Picked up an 04 325ci m56 recently with a bad fuel pump. See previous post:
The notorious M56 SULEV... fml
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I will be working to convert the fuel system from a SULEV to a non-SULEV version.
I tried looking up how to do this but could only find articles on how to replace the metal tank since the pump is built into the tank and the whole tank must be replaced to replace the fuel pump. I thought I would start a thread in case this can potentially help other SULEV owners in the future.
I have a regular non-SULEV e46 I’m parting out so I will use the parts from this donor for the project.
Pics and updates to come
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Last edited by HyptisX; 12-24-2019 at 03:34 PM.
It seems entirely possible to swap in a standard fuel tank and splice wiring and fuel lines. You may experience problems with the electronic aspect though. The fuel pump just needs 12 volts to run but the extent which the DME is involved with every single thing in these cars may cause problems. Fuel level senders may be a pain in the ass too.
Seems worth a try though.
Sounds like a pain in the ass
A big pain in the ass now for less pain later..
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Conversion is done. Pics to come this week. It was a gaint PITA to source all the parts (since I didn’t want to reuse old gaskets from my donor) but worth it at the end. Still waiting for my last gasket for the driver side sending unit to come in but it runs and starts now!
Last edited by HyptisX; 12-24-2019 at 03:36 PM.
$30 for a plastic tank
$45 for drivers side sending unit
$25 for fuel pump assembly
$10 sending unit gasket
$20 parts from salvage yard
$20 for hose adapters/clamps
$120 total
UPDATE:
$20 340 LPH fuel pump made of Chinesium (courtesy of eBay)
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Last edited by HyptisX; 12-24-2019 at 03:38 PM.
While the retrofit worked, there’s still some issues. The default fuel pressure for a SULEV is 5 bar vs regular is a 3 bar. I’m noticing the difference in responsiveness.
Going to look into using a m3 pump as a alternative.
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Here’s the plastic tank before it went in.
Last edited by HyptisX; 12-24-2019 at 03:30 PM.
Got a 340LPH fuel pump and popped it right in. This worked! No more lean conditions on acceleration and response time is back to normal.
Here’s a pic of the messy rewiring. Going to clean it up now that it’s confirmed working!
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Last edited by HyptisX; 12-24-2019 at 02:38 PM.
Did you have to do coding?
No
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I have a donor 325i, and I am wondering if it would make sense to swap out the M56 intake for the M54 and use standard injectors - think that would work?
HyptisX
It's great to see that you were successful with the tank swap on your M56. I've been researching this for a while based on the fact that with 134K on the clock, my 2004 325i wagon will eventually be needing the swap. Do you have more details of your process and a parts list so all of us M56 suckers can benefit from your experience?
It would be greatly appreciated! Thanks,
Wardto
I'm just finishing up my M54B30/5-Speed swap into a SULEV. I swapped out the entire fuel system and emissions stuff. The only thing left is to re-wire the fuel tank harness. What M56 wires did you connect to the M54 fuel tank harness?
Hi can u help with what are the parts that need to be changed other than the tank
OP appears to be gone
It has been a month and one week since he last logged in. Perhaps he’s too busy enjoying his ride after his accomplishment. I myself wanted to do this because SULEV are just going to the boneyards here in SoCal. I just want to make sure before I jump in into this project. They’re so cheap nobody wants them. Merry Christmas!
Hello HyptisX
Please let us know what kinks are still giving you trouble...
Thanks
Got inspired by your swap and did it on my wagon. I decided to use the whole m54 fuel system including injectors and rails. It starts and runs. No codes.
I have a PDF guide with the instructions and parts list.
Preview:
Screen Shot 2022-10-31 at 10.34.50 AM.jpg
Last edited by harrier; 03-18-2024 at 02:39 PM. Reason: broken link
You definitely need to do coding, at least for the fuel tank level. It is not as simple as just swapping the tank and the pump by any stretch of the imagination. I am not sure how the OP hodge-podged together the connection from the tank to the filter and regulator to the fuel rail, but it is not plug and play. If you decide to go with 3bar pump and standard injectors you will need to do coding for that as well.
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