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Ask A. Penland Your Own Question
A. Penland
A. Penland, Ford Senior Master Technician, ASE
Category: Ford
Satisfied Customers: 6563
Experience:  ASE Master Certified, ASE Advanced Gasoline Engine Performance
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1994 ford ranger: i first crank it up it starts up fine..engine warms

Customer Question

my 1994 ford ranger 4.0 sometimes does not want to start after it warms up i cant seem to figure out why? it's only after it runs in the morning when i first crank it up it starts up fine. so it has to do with something when the engine warms up the engine light is not on by the way
Submitted: 7 years ago.
Category: Ford
Expert:  A. Penland replied 7 years ago.


You should check for fuel pressure when the truck will not start. On the metal fuel rails for the fuel injectors there will be a schrader valve. It looks like a tire valve stem. Press the needle valve down in the schrader valve and see if you get a big spray of fuel. You may have a bad fuel pump or fuel pump relay. But check and see if you have fuel pressure when the Ranger will not start when hot. Let me know what you find. Don't replace anything just yet.

Customer: replied 7 years ago.
ok actually i just got threw replacing 3 fuel pumps before i found out that the fuel filter was so bad it was buring up the motors and i can hear it runing when i turn the ignition on, so i hope it isnt that but the fuel pump relay could be bad havent tryed messing with it yet but thanks i will let you know what happens im asuming i just put a regular tire preasure gauge on the schrader value and i will be able to see what the presure is
Expert:  A. Penland replied 7 years ago.


Do not use a tire pressure guage. You will need a fuel pressure guage. A tire pressure guage only measures air pressure. It will not measure fuel pressure and the system needs to be enclosed when testing fuel pressure. You do not want any fuel leaks. Fire hazard may happen.

Below is a fuel pressure guage.


Plus if the fuel pumps were burning up, the relay may be burned up also.

Edited by APenland on 4/8/2010 at 12:29 AM EST
Customer: replied 7 years ago.
ha i just tryed it before i got your reply it was saying around 29 psi but i see what your saying about the fuel presure gauge i really dont think it has anything to do with the fuel i think its more of an air problem you dont think it could be any of the sensors or anything
Expert:  A. Penland replied 7 years ago.

Try a couple of test.

Unplug the IAC and start the truck and see if it stalls. You may have a vacuum leak.

The only way to find out if you have any bad sensors is to get the codes from the engine computer. The connectors to connect to are under the hood. Below are a couple of diagrams to use to get any codes. You will need a jumper wire graphic


No special equipment hookup is required. STI is jumpered to SIG RTN at Self-Test Input (STI) connector and the Data Link Connector (DLC).

Then count the check engine light flashes for any codes and write them down. They will be 2 digit codes.

Customer: replied 7 years ago.
ok i will