I've recently had swapped in a complete rebuilt 22re and rebuilt auto trans into my 84 4runner. I've gotten the injectors cleaned by RC Engineering, new pressure reg on rail, fuel filter, gas tank cleaned, and new wiring. It takes a few tries to get it to turn over then it slowly gets better and eventually starts. But if i shoot starting fluid in then it hits almost instantly and runs rough for a minute then is ready to go. But what really makes me is when if i take the rubber hose off the pressure reg on the back of the fuel rail and then turn it over it cranks right up. WHAT DOES THAT MEAN???

 

Disconnecting the vacuum line to the pressure regulator makes the regulator max out the pressure in the fuel rail and this causes the injectors to squirt more fuel in.

Given that, it appears the ECU is not realizing the engine is cold thus the ECU is injecting the incorrect amount of fuel for the cold engine. Most likely, the coolant temperature sensor on the front of the intake manifold is not reading properly or the wiring from it to the ECU has a problem. This is somewhat bolstered by the fact that you can use starting fluid to get the engine running, and it runs rough for a few moments until things warm up a bit and start working properly- if you've ever driven a vehicle with a carburetor when the choke doesn't work properly you may be able to relate.

Now, though, we have a few other things to check... things which are part of the cold starting system on the 22re.

First is the Cold Start Injector (referred to later as "CSI"). The CSI is mounted to the side of the intake manifold and has an electrical plug and a fuel line connected to it. When voltage is applied to the electrical plug, the injector opens allowing fuel to be sprayed into the engine.

Second is the Cold Start Injector Time Switch (referred to later as "CSITS"). The CSITS is exposed to the coolant in the manifold. When you turn the key to start the engine, and when the coolant is below approximately 60 degrees Fahrenheit, the CSITS sends voltage to the CSI causing it to inject fuel. It can cause the CSI to inject fuel after the engine has started, but that is determined by the ECU.

Third is the auxillary air valve (sometimes called the idle air valve, heretofore referred to as either AAV or IAV). It is mounted below the throttle body and is basically a variable air valve that allows air to bypass the throttle plate in the throttle body based on the valve's temperature. It's purpose is to let air around the throttle so the engine idles higher when cold and lower when warm. On your truck. it is heated by an electric coil which causes the valve to slowly close, thus cutting off air, as it warms up (on later models, it's heated by the coolant). This basically means that when cold, the engine should idle at a higher RPM when cold than when warm.

Those three components perform functions similar to the choke on a carbureted vehicle.

Additionally, there are other sensors used by the ECU to determine the temperature of the engine which allow the ECU to calculate how much fuel is required (and if the CSI is required to help the engine start cold). They are the coolant temperature sensor (which is located on the front of the intake manifold and typically 'green' in color) and the intake air temperature sensor (which is located inside of the air-flow meter and would require replacement of the air-flow meter if it has failed).

Given that starting fluid gets the truck running, my opinion is that there may be issues:
... with the CSI. Check for voltage across the terminals in the CSI plug. Voltage at the plug means the CSITS is working. No voltage suggests that either the CSITS is not working or there is a problem in the wiring.
... with the IAV. As mentioned, the engine should idle higher when cold and lower when warm... and the idle should never go below the idle spec printed on the sticker on the underside of the hood. Typically, 750 for the 22re with a manual, and around 800 for the 22re with an automatic.
... with the coolant temperature sensor. It may be telling the ECU the engine is warmer than it is, causing the ECU to not inject the proper amount of fuel for the cold engine.

Don't know if that helps you out, but here's hoping it does.

 

Understood, but its not the vac line that I'm pulling, its the return hose that leads back to the gas tank. I take that off crank it while its off and it starts right up, messy but its what it does. Thats what i dont get...

 

maybe its plugged up

 

the return line to the tank you mean right?

 

this covers all the cold start threads I have read so far. best post ever.

 

yep, the return line. If it's plugged, or even significantly restricted / pinched, the fuel pressure will go too high and cause the injectors to squirt too much fuel which in turn makes the engine run too rich, almost flood out. So you need to check it for blockage. You may be able to 'snake' some wire through the line and knock whatever's blocking it loose, or you may have to drop the fuel tank.

 

Glad I found this thread. Gives me more ideas to check out on why mine runs poorly.