Idle stumbles when load placed on engine

[ChristianWarrior]

Has anyone had engine stumble at idle about 100rpm drop. Happens when operating windows, turning steer wheel ,slightly ,but is the worst when a/c clutch engages. Also sometimes my a/c clutch engages/disengages every few seconds for 10x until stepping on throttle and going off idle. I checked my charge and it was full.

 

[ChristianWarrior]

I don't think its a sticky throttle body but possible. Also possibly a software update for engine ecm? Any ideas?

 

[peterk9]

Has anyone had engine stumble at idle about 100rpm drop. Happens when operating windows, turning steer wheel ,slightly ,but is the worst when a/c clutch engages. Also sometimes my a/c clutch engages/disengages every few seconds for 10x until stepping on throttle and going off idle. I checked my charge and it was full.

I've never really looked for anything like that before. All those things you mentioned create a load of some kind so I wouldn't be surprised to see a small drop in RPM. The constant engage/disengage of the A/C doesn't sound right.

Peter

 

[ChristianWarrior]

yes small load that should barely be noticeable. This is very noticeable ,not normal to drop that much.

 

[ChristianWarrior]

Do you know if Ford uses a clutch switch and high pressure switch in their a/c systems? I can't locate a switch on the low side.

 

[ChristianWarrior]

Its like the engine does not compensate for the load that is placed on the engine quick enough.

 

[kmarnes]

Just throwing this out there, but could it possibly be an alternator on it's way out? Sometimes when the battery is near death, it can put an undue strain on the alternator causing that to fail too.

 

[peterk9]

Just throwing this out there, but could it possibly be an alternator on it's way out? Sometimes when the battery is near death, it can put an undue strain on the alternator causing that to fail too.

Good morning. That though had also crossed my mind.

 

[ChristianWarrior]

Charging system is fine. 14.2V, bearings are smooth and not noisy.

 

[ChristianWarrior]

Its a tough one to figure out for sure.

 

[kmarnes]

How about this? https://www.yourmechanic.com/article/symptoms-of-a-bad-or-failing-idle-control-valve

 

[ChristianWarrior]

Thanks for that info. I don't think there is a ICV on these engines. I think just a throttle body consoled by the ECM. Might be a problem with the throttle body though,not sure.

 

[ChristianWarrior]

I might try cleaning the throttle body in case its sticking slightly . I would think i would notice that on the pedal though

 

[kmarnes]

Good luck. Btw, I've heard lots of general complaints about throttle body issues in these forums and all I know is it doesn't apply to the Ecoboost engines.

 

[ChristianWarrior]

Yeah thanks.

 

[ChristianWarrior]

Wish i had twin turbos

 

[peterk9]

Okay, I just had a chance to test mine after warm-up. In idle, activating A/C, windows and moving steering wheel side to side had no effect on RPM. Needle did not move at all.

Peter

 

[ChristianWarrior]

yeah thats how it should be. very slight rpm change from load that you do not notice it.

 

[CommandPresence]

Interesting. I just noticed this on my 14' 3.7l Explorer. Turn a/c on, rpms drop to under 1k until I blip the throttle.

 

[ChristianWarrior]

yes that is the problem. When warm though idle will be about 6-700rpm and mine drops around 150rpm. Cleaned throttle body,wasn't dirty and had no effect. Didn't think it would help. Also try with the windows closed moving both buttons to closed position. My rpm drops but not as bad as when a/c clutch engages