local auto parts store and check their adapters. Ask for a tire valve stem to use for reference, and then when you think you've got the correct adapter, double check it on your schrader valve. Before you install the sender, you MUST remove the valve from inside the schrader fitting. You will need a special valve stem cap to do this. If you don't already have one, pick one up while your at the auto parts store. Shouldn't cost more than a quarter. If you forget to remove the valve, the guage will always read zero.

Take care,
-Chris

 

thanks for all the help!