E46 M3 Sputter/Hiccup at 1.1-1.9k RPMs?

[shumile.swift]

This is an issue I have been chasing for almost 10 months now. Once the car is at operating temp, and has been driven around a bit, if I rev the car up to 1.1 to 1.8k rpms, it has a sputter... kinda like its starved for fuel? I dont know how to explain it, I think i'll have to get it as best as I can on video, but background on the car

NO CEL/NO CODES ON ISTA/P

2004 mss54hp car, 90k miles on engine.

karb csl airbox

alpha n tune from HTE

megan catless headers

smg swapped to 6mt (swap is done 100% correctly. 6mt bell housing, I have a brown clutch switch, and the GPS is tapped into the trans, wired, and coded in.)

In the last 10 months chasing the issue, I have done the following

New Coils and Plugs

all 4 o2 sensors

Fuel pump

I had to do my starter recently, and so while the airbox was out i cleaned the throttle bodies thoroughly, AND the ICV

I did the TPS sensor as well, the one thats under the intake manifold, but thats it. I know theres 3, maybe doing the other 2 might help? i dont know.

Vanos not done yet, but tested on ISTA/P twice and it passed the vanos test (not sure if thats worth anything anyway)



If i put it in 1st, start clutching out with some gas, it cuts alittle bit, but not nearly as much as when i just rev it in neutral and hold it at 1.4-1.8k.. AS SOON as i pass 1.9k its like it clears up and is just fine.

Car overall drives JUST fine, pulls SUPER hard. Really getting annoyed with this.

HTE says its just how Alpha N is, I have a Kassel Map sensor sitting around, I might switch to map or get a Dyno tune to fine tune it. Not sure what is going on. Ill put pics of my Fuel trims at idle and at load.

Let me know what you think, I want to get to the bottom of this, its frustrating as all hell.

[Slideways]

Does it do that in all gears and will the condition change when you reset adaptations?

Did this happen after the airbox install and are you running CSL software on the HP DME?

[shumile.swift]

Slideways IT only does it in neutral tbh, and sometimes while taking off in first, but say im at a speed where im driving at 40-50mph, and im at 1.4-1.9k rpms (which is honestly never) it wont do it. I tested it out and it doesnt really do it. It wont do it the first 2-3 minutes of resetting adaptations. but after a 10 min drive at operating temp itll start doing it again..

This was not a thing the first 10 or so months of the airbox install. I am not running CSL software on my DME, I have whatever HTE remote flashed to my DME.

[Slideways]

Slideways IT only does it in neutral tbh, and sometimes while taking off in first, but say im at a speed where im driving at 40-50mph, and im at 1.4-1.9k rpms (which is honestly never) it wont do it. I tested it out and it doesnt really do it. It wont do it the first 2-3 minutes of resetting adaptations. but after a 10 min drive at operating temp itll start doing it again..

This was not a thing the first 10 or so months of the airbox install. I am not running CSL software on my DME, I have whatever HTE remote flashed to my DME.

Before it started happening, did you change or service anything on the engine or fueling system?

[shumile.swift]

Slideways yes. it started happening after i picked my car up from orlando florida for a bottom side and top side RACP reinforcement. When i picked up my car to drive back to NC, my fuel pump started whining like crazy so we realized it failed. The dude who did my RACP repair had a spare Fuel pump and so we swapped it.
Thats when i noticed the sputtering at 1.1-1.9k
When i used BMW logger to scan codes, there was none, when i used my buddy jordans (rk tunes) dtc reader, it would say a bunch of random things, once it said something about knock sensors, then it said something about the sucking jet pump (i have no issues with driving under a 1/4 tank), and then it said something about o2s, then my fuel injector.. That software made me literally throw o2s at the car and then i realized every time i hit refresh it was saying something new. So i used ista as my code reader, and it does not say anything, even while doing the vanos test on ista, the car was sputtering cause it holds the revs at 1.5k the whole time its doing the test. Really weird.

[Slideways]

Slideways yes. it started happening after i picked my car up from orlando florida for a bottom side and top side RACP reinforcement. When i picked up my car to drive back to NC, my fuel pump started whining like crazy so we realized it failed. The dude who did my RACP repair had a spare Fuel pump and so we swapped it.
Thats when i noticed the sputtering at 1.1-1.9k
When i used BMW logger to scan codes, there was none, when i used my buddy jordans (rk tunes) dtc reader, it would say a bunch of random things, once it said something about knock sensors, then it said something about the sucking jet pump (i have no issues with driving under a 1/4 tank), and then it said something about o2s, then my fuel injector.. That software made me literally throw o2s at the car and then i realized every time i hit refresh it was saying something new. So i used ista as my code reader, and it does not say anything, even while doing the vanos test on ista, the car was sputtering cause it holds the revs at 1.5k the whole time its doing the test. Really weird.

Either something was not installed correctly when the fuel system was reinstalled during the RACP reinforcement or that spare pump has an issue.

[shumile.swift]

Either something was not installed correctly when the fuel system was reinstalled during the RACP reinforcement or that spare pump has an issue.

Slideways could it be fuel pressure regulator? fuel filter?
I just cant think of what else causes the symptoms im having smh

[Slideways]

Slideways could it be fuel pressure regulator? fuel filter?
I just cant think of what else causes the symptoms im having smh

It sounds like the pump is the issue, but the fuel filter is cheap and a good place to start.

[shumile.swift]

It sounds like the pump is the issue, but the fuel filter is cheap and a good place to start.

gotcha, but wouldnt a bad fuel pump cause sputtering at higher RPMs/wot and long cranks?

[sapote]

megan catless headers

smg swapped to 6mt (swap is done 100% correctly. 6mt bell housing, I have a brown clutch switch, and the GPS is tapped into the trans, wired, and coded in.)

In the last 10 months chasing the issue, I have done the following

New Coils and Plugs

all 4 o2 sensors.

These are not related to the issue, but why need to replace the post cat O2 with catless? It has the bell housing from another tranny and no input shaft bearing noise issue?

Have you tried with MAF disconnected to see any differences? Can you log the fuel trims at the interested rpm?

[shumile.swift]

These are not related to the issue, but why need to replace the post cat O2 with catless? It has the bell housing from another tranny and no input shaft bearing noise issue?

Have you tried with MAF disconnected to see any differences? Can you log the fuel trims at the interested rpm?

I don't have a MAF sensor. I'm running a CSL airbox with Alpha-N. The purpose to tell why i have the 6mt bellhousing is explain that every part of the swap has been done right, when not done right, it causes a surging idle/throttle sensitivity issues/stalling out. Which is what my car does sometimes when it sputters and i immediately let go of the throttle. I did all 4 o2's out of frustration, but knew i just needed to do the pre-cat.
I posted my Fuel Trims at 1200 rpms, i'd have to get a scanner and log it again, but it starts at 1200 rpms or so. sometimes itll start at 1100 or 1500.. its random af. very annoying.

[Arith2]

Are you dyno tuned or is this just the initial tune?

[shumile.swift]

Are you dyno tuned or is this just the initial tune?

Just a flash tune...
Update though, i checked my spark plugs to see if it was that or ignition coils... my spark plugs were ALITTLE loose, not VERY loose, but every cyl took very little strength to take out... like literally a small push and it broke loose.
since then, it has not sputtered at all...
ill see if it comes back, but its been 6 days and so far so good.

[Arith2]

You have to get it dyno tuned. The base map is not good enough to adapt to every car. This is not Hassan's intent either. It's to get you through until the dyno and it is a very rich tune so you don't end up with a blown engine... unlike Buildjournal. I can almost guarantee you It's going to come back. This is how it is until you fine tune your map.

[shumile.swift]

You have to get it dyno tuned. The base map is not good enough to adapt to every car. This is not Hassan's intent either. It's to get you through until the dyno and it is a very rich tune so you don't end up with a blown engine... unlike Buildjournal. I can almost guarantee you It's going to come back. This is how it is until you fine tune your map.

Lol, still have not dyno tuned it, and it came back. Came here to tell you you were right, ill get it dyno tuned asap. I just put 4.10 gears in the car and I was RIPPING on it and then got home and the sputter came back. Its been a little while since i have felt it, but i also had the car stored for the winter while i was in nyc.