[BadContrakt]

2008 N54 AWD 140k miles

DCI
Catless DP
Stage 2 MHD tuned (stock intercooler)

On cold start in the mornings before work, my idle is funky. Car starts normally and does cold start high idle normally for ~7 seconds then the idle fluctuates uppppppp like 3-400 RPMs and thennnnn droppppps back downnnnnn to 800 then a few seconds more drops down again to standard idle of 650 and stumbles and rumbles and misfires.

Then I tap the gas a couple times and it all evens out.

This had NEVER happened until the MORNING AFTER I installed my catless DPs. Didn't touch plugs, coils, or fueling in any way shape or form. Plugs are standard non-iridium tipped Bosch with 10k miles on them and coils are standard OE Delphi with 10k miles on them. Injectors are probably factory. Most likely not index 12.

I thought maybe because I'm missing the downstream O2 sensors now, maybe the car is just acting funky because of the Service Engine Soon light. So I tuned MHD and coded out the O2 sensor light. Nope. Still misfiring on cold start.

I understand colder plugs and their function and I understand why they're necessary for higher boost applications but I don't understand why they'd be needed for a cold start idle. Do I miraculously have leaky injectors the day after installing DPs/tune and the misfire isn't related at all to the DPs or the tune? Just ridiculous. One thing after another.


PS:
BMS says "Note: these plugs are on national back order. Most still floating around the internet are counterfeit. We suggest the NGK 2-STEP plugs as an alternative for all tuned BMW applications."

I doubt with simple bolt ons I should be running 2 step colder plugs? Does anyone do this?

[hellokitty]

Originally Posted by BadContrakt

2008 N54 AWD 140k miles

DCI
Catless DP
Stage 2 MHD tuned (stock intercooler)

On cold start in the mornings before work, my idle is funky. Car starts normally and does cold start high idle normally for ~7 seconds then the idle fluctuates uppppppp like 3-400 RPMs and thennnnn droppppps back downnnnnn to 800 then a few seconds more drops down again to standard idle of 650 and stumbles and rumbles and misfires.

Then I tap the gas a couple times and it all evens out.

This had NEVER happened until the MORNING AFTER I installed my catless DPs. Didn't touch plugs, coils, or fueling in any way shape or form. Plugs are standard non-iridium tipped Bosch with 10k miles on them and coils are standard OE Delphi with 10k miles on them. Injectors are probably factory. Most likely not index 12.

I thought maybe because I'm missing the downstream O2 sensors now, maybe the car is just acting funky because of the Service Engine Soon light. So I tuned MHD and coded out the O2 sensor light. Nope. Still misfiring on cold start.

I understand colder plugs and their function and I understand why they're necessary for higher boost applications but I don't understand why they'd be needed for a cold start idle. Do I miraculously have leaky injectors the day after installing DPs/tune and the misfire isn't related at all to the DPs or the tune? Just ridiculous. One thing after another.


PS:
BMS says "Note: these plugs are on national back order. Most still floating around the internet are counterfeit. We suggest the NGK 2-STEP plugs as an alternative for all tuned BMW applications."

I doubt with simple bolt ons I should be running 2 step colder plugs? Does anyone do this?

If BMS says 2 step colder is fine then you should be good.

I run 97506s and they work great.

[BadContrakt]

Originally Posted by hellokitty

If BMS says 2 step colder is fine then you should be good.

I run 97506s and they work great.

You have a decent amount more mods than your standard FBO like me.

I notice in your signature you're gapped to .028 which is way wider than I've heard of for tuned N54s. Maybe your larger gap is accommodating the overly cold plugs?

[TheMidnightNarwhal]

I am FBO on Stage2+ 93 Octane and using factory Bosch plugs and all is good.

Maybe you're plugs are just more used and it's coincidental.

I was doing like -2.7 corrections but when I put in brand new Bosch plugs and coils my car runs like new.

Or maybe injectors... a lot of variables here IMO.

[hellokitty]

Originally Posted by BadContrakt

You have a decent amount more mods than your standard FBO like me.

I notice in your signature you're gapped to .028 which is way wider than I've heard of for tuned N54s. Maybe your larger gap is accommodating the overly cold plugs?

I'm running Precision Raceworks coils so that's why I am running a larger gap. Helps with extending the life of the plug.

[BadContrakt]

Originally Posted by hellokitty

I'm running Precision Raceworks coils so that's why I am running a larger gap. Helps with extending the life of the plug.

Oh cool, glad I asked!

[BadContrakt]

Originally Posted by TheMidnightNarwhal

I am FBO on Stage2+ 93 Octane and using factory Bosch plugs and all is good.

Maybe you're plugs are just more used and it's coincidental.

I was doing like -2.7 corrections but when I put in brand new Bosch plugs and coils my car runs like new.

Or maybe injectors... a lot of variables here IMO.

I'm really thinking I'm just going to swap to NGKs and gap them to .022 and I think this will do nothing but help. Can't hurt. All of the 1 steps are backordered though I've checked a few places. I really don't want to do 2 step colder plugs but if I have to I guess I have to. I'll see if I can find some compelling arguments as to why 2-step colder plugs are fine for simple FBO cars running 91 octane with no meth or corn.

[TheMidnightNarwhal]

Originally Posted by BadContrakt

I'm really thinking I'm just going to swap to NGKs and gap them to .022 and I think this will do nothing but help. Can't hurt. All of the 1 steps are backordered though I've checked a few places. I really don't want to do 2 step colder plugs but if I have to I guess I have to. I'll see if I can find some compelling arguments as to why 2-step colder plugs are fine for simple FBO cars running 91 octane with no meth or corn.

Yeah originally was getting NGK but on FCP they were back ordered as they are everywhere.

I did a post asking if I really needed 1 step colder and people reassured me no. I even ran a E30 e85 mix map and no missfires or anything. All good.

So idk if step colder plugs are really needed on factory turbos... I don't want to spread misinformation but this is what I seem to notice.

[BadContrakt]

Originally Posted by TheMidnightNarwhal

Yeah originally was getting NGK but on FCP they were back ordered as they are everywhere.

I did a post asking if I really needed 1 step colder and people reassured me no. I even ran a E30 e85 mix map and no missfires or anything. All good.

So idk if step colder plugs are really needed on factory turbos... I don't want to spread misinformation but this is what I seem to notice.

Quite possible I could just pull my plugs this weekend with only 10k miles on them and give em a light clean up and make sure they're gapped properly. Maybe that could help smooth things out until I can get my hands on some NGK -1 step plugs.