Leaky injectors?

[fstm5]

So, I'm having a bit of a worrisome thought. I had originally made a post about my car running rough on idle at times and cold starts after cleaning my MAF sensors.

I recently had downpipes installed and ever since then, now my car stalls out on cold starts after the computer turns down the rpm for the cat-heating (Which I do not need anymore) As soon as the idle settles down on cold start, it starts surging then just stalls out. Which is starting to worry me because I don't have a tell-tell sign of what is going on. I do not wanna be dealing with a leaking injector without knowing since I daily the car.


I had originally gotten a code of the car running to rich "11811 Mixture Control 2, across banks mixture too rich" I had cleared it and it hasnt come back since, but still, the car on cold starts has been acting very very weird


Once it is warmed up I don't really notice an issue, it seems to pull great and doesn't surge at all. No check engine lights on either.


I am lost as to what could be going on, I also tried unplugging MAF's while the engine was running to see if anything would act up but it kept idling like normal, which I'm sure doesn't always rule out that the MAF's are bad as the car can still run without properly working MAF's. So i am lost on what could be going on

[fstm5]

To add to the post, once it stalls out once, I start it back up and it runs fine, it's just that initial 1-2 seconds after the RPM settles from the cold start

[M6Roar]

ISTA can check for leaky injectors if you suspect that but in my opinion I would say O2 sensor on Bank 2.

BTW did you replace the gaskets when you installed the DP?

HFM disconnected will cause the car to go into open loop regardless of the reading from other sensors hence the normal idle but if you suspect that, switch bank 1 to bank 2 and vice versa and see if the code moves to bank 1

[M5_Raz]

Could be O2 sensors. Did you hit them when they were removed or put back on? They're pretty fragile so you have to be super careful with them.

Also check all your connections to the ecu to ensure they're tight. People (myself included) have had all sorts of erratic problems due to loose connections.

[Flo1989]

Mine was doing the exact same thing after I had my downpipes, tune, plugs, etc. installed. Pretty annoying because I could never let the car warm up without sitting in it and feathering the throttle. Never did this on my previous m6 with the same mods so I was dumbfounded. No codes ever thrown, though. I ended up thinking it was a spark plug issue and welp, it was. Just got my car back from another shop last week and they said my plugs were gapped incorrectly and over torqued. New plugs are in gapped to .020” with no issues since.

[fstm5]

Originally Posted by Flo1989

Mine was doing the exact same thing after I had my downpipes, tune, plugs, etc. installed. Pretty annoying because I could never let the car warm up without sitting in it and feathering the throttle. Never did this on my previous m6 with the same mods so I was dumbfounded. No codes ever thrown, though. I ended up thinking it was a spark plug issue and welp, it was. Just got my car back from another shop last week and they said my plugs were gapped incorrectly and over torqued. New plugs are in gapped to .020” with no issues since.

Hm interesting, Although I didnt change my plugs, id take a look at it

But definitely the first thing im going to do is change my maf sensors because all these issues started as soon as I touched them.

[Mr. M6]

i had this code before and it was leaky injector, be careful if leaky injector dont drive the car.

[SpeedProtocol]

alot of leaky injector talk going around but no action.

smooth running test in ISTA. Find out real quick.

If you dont have ISTA, get it.

[fstm5]

Originally Posted by Droner

alot of leaky injector talk going around but no action.

smooth running test in ISTA. Find out real quick.

If you dont have ISTA, get it.

I just don't have a windows computer only mac

[Blaxwil]

Originally Posted by Droner

alot of leaky injector talk going around but no action.

smooth running test in ISTA. Find out real quick.

If you dont have ISTA, get it.

Been saying I need to get ISTA. What's the process?

[SpeedProtocol]

Injector solenoid leak test is in the misfire detection module. I just found it again. I have to find it every time I look for it lol..


Oh its a process... I have all the files at work. Maybe I can look tomorrow. You will want to dedicate a laptop to it.

[SpeedProtocol]

Originally Posted by fstm5

I just don't have a windows computer only mac

Go get a cheap one on Ebay. Just wipe it first(format disc, reinstall windows) because its sure to be loaded up with backdoor booty snatcher apps.

You gotta have ISTA!