Hi all, have a 2005 r53, recently started to die when coming off throttle, like when stopping at a traffic light.

It happens mostly when the engine is cold and less (or not at all) after warm.

also, a bit further back, it has started to yo-yo slightly when steady on throttle (or when not going harder on throttle). Almost feels like hesitation but goes away with more throttle. Not sure that’s related.

Got some screenshots from inpa (will post below)

Hoping someone has seen this before for a fix

 

370 system too rich

 

Short term fuel trims -30?

 

Yeah, you're running rich.
Check your fuel pressure, a bad regulator can make it go too high and cause a rich condition
See if you can pull up the readings from both MAP sensors (yes,there's two!) in INPA with the engine idling; I'm curious to see.

 

thank you for the reply mrbean. I will look for map sensor readings in inpa and get a snap, post back here.

I'll need to look into the fuel pressure test. never done one so don't have a gauge...will look into this.

 

Following

 

ok some additional data, all while at idle

 

I noticed that when coming off throttle the short term fuel trims go down to zero, but then right back up after reaching idle.

also from this sticky in the “stock problems/issues” section, seems this has been an issue that is fairly common. I went through the thread but did not see a resolution.

https://www.northamericanmotoring.co...-starting.html

 

Those readings seem normal.
When you come off the throttle the DME cuts off the injectors which is why you see fuel trims go to zero.
I would check fuel pressure next.

 

ahh I see

Ok fuel presure test is next

 

Looked up the process for fuel pressure test. Seems straight forward.

Remove intercooler, attached gauge, reinstall intercooler, start engine and read fuel pressure.

I picked up this gauge from Harbor Freight . Should this work?

https://www.harborfreight.com/basic-...kit-64939.html

 

here's a pic

 

also noticed today. short term fuel trims were totally normal. so it seems that the condition comes and goes. seems to go more often after engine at temp.

Failing or faulty O2 sensor?

 

I feel like this could be the t-map sensor also...now I'm just guessing

 

I'm not a mechanic but had this behavior, stall at idle. For me it was usually in stop and go traffic, very stressful. Have you checked your coil pack, particularly the number 3 cylinder contact? Mine was badly rusted. A 10 minute job to replace with an aftermarket pack with brass contacts and I haven't had a stall since.

 

easy enough. I will check this

 

Anyone use the harbor freight gauge on our cars?

would hate to take off the intercooler just to find out it doesn’t fit.

https://www.harborfreight.com/basic-...kit-64939.html

 

Another bit of info. I don’t seem to have my pops and “bangs” when coming of throttle like before. They are mostly gone.

I don’t know what that means

 

Hold the phone, on the way home today, my pops and bangs were back. And it held idle. No stalling.

I took a quick look at fuel trims. Short-term was +30 again. Long-term multiplicative was -10. Don't know what that means. Seems strange to me that they would be opposite like that (attached pic).

Last, im seeing a new error code.

1089 Evaporative Emission Control System Incorrect Purge Flow (attached pic)

 

Paging @mrbean

I'm I on the right track with this fuel pressure gauge?

 

1089 Evaporative Emission Control System Incorrect Purge Flow

Apparently the code above is caused by a bad purge valve or "fuel tank breather value" as bmw calls it. #1 in the pic attached.

This part is $80 plus for OE. However its a common valve in may cars and I found a thread where it can be purchased for much cheaper...

This would be my second time replacing this valve tho. Maybe the OEM valve is not a good?

But the real question, could this purge value be causing my rich condition?

 

Or is it a lean condition? STFT +30.

 

Still waiting on parts however the drama continues...

The other day I started it for work and it idled very rough then died. Tried again same thing. Tried again, and realized it was in limp mode. RPM would not go over 2k iirc.

So I took the kiddo's r50 to work. When I got home I pulled codes. I'll post them below. Cleared adaptations, and all returned to normal.

 

5769 Electronic Throttle Control Monitor Level 2/3 Torque Calculation Error

264 Manifold Absolute Pressure / Barometric Pressure Circuit High Input

 

More often than not, this is the culprit.
They get fouled from heat and oil residue in the intake.
Sounds like yours is on its way out, just not quite there yet.