Long crank times + misfire?

[enigma99a]

Sometimes my 2009 E92 335i takes a long time to crank (3-4 seconds) on start. In fear it could be the HPFP, I took it in for service. I was trying a new dealer and didn't bother taking off my dual intake (my only mod) to feel them out.

Anyway here is what they said:
Misfire faults ran short test, multiple cylinder misfire faults stored, customer has aftermarket intake filters -- possible cause of extra fuel being injected due to extra air coming into intake, air fuel mixture.

And they asked me take it restore it back and come in again. Has anyone heard of more air causing misfiring? I'm @ 49,000 miles so I am still under warranty but I wanted to ask if anyone thought it might be injector/coil/plugs?

[02325]

it could be bad fuel, plugs (which i think gets changed every 45k miles), dirty injectors, or possible bad coils.

the issue here is you car has no MAF. so you car it only gonna use what ever air it needs and no more. but to determine if it is the intake, put your OEM back on and see what it says.

[Ferruccio]

I want to call BS on the intake blame. Sure, the intake lets in a very different volume of air under load, but, from a cold start? The air flow should be about the same. I could be totally wrong, though.

I've had a couple of long cranks in the past several weeks, but that is because I am running a different fuel blend, so I can see the fuel being to blame, as well.

Also, someone help me here: I didn't think the car would suddenly start injecting in more fuel to compensate, anyway. From a cold start, isn't the fuel system open loop, and it just dumps it in until it reaches temperature? I'll definitely need to be corrected.

[PTFunk]

When I got a long crank time on startup it turned out to be the HPFP without a doubt. I don't really know enough about the air/fuel mixture management at startup to speculate on the effect of your aftermarket intake, but like Ferrucio I also suspect that's not it.

[enigma99a]

Yeah sucks, I guess I should have known better though than to take the car in with anything aftermarket on -___-

I did ask him about voiding warranty and as others as said, they generally don't care but if a part breaks, and they can blame it on the mod, they won't fix it. Also he said software mods will render the entire engine unfixable.

[enigma99a]

Spent 30 min last night putting the factory airbox on... took it in today, HPFP! Getting replaced today and will do some driving tomorrow to make sure all is good before handing it back to me.

[PTFunk]

Spent 30 min last night putting the factory airbox on... took it in today, HPFP! Getting replaced today and will do some driving tomorrow to make sure all is good before handing it back to me.

Glad to learn that it was a straightforward (and well known) problem... oh, and one you won't have to pay for! :alright

[enigma99a]

Yeah but the last HPFP only had 15K on it. Hopefully the next one will last longer lol.

[e66man]

Aftermarket intake will have NO effect on longer cranks, misfires, extra fuel, etc during starting. Make no mistake about it.

[enigma99a]

Well, back to square 1...........:rolleyes

A day or two after the HPFP was replaced, startup issues continued. And today it got way worse. I thought it wasn't going to start when it finally did but threw a service soon light.

So I decided to go to autozone so I could pull the codes and it is misfiring on Cylinder #6. I swapped coils #1 and 6 to see if the issue follows over to #1. The plug was changed 4,000 miles ago so I wouldn't even attempt changing that. Otherwise it might be fuel injector or some other issue. *sigh*

UPDATE ************

Still throwing misfire codes on Cylinders #5 and #6 so I guess the injectors.

I would like all 6 to be cleaned if possible, but I worry the dealership will only do the bare minimum

[enigma99a]

Update *** the dealer replaced all 6 injectors under warranty and now it's running awesome and is waay more responsive to throttle. :D