fuel check valve

Where is the fuel check valve to prevent backflow? I heard one is in the fuel tank just downstream of the fuel pump. I don't see it in the diagrams. Is it part of the pump (23220P in diagram) and not replaceable separately? The pump is fine.

https://parts.toyota.com/showAssembly.aspx?ukey_product=63069361&ukey_assembly=6722450

 

The only valve I know of is in the fuel tank to prevent fuel leaking when your or the left side or upside down.

completely mechanical

 

The pump itself has two internal check valves. One located in the outlet hose nipple and one in the outlet housing iteslf. The one in the outlet nipple (yellow arrow) is for backflow the other (red arrow) exits to the tank. I'm guessing the one to the tank is some attempt at over pressure relief and/or a means of allowing some minimum amount of "flow" thru the pump for cooling. Parts are not sold by Toyota separately. Frankly they are not likely to fail, just a spring and a ball.

You didn't state a symptom/problem but a guess would be excessive cranking before finally starting. If so, keep in mind that the pump will fill a drained fuel system including the fuel filter in just a few seconds. Many excessive cranking issues are due to leaking injectors causing a "flooded" condition that clears out as the engine is cranked for a while.

 

It’s in the outlet nipple of the pump itself.

 

Yes, long crank after sitting a while. 7 cam rotations consistently. I noted it as 6 a few months ago but it seems to have increased to 7 as the weather has gotten colder. Maybe it hasn't changed. Restarting cold or warm it's much quicker.

Any way to confirm a leaky injector or flooded condition? I saw a vague reference to a procedure involving sticking a borescope in a spark plug tube? I'm not familiar with the injectors and my only interaction is I think I had disconnected the wire connectors to them while I did the valve cover gaskets. As far as other leaky injector symptoms, it idles smooth, passed smog easily, gas mileage is good. A visible but very light amount of white smoke out of exhaust while engine is cold in ~50F weather, and clears away as engine warms up.

 

I from what I understand a leaky injector would be much more evident on a warm/hot start.

if it’s a leaking injector or would run rough right after starting.

If it’s a OEM pump It’s probably not that.
If it’s aftermarket it’s probably the shitty check valves they use.

TPS/PPS/idle air control valves/ throttle bodies can cause long starts. Difficult to diagnose small inconsistencies in voltages so the easiest method is throwing parts at it when it does to the sensors.

You can probably find a thread on checking for worn out bore/throttle blade as well. It’s probably one of those things.

 

Should be original fuel pump. The previous order kept most or all records down to every oil change and paint scratch repair. Throttle body is good, IAC valve is good, hoses all good. No typical symptoms of TPS issue.

If I can see above the tank with the wheel and fender cover off, and there's a supposed fuel hose segment there in place of a rail, I might try installing an inline check valve into a new hose.

 

Could be a coolant leak......long term it would get worse.....
also would start to rust in the cylinder(s) affected....
if so......
borescope would allow u to see rust.....