Car idling rough with A/C on

[utilitytristin]

Hello, on my 2015 Explorer (not Police Interceptor) has a problem where if the A/C is cranked the car has a rough idle and the RPMs fluctuate. Not sure what could be causing it.

 

[Fix4Dirt]

Hello, on my 2015 Explorer (not Police Interceptor) has a problem where if the A/C is cranked the car has a rough idle and the RPMs fluctuate. Not sure what could be causing it.
View attachment 437584

iac? compressor starting to freeze up? cant play the video some reason. had this issue before, no clue hw to resolve it.

 

[utilitytristin]

iac? compressor starting to freeze up? cant play the video some reason. had this issue before, no clue hw to resolve it.

We just replaced the compressor on the car via dealer warranty.

 

[ProjectSHO89]

We just replaced the compressor on the car via dealer warranty.

Did it have this problem before the compressor repair?

There is no IAC valve in the newer trucks.

 

[utilitytristin]

Did it have this problem before the compressor repair?

There is no IAC valve in the newer trucks.

Had this problem before, yes.

 

[kylebryan]

any luck fixing this? My 2014 Explorer has the same issue.

 

[utilitytristin]

any luck fixing this? My 2014 Explorer has the same issue.

No I haven't had any fixes, I've replaced the compressor once already.

 

[Mike D S]

@kylebryan I've read for cars that are otherwise running fine but where teh engine "hunts" for idle rpm with the engine on there is potentially a TSB that applies to reprogram the PCM to help the engine compensate for the AC load at idle to smooth this out. This may not be your problem but something to look into.

 

[J_C]

My '14 just started doing this, "barely".

Almost all of the time, it's not happening, but if it is parked and idling with the A/C on, every now and then the idle drops too low and it stumbles for... maybe a second then picks back up, but then repeats the low idle for only a second, every 5 seconds or so, a few times, and then it goes away by doing nothing.

It has not happened enough for me to spend more time on it yet, but I'm getting closer to that point of hooking up a scan tool to monitor things the next time I am waiting like that. I was waiting in a drive-through line, a slow one where I put it in park every time I advanced forward and stopped, so it wasn't like a cold engine sitting in my driveway, but unsure what temp it had reached yet either as it had only been driven about 5 minutes at suburban speeds.

I don't know about new TSB's, but it wasn't that long ago I had it in to do the rear (links?) for the recall and they didn't advise or inform that they did any PCM update at that point. Is the PCM firmware update *universally* applied or only to vehicles showing the symptom, or Mike D S, just a theory not necessarily applicable to these specific vehicles?

I do think firmware could up the idle a bit, at the expense of fuel economy, but is it a fix or a band-aid for what the problem is?

More data collection needed (on my part) !

 

[ProjectSHO89]

Is the PCM firmware update *universally* applied or only to vehicles showing the symptom, or Mike D S, just a theory not necessarily applicable to these specific vehicles?

Maintenance activities in TSBs are not recalls, they do not get done automatically and will rarely, if ever, get mentioned unless the vehicle owner raises a specific concern that the TSB is meant to address.

.

 

[donalds]

Stupid question but did you check your air filter?

 

[J_C]

I've heard of TSBs being applied to vehicles when they were in shops for something else.

Yes the air filter is good, and no codes or other performance issues.

 

[Mike D S]

@J_C
I went and looked it up and you'd need to verify, but the TSB is for 13-15 3.5L for rolling/surging idle with the AC on. I agree with the post above, if there is a TSB but you don't mention any of the symptoms I'm not sure they would just do the service. So just because you had the toe links done I'm not sure I would have expected them to have done anything else. Unless you specifically discussed another issue.

TSB 15-0149
2013-2015 Explorer 3.5L Ti-VCT: Reprogram The PCM (Do Not UseWith Any Other Labor Operations)

 

[Mike D S]

And just as an example, my 2013 3.5L limited doesn't have any issue with rough idle with the AC on, so for me the PCM flash might be totally wasted effort by the dealer.

However I do have vibration at idle but I suspect my transmission mount / torque strut have given up the ghost at 180k. But my RPMs are dead flat at about 600-700 with the AC on. And I'm 99% sure I haven't had the PCM flash done as it's not listed in any of the itemized records for the times it actually went to the dealer under warranty.

 

[J_C]

@J_C
I went and looked it up and you'd need to verify, but the TSB is for 13-15 3.5L for rolling/surging idle with the AC on. I agree with the post above, if there is a TSB but you don't mention any of the symptoms I'm not sure they would just do the service. So just because you had the toe links done I'm not sure I would have expected them to have done anything else. Unless you specifically discussed another issue.

TSB 15-0149
2013-2015 Explorer 3.5L Ti-VCT: Reprogram The PCM (Do Not UseWith Any Other Labor Operations)

Thanks. I found a topic with a video and this looks a lot like what is happening, just not as repeatable as in the video. I might have noticed it one time previously a few weeks ago, but only a couple RPM drops instead of a dozen before it stopped doing that. The video suggested it might be outdoor temperature related so that might be the variable, as it was only ~70F at the time, though I never noticed it all summer when it was hotter, besides the one brief time a few weeks ago.

Rolling/Surging Idle w/ AC On (TSB 15-0149)

I think I understand the issue related to TSB 15-0149. See video below for my thoughts. Here was a video I made before (Oct 2015) showing the issue but the dealer just said it was a little low on Freon, still seemed to have the issue and then I found the TSB (of course after the warranty...

www.explorerforum.com

I doubt it's a mount because it's had an easy life, only ~18K mi. on it.

 

[J_C]

Just made the same trip as when it idled roughly last time. Same time of day, very near the same ambient temperture & humidity, cold engine starting out both times, driving same amount of time/distance to same place, waiting in same drive-thru line a similar amount of time, with same A/C settings. Not a hiccup, no roughness at all.

Only thing I can think of that changed is the gas tank had been refilled since it last idled rough, but same grade gas at same gas station I used the time prior and have used *most* of the time I refill.