Check both air Intake hoses, vacuum lines along the back of the intake and the little plugs. Could also be the Valve cover gasket, DISA gasket as well. How did you perform the smoke test?

 

Hey tommy d, I'm not to far from the Lehigh valley. Used to live there a fee years back.

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Does it do the same thing when you unplug the MAF?

 

P0171 is caused by a vacuum leak in bank 1 (cylinders 1-3). Tge only way to find all the vacuum leaks is to professionally smoke test the intake manifold. Find a reputable indie shop that specializes in bimmers at www.bimrs.org.

 

One of the biggest differences between a Harbor Freight (or the like) smoke testing machine and the one we use is the ability to not only visualize smoke leaking, both in full stream and 50% pulsed mode. Is the ability to have a reference number after about 90 seconds.

If we see a number such as 45 displayed on the panel, we know we still have a medium sized leak. Something on the order of high teens tells us that we're leak free.
It's not only about the visual smoke, but also the amount of back pressure obtained. Really a leak-down test of the crankcase as the smoke machine applies pressure and smoke into the engine.

Each engine family has slightly different values. Newer "N" engine cars are by regulation of the need to be much tighter. Once in a while we're tasked with chasing down a "Micro-Leak" displayed in the fault diagnosis. They're fun, NOT.

 

Don***8217;t forget about the SAP hoses going to the back of the intake and the CCV. I remember scrambling with lean codes with inspection approaching.

 

If you have a significant vacuum leak, your car would not idle well and it would perform normally while accelerating. You have the opposite symptoms. Check your fuel pressure first. Buy, borrow or rent a fuel pressure gauge. Connect it to the fuel pressure test port and secure it to the wiper arm so it's visible when driving. Fuel pressure should be about 50 psi and not drop when accelerating and the car is bogging. Bad MAF or clogged catalytic converter(s) are also possibilities. Let me know what you find.

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What are the long term fuel trim values of both banks and MAF value at hot idle?
What is the fuel pressure?

 

I have the VEEPEAK OBD scanner with OBD Fusion but I'm not sure where to find this information on the app.... Is it even available?

I also have INPA which connected fine to my old 330ci but will not connect to this 325ci for some reason:hmm:

The valve cover does leak a bit of oil into 2 of the spark plug wells but enough to cause a vac leak??? I may change it soon anyway if it's easy enough to do.

I'm planning to smoke the car again tomorrow with my home-made paint can smoker which works well enough. I've found leaks on other cars without issue.... unfortunately cannot afford to take it to a shop or throw parts at this problem. Just need to pass emissions for now so I can sell this thing

 

P0171 is not necessarily a vacuum leak, though likely that is part of it. It is only one bank, which would suggest a sensor issue on that bank, but I suspect that both banks have high LTFTs and only one is high enough to trigger.

You should do a proper smoke test or pay someone to do it. You should also replace every vacuum hose, o-ring, and seal that touches the intake. It is not expensive:
DISA gasket GA-BM-DISA-ORING-M54-S 1 $5.65
Intake manifold gasket - Elring 11611436631 1 $22.52
Air temp sensor o-ring 13621743299 1 $0.27
Dipstick upper o-ring - Reinz 11431717666 2 $0.24
Dipstick lower o-ring - CRP 11431740045 1 $0.38
Engine air distribution o-ring - Elring 11617502761 6 $5.94
Throttle body gasket 13547504728 1 $4.44
Intake lower boot 13541438759 1 $10.03
Intake upper boot 13541705209 1 $14.46
Silicon vacuum hose - black - CRP 11727545323 2 $5.42

Use the hose to replace the line from the SAP to the SAP solenoid, from the solenoid to the one-way valve, and the one-way valve to the manifold.
Replace the line from the F-connector to the fuel pressure regulator.
If you have a vacuum canister, replace the line or cap the port for it.
Make sure the large port cap on the back of the manifold is intact (it probably isn't)

If your valve cover gasket is more than 80k, replace it. Easy.

That will put you in good stead on leaks (yes, brake booster can also leak, it is not hard to test if you are interested)

Then if your fuel pump is over 125k, replace it.
If your pre-cat sensors are over 100k, replace them.
If your MAF is over 150k (frankly over 125k), replace it.

Somebody will accuse me of "throwing parts at a problem", but it is just maintenance. I have never heard anyone say that changing oil at intervals is "throwing fluids at a problem". You can't test a MAF (unplugging is not a diagnosis, it is a parlor trick, and cleaning is not useful). You can diagnose O2 sensors (not simple, you compare them against response rates of a known good emissions system), but your car is likely well over 100k, and they are wear parts.

If you are manic about diagnostics (which I respect) then get OBDFusion and ignore the codes. Focus on fuel trims.
- If your fuel trims are high at idle and low at cruise, it is likely a vacuum leak (leak becomes a smaller percentage of overall air volume as speed increases)
- High at speed and low at cruise is more likely fuel pump (increasing demand stresses a failing pump more)
- High at both is likely sensors.

But honestly, it is probably all three. It is not clogged cats or a bad ECU. It could be bad gas (it isn't).

If you pulled the manifold, replaced everything underneath ($66-200 depending on if you do hard lines and OFHG), then replaced the O2 sensors, fuel pump and MAF (about $462), your car would run fantastic.

You can't get a dealer to replace two FCABs for that money, so it is a steal, and you will pass emissions for the next 8 years.

As one of the old guys on this forum would say: In the end, it was the MAF...

 

I’m with a bad fuel pump on this one. How many miles?

 

I'm with a bad fuel pump on this one. How many miles?

Car has 180k. I bought it as a replacement for my old 330ci that was Tboned. My plan was to swap my old 2001 330ci engine into this 2002 325ci as they are identical and loved the car so the mileage didn't matter to me at the time (the 325ci even came with nice black sport interior:drool but lost my job and am scrambling to get back on my feet. I hate to do it as the E46 is an amazing chassis but I just need to get something more reliable and get myself into a stable position before owning something that constantly takes my attention away from what is important in my life such as a roof over my head.

I have no idea what the previous owner did as far as maintenance. Hopefully OBDFusion can point me in the right direction

 

There is a complete guide to setting up OBDFusion by JFOJ.

https://e46fanatics.com/forum/attachment.php?attachmentid=624644&d=1455986317

This is a very simple problem to solve if you take it one step at a time. Did you read my post above?

 

Yes, I appreciate all the info but it's a bit much. I need to get to the bottom of if this is a vacuum problem or a fuel/sensor/maf problem and I believe the fuel trims through OBDFusion will do so. Just need to figure out how to use the app and what the data means:hmm:

Ironically enough my neighbors 2006 Suzuki Grand Vitara has the same code so trying to help her out with this as well.

 

I've had this code due to a weak fuel pump. Changed the pump and fuel filter and it ran like a top. Even got better fuel economy. If you can't find a vacuum leak, I would explore lack of fuel.

 

But wouldn't I get the bank 2 code as well if it was fuel pump related??? My thing is the P0171 (bank 1) code is the only code I'm getting:hmm:

 

But wouldn't I get the bank 2 code as well if it was fuel pump related??? My thing is the P0171 (bank 1) code is the only code I'm getting<img src="http://s1.E46Fanatics.com/forum/images/smilies/thinking.gif" border="0" alt="" title="Hmm" class="inlineimg" />

I had the same concern, as I was only getting the P0171 code. Honestly the lean codes are generated by the O2 sensors. It's certainly possible to have one sensor more sensitive than the other. So if the fuel pump/filter are starting to fail I would expect them to show lean on one bank before the other. That is what was happening with my car.

I didn't test my fuel flow or pressure, figuring changing the pump and filter would likely solve it, which they did. I figured that the pump was likely the original and with nearly 200k miles, it was likely to fail sooner than later even if it wasn't causing this particular issue. Sloppy diagnostics, but it worked.

 

For us, it was the DISA that got rid of that darn DTC. Everybody replaces the outer o-ring, when it's the internal valve flapper that is toast(much like the CCV). I replaced ours with a factory part and is ran much stronger afterwards. You might pull the DISA and check it. Ours was so bad, the metal pin for the flapper was lying in the intake(caught just in time).
regards.

 

A little update... I now have a new code P0492 "Insufficient Flow to Secondary Air Pump". I recently replaced the secondary air pump with a known good unit so maybe related to my other issue?

Here are the 3 logs.

Before warmup idle (let the car idle for a few minutes about two hours earlier so wasn't entirely cold)
https://www.dropbox.com/l/scl/AAA-FUu09KDvc6WJwPhXTswQ7MgF4skCR8A

After warmup idle
https://www.dropbox.com/l/scl/AAD0ICSsWo6FlwcwtGl2Z6E9XT9dpjR1jp4

Freeway cruise @ around 60mph (wasn't perfectly flat but not too hilly either)
https://www.dropbox.com/l/scl/AAC_5EVpT32a00ojLwb0Y6rxkqj22s4ldr4

Any help with this is greatly appreciated!!!!

 

Here are the 3 logs.

Before warmup idle (let the car idle for a few minutes about two hours earlier so wasn't entirely cold)
https://www.dropbox.com/l/scl/AAA-FUu09KDvc6WJwPhXTswQ7MgF4skCR8A

After warmup idle
https://www.dropbox.com/l/scl/AAD0ICSsWo6FlwcwtGl2Z6E9XT9dpjR1jp4

Freeway cruise @ around 60mph (wasn't perfectly flat but not too hilly either)
https://www.dropbox.com/l/scl/AAC_5EVpT32a00ojLwb0Y6rxkqj22s4ldr4

You need to publicly share these files so people can view them.

 

Is there a certain thread I'm supposed to post the logs in or person I'm supposed to PM?

Itching to get this goin

Also, if it shows "heated catalyst" is "available" and "failed" on OBDFusion is it safe to assume the O2 sensors are bad? I have extra Bosch O2's that I was planning on selling but if the ones that are currently on the car are known to be bad I will change them.

 

Just read through all the posts in this thread. There was a lot of advice given that you ignored or didn’t report back on. Honestly, if you want help it’s a two way street, you have to do your part. Go back and read the suggestions and check those things and report back.

Measure the fuel pressure at the fuel rail, do a thorough smoke test, and repair all vacuum leaks.

I ‘ll look at your logs and report back in a bit.

 

Looked at the logs and have these comments.

Before and After logs
- MAF value around 3.0 g/s seems a bit low. Usually expect 3.4 to 4.2 g/s at idle.
- Both LTFTs are too high and never moved.
- Both STFTs started moving right at closed loop, and have reasonable values.
- Both pre-cat O2 sensors seem to be working fine.

Freeway log
- Bank 1 LTFT at 11.72% is too high. It should be below 5.0%.
- Bank 2 LTFT at 6.25% is a little high, but not enough to trigger a fault code.

Things I would check:
- make sure MAF is genuine BMW or VDO, swap it with a known good MAF if you have access to one
- do a thorough smoke test, likely have a vacuum leak as indicated by high LTFTs
- check fuel pressure at the schrader valve at the fuel rail, it should be 50 PSI
- post the freeze frame data for the trouble code, it describes the engine conditions when the fault code triggered

Smoke test tips and videos in post #1 of this thread.
https://forum.e46fanatics.com/showthread.php?t=1261077

 

Thank you sir:bow:

-I will try to track down a good MAF.... sucks because I just sold my spare the other day:facepalm:

-Will do another smoke test with the engine bay a bit more cleared out for better visibility. I introduce the smoke the same way the 50s kid does it through the brake booster hose.

-Is the 50psi at idle? Will do that in a few hours.

-Not sure how to do this but will research later.

 

You are correct - it is not a $15 tool. It is a $24.99 tool at Harbor Freight.

Also, if you are just trying to unload a car, mention that in the first post. We presume people are here because they want to be e46 owners. No worries if you don’t, but I would not have spent the time on my responses otherwise.

I have a used but good working order pump I will sell you for $35. BMW genuine. It will at least eliminate that part.

 

I mentioned selling the car in my 2nd post in this thread. I also mentioned that I have recently replaced the secondary air pump with a known good unit. From what I can tell the small vac line going to the pump is good but I will have to dig back there and double check behind the IM later when I have time.

 

https://youtu.be/oymVvM7Wxbc

 

Tore some of the car apart and checked everywhere for vac leaks. The only thing that could possibly be leaking from what I can tell... there were some tiny wisps of smoke coming from the brake booster hose at the joint connection (has a crimp clamp holding it in place) just above the throttle body and also at the piece that sits above the intake manifold there is a hard vent line that goes to a softer line there are some wisps at that connection but nothing substantial and could only see this as the pressure was a bit high (could tell from how big the glove was getting at the boot) so I'm not sure that's enough of a leak to actually replace those pieces. BTW I had the smoke THICK pouring out of the oil cap hole.

Checked fuel pressure and it fluctuates between 48-50psi at idle.

Did a proper before and after run with the MAF unplugged and there is no denying it has a bit more power with the MAF unplugged so I'm going to try to find a replacement without breaking the bank. Kills me that I sold my spare.

 

Well done! I would get a replacement MAF sensor. Since you’re selling the car, you might just get a good used one (with warranty) from a local junkyard. Or, check our Classifieds forum.

I got mine for $220 at fcpeuro.com, as it was the cheapest new VDO branded unit I could find. Unlike yours, mine was over-reporting air mass, typically around 5.0 g/s at warm idle, giving me negative fuel trims in the -8% to -10% range.

 

Thanks everyone. I'm fairly confident a good used MAF will do the trick.

BaliDawg, you're the man. I know you've helped me in the past and really appreciate you getting me through this one. This forum wouldn't be the same without you.

Archbid, no hard feelings man. Lots of great info and I appreciate your help as well.

 

Here***8217;s to hoping the replacement MAF clears this up.

Please post back when you install it, clear trouble codes, and do a cold start log.
That will tell us right away if the new MAF makes a difference.

 

OK installed the MAF yesterday and it definitely drives better but still bogs a bit and has a lack of power when giving it full throttle. I had someone with a 325i e46 come by and look at the car and he mentioned the lack of power at full throttle so it's definitely noticeable.

Here is an updated cold start log I took yesterday after installing the new MAF.

https://www.dropbox.com/s/mq1nut3xyol7161/CSVLog_20200125_113631.csv?dl=0

Is it possible the fuel pump is cutting out at full throttle even though it shows the normal 48-50 psi at idle?

My other thought is maybe the cats are clogged? I'm thinking of pulling the o2 sensors and ziptie them out of the way to see if that makes a difference.

Maybe the minor valve cover gasket leak in one of the spark plug wells has something to do with it?

No new codes have come up since clearing them the other day.

 

OK installed the MAF yesterday and it definitely drives better but still bogs a bit and has a lack of power when giving it full throttle. I had someone with a 325i e46 come by and look at the car and he mentioned the lack of power at full throttle so it's definitely noticeable.

Here is an updated cold start log I took yesterday after installing the new MAF.

https://www.dropbox.com/s/mq1nut3xyol7161/CSVLog_20200125_113631.csv?dl=0

Is it possible the fuel pump is cutting out at full throttle even though it shows the normal 48-50 psi at idle?

My other thought is maybe the cats are clogged? I'm thinking of pulling the o2 sensors and ziptie them out of the way to see if that makes a difference.

No new codes have come up since clearing them the other day.

I looked through this latest log and the STFTs look fine, MAF values look better, precat O2 sensors switching fine.

Take it for a long varied drive getting it up to full operating temp and see if any of the codes trigger or not. Might as well do another highway cruise log at that point.

Good idea to check for clogged cats by taking a short drive with the precat O2 sensors removed. If the power goes up noticeably, you have clogged cats. Can also do an exhaust back pressure test for a more accurate check. I somehow missed the low power/bogging comment earlier or would have suggested this already.