hard start when cold

[christian1]

Have a 96 2wd 3.0 auto that is a bear to start when cold. It will crank and try to fire but not start. If I give it any throttle I can hear it detinate through the intake. After cranking several times it will finally start. After the initial start it will start right up every time. I seem to have the Ford mechanics baffled in my area.

 

[Earl43P]

Test if fuel pressure is bleeding down overnight.

Try this next cold start:

Turn key to Run (your dash lights will test, wait while fuel pump runs for two seconds, DO NOT crank the starter). Turn key to OFF. Repeat 3x, THEN crank the starter.
Should fire right up with minimal cranking.

If so, you may have a leaking fuel pressure regulator, bad fuel filter, or a stuck open (dirty) fuel injector. Examining your spark plugs might indicate which injector is leaky.

Most in-tank fuel pumps have a check valve to hold pressure. If it is bad, replacing the fuel pump is the only repair, or you can continue to just prime the fuel system before cold start as described earlier, which is a good practice for all fuel injected vehicles.

 

[RonD]

+1 ^^

Fuel injected engines can't use a regular Choke plate, no jets to suck extra fuel out of.

So they have a "cold engine" computer setting, this setting runs the engine rich and with advanced timing, also sets idle at about 1,000rpms
Gee, sounds just like having a Choke, lol......

This cold engine setting is triggered or determined by the ECT(engine coolant temp) sensor, this is a 2 wire sensor only used by the computer, there is a 1 wire sender used for the dash board temp gauge, they look similar but are not the same.

If after starting the cold engine the idle goes up to 900-1,000rpms then ECT is OK, computer knows engine is cold, but if idle is low, 700-750rpms then ECT sensor could be the problem, they rarely fail but not never fail.

Testing data for ECT sensor is here:
http://oldfuelinjection.com/?p=28

Very easy to test with an OHM meter