Hot Start Issues | Page 2 | Ford Explorer Forums

  • Register Today It's free!

Hot Start Issues

On my 94, the bubbling sound, when restarting warm, is definately coming from the fuel tank. Bubbling and rough warm start is ocurring less now that i have the engine running cooler after a good cooling system flush.

As for the PCV, remove the black plastic elbow and plumb straight off the metal. It pointing in a better director, up!

Purchased a fuel pressure gauge so fuel system pressure checks
to perform this weekend.
 



Join the Elite Explorers for $20 each year or try it out for $5 a month.

Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!
.





lol thank you! i feel so stupid for not noticing i could do that!
i took off every vac line from the octopus and put my finger over it, didnt work. i replaced a vac line on the charcoal canister also. vac line on the throttle body is fine. so its gotta be the exploders old fpr i used or i broke a plug wire. looks like ill try putting the other fpr back in first.

but i have lots of yard work to clean up before i mess with the truck
 






Fuel Pressure Test Results

So here are the pressures I measured......

KOEO 38 PSI
Holds that pressure for >5 minutes (Haynes Spec 30 PSI min after 5 minutes)

Idle 26 PSI (Haynes Spec 30-45)
RPM 36 PSI (no spec, just an observation)

Idle w/ FPR vacuum disconnected 38 PSI (Haynes Spec 40-50 PSI)

Haynes says to pinch off the return line and measure the pressure when you have low idle pressure. I have steel braided pressure and return fuel lines so I am not wild about crushing those. My pressure gage kit only came with the Schrader adapter.

Suggestions on my next step are welcome here!

Maybe a test shut off valve inserted between the FPR and return line so that I can shut off return flow and observe the pressure?
 






Idle 26 PSI (Haynes Spec 30-45)...Idle w/ FPR vacuum disconnected 38 PSI (Haynes Spec 40-50 PSI)
Were the other symptoms present (rough idle on warm start) present during these measurements?
 






No. The rough idle warm only lasts for a minute then smoothens out. The rough idle can be cleared more quickly, say 10 seconds if I rev the engine.

So...is it the increase in fuel pressure that occurs with increased RPM that is smoothening out the idle?
 






So...is it the increase in fuel pressure that occurs with increased RPM that is smoothening out the idle?
I find with something like this that it is important to get the fuel pressure readings when the symptoms are occurring. I'm sure your hypothesis is a possible explanation, but you will need to set it up and test it so you can actually see if the pressure looks normal or not while it is idling rough. Can you consistently recreate the symptoms? If so, I would probably hook up the pressure gauge and secure it under the hood. Drive it to warm the engine up (or whatever the "drive cycle" needs to look like to create the symptoms). Turn it off, pop the hood, and restart while watching the fuel pressure gauge.
 






Is there value in measuring the fuel pressure with the return line blocked as Haynes suggests?
 






It is an effective test for checking to see if the FPR is stuck open. If the pressure is too low, and it spikes when the return line is clamped off, then the FPR is opening prematurely. If the pressure remains too low when the return line is clamped off, that indicates that the pump is unable to generate sufficient pressure to open the FPR.
 






Featured Content

Back
Top