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Discussion Starter #1
As with some of the other's on the board I had the same issue with fuel starve at around 1/2 tank or slightly less in my E46 330. 95% of the time was around long sweeping right hand turns such as big bend at LRP. I started looking for a solution and found out about the M3 fuel baffle that can be dropped into the tank for about $16 and decided to go for it. The other option is the dual pump setup from Bimmerworld, but you loose your factory fuel gauge which was not an option for me. The part # needed for this project is 16 11 2 229 656. I ordered mine from realoem.com and had it about a week later.

Tools and parts needed:
E46 M3 fuel baffle part #16 11 2 229 656
Small hose clamp
10mm socket and ratchet
wire cutters
misc. flat head screwdrivers
hammer

First thing's first is to gain access to the rear seat area.



To do so lift up on the front edge of the rear seat. There are clips on each side. Then Pull forward and remove the rear seat bottom from the car.



You'll be left with this.



From here, locate the pass side round cover with the wire going into as shown below.



Lift the cover and remove the 4 nuts with the 10mm socket and ratchet.



Next you need to remove the electrical connection for the pump/gauge.
To do so, slide the outer part of the connector to the left, this will release the plug so you can remove it.





Next remove the fuel line. You will need to cut the clamp off of it. This is where you will use your small hose clamp when you put things back together. Some fuel will leak out of the line when it is removed, so be ready.



After that, you can then remove the pump. To do so, use a screwdriver and hammer to tap the metal ring counter clockwise to release the pump. Once this is done remove the fuel pump from the car. You will then be looking at this.



Look straight down into the tank and you will see a black hose that goes into the plastic tray on the bottom on the right hand side. Remove the hose from the tray. It will go into the new fuel baffle once it is installed. To install the new baffle simply, drop it into the existing plastic baffle. It will clip in on the right hand side. once it is in, slide the black hose into the top of the new baffle.



Then put everything back in as it came apart and your good to go. I did mine with 1/2 tank of fuel still in the car. I would highly advise running your tank down before doing this. it is much easier the less gas you have in it. Please feel free to contact me with any questions.
 

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Great DIY!
And this can be done to all 330 models? Ore maybe all E46 models?

But can You elaborate the problem a bit more?
And how will this baffle make things better?
 

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Discussion Starter #3
Great DIY!
And this can be done to all 330 models? Ore maybe all E46 models?

But can You elaborate the problem a bit more?
And how will this baffle make things better?
Works on all E46's. M3 already have this baffle in place.

This is to fix the fuel starve issue that is commonly experienced on the track. It usually starts to occur at about 1/2 tank of fuel left when you are in long sweeping right hand turns. The fuel all moves to the driver side of the tank, leaving the pump dry and then as you go to accelerate out of the corner, the car starts stuttering as there is no fuel at the pump. The baffle holds about 6oz of fuel and when your making the turn , as fuel disappears around the pump, the baffle drains out into the pump pickup preventing the pump from running dry, so now you can run the car down to about 1/4 tank on the track with no issue's.
 

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Great writeup :thumbsup: :bow:
 

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Keep us posted on how this works out for you. I didn't get much benefit on my car, maybe an extra 1/8 tank before starvation problems become an issue. Every little bit helps but I still just have to fill up when I reach 1/2 tank. With the SC'er, I've had starvation problems accelerating hard in a straight line from a stop with as much as 1/4 - 3/8 tank.

My latest (unproven) thoughts on the subject are that this may be the result of a weak fuel pump. Gas is siphoned from the left side to the right side of the tank as a result of the fuel returned to the L side of the tank from the regulator. If the pump isn't pushing enough excess fuel through the regulator to drive the siphon, it may cause the fuel to be transferred more slowly from the L to R side of the tank. This in turn may be leading to starvation when tank levels get low as the pump may empty the R side faster than the siphon can return the fuel from the L side. Again, this is all unproven (so don't anyone go rushing to replace your fuel pumps just yet) but I hope to get to the bottom of this issue later in the summer.
 

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Discussion Starter #6
will do. I'll be at NHMS sun/mon, but there are no turns there that really apply to this. I'll see if I end up back at LRP this year.
 

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2003 M3 6MT Slicktop
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I'd like to add a few things when doing this DIY.
Clean the dirt from the top of the fuel pump cover so dirt doesn't get into the tank when you open it up.
Use a bolt to plug up the hose on the top, as a little fuel is still alot when it comes to your interior. Even better, use a fuel hose crimp to keep gas from going everywhere. First time I did this, I had a lot of fuel inline under pressure. Have a bucket and towel close by and very handy.
Unscrew your gas cap to release pressure in the system. *Be sure to replace it tightly when done.
 

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Thank you for this. I had starvation at the carousel coming onto the back straight at Tremblant this past weekend. A friend with an e46 mentioned this fix. I will be doing this asap.
 

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Small Detail in Fuel Baffle fixture install

Did this to my 323 and it works as advertised. My mechanic did one additional thing that was not mentioned in the thread though. Something to do with depressurizing the fuel system usually throws an error light and the car runs poorly until all is back up to normal. Then it runs fine but the dash error light stays on unless you have a special tool. He attached a gauge to the Schraeder valve on the fuel rail that showed the fuel system pressure was low then had me turn the key on and off (not start) several times and then bled pressure out the gauge until fuel came out and pressure went up. THEN we started the car and no warning light came on or any error thrown to the computer. Car ran smooth and fine right off the bat. Last AutoX I only ran with 1/4 tank and had no issues except going faster from the loss of 60lbs of sloshing fuel!

I'm sure those with a more mechanical aptitude can clarify my post but that is essentially it.

Racer5
 

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I did this modification this afternoon, but I did not feel the baffle "clip" in. Can you please elaborate some? Did you have to firmly seat it, or did it clip very easily? Thanks!
 

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Nhms

will do. I'll be at NHMS sun/mon, but there are no turns there that really apply to this. I'll see if I end up back at LRP this year.
I have this exact problem on the uphill after turn 3 at NHMS. Were you there last sunday, i was nice day! Any idea if they have something similar available for an e30? My track car is a 1989 325is.
 

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Thanks for the useful details and pics. Thought I'd mention that it's recommended whenever working on fuel systems to always disconnect the battery.
 

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Subscribed for later, and also I have to say the interior fabric you have is awesome. ZHP coupe, right?
 

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when i installed mine, it didn't really clip in, more like just sitting in there, i haven't notice any rattling
there was a pronged arm that mine clipped into if i recall. i imagine if under a lot of gas one might not hear or notice it clipping in. but when in if you can pull it out rather effortlessly then i'd say you didn't get it in correctly.
first time i went to install this it took me 45 mins and i gave up. :confused:
hearing how the hose relocates to the top it went in under 2 minutes. :shhh:

*yes my preconceived idea how and where it was suppose to fit was over thought. very easy mod.:thumbup:
 

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I have had fuel startvation issues and lean codes following track days and was looking for a solution. This seems to be the hot tip. I hope it works.

I just did this on my car and can offer a few tips for the less experienced:

1- After disconnecting the pump electrical connector, try starting the car. It will not start but this will bleed pressure from the system avoiding the fuel squirting being discussed above. When you disconnect the feed hose, all you should get is a few drops from the hose itself.

2- after finalizing your install, turn the ignition on and wait foe all sounds to disappear, letting the pump prime the system, then turn off the ignition. Do this at least one more time then start the car. The fuel system will be fully primed and it will start with no hesitation and no warnings.

I will give feedback after my next trip to the track in a few weeks.
 

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I can run mine down to the low fuel light with no starvation at NJMP Lightning. Those who know the course know the last corner is a loooong right hander.
 

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for those asking in another thread linked to this, it's part #7. the tube on top of it gets the gas delivery in the tank and thus keeps a small chamber of gas for direct pick-up from the fuel pump
 
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