no start

[karsyn28]

Hello,
I have 94 ford ranger 4.0 xlt. It will run if i spray contact cleaner down throttle body so it has spark. has new fuel pump and regulator. fuel pressure is at 35 psi with key on. key on and not cranking the fuel pump never stops running. i have switching voltage coming from cam sensor. i cant pull codes using the on board diagnosing system. the check engine light does work. before is by a used pcm any ideas?
thanks for any input

 

[RonD]

PCM is probably bad.

I would check if the injectors are opening which it reads like they are not, there should be a "tick/click" sound from an injector when it opens and closes, you should hear that when engine is cranking.

Remove one injector's electrical connector, turn key on, you should have 12volts at that connector.
This 12volts comes from the EEC relay in the power box, the EEC relay also powers the coil, so if you have spark the relay should be good but the splice might be bad going to the injectors.
If you have less than battery voltage at an injector then you have a corroded wire/connection.

The PCM grounds the injectors to open them, so also check around the PCM for loose or corroded ground points, the PCM has several separate grounds.
There is also a "Noid light" that can be used to see if injector is getting it's firing ground from PCM.


The fuel pump is control by the PCM via a relay(PCM grounds relay), these Fuel Pump Relays can stick closed, so when key is on fuel pump is on, but it could also be the PCM since, I assume, both of these problems, fuel pump always on and injectors not working, happened at the same time.