4 BW Idle

[G.Newt]

Does anyone else's 4BW have an unsmooth idle? Is that just the nature of the LF4? Pulls strongly when going WOT. Very smooth, no misfires. Just the idle is a bit unsteady and I can see the rpm needle wiggle and slight vibration in the car and shifter (6MT).

Also, if I rev it a bit in neutral, the rpm's dip back down almost like the car wants to stall then it comes back up. Does it in any mode.

 

[Blackwing16]

I’ve experienced something similar to what you described. The revs dip for a short period at idle and then go right back like nothing happened. It doesn’t happen very often for me, so I hadn’t thought too much about it

 

[Lithoss]

My idle is slightly rough, but from what I understand that's the nature of the LF4, I think. I'm OK with it as long as that's actually the case, cause it's awesome otherwise! Hopefully someone with knowledge on it can confirm it.

 

[G.Newt]

I’ve experienced something similar to what you described. The revs dip for a short period at idle and then go right back like nothing happened. It doesn’t happen very often for me, so I hadn’t thought too much about it

Yeah I don't tend to rev in neutral often. Will put it in my mind as a "do not do" lol.

 

[G.Newt]

My idle is slightly rough, but from what I understand that's the nature of the LF4. I'm OK with it as long as that's actually the case, cause it's awesome otherwise! Hopefully someone can confirm it.

Okay good to hear. It's super silky smooth when doing WOT pulls. It's straight-six like. Didn't expect this level of polish from a GM product. Might just be the nature of the beast, thanks!

 

[Lithoss]

Okay good to hear. It's super silky smooth when doing WOT pulls. It's straight-six like. Didn't expect this level of polish from a GM product. Might just be the nature of the beast, thanks!

Just want to clarify, I just read it in passing. I definitely have not confirmed it nor do I have any hard technical knowledge on it. I was hoping someone who did could put our minds at ease. I'll edit my original post to make that more clear, sorry

 

[G.Newt]

Just want to clarify, I just read it in passing. I definitely have not confirmed it nor do I have any hard technical knowledge on it. I was hoping someone who did could put our minds at ease. I'll edit my original post to make that more clear, sorry

My dealer had another used BW and I brought it up as a concern, and they said that one had the same characteristics: slightly lumpy idle and the rev dip if you rev it in neutral. Just wanted to ask the forums for further confirmation.

 

[G.Newt]

Okay got confirmation from the ATS-V / 4 BW FB group that it's very common/normal for LF3/LF4 to have a slightly rough idle and not to worry.

 

[V56]

Mine is exactly the same as described, rough at idle and when giving it gas in neutral initially. As soon as get into the RPM range, smooth as pie. Good to know its normal characteristic as I was wondering about it.

 

[Tall Steve]

Is this like a manual thing? My A10 is smooth, no rough idle at all....

 

[V56]

Mine is manual

 

[Exia]

I find this is a manual thing for anything over 400hp if you're idling for an extended period (5min+).

You leave it in idle and after a little while you will see a little dip in revs and feel a little more vibration and then it goes right back to normal.

I've had this in my Z06 and my ZL1.

 

[LF4472]

My A8 Z06 lopey idle can be felt. I haven't felt it in my A10 4BW but wouldn't be surprised if the engine has a little of it.

 

[G.Newt]

I find this is a manual thing for anything over 400hp if you're idling for an extended period (5min+).

You leave it in idle and after a little while you will see a little dip in revs and feel a little more vibration and then it goes right back to normal.

I've had this in my Z06 and my ZL1.

My B58 wasn't super smooth at idle but nothing like this LF4. And that was pushing 530+whp. Just took me a bit by surprise for a luxury performance car.

 

[Tall Steve]

My SS Sedan had a rough idle, never could figure it out..

 

[G.Newt]

My SS Sedan had a rough idle, never could figure it out..

Might've been a worn flux capacitor. I'd get that checked out.