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-   -   New Fuel Filter = better performance? (http://forum.e46fanatics.com/showthread.php?t=947776)

White_Knuckles 09-30-2012 01:50 PM

New Fuel Filter = better performance?
Okay, I may be crazy but...

My fuel pump left the party instantly when I went to leave a parking garage the other day. It would crank - start - die, crank - start - die. Then no start. I yanked the rear seat and had a helper turn the key where I could hear nothing with my ear on the pump location.

I got lazy and had it towed to my Indy who was closer then my house and thought whatever, let them deal with it. The diagnosis was a DOA pump but he suggested I should have the filter changed as well. Why not? I had neglected it now at 80K miles.

So $500 later I get her back. The strange thing is, I swear the car runs better now! The off idle and mid-range throttle response is clearly more responsive. I have driven it a week now and the same route I take every day is a great test with on ramps and long, steep hills. The car runs like I added a mini super charger.

Could the fuel filter actually make that much of a difference? I know it has a pressure regulator built in that may play into this. If this is plausible, I highly recommend you lazy guys (like me) jerk that old filter and possibly restore lost ponies. The stupid filter is around $100 so be prepared.

zabalzae 09-30-2012 02:31 PM

Why jerk it? Why not just replace it? You want crap to go to the injectors? More expensive... the fuel filter makes a big difference when dirty because it doesnt allow enough fuel to the injectors. Imagine if one of ur heart Arteries clogged, then you wouldnt work..

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White_Knuckles 09-30-2012 02:45 PM

By "jerk", I meant replace it not bypass the filter/regulator. Sorry for the confusion.

Foxtrot_Uniform 09-30-2012 02:52 PM

Yup... I have one in the garage... I just need to install it.

SharkmanBMW 10-01-2012 11:49 AM

I agree - I too have found a slight increase in pep/response after a filter change.

SamDoe1 10-01-2012 01:41 PM

I have one sitting on the shelf to install, just haven't had the time to put it in. :banghead:

tomoyer 10-02-2012 03:31 PM

The fuel filter will start to clod with age and miles, slightly reducing flow and pressure and the pressure regulator itself will start to weaken with age and miles. Best to replace as the maintenance schedule recommends for cleaner fuel, better performance and cleaner injectors.

VG1134 10-02-2012 03:38 PM

Yep- this is my next preventative maintanence on the list.

Solidjake 10-02-2012 06:01 PM

Yea, filter does make a small difference but what you're feeling are the effects of a new fuel pump.

TonyDiv 10-02-2012 06:04 PM

Universal rule of thumb. If you notice a difference after changing a filter... you waited too long to change that filter.

White_Knuckles 10-02-2012 07:29 PM

Pump gas isn't exactly loaded with contaminants and debris. In the old days, metal tanks would scale and rust creating all kinds of nastys to get trapped in filters. I went crazy and chopped my filter in half to inspect the element. It was discolored, sort of gray but definitely not clogged with scary stuff. I'm leaning toward a weakened pressure regulator or as Soildjake mentions, a fresh pump pushing the juice harder.

May never know what performed the magic but nice to see others noticing an improvement as well.

2002GreenBMW 10-20-2012 08:07 PM

Damn son, 500 bucks? It took me 30 minutes to replace the fuel pump with a YouTube diy

willkenni05 10-21-2012 12:41 AM


Originally Posted by 2002GreenBMW (Post 14832249)
Damn son, 500 bucks? It took me 30 minutes to replace the fuel pump with a YouTube diy

Exactly! Probably not the job to get lazy on! Cost of the pump + 30 min would have saved you quite a bit of cash...

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redbull 325is 10-21-2012 11:39 AM

Your fuel filter probably did help alot, but also if your fuel pump was getting weak it could have been delivering less than optimal fuel pressure.

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