HI all. Been noticing for the past ~6 months that I have to let my car revs drop when i first start it up in the morning. I had thought maybe it was just cold weather but I'm not sure now. Car will start idle at 1200 and drop to sub 1000. If I try and shift into reverse when it is still above 1k it will fluctuate between 600 and 800 rpm and act like it is going to die.
Anyone have an explanation or have something similar happen? Have a intake and exhaust. Had thought it was a back pressure issue with the exhaust but have closed the flap and still happens. No check engine light.

Appreciate the help.

 

yea, following this> you've articulated my cold problem perfectly! I'll put it into first, start to let the clutch out and have a massive bog. happens a few times then goes away after a few hundred yards.

 

Hoping once the weather warms up it will stop. People sit it my car and wonder why I'm not going. I tell them it's a race car and I need to let it warm up first.

 

Following this for sure. I had a manual F56S until recently with the pro exhaust and CravenSpeed intake, but never ran into this issue. Then again, I always warm up my cars for a few minutes especially when cold. Are you starting from cold, and shifting into reverse right away?

 

If it's actually cold out, aka snow weather, I let my cars warm up. I don't consider 40-60F cold for a car though which is still when I'm encountering this issue. I have an auto but my usual car process is sit down, turn on car, buckle up and go. Never have seen having to let the car idle for 30 seconds before I can drive off.

 

Okay, cool, so I have an auto F56 JCW now with the same intake and exhaust, and I move my car as soon as I start it up (too loud to let warm up RIGHT next to my neighbors window), and it's almost like the car is surprised by being put into gear so quick. Only on cold start, regardless of ambient temp. What intake do you have?

 

I have a Craven speed intake and a Remus catback exhaust. And agreed, I try to move my car out of the neighborhood quickly when I have to get up before dawn. Don't want to be "that" guy.

 

Yeah, REALLY don't want to be that guy.

Hmm alright, so we have a close setup. I've for the JCW Pro one. My gut is telling me it's just the ECU being funny on a cold start, and it's nothing to worry about.
But let's see who else has some input!

 

The problem had escalated over the past year. Of course right out of warranty (50500) the car decided to die at 2 different stop lights when letting off the brake. At 56000 now and it was stalling more and more from switching from park to drive, where I'd have to restart and then be fine. Ran a can of seafoam thru the intake right past the MAF and it seems to have solved the problem for now. I am close to 500 miles without a stall. Looking back I think when I installed my CAI I did have the boot all the way on for like 10k miles so thinking maybe some dirt got in and was potentially messing with the throttle body.

 

I have cold start and stall when put to reverse... car restart will have no issue...afterward. dealer did a software update fixed the issue...

Speak of it too soon, ok on the first day...same problem again.....

Going back next Tue...

 

Do you have any update on this issue? Did the dealer end up doing anything?

 

unfortunately, they can't find anything wrong,, and say it's my aftermarket exhaust...that may provide incorrect reading to the ECU.... they said they can report to mini but it may void my warranty because of aftermarket stuff.

The issue is if I idle it for a minute, it won't happen and it doesn't happen in Summer....and my case not only reverse....it will happen in cold weather first cold start, engage any gear, within the first minute(roughly, i didn't really test it out thoroughly). It won't happen if I restart the engine though..

 

I have the same issue, but I don't have an aftermarket exhaust or intake. I've only had my mini for just over a month, so it's been sort of cold here in the PNW. The car doesn't do it if I start it up and let it sit for a couple minutes before going into reverse.

Thanks for following up.

 

if i m still under warranty with all original stuff, i will leave them my car...... I think it's a software glitch they should fix...

Have u tried "D" forward as well?

 

I have this same issue, no matter the outside temp. Never been able to figure it out, nor has the dealer. I just start the car and let it run until RPM falls below 1000 (about 10 seconds). It doesn't stall then...

 

Addressed (mostly) by a software update. I forget where I found that info originally, but I got directed to a local shop that knew about the issue (probably in this forum... somewhere...). They updated the software and I no longer have to worry about how soon after starting I put it in reverse... mostly.

By "mostly" I mean about 95%. There is still occasional weird/stumble that is just part of that really short 10-ish second window just after starting the car -- I suspect my ignition coils right now, but it's not consistent or frequent enough for me to be sure. Anyway, when that stumble occurs, should it coincidentally intersect with me putting it in reverse, the car will almost stall out. But the gearshift has to land on a stumble for that to happen.

One time -- just once -- the engine pretty much *did* stall out for half a second when I had that intersect happen. But then the engine picked right back up and kept going (I wasn't sure whether to be spooked or impressed).

 

It's the cold start cycle. New spark plugs help the stalling. Cheap gas does not help the occurence (non tier 1), as well.

 

Can definitely confirm that new plugs help the stalling. And that as they get older the cold start stumble starts to come back (though, in my case, partially mitigated by the software update).

Can you elaborate on what the “cold start cycle” actually is? I’ve always thought the car felt like it was trying to “figure out something” and then settling in after about 15 seconds and doing fine from there.

 

As explained to me by a great dealer mechanic (8 years ago), the F56 S and JCW goes through a computer sensor check, O2, temp, fuel, etc and adjusts to optimum settings. And yes, with a modified exhaust it will sound louder and be noticeable. It appears that during colder temps older plugs do not fire at as well in colder temps and you get a "stall" with too much fuel. As mine is a MT, it woud appear that an AT "stall" would be more pronounced.

It noticed that it hasn't done it when I changed the plugs. I also "back in" park. Reverse also relies on more torque (lower gear ratio). As my drive is 300ft+ long, down hill, after pulling forward I go to neutral and coast down.

It appears that software updates may have changed this "sensor" procedure. With the JCW exhaust, valve always open, it can get loud. Neighbors far enough away so no worries.

 

That's wicked interesting -- and informative, thank you! Makes sense that a software update could resolve this, since the sensor procedure is literally nothing but execution of a software routine by the DME and whatever other control units might be involved. And my S is bone stock but the exhaust is still louder.

What plugs are you using in your engine? I'm using BERU plugs; they have about 25K miles on them now, and the "startup stumble," while still very much occasional, got a ton better when they were new but had started to reappear at or before 20K miles (at 25K miles, it's still not bad or even consistently-appearing, but it is definitely getting worse -- just really slowly). I may end up changing the plugs at 30K, and may well switch to what you're using at swap time.

 

Had this issue last year with our 17' CM. I switched to NGK plugs and also had the dealer do a software update and it rarely occurs anymore. It only happens on a cold startup and I immediately switch to reverse, which is like under 2 seconds. So I usually start her up and then plug in my iPhone by then it's been a few seconds and no more stumbling.

 

I ended up with Champions. As I mentioned in another thread, most sites list the '15 S as a B48. Not true, it's a B46. They list the F55 as a B46. NGKs for the B46 were out of stock. I would suggest using a good parts company like ECS. It appears that tier 1 gas is a must and even that varies. I usually start the car first, in neutral, put on seat belt, etc. and then drive. Works for me.