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BMW CCA 69606
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1) There is an engine code......multiple misfires. There are likely too many misfires for DME to identify the bad cylinder(s). Do you get this code every time the engine runs poorly? This may point to bad coils.
2) There is no point in checking plugs AFTER car has been running well. You MUST shut down when running poorly and check for wetness BEFORE the plugs have a chance to dryout. There is no way to be sure that a dripping injector will put fuel on plug, it may drip onto top of piston keeping plug dry. However after running poorly, the fuel is distributed throughout the cylinder and plug should be wet if excess fuel is cause of misfires.
3) Use the Innova OBD2 code reader you used in the first post. It only reads OBD2 codes and will read OBD2 codes much faster than Carly that takes 2-3 minutes to scan EVERY module in the car. Clear all codes before you start the car, check for codes while running rough. Repeat until you are able to scan while engine is running poorly.
4) There are no VANOS codes, leave them alone. Follow the code you have.
5) Take kd7iwp up on his offer. Install (3) index 7 injectors in bank 2. You can figure out how to code the DME later.
6) Search for the source of the fuel you smell after a rough running start? At the exhaust? under the hood? Are you sure you don't have a fuel leak under the hood?
7) Plug 4 CLEARLY has more soot than plug 5. It's on the backside of the ground electrode and below the 1st thread. Swap locations and see if plug 4 soots up again.
 

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2008 BMW 535xi
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54 Posts
Discussion Starter · #42 ·
I can try to prime the fuel like you are suggesting . I took the spark lug 4 out and inspected for leaking injector.it is bone dry and plug color is tan .. good condition. I pulled that intake charge tube out and checked boost sensor . The charge pipe connecting to throttle body and to intake manifold. There was a bit of oil pool up at the O-ring and boost sensor is wet with oil. I cleaned the tube and sensor perfectly clean. All back together now. I didn’t start the car yet. Just trying to think what I should be doing before starting the engine .
 

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I can try to prime the fuel like you are suggesting . I took the spark lug 4 out and inspected for leaking injector.it is bone dry and plug color is tan .. good condition. I pulled that intake charge tube out and checked boost sensor . The charge pipe connecting to throttle body and to intake manifold. There was a bit of oil pool up at the O-ring and boost sensor is wet with oil. I cleaned the tube and sensor perfectly clean. All back together now. I didn’t start the car yet. Just trying to think what I should be doing before starting the engine .
I don't know how you can check for leaking injector by simply looking at the spark plug. To test an injector for leakage you need to pull the suspect injector and leave it connected to the fuel rail emerged in a container overnight. Plug the injector back and start the engine. If it runs fine then very likely injector is the problem. Maybe you could do this to all injectors to be certain. Another test is to pull the fuel pump fuse or relay, start the engine running until it shutsdown and then leave it overnight. In morning reconnect fuse or relay and fire the engine up. Runs better then likely to be injector leaking. Just because you smell fuel does not mean an injector is leaking either.

From all the checks that you have done so far, it is clear that you have a misfire on cylinder #4. The OBD reader cannot tell you any more than that. VANOS and MAF would not cause a single cylinder misfire or multiple misfires so forget that scenario. Starting the engine in closed-loop, the DME would also ignore most of other the sensors and only use crank/cam sensors for the initial timing and temp sensors along with the ICV to control idle. VANOS gears are not really activated or come into play until oil temp/pressure is up and RPM's above 1500 RPM and underload.

The coils and plugs are good as you checked/swapped them and engine runs fine above idle RPM's. Compression or leak down test is next step if injector or signal from DME to injector is good. IMO some kind of leak or compression (injector, valves, piston rings, crack) in cylinder #4 is causing the misfire.

I'd be very surprised if it turns out to be a coil or spark plug as these are the first checks and can easily be found within 15 mins of popping the hood and without an OBD reader.
 

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2008 BMW 535xi
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54 Posts
Discussion Starter · #44 ·
I cleaned the charge pipe and this sensor. It was wet with oil from intake charge pipe. I am not sure if this is the problem but the car cold start fine today. I started the engine and let it run for about 1 min enough to take a short 20 seconds video of idling.

When I said I pulled number 4 spark plug to check for leaking injector, I mean if the injector is leaking, it will drip on the tip of the spark plug. That is what happening till I pulled the injector and clean it. The plug has been dry since (driven for a week and still dry).

First two photos is the condition of charge pipe and sensor (the sensor seal was damage before 🤔)
Last photo ..sensor after I cleaned


Work I did today:
1- cleaned intake charge pipe - completely clean and dry charge pipe
2- clean sensor (boost sensor MAF sensor) with carb cleaner.
3- pull spark plug 4 to see if it dry and check the color of the ceramic (tan and clean)
4- cold start the car for ~ 1 min. No issue.

1032733
1032734
1032735
 

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I cleaned the charge pipe and this sensor. It was wet with oil from intake charge pipe. I am not sure if this is the problem but the car cold start fine today. I started the engine and let it run for about 1 min enough to take a short 20 seconds video of idling.

When I said I pulled number 4 spark plug to check for leaking injector, I mean if the injector is leaking, it will drip on the tip of the spark plug. That is what happening till I pulled the injector and clean it. The plug has been dry since (driven for a week and still dry).

First two photos is the condition of charge pipe and sensor (the sensor seal was damage before 🤔)
Last photo ..sensor after I cleaned


Work I did today:
1- cleaned intake charge pipe - completely clean and dry charge pipe
2- clean sensor (boost sensor MAF sensor) with carb cleaner.
3- pull spark plug 4 to see if it dry and check the color of the ceramic (tan and clean)
4- cold start the car for ~ 1 min. No issue.

View attachment 1032733 View attachment 1032734 View attachment 1032735
I think you found the issue then. Sometimes the simple causes are quite easy to miss when you start a post about faulty crank sensors, injectors leaking and wet spark plugs. Keep an eye on it for the next few weeks.

And no, a leaking injector will not drip onto the tip of a spark plug enough to foul it with fuel, but it would bore wash the cylinders and cause misfires or poor compression.
 

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2008 BMW 535xi
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54 Posts
Discussion Starter · #46 ·
Just want to close on this . My random misfire on cylinder 4 did not come back as of now yet. I have driven with hard acceleration and simple gentle cruising at highway speed. It is working fine. I am still confuse about wet injector on cylinder 4 but as long as it doesn’t come back by now . I think it is okay. Thanks everyone for chiming in. Thanks for this forum!
Regards
Mannig
 
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