No start

[Darascal101]

Just wondering if a 1994 3.0 should start without the o2 sensors plugged in. Also are there any other wire I should look for I may have forgotten. I can hear the old pump prime and it will start if I manually feed it gas. HELP

 

[RonD]

If it starts using 50/50 test(add gas manually) then you have spark and at the right time
So there is no fuel delivery inside the engine

In 1994 fuel injectors are controlled by the engine computer, PCM
As is the fuel pump which you say you can hear run for 2 seconds with key on?

Look at the CEL(check engine light) on the dash
With key on CEL should come on, that means PCM has booted up
When you crank the engine CEL should go OFF as soon as engine is spinning, that means PCM is getting a good timing signal from TFI spark system
If CEL stays on then no timing pulse, so no injectors, check wiring on TFI module, usually under battery tray on a 3.0l

If CEL is going OFF then time to test the "gasoline" in the tank
Crank engine over a few times
Pull out any easy to get at spark plug
Tip should be WET with fuel, light the tip with match or lighter, should burn fast and easy, if not "it ain't fuel", lol

If tip is DRY and CEL goes off then most likely the PCM is bad

There is no sensor on a 1994 that can cause a no start, except spark system and you have spark
In 1995 and up only the crank sensor can cause a no start, and in some years MAF sensor being unplugged, but that's software thing

 

[Darascal101]

If it starts using 50/50 test(add gas manually) then you have spark and at the right time
So there is no fuel delivery inside the engine

In 1994 fuel injectors are controlled by the engine computer, PCM
As is the fuel pump which you say you can hear run for 2 seconds with key on?

Look at the CEL(check engine light) on the dash
With key on CEL should come on, that means PCM has booted up
When you crank the engine CEL should go OFF as soon as engine is spinning, that means PCM is getting a good timing signal from TFI spark system
If CEL stays on then no timing pulse, so no injectors, check wiring on TFI module, usually under battery tray on a 3.0l

If CEL is going OFF then time to test the "gasoline" in the tank
Crank engine over a few times
Pull out any easy to get at spark plug
Tip should be WET with fuel, light the tip with match or lighter, should burn fast and easy, if not "it ain't fuel", lol

If tip is DRY and CEL goes off then most likely the PCM is bad

There is no sensor on a 1994 that can cause a no start, except spark system and you have spark
In 1995 and up only the crank sensor can cause a no start, and in some years MAF sensor being unplugged, but that's software thing

Okay. Thanks for the info. I drained most of the old fuel and replaced with new gas.

 

[Darascal101]

So here is where I stand. I have 40 psi at the fuel rail. Engine will start and briefly run if I manually add fuel. The CEL light goes off while cranking and I have tested the injectors with a noid and they show they are firing. I checked the OHMS and each injector show between 13 and 14. Drained the old gas out and added 5 gallons of fresh fuel. I have noticed the plug is dry when I pull it out after cranking the engine

 

[RonD]

Injector are plugged or fuel rail is, after pressure port

You can ground an injector manually with a jumper wire
Each injector will have a RED wire, that has 12v with key on, the OTHER wire is its ground
Find an easy to get to injector put a paperclip or wire in with its ground wire
Key on
Ground that injector just count to 1, lol
remove ground
Try to start engine, it should fire if fuel came out that injector, or you can check that cylinders spark plug tip

 

[Darascal101]

Injector are plugged or fuel rail is, after pressure port

You can ground an injector manually with a jumper wire
Each injector will have a RED wire, that has 12v with key on, the OTHER wire is its ground
Find an easy to get to injector put a paperclip or wire in with its ground wire
Key on
Ground that injector just count to 1, lol
remove ground
Try to start engine, it should fire if fuel came out that injector, or you can check that cylinders spark plug tip

So I removed the plenum so I could check all the injector connections which brings up the question ,can I start it like that while trouble shooting?

 

[rusty ol ranger]

So I removed the plenum so I could check all the injector connections which brings up the question ,can I start it like that while trouble shooting?

I wouldnt try.

It would be like holding your foot floored on the accelerator if it did start, and no way to control the free rev. Your bottom end bearings will thank you

 

[Darascal101]

I wouldnt try.

It would be like holding your foot floored on the accelerator if it did start, and no way to control the free rev. Your bottom end bearings will thank you

I figured it was bad idea

 

[RonD]

Disconnect the coil wire to distributor, so NO SPARK and you can crank engine to check injectors

 

[Curious Hound]

These things are absolutely horrible for making reliable electrical connections. They are absolutely wonderful at creating troubleshooting headaches.

 

[Darascal101]

So I went back and tested voltage and pulse at all the injectors. Also retested resistance and all 6 injectors are very close to each other. I pulled the fuel lines and tried blowing into the inlet and return side. No air passed through the inlet side but air and fuel passed through the return and out of the inlet side. I went to remove the rail and it appears you have to remove the distributor to get the gray hose out. Am I missing something?