[JJT211]

Im chasing P0171 and P0174 codes and Im pretty sure ive elminated all possible vacuum and fuel issues.

I have a rough start, idle for first 5 mins then goes away. Long-term fuel trims slightly high at idle (12-15) or deceleration (15-20). LTFT's normal during acceleration or high idle.

Bought the car used with plenty of codes and have made a pretty sizeable improvement. But still chasing this one down

I've replaced:

- all four O2's (started this journey with post cat O2 fault)
- all spark plugs, coils and fuel injectors
- valve cover (discovered several leaks and now fixed)
- oil filter housing gasket
- maf
- OEM VANOS solenoids, cleaned filters
- fuel pump and fuel press regulator (had a bad fuel pressure tester, leading me this direction )
- oil cap
- gas cap

Ive smoked tested as well as sprayed a few bottles of starting fluid all over the engine. No more intake leaks that I can tell.

Now I believe im left with a possible exhaust leak. How do I test/troubelshoot this?

[gbalthrop]

Originally Posted by JJT211

...P0171 and P0174 codes... I have a rough start, idle for first 5 mins then goes away...I've replaced:............
How do I test/troubelshoot this?

What Diagnostic Software (INPA/ISTA) do you have? What Scan Tool do you have? Anything that will read MAF Flow Rate & show PRECISE Idle RPM at SAME time will go a LONG way toward diagnosing the issue. Please confirm that the vehicle in question is 2009 328i & furnish that Live Data from "Cold Start".
George

[lowrydr310]

What was your smoke test setup? Where did you inject the smoke?

[JJT211]

Originally Posted by gbalthrop

What Diagnostic Software (INPA/ISTA) do you have? What Scan Tool do you have? Anything that will read MAF Flow Rate & show PRECISE Idle RPM at SAME time will go a LONG way toward diagnosing the issue. Please confirm that the vehicle in question is 2009 328i & furnish that Live Data from "Cold Start".
George

I have INPA, ISTA D and Bimmergeeks Pro Tool.

I imagine I would have to enable logging to record data. Any guides on setting that up with any of the above mentioned software?

EDIT:
Car is a 09 e92 328i N52.

I also don't see any CCV or DISA valve. I assume this model or version I have doesn't have one.

[JJT211]

Originally Posted by lowrydr310

What was your smoke test setup? Where did you inject the smoke?

Good question, as it brought to mind a possibility. Throttle body issue? I'll explain procedure and let me know if anything sticks out.

I just disconnected the air box, attached a glove and cut hole in one of the fingers to insert plastic tube with an air pump and a cigar attached to the auction end. I would then pump cigar smoke with oil cap open until I saw smoke inside valve cover (takes a LOT of smoke). Once I start to see a healthy amount of smoke then I'll close oil cap and keep pumping and look for songs of smoke.

I've I discovered a valve cover crack and then after replacement, a leak in the eccentric shaft sensor gasket using this method. Both have been fixed since and I'm not seeing anymore smoke

[marvinstockman]

Have someone hold a rag in the tailpipe, while you search for the exhaust leak.

[mainbearing]

I am not sure if the PCV valve diaphragm is closed when the engine is off. You might want to send smoke into the intake manifold and check there is no leak there, as well as no smoke from the PCV vent pipe.

[gbalthrop]

Originally Posted by JJT211

I have INPA, ISTA D and Bimmergeeks Pro Tool. I imagine I would have to enable logging to record data. Car is a 09 e92 328i N52.
I also don't see any CCV or DISA valve. I assume this model or version I have doesn't have one.

Neither INPA or ISTA will "Log". Did you check for RPM & MAF rate in Freeze Frame Data related to either P0171 or P0174?
If your problem occurs at idle in first 5 minutes after cold start, why log? Just watch the MAF Signal Parameter as Live Data.
INPA will show you the MAF rate in Kg/Hr and Engine RPM, on SAME Screen:
INPA > DME (Engine | MSV80) > F5 Status > F2 Analog > F1 Measured Values (Parameters) Group 1.

You can press "PrtSc" (PrintScreen) button and save/paste as jpg file in Paint. My N52K engine idles at 660 RPM (warm idle, 90 to 120 seconds after cold start), and MAF Rate is 13 kg/hr at that idle speed. Your 3.0L engine should have ~ same MAF Rate vs. RPM ratio.

328i with N52 has NO DISA Valves. If you had N51 Engine, you WOULD have DISA Valves. The PCV Valve is incorporated in the Plastic Valve Cover, and NOT a separate part.
George

[lowrydr310]

Originally Posted by JJT211

Good question, as it brought to mind a possibility. Throttle body issue? I'll explain procedure and let me know if anything sticks out.

I just disconnected the air box, attached a glove and cut hole in one of the fingers to insert plastic tube with an air pump and a cigar attached to the auction end. I would then pump cigar smoke with oil cap open until I saw smoke inside valve cover (takes a LOT of smoke). Once I start to see a healthy amount of smoke then I'll close oil cap and keep pumping and look for songs of smoke.

I've I discovered a valve cover crack and then after replacement, a leak in the eccentric shaft sensor gasket using this method. Both have been fixed since and I'm not seeing anymore smoke

Unless you held the throttle valve open or removed the throttle body entirely, that's not really a good test.

I had similar air leak codes and stumbling idle, which ended up being a cracked CCV hose under the intake manifold. When I did my smoke test, I removed the air box and wedged the throttle plate open with a piece of a rag. It didn't take much smoke to reveal the leak. I left my oil cap on when I did it.

[fastboatster]

Which engine do you got, n52 or n51? N51 has secondary air injection system which, if it has its air injection valve open (say, from carbon buildup), can let the extra unaccounted air to the oxygen sensors. Something to check for if you got an n51

[JJT211]

Originally Posted by gbalthrop

You can press "PrtSc" (PrintScreen) button and save/paste as jpg file in Paint. My N52K engine idles at 660 RPM (warm idle, 90 to 120 seconds after cold start), and MAF Rate is 13 kg/hr at that idle speed. Your 3.0L engine should have ~ same MAF Rate vs. RPM ratio.

Oh hell yea, some hard numbers!

Warm idle for me is 710RPM @ 5kg/hr

So yea, I def still have a vacuum leak.

[JJT211]

Originally Posted by lowrydr310

Unless you held the throttle valve open or removed the throttle body entirely, that's not really a good test.

I had similar air leak codes and stumbling idle, which ended up being a cracked CCV hose under the intake manifold. When I did my smoke test, I removed the air box and wedged the throttle plate open with a piece of a rag. It didn't take much smoke to reveal the leak. I left my oil cap on when I did it.

Ok cool thanks....thats where I was going wrong.

[gbalthrop]

Originally Posted by JJT211

... Warm idle for me is 710RPM @ 5kg/hr
So yea, I def still have a vacuum leak.

OR a (1) MAF Sensor fault or a (2) Fault in MAF Sensor Connector or (3) wiring between Connector & DME. Is IAT (Intake Air Temp -- also measured by MAF Sensor) in the ballpark with Ambient Temp (depending upon vehicle movement)? My IAT (Ansauglufttemperatur) sitting at idle, is ~ 40C with ambient 25C. That Parameter is ALSO on Messwert (Measured Values) Group 1, between RPM & MAF Rate.

ASSuming my MAF Rate of 13 kg/hr @ 660 RPM is correct, at 710 RPM, your MAF Rate should be 14 kg/hr instead of 5, so the value being received by YOUR DME is only 37% of what it SHOULD be. I'm curious to know if Rate increases after engine has run ~ 10 minutes (and idle smoothes)?

You might ALSO monitor the Raw Voltage/"Mikrosek" Data for BOTH IAT & MAF Rate using the "Rohwerte ADC & Messwert Screen. In short, can't tell if you have (1) an actual Vacuum Leak (QUITE large if so, with nearly twice as much air entering via LEAK as is passing MAF Sensor), OR (2) an issue with Sensor, Connector, or wiring. Don't forget the Connector at the DME.
George