[Tpriest7893]

I have 2012 bmw 335i. It has always had that type of idle after a cold start when you turn it on it almost hesitates for a second and then the rpm goes up with the loud cold start sound.

I recently got a new intercooler and charge pipe. Upgraded it all.

When I start the car ONLY on a cold start when the car has sat for a good 5-6+ hours it hesitates and is louder then normal. And then goes too normal. If I drive around and start the car after let's say running errands it's fine. It's something that I'm ok with dealing with because it's only on a cold start but I'm just curious as to why it does that.

Car is on stock spark plugs, no tune. Fully bolted. CP/IC/intake/DP.

Car is driving phenomenal. I don't feel any leaks, open throttle and normal driving it's so much better then it was before I did the upgrade. I know it's not an O ring issue or anything like that. Just strictly cold start.

Any one encounter this?

[Jake From State Farm]

Originally Posted by Tpriest7893

I have 2012 bmw 335i. It has always had that type of idle after a cold start when you turn it on it almost hesitates for a second and then the rpm goes up with the loud cold start sound.

I recently got a new intercooler and charge pipe. Upgraded it all.

When I start the car ONLY on a cold start when the car has sat for a good 5-6+ hours it hesitates and is louder then normal. And then goes too normal. If I drive around and start the car after let's say running errands it's fine. It's something that I'm ok with dealing with because it's only on a cold start but I'm just curious as to why it does that.

Car is on stock spark plugs, no tune. Fully bolted. CP/IC/intake/DP.

Car is driving phenomenal. I don't feel any leaks, open throttle and normal driving it's so much better then it was before I did the upgrade. I know it's not an O ring issue or anything like that. Just strictly cold start.

Any one encounter this?

Totally normal. The purpose of the cold start is to warm the catalytic converter. You can tune this out if you don’t like it with BM3 or MHD.

[Tpriest7893]

Originally Posted by Jake From State Farm

Totally normal. The purpose of the cold start is to warm the catalytic converter. You can tune this out if you don't like it with BM3 or MHD.

Yeah I know but the car almost stalling and it didn't do that before I changed the charge pipe and intercooler. I don't have a tune at the moment.
Nonetheless, it hasn't done it since. I'm in Florida and we had a few days of morning 50 degree weather and since those cold days it hasn't done it. Very odd

[Jake From State Farm]

Originally Posted by Tpriest7893

Yeah I know but the car almost stalling and it didn't do that before I changed the charge pipe and intercooler. I don't have a tune at the moment.
Nonetheless, it hasn't done it since. I'm in Florida and we had a few days of morning 50 degree weather and since those cold days it hasn't done it. Very odd

Usually rough idle problems are coil related. When was the last time you changed them out?

[Tpriest7893]

Originally Posted by Jake From State Farm

Usually rough idle problems are coil related. When was the last time you changed them out?

Haven't. One coil failed around 50k miles replaced under warranty.
Spark plus are stock which I plan to change once I tune but lately the start has been good and normal. It was just off during those cold days

[Jake From State Farm]

Originally Posted by Tpriest7893

Haven't. One coil failed around 50k miles replaced under warranty.
Spark plus are stock which I plan to change once I tune but lately the start has been good and normal. It was just off during those cold days

Glad to hear it’s better now. If it begins doing it again swapping them out would probably help, especially if they’re stock and your MY2012. I have the same year and had to swap them out as soon a I tuned it.

[thejeremyman9]

Originally Posted by Tpriest7893

Haven't. One coil failed around 50k miles replaced under warranty.
Spark plus are stock which I plan to change once I tune but lately the start has been good and normal. It was just off during those cold days

What intake do you have? Usually cold start and rough idle are attributed to intake.

[Tpriest7893]

Originally Posted by Jake From State Farm

Glad to hear it's better now. If it begins doing it again swapping them out would probably help, especially if they're stock and your MY2012. I have the same year and had to swap them out as soon a I tuned it.

Yeah I figured I would tune soon, and see how it runs and if it sucks I'll swap them. Did you go with stocks or the smaller gap?

[Tpriest7893]

Originally Posted by thejeremyman9

What intake do you have? Usually cold start and rough idle are attributed to intake.

Injen but the issue started after I did the charge pipe and intercooler but now that my car hasn't done it I notice it was only on a few very cold days. It's been the normal cold start now. We had a few cold 50 degree days( I'm in Florida) but since then it's been fine. Had the intake for about year and a half and hasn't gave me any issues

[Jake From State Farm]

Originally Posted by Tpriest7893

Yeah I figured I would tune soon, and see how it runs and if it sucks I'll swap them. Did you go with stocks or the smaller gap?

I tried NGK 97506 and several gap sizes (.20, .22, .24, etc.) and had issues with all. My car did not like those plugs and would studder/misfire at high speed under load. It drove me crazy trying to figure out what was going on. Finally I ordered stock Bosch plugs (stock gap) paired with PR coils and it runs perfect.

I know many have luck with the 97506 so i guess it may just depend on the car.

[Tpriest7893]

Originally Posted by Jake From State Farm

I tried NGK 97506 and several gap sizes (.20, .22, .24, etc.) and had issues with all. My car did not like those plugs and would studder/misfire at high speed under load. It drove me crazy trying to figure out what was going on. Finally I ordered stock Bosch plugs (stock gap) paired with PR coils and it runs perfect.

I know many have luck with the 97506 so i guess it may just depend on the car.

That's good info, i spoke to Bryan from kiesmotorsports and he used stocks until he went pure stage 2. So I will more then likely stick with stock and if it gives me issues mess around

[Jake From State Farm]

Originally Posted by Tpriest7893

That's good info, i spoke to Bryan from kiesmotorsports and he used stocks until he went pure stage 2. So I will more then likely stick with stock and if it gives me issues mess around

That’s a good call

[Tpriest7893]

Originally Posted by Jake From State Farm

That's a good call

Which tune did you go with?

[Jake From State Farm]

Originally Posted by Tpriest7893

Which tune did you go with?

I went BM3 and opted for the WiFi agent. It is very user friendly and their customer service is awesome. I’ve heard good things about MHD as well and have a few buddies running it. I don’t think you can go wrong with either except MHD runs off of android only and doesn’t offer an apple option.