Early Model 255 Fuel Pump Retro Fit - **Is it even possible?*

[Jkersh]

After reading several write up before and during my attempt at replacing my in tank fuel pump with a TRE 340 255LPH I ran into some problems.

All of the write ups seem to refer to a "newer" fuel pump cradle with a single outlet and a bottom support that requires some dremel modifications.

When I pulled my pump today I noticed my cradle was quite different. I had one positive wire, no ground wire, just a bracket that acted as a support and two outlets, one 5/16s and one 3/8s.

The 5/16s outlet seems to go straight to the fuel rail (most inner line) and the 3/8s goes to the external transfer pump when then goes to the fuel filter via a 5/16s.


Since there is no bottom support and two outlets I am a bit confused on how to correctly finish the job.

If I delete the external pump, how do I go from a 3/8s outlet to the 5/16s needed for a fuel filter?

How does the pump actually mount to the cradle?

I hope this makes sense.... I could really use some help.

The Green arrows show the larger (3/8s) outlet which goes to the pump and eventually the filter. The Blue shows the 5/16s that seems to go direct to the rail.

Any insight would be great.

Thanks

[Jkersh]

Additional view of the OEM fuel pump cradle.

[jlevie]

I realize that you are trying to do this "on the cheap", but the right way to convert to a single pump is to use the fuel pump from a very late production 318is. It has the correct sized fittings.

[Jkersh]

I wouldn't say its on the cheap - I just want to do it right, and use the 255 - so you're suggesting get a cradle to a late model 318is and hook up the 255?

[jlevie]

I wouldn't say its on the cheap - I just want to do it right, and use the 255 - so you're suggesting get a cradle to a late model 318is and hook up the 255?

Well actually I'm suggesting that you get a new late 318is pump and use it as is.

[Jkersh]

That wont work - since its a single outlet the return hose is located in the tank i beleive. My carrier has the return hose on the top.


Is it even possible to replace it and delete the transfer?

[jlevie]

The very late 318is pump has a return line fitting, like the early transfer pump you have. A clean installation will require the tank to be dropped to replace the large line with an 8mm line.

[Jkersh]

Hey Jim, I still have the issue of an 8mm (5/16) hose trying to fit onto a 3/8s OD outlet coming from the pump assembly, regardless of dropping the tank.... right?

[Mr. Tasty]

would it end up being better just to get http://www.blunttech.com/ShopByVehic...sembly&mode=PA rather than retro fitting a 255 with a 318is cradle? What applications make you need the 255? I am in the same situation with replacing a loud inside the tank pump, but I have a stock eta. Should I go ahead and use the link'd pump assembly?

[jlevie]

Hey Jim, I still have the issue of an 8mm (5/16) hose trying to fit onto a 3/8s OD outlet coming from the pump assembly, regardless of dropping the tank.... right?

If you don't drop the tank and replace the large line you will have to come up with reducers for both ends.

[Dj Buttchug]

bump. im retro fitting a high pressure in tank pump to my 84 318i and I have the same problem. Can anyone in this thread post results or modded pics of it done. Im running into issues with a high pressure in tank pump being too large and not allowing the assembly to sit correctly in the tank. the pump ends up touching the bottom of the tank and bottoming out before the assembly can be locked into place

[FLG]

Did this already.

Cut the feed line shorter, reuse short stock rubber hose that will adapt the larger feed line to the smaller pump outlet. Make sure the pump is hose clamped very secure to the return line or you'll do what I did and over time wound up splitting that little hose.

I wound up having to squeeze a hose over the larger feed line and then tightly hose clamp it to the pump outlet... Wound up working just fine though.

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