Hard to start when it's 70 deg out, 40 it starts fine

[SLR_65]

Hi Guys,

I have an small problem that's crept up with my '92 Ranger V6 3.0 5 speed just recently. I'm planning on working on it this weekend and I hoped someone could point me in the right direction.

When I go to work in the morning and it's in the 40's for an outside temperature the truck starts fine and drives to work just fine. When I get off work though and it's in the '70s it starts, runs rough and may die unless you give it some gas. Give it a little gas and a moment or two to warm up though and it settles right down and runs and drives fine.

If it were carbureted I would be checking the choke mechanism but since it's fuel injected it doesn't have one. I imagine it has a sensor somewhere though that tells it if the engine is cold or hot though and I wonder if that sensor isn't getting out of calibration?

The check engine light is off, I haven't had time to go and get any codes pulled yet.

Any thoughts or suggestions as to where to start?

Thanks!

Steve

 

[locovaca]

If it were carbureted I would be checking the choke mechanism but since it's fuel injected it doesn't have one. I imagine it has a sensor somewhere though that tells it if the engine is cold or hot though and I wonder if that sensor isn't getting out of calibration?

That sensor is the ECT, and it's the two wire sensor by the thermostat, and yes, it can cause issues like this if it's going bad.

 

[SLR_65]

Thank you Locovaca!

Doing a little research tonight it appears many, many things can cause this but a very frequent culprit is the fuel pump relay - I think I'll stop by and pick one up tomorrow after work. I'll post back if it helps . . . if it doesn't I'll try the ECT sensor.

Thanks again - it's much appreciated!

Steve