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Discussion Starter · #1 ·
Heyall.

I got a 2002 model 520i (automatic) and when it's cold the engine gets hard to start. Sometimes throwing lean code. Girlfriend ran the tank dry and the fuel pump is making big noises. It also throws code for O2 sensor. 02 sensor codes does not trigger engine light but the lean code will.

Sometimes it will throw the code and trigger engine light while driving away (when I put throttle down) and other times instantly when engine starts.

I had issues with startup for a while, in the beginning the car started normal but lost revs and almost died. Then after a while it started dying when losing revs and now doesn't start when cold unless I give it some throttle.

I removed the spark plugs and gave them a bit of cleaning and that helped for a few days. Plugs looked pretty black (a year and half old with not too many miles on them). I'm thinking maybe oil in the chambers but exhaust smells normal and doesn't look blue. Got some oil leaks from the valve cover, may that affect the plugs?

Any ideas appreciated.
 

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Wingnut
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before replacing anything, unless you just wanna fire the parts cannon, check the fuel pressure. your y/m has the schrader valve on the fuel rail, even a simple pencil type tire pressure gauge will give you an indication of whats going on, or not going on. a lean code could be an indication of low fuel pressure, vac leak etc.
if youve any oil pooling in the spark plug wells, thats a VC leak, and will cause a miss and rough running.
 

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Discussion Starter · #5 ·
before replacing anything, unless you just wanna fire the parts cannon, check the fuel pressure. your y/m has the schrader valve on the fuel rail, even a simple pencil type tire pressure gauge will give you an indication of whats going on, or not going on. a lean code could be an indication of low fuel pressure, vac leak etc.
if youve any oil pooling in the spark plug wells, thats a VC leak, and will cause a miss and rough running.
Yeah thanks. I know a guy who knows a guy and he may have something to measure the pressure. He also have proper diagnostics tools and he knows E39 so gonna go there tomorrow. I got a bit of a VC leak at cylinder 5-6 (?) in the rear of the VC, didn't see any oil pooling down there with the spark plug but it didn't look clean either. Though the tool I've been using doesn't read any misfire codes.

Hmm by the way if the guy doesn't have anything to read the pressure from the schrader valve do you think this will be able to?




EDIT: I think the fuel filter should be replaced regardless, can't be good for the pump if the filter is old and dirty. Probably wanna replace the pump as well, if it appears to be the original one. Over 170k miles on the car and some decent 3rd party pump wont be so expensive.
 

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Wingnut
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filter is a good PM thing....noise from the fuel pump should be looked at too. mahle for the filter, pierburg for the fuel pump. no other pumps that are known around here are considered to be long term reliable.
 

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Discussion Starter · #7 ·
filter is a good PM thing....noise from the fuel pump should be looked at too. mahle for the filter, pierburg for the fuel pump. no other pumps that are known around here are considered to be long term reliable.
Alright, thanks for that as well. I'll go for those then. I was considering mahle, champion or bilstein for filter and wasn't sure at all for the pump but cheers. Now I now what to get. :D

On sale right now as well. Could it be better? heheh
 
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