Idle vibration

[suss6052]

Originally Posted by Michaelc1220

Ill have to give the dealer a call tomorrow and ask if mine had the recall fixed. I bought it new on July 23rd so im not sure when that recall was released but its definitely worth a try. Do you know if I have to take it to the dealer I bought it from? or can I take it to the nearest Ford dealer.

If your car was built before 3/28/12 it might apply, but the way to check would be to put the vin into www.etis.ford.com and see if you have any outstanding field actions.

[Michaelc1220]

hm Ill have to do that tomorrow. I would immagine it wasnt built before 3/28/12 becuase it only had 4 miles on it when i got it, but you never know

[jdetzel]

With the A/C on mine idles very smooth. Turn off the A/C, the RPMs drop a little and I get a vibration. Not bad but noticeably different. It doesn't seem the be a problem but it is a little annoying. The next time I am at the dealer I thought I might ask if the idle could be adjusted.

[suss6052]

Originally Posted by jdetzel

With the A/C on mine idles very smooth. Turn off the A/C, the RPMs drop a little and I get a vibration. Not bad but noticeably different. It doesn't seem the be a problem but it is a little annoying. The next time I am at the dealer I thought I might ask if the idle could be adjusted.

I haven't noticed a difference in idle between a/c on and a/c off at idle with a foot on the brake, but idling in park with the foot off the brake seems to be about 680 rpm target idle with the DCT at least vs the 750 with the foot on the brake with or without the a/c on.

[Michaelc1220]

I was thinking maybe it had something to do with the whole "switching to neutral" thing when your on the break but I never really completely understood how that worked. Im talking about like when you sitting on an incline and slowly let off the break; it will roll back a little until you fully let off the break

[jdetzel]

Originally Posted by suss6052

I haven't noticed a difference in idle between a/c on and a/c off at idle with a foot on the brake, but idling in park with the foot off the brake seems to be about 680 rpm target idle with the DCT at least vs the 750 with the foot on the brake with or without the a/c on.

It has just been the last few weeks that it has been cool enough here to turn off the A/C. So I just noticed it. That is in gear, foot on the brake at idle and I don't remember at what rpm but 680 to 750 sounds about right. It picks up about 50 to 100 rpm when the A/C compressor comes on. So I would say at 680 it is a little rough and at 750 it is smooth.
The other thing I notice is the rough idle is not consistent, it seems to modulate a little.

[suss6052]

Originally Posted by Michaelc1220

I was thinking maybe it had something to do with the whole "switching to neutral" thing when your on the break but I never really completely understood how that worked. Im talking about like when you sitting on an incline and slowly let off the break; it will roll back a little until you fully let off the break

With the DCT the car has to be in neutral at idle or else it would stall. The same as letting out the clutch on a manual transmission car at zero vehicle speed. If you had a torque converter the engine is separated from the wheels via the torque converter and allowing for the slippage cooled by fluid trapped inside the gearbox. Since the mechanism on the DCT is mechanically similar to a manual gearbox.

[Michaelc1220]

Originally Posted by suss6052

With the DCT the car has to be in neutral at idle or else it would stall. The same as letting out the clutch on a manual transmission car at zero vehicle speed. If you had a torque converter the engine is separated from the wheels via the torque converter and allowing for the slippage cooled by fluid trapped inside the gearbox. Since the mechanism on the DCT is mechanically similar to a manual gearbox.

I see now. But I have noticed that sometimes when I let the break out a little, the vibrating becomes more noticeable

[suss6052]

Originally Posted by Michaelc1220

I see now. But I have noticed that sometimes when I let the break out a little, the vibrating becomes more noticeable

Probably because the car thinks you want to go and prepares to engage the clutch? Not 100% certain there.

[paul21]

If your car feels mostly smooth then random harder jerks at idle, you should reset the car computer by disconnecting the battery for ~30 minutes or something and letting the engine idle for 5 minutes when you start it back up.

If your idle is smooth but causes a lot of vibration in general, then it's the motor mounts.

12B37 increases idle RPM from 700 to 800.