94 explorer starting issues when hot

[bandit75]

I have a 94 explorer 4.0 when the motor is hot tends to act like its vapor locked when trying to start. changed fuel pump,filter and same thing keps happening any help would be great

 

[MrShorty]

One fairly common cause of hard hot start problems is a bad fuel pressure regulator (the diaphragm ruptures and lets excess gas into the intake). Pull the vacuum line off of the FPR next time and see if there's gas in there (gas=bad FPR). Then I'd probably put a fuel pressure gauge on it and see what fuel delivery is doing on hot starts.

 

[bandit75]

ok I pulled the vacum line and no fuel coming out. Im trying to get a pressure tester right now. Is the fact there is no fuel coming out say its ok??

 

[MrShorty]

No fuel in the vacuum line suggests that the diaphragm in the FPR is still intact, which is the usual way that the FPR contributes to a hard start. It does not necessarily mean that the FPR is regulating fuel pressure correctly.

 

[bandit75]

Ok new fuel pump new fuel pressure regulator new crank sensor and still having starting issues when the engine is warm. HELP!!!

 

[YBCold]

could be the sending unit to the computer that measures the coolant temp. it has a connecter . its right nex to where the heater hose connects to the engine. sometimes those go bad.

 

[YBCold]

ill post pix in a bit

 

[bandit75]

Ok please send pics!!!

 

[Doomie17]

check the starter relay

 

[bandit75]

starter is engaging

 

[mawrazen]

O2 sensors!

: eace

 

[MrShorty]

After replacing those fuel system parts, did you ever put a fuel pressure gauge on it to see what the fuel system is doing?

 

[bandit75]

pressure is good and its getting spark I changed the temp sending unit today seems to be running better so far?? Gonna give it a run in the AM and see what it does