Have a sluggish jerky truck? Poor MPG? check your belt acc's!

[Ranger44]

I know some may say duh! It's a commonly overlooked cause for a jerky/sluggish symptom.


I had a seizing a/c compressor on my 3L. I was constantly having sluggish acceleration, and a jerk when i let off the gas(coast) and went to add throttle again. You can see how this could drive somebody crazY?

After looking over engine controls and drivetrain components, and was stumped for a week, I decided to just stare at it and hope an answer would come to me. So I remembered belt drive load, and I unplugged the a/c compressor (cause it was easiest) and voila!

Do remember though, that when you unplug the compressor, the pressure switch will still send input into the PCM to adjust for load. So pull the a/c fuse. Otherwise your rpms will be all over, and/or sit at 2K w/ defrost on.

 

[srteach]

Was it the AC pump or the AC bearing that was seizing? The bearing is about $10, the pump is about $150+. Check both.

 

[fixizin]

I'm not following... why couldn't you just shutoff the A/C? Are you saying the electric pulley clutch was sticking, and turning the compressor even in "Vent" mode?

 

[Ranger44]

In defrost your a/c runs, whether you have it turned on or not.

 

[chubster2003]

in all of fords brilliance, they made the a/c run on all settings EXCEPT floor only.... so the only way to not have the a/c rob the o-so-precious little horse power the 3.0 has, keep your stuff on floor

 

[Ranger44]

Maybe on later models they did that?

I'm pretty sure it's only defrost on my truck. They do it because the a/c evap acts as a dehumidifier. It then clears a window faster when it's humid outside. This helps both in the summer and winter in IL.

 

[TomB1269]

On the newer models (2000/1999 and up) the A/C should only run in 5 modes and under 40 or 50 degrees only 2. The A/C should enage when in A/C max or in A/C always (I do not think the temp is checked). However, when the temp is below 40 or 50; Defrost, Defrost/heat and Bi-level (dash & feet), should not have the compressor engaged (unless of course you have an A/C button and press it. As for just feet and just dash, the A/C should never engage. I have physically confirmed this on my 02 Ranger, also my 06 Freestar, and an 05 F150, and an 05 Tarus (w/3.0 liter).

 

[turtle3.0]

My 02 engauges the AC on ALL settings except Vent and of course OFF regardless of temperature. Has since the day I bought it. Believe me, everytime I go to merge onto the highway on an uphill ramp, I turn the dial to vent or off just to get a little more umph.

 

[Viper Command]

just unplug the clutch wires....

presto, no bogging

 

[TomB1269]

Turtle3.0, If that is the case, and your A/C compress clutch is engage down 30 to 40 degrees you have a problem. It should only engage as I had listed............ You may want to fix it as the A/C compressor also robs MPGs, but for summer months when you want the A/C but need a temporary off switch at wide open throttle. Rig a normally close switch to be opened when the pedal is floored or near. It has not been a big issue but now that I think about it I may do the same for the hills and like around me.

 

[lorenambrose]

Turtle3.0, If that is the case, and your A/C compress clutch is engage down 30 to 40 degrees you have a problem. It should only engage as I had listed............ You may want to fix it as the A/C compressor also robs MPGs, but for summer months when you want the A/C but need a temporary off switch at wide open throttle. Rig a normally close switch to be opened when the pedal is floored or near. It has not been a big issue but now that I think about it I may do the same for the hills and like around me.

I used to think the same thing. However Turtle3.0 is correct. There are two positions Vent and Floor that do not engage the clutch. All other positions the A/C clutch is engaged. This is not temperature dependant in any way, shape or form. The A/C compressor will engage at 10 below zero. The colder it is the more it will cycle but it still comes on. If yours does not then you should be the one looking for problems. I do not know who told you how it works, but they were wrong. I hope it was not Ford. It is wired to work the way I described, just look at the schematics.

The A/C is a huge source of parasitic drag as it is, and if not working properly it can really rob your truck of available power.

 

[Caps4x4]

I just spliced the compressor wiring, and installed an 'a/c' switch. When it's on, all is normal, when I flip it off, no more compressor drag. I used to just unplug the compressor except for when I thought I'd use it on warm days.

My 2000 runs the compressor in all positions except Floor, regardless of ambient temp.