1998 turns over but won't start

i have a 1998 tacoma 3.4l 4wd a couple weeks ago it started intermittently doing this but after a few tries it would start. Yesterday it decided it was done and will not start so i replaced the fuel pump and strainer that did nothing then before i hooked up the fuel lines i applied 12v straight to the fuel pump to make sure fuel would flow and it did, so i plugged it back in. so then i plugged it back up and tried the key with hoses open and nothing. so after some more web surfing i found several posts that say try starter fluid to see if it will even attempt to start which it does but dies instantly. so that same post said replace the crank position sensor and i did that and still nothing. something is keeping the fuel system from pumping and injecting because after i hooked up the hoses i tried applying 12v straight to the pump again and even with + pressure it wouldn't run. please help this is my families only form of transportation.

 

Fuel filter maybe?

 

the pump isnt pumping unless i apply voltage straight to pump something is keeping the fuels system from working

 

Check the EFI fuse

 

checked all fuses

 

So you have spark, right? Then it can't be the disabling system... Hmmmm....

 

I don't know which other sensors disable the fuel pump from pumping to protect the engine. You are positive you have spark, right?

 

I would suspect the IAC (idle air control)

They become dirty with carbon build up/gunk
Much like the intake plenum does over time.
It can become even worse (dirtier) if using a free flow/oiled type filter element.

The IAC cannot be cleaned by running intake cleaner thru.
It must be removed and cleaned manually.

The carbon/gunk build up occurs on the IAC's vane.
Initially the start ups and running intermittently suffer...
eventually it quits functioning altogether and the engine will not start.

Purdy expensive unit to replace with new...
tho' occasionally they can be cleaned and will work just fine.

There is a value test described in the FSM
to determine that it's function value is acceptable
and that the unit has not failed completely.

But it will likely need be cleaned first
in order to conduct the test.

It is a common failure with the 5vze engine.
The IAC is located atop of the intake near the throttle body.

Mine became dirty once and was cleaned.
Another time the value was below standard and needed replacing.

On another junk yard motor I was helping someone install.
The engine would not start - run initially.
But when the IAC was cleaned... it did.

good luck

 

Fuel pump relay?

 

Ok it doesn't seem to have spark how can I test the coils

 

I pulled the plugs in the first 2 cylinders on the driver side put them in the boots and laid the threads on metal and got no spark.

 

The reason I was asking is because I think the Toyota disabling system alarm deal, shuts down the spark as well as the fuel. So if I'm thinking right, not sure, then your issue could be related to the factory alarm system. Wait, do you have the factory alarm?

 

I don't think I have the factory alarm system I don't have an alarm on it at all that I know of.

 

When you tried the starter fluid, it just cranked still, like it was before? Or it started, stumbled, then died? Just trying to clarify is all.

 

Started for a second but never really ran then stumbled and died.

 

Okay, well if there was no spark, then it would've just continued cranking like before without the starting fluid. So it sounds like you have spark, at least.
Did you end up checking the fuel pump relay?

 

Not sure I checked a bunch of relays and all seemed to be ok.

 

A bad relay won't be visible with the eye. You'd actually have to remove it and put a multimeter on it, or if I remember right, you can remove it and hook up 12 volts to two of the prongs or leads and get an audible click out of it, if it's good. I don't remember off hand which leads would get the connections. Okay well the same way you put 12 volts to the fuel pump. Do you have a way to try that with the relay?

 

Also, do you have power windows? The power windows might use the same relay and you could pull the power window relay and plug it in in place of the fuel pump relay to see if that gets the truck to start up. But that's only of they're identical. I'll try and look that up.

 

Oh you know what, I forget that the fuel pump shares a circuit with the EFI system.