94 ad 95 pickups

New here so bare with me.
Better half stopped at the store on the way home from work, came back out and guess what, it would not start. Motor would turn over but not run. Got it home started trouble shooting best I could. Checked for spark on #1 plug that's good. Plug appears to be dry. Once helper got there(this is her truck) turned on the key to start to see if fuel pump was on , no fuel pump. Checked fuses all good. Jumped B+ to FP turned on key heard pump running. How do I go about testing the air flow sensor and the cold start injector? Only resent work on it was an oil change a few weeks back. Any help on this would be great.

Thanks

scope103

How did you know the fuel pump was not "on" with key turned to STArt? I sure can't hear my pump over the sound of the starter.

If you mean you turned the key to "ON," the pump is not supposed to run then.

Did you try to start it with FP jumped (and fuel pump running)? (If it starts then, you have a problem in the VAF-COR circuit. If not, don't bother with the air flow meter yet.)

It's probably not the CSI, but it's easy to test. Remove the CSI (DON'T disconnect the fuel line; you must replace the crush washers if you do), put it into a suitable container, crank. If cold enough, it should spray.)

To check for blocked fuel, replace the fuel return line with a 6mm (1/4") clear vinyl tube to a suitable container. With the jumper in to run the fuel pump, I get about 1/2 liter/min. If you get ANY fuel you should have enough fuel pressure to start it.

94 ad 95 pickups

scope103 Thanks for the reply. Yes I did try to start it with the FP in 'TEST" B+ and FP jumped and the FP running but it did not start. Going to replace the fuel filter this weekend and try what you have suggested. As far as hearing the FP most of the trucks/jeeps/tractors ( non Toyota) I've worked on in the past with electric FP when the key is in the "ON' position the FP starts a prime. Is this not how this model works as well? Or does the FP come on once the start sequence is stared? Just trying to lean a little bit.

scope103

You have a fuel-injected engine. There is no such thing as "prime."

Imagine you get in an accident that breaks a fuel line. Would you like the fuel pump to keep running, spraying fuel everywhere as you try to get the door opened? Neither would anyone else. The fuel pump starts with the key to STArt, not just on. Once the engine starts (and is sucking air), it closes a switch in the VAF which keeps the pump running. As long as the engine is sucking air. The two switches interact through the Circuit Opening Relay (COR). The jumper is to bypass the COR (and VAF).

ev13wt

The flapper valve in the air meter trips the fuel pump to "on".

scope103

It CAN happen that way, if you have a bad COR (or wiring to ignition switch). The fuel pump should be started with the ignition key to STArt, and then kept running with the switch in the VAF. If the ignition-side of the COR fails, you can still get it started, it will just take more cranking.

old87yota

Let's back up a moment. It is true that many vehicles do in fact turn on the fuel pump on when the key is turned to the ON position for a few seconds. Both of my parents' Hondas turn on the fuel pump for a few seconds then shuts off when the key is turned to the ON position with the engine not running. This few second turn on can be called a fuel pump prime.

However, with the way the fuel system is designed on your engine, the fuel pump should not run with the key turned to the ON position with the engine off.

94 ad 95 pickups

OK so I'm not crazy. It's just a different set up from what I've worked on in the past. Cool I learned something.

94 ad 95 pickups

Update new fuel filter installed royal PIA to do. I have fuel at the CSI. Spark on 4 of 4 plugs (broke one of the wires). Going to replace the plugs and wires while I'm in there. If I have fuel at the CSI that means the fuel pump is work correctly. Right? Now what should I check?