Anyone know what exactly the fuel pressure up switch does that is located on the thermostat housing? Currently it's unplugged and I haven't noticed any difference in performance or starting. My thermostat housing is cracked and no replacement is available. Also on my 22rte I have 2 sensor/switches on the thermostat housing I know one for sure is A/C related. My 4runner is converted to 5 speed so I'm not worried about overheating using the A/C. Could I just wire in a resistor for this switch to allow the A/C to work?

 

The fuel pressure-up VSV is located on the apron. http://personal.utulsa.edu/~nathan-b...ne/41fuelp.pdf I'm not sure what you are referring to. What the FPU system does is raise the fuel pressure when the engine is hot to prevent (or overcome) vapor lock. Vapor lock isn't too common (so you're not likely to notice much), but if it happens you won't be able to start.

When you refer to the "thermostat housing" could you be talking about the water bypass outlet? http://personal.utulsa.edu/~nathan-b...68cylinder.pdf That is where the temp sensor for the A/C is located. It's just a switch (a resistor replacement would make no sense). Best as I can tell, grounding the lead should make the A/C work.

 

Thanks for the reply, in this pdf attached it is called temp switch no.2. This is the part I am referring to.

The thermostat housing is just the water outlet that connects to the upper radiator house that has the thermostat in it.