Won't run in the heat

SmurfTruck · #1 07-25-2011, 08:22 PM

Hi there! I have a 1994 Ranger 3.6L, V6, 5 speed manual that I've owned for about 5 years. Since summer started, it doesn't want to stay running if it is really hot outside and/ or has been sitting a few hours. I have no problem driving at night or in the morning. It turns over but won't pick up and if it does it revs above 1200 RPM only to die a few seconds later.

I recently took it in and the repair shop could not duplicate the problem - of course! Like taking a sick child to the doctor.

The fuel filter was fine as were the volume and pressure.

There are no other problems with this truck. The gas gauge is accurate and the tranny was overhauled and the fly wheel was machined Fall 09. There are no fuel or tranny leaks either.

I've researched this problem but haven't found any similar issues with the heat being significant. I don't think it's the fuel injectors because it doesn't run rough when it finally does decide to get going.

Any suggestions? I want to avoid dropping hundreds of dollars to see if it's the fuel pump if I haven't tried other options.

Thanks a bunch!

north44 · #2 07-26-2011, 12:57 AM

Don't know if this can help, but the first thought I had was "vapor lock" in the fuel delivery system somewhere, since the symptons seem to be triggered by heat.

Second thought was that there may be a problem in the return line?

Hope you can get it pinpointed.

mt1986 · #3 08-01-2011, 02:03 PM

check the elecrical connections at the fuel injectors, corrosion in there changes the signal from the computer and it wont inject fuel, when the temps go up it increases the resistance thru the connector and it throws the parameters out of whack, all the sensers on our trucks use the resistance value to send signal to the computers a small amount of crud will have a profound effect on driveability i used PB blaster and an old toothbrush to clean mine the PB just melts the crud, be sure to use dielectric grease to insulate the connection when going back together with the now clean connectors, good luck