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Old 09-20-2012, 12:16 PM
idjit's Avatar
idjit idjit is offline
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Location: Fredericton area, New Brunswick, Canada
Join Date: Feb 2012
Posts: 147
Mein Auto: 2003 525i
OK, I unplugged the intake solenoid on the vanos and it started fine. That may have been a fluke so I'll repeat it every day for a week to be sure.

Here's my theory:

I think vano's might play a part. It's not bad enough to be throwing codes except for cylinder 3 cause there is an issue there that does not show up on warmer days when the vanos does not come into play. I've swapped the coil and the plugs were change since last spring when I last had the issue so it's probably the injector. Of course compression could be a factor but I'd prefer to think I didn't say that.

Maybe vanos if fine and it's just the added bit of fuel from the cold start injector that tips it to misfiring (flooding). I assume the cold start injector is used on cold days? Maybe more so on cold days?

Once the computer senses the missfires, it shuts down the injector to prevent cylinder washdown and catalytic failure. Meanwhile, with the car running, things warm up a bit. Perhaps the vanos goes normal or maybe now the cold start injector is off or something other "cold start feature". Now missfire would be gone if not for the fact that the fuel remains shut off until computer reset. So I restart the car and all is fine.

So what can I do for less than $20.00 without getting my hands dirty?....

I'll keep checking the vanos for a week (as mentioned above). I'll try some "Techron" injector cleaner on the next fillup (if I can find it here). "Redline SI-1" seems to have a good reputation as does "BG-44K" (again...if I can find it). In fact I've read "BG-44k" might be the best. I know where I can get "Lucas" injector cleaner, another favorote from what I read.

Then, on the fillup after that I'll "seafoam" it if I still have the problem. Having owned a 1980 golwing I've learned to respect seafoam, but it's for a lot more than just injectors. Very gentle on seals. Lot's of cool smoke to impress people when taking off at green lights. Fun to watch in the rear view mirror as they fade away into the fog.

After that? I'll swap #3 injector with whichever other injector looks easiest to get at to see if the problem moves (now my hands would be dirty and $25.00 wasted).

After that? Ignore it if I can. Otherwise compression check or something.

I've read people suggest computer, but I highly doubt it. That theory seems to come from the fact that they have to reset, which I think is by design to protect the car. The shut off is a result of the missfire, not the cause of it. I don't believe being cold is going to repetively cause the DME to shut down the same injector.

I wouldn't doubt that my vanos is on the way out. Does anyone have an exchange program for vanos using the seals from ""?

Thanks for your helpful replies, I let you know....


Last edited by idjit; 09-20-2012 at 12:20 PM.
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