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Discussion Starter · #1 ·
So, here's the historical fault logs from my car. It's been throwing SES on startup for the last month or so, maybe three times a week.

11/21
P0171: System too Lean (Bank 1)
P1345: Misfire Cylinder 2 With Fuel Cut-off
P1347: Misfire Cylinder 3 With Fuel Cut-off
P1349: Misfire Cylinder 4 With Fuel Cut-off
P1341: Multiple Cylinder Misfire With Fuel Cut-off

11/22
P0172: System too Rich (Bank 1)
P1345: Misfire Cylinder 2 With Fuel Cut-off
P1347: Misfire Cylinder 3 With Fuel Cut-off
P1349: Misfire Cylinder 4 With Fuel Cut-off
P1341: Multiple Cylinder Misfire With Fuel Cut-off

12/1
P0171: System too Lean (Bank 1)
P0313: Misfire Detected with Low Fuel

12/2
P0172: System too Rich (Bank 1)

12/3
P1342: Misfire During Start Cylinder 1
P1344: Misfire During Start Cylinder 2
P1346: Misfire During Start Cylinder 3
P1348: Misfire During Start Cylinder 4
P0316: null

12/5
P1342: Misfire During Start Cylinder 1
P1346: Misfire During Start Cylinder 3
P1348: Misfire During Start Cylinder 4
P0316: null
P0172: System too Rich (Bank 1)

12/6
P0171: System too Lean (Bank 1)

What should I be replacing next? The car seems to run fine, doesn't have any strange acceleration hiccups or performance hits. I've replaced both MAFs, both precat O2s, cleaned out the injectors about twelve times with Seafoam & Techron (not at the same time), and replaced the fuel filter. It's clearly always bank 1 that's having the issue; what can I check over there?
 

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Just thinking out loud here. I wonder if this could be the start of an intake CPS going bad on that bank. The challenging thing about fuel and misfire codes is they could (in theory) cause each other. Unburnt fuel due to an ignition issue could cause a "rich" code to occur. A lean fuel issue could could, in turn, casue a misfire. Since the fuel pump, filter and fuel pressure regulator are shared between the banks it would seem unlikely they would be the culprit. Could a coil or wiring/ground to that bank of coils perhaps be an issue. Sorry, I know this isn't much help, but figured I would toss this out there.
 

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Weird rich one day then lean the next. According to your codes the injectors are being shutoff, but you say that there are no symptoms? Don't you hear pop pop from the exhaust?
Do I understand you right, the SES lights when you start the car(how soon) but was not on when you parked the car?
 

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Discussion Starter · #4 ·
Correct. SES light comes on 5-10 seconds AFTER starting the car, and was NOT lit when the car was parked.
 

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All I can say is weird. check the codes if you can a few times before you shut it off. See if some are just pending and not triggering the light. Might very well be what Cab is thinking. The only other thing I could guess at is, hows your battery? If all things are equal the symptoms will show up in the future.
 

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Discussion Starter · #7 ·
Any way I could diagnose further with DIS or INPA? What about the intake/exhaust CPS on bank 1, or the VANOS (I doubt it's VANOS, although I tend to hear them knocking around on cold accel)
 

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Can you do a vanos test? Really it does look like vanos. As cab pointed out the other systems are shared. I just don't see why you are getting those codes on start up. There are other misfire codes for the first 1000 revs on startup. The other thing is the injectors usually get turned off while those codes are present/active/misfiring and you feel it. See if you can find any screen that is reporting the vanos position.

How old are your plugs and your battery? If it is happening in the first 1000 revs there are somethings that go on to keep the plugs clean in the rich environment. Plugs that are dirty will not respond well and a weak battery will not fire the coils correctly with the extra load at this time. Still I would think it would not be confined to one bank. Can you see misfire info in either of your programs? It is usually a list of all cyls 1-8 and you will see number going from - to + never much more than 50 but if things are off a bit you see numbers up to 100 and if off a lot numbers greater than that.

You may just have to pull the plenum and check things as Phakes has said, you may rule more things out with an inspection than looking at a scanner for this.
 

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Discussion Starter · #9 ·
It's still doing this, by the way.

New code, though.


Current Fault Log
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P0171: System too Lean (Bank 1)
P1342: Misfire During Start Cylinder 1
P1344: Misfire During Start Cylinder 2
P1346: Misfire During Start Cylinder 3
P1348: Misfire During Start Cylinder 4
P0316: null
Pending Fault Log
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P0491: Secondary Air Injection System (Bank 1)


Should I replace the VANOS unit/solenoid? Which one? I really have no idea where to go from here. I've tried swapping plugs, coils, and MAFs around between banks and it's always Cyls 1-4 and Bank 1 too rich or too lean.
 

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No don't replace anything except what is causing the air leak. Phakes nailed it further up in the thread. Get a can of O2 sensor safe carb cleaner, remove the plenum and unplug the MAFs.
Start the car and spray the can on the hoses for the IACV and in likely hood you will find that when you spray on one of the tubes that joins the throttle bodies you will get a rise in idle. That spot is where you have an air leak.
 

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Discussion Starter · #11 ·
Where would the leak be? The runners? I pulled the plenum off today and sprayed some Seafoam Deep Creep into each of the runners; the car seems to have noticeably improved throttle response, so I'm debating pulling all the runners off and spraying it into the TBs directly.
 

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RealOEM.com * BMW E39 M5 Idle regul.valve/fuel tank vent valve is under RealOEM.com * BMW E39 M5 Mass air flow sensor
Part#9 there is a 10 in a circle at either end. 10 is what is likely leaking it is an oring. Follow the line you will see they go between the throttle bodies. Any of those parts could be leaking or the other hoses maybe part 17. Deep creep will not do the job here. I use propane but that is advanced, you have to know what you are doing or could have a boom you don't want. Carb cleaner, brake clean, but it must say O2 sensor safe, will be flammable enough for you.
 

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hiha I guess he has not read the other tools more frequently used on the site. Think we are going to blame jfoj for this. Maybe we brought it on ourselves ordering to much at one time. I don't want to remember how much I sent that day on that site. Still all in the box.
 

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Don't know, would if you knew the leak was there. Might but might not that is what the carb cleaner is for. If it gets sucked in with the air the rpm will come up. If the hole is big on occasion too much goes in and the car bogs. Still means there is a hole. You respray lightly in the same area and see if the rpm goes up. There are a lot of things that can leak.
 

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Discussion Starter · #19 ·
I got some new codes today, after doing the muffler delete.

Current Fault Log
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P0491: Secondary Air Injection System (Bank 1)
P0102: Mass or Volume Air Flow Circuit Low Input
P1117: Mass Or Volume Air Flow Circuit Low Input (Bank 2)
P0113: Intake Air Temperature Circuit High Input

Pending Fault Log
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P0420: Catalyst System Efficiency Below Threshold (Bank 1)


These are the ones that have always shown up:

P1342: Misfire During Start Cylinder 1
P1346: Misfire During Start Cylinder 3
P1348: Misfire During Start Cylinder 4
P0316: null
P0172: System too Rich (Bank 1)
P1344: Misfire During Start Cylinder 2

What do you think the new ones could be? The old ones (misfire cyls 1-4, too rich bank 1, etc) are all still there, but now I have some intake-related errors as well. Do you think it could be those same O-rings?
 
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