Help please

[danny k ply]

Help please I have a 93 Ford ranger 4.0 I put a new fuel pump new fuel pressure regulator new fuel filter I have a new ignition control module I checked the fuel pressure at the pump and it's got 70 PSI when I go up to the fuel rail and check the pressure it has around 27 to 30 PSI when I start the truck it idles great but when I accelerate in neutral just revving the engine it gets around 4,000 RPMs it shuts off like you turned it off with a key if you have it in gear and driving it it'll shut off at 2,000 rpms like you turned it off with the key I've also put new injectors in I've checked them with a stethoscope to make sure they're working I hear them clicking new plugs new wires just about every sensor well actually every sensor on the vehicle I have changed any input on this would be greatly appreciated

 

[RonD]

Welcome to TRS

Manual or Automatic?

Do you have a Tachometer on the dash?
And is that where the quoted RPMs are from?

Does the CEL(check engine light) work?
It should come on with key on
It should go OFF when you try to start, i.e. engine spinning from starter motor
Does the CEL come on after engine is running?
This means OBD codes are set which could help your diagnoses


Yes, electric fuel pumps are capable of 80+ PSI, at the pump itself
1993 Ranger should be running 30-40psi at the fuel rail if Fuel Pressure Regulator is working as it should
So all that is fine on your 1993, 27-30psi is OK

Next step would be to pull out the computer and open it up
There are 3 capacitors inside that need to be changed, blue ones seen in this picture: http://www.auto-diagnostics.info/ford_eec_iv

If they are black then they have, most likely, already been changed, but look for leaking around their bases, under $5 fix

"shuts off like you turned it off with a key"
Does this mean the engine completely stalls, doesn't go back to idle RPMs?

All engine computers have a REV limiter, usually about 3,000rpm
Depending on transmission type, manual/auto, this Limiter can be triggered by "in gear status", clutch pedal status, and/or speedometer status, 0MPH always triggers it

 

[danny k ply]

It's a manual transmission the cel comes on soon as u turn the key and yes the truck stalls completely out

 

[RonD]

Does the CEL come back on without you touching the key when it stalls?
If not then Computer(PCM) was shut off, lost its 12volts
Which would cut off power to injectors and fuel pump

PCM Relay in engine fuse box powers the Computer and injectors and Fuel Pump Relay

With engine running, turn the key a little one way and the other to see if engine stalls out
The ignition switch under the steering column, above brake pedal, can get worn contacts, so can shut off PCM relay or spark if a contact opens

 

[danny k ply]

Hey my check engine light stays on all the time after it starts because I've got a an O2 sensor that is not hooked up for some reason it got wires got broke but it's run fine free to three years without that hooked up

 

[rusty ol ranger]

Hey my check engine light stays on all the time after it starts because I've got a an O2 sensor that is not hooked up for some reason it got wires got broke but it's run fine free to three years without that hooked up

Have you pulled codes to see if theres anything else besides the O2 code?

An unplugged O2 isnt gonna cause it to do what its doing.

If it quits like you hit the key its something electrical/spark related....if it was fuel it would kinda putter to a stall