S54 swap questions and concerns

[jink0619]

I bought a 300DW fuel pump(universal fit) from Deatschwerks, removed my stock fuel pump and it looks different from normal e30 pump, it has one line(power) from connector, where does the negative go? On the stock pump it's grounded to the pickup tube part on the housing. I would assume the same but worried it won't work.

[jink0619]

Here's a pic of stock pump. So power line goes up to connector and negative bolts up on tab that's connected to return tube. How would I wire up the new pump?

[jink0619]

Help...anyone?

[dmjensen]

If the factory pump was grounded via the delivery assembely then I would do the same with the new pump but maybe use a slightly larger gauge wire and a new eyelet. BMW wired the pump the way they did because it works (and it did for 20 plus years) putting in a larger pump will draw more amps. Using a larger gauge wire for the ground should be more then enough.

[jink0619]

If the factory pump was grounded via the delivery assembely then I would do the same with the new pump but maybe use a slightly larger gauge wire and a new eyelet. BMW wired the pump the way they did because it works (and it did for 20 plus years) putting in a larger pump will draw more amps. Using a larger gauge wire for the ground should be more then enough.

It's also not a wire but a thin metal strip so maybe swapping out the new pump ground with something bigger like you said would work also I assume. I'll try that after I figure out a way to get the filter flap from the pump out the gas tank, it dropped in there while trying to test fit the new pump fml.

[jink0619]

Here's a pic of stock pump. So power line goes up to connector and negative bolts up on tab that's connected to return tube. How would I wire up the new pump?

I did some research and realized that my 89m3 has duel fuel pumps, ,my intank pump looks exactly like an early model pump. So now comtemplating my options, either keep the duel or converting to single. The early model pump assembly is shorter then the late model so what i may do is cut the feed line on early assembly shorter to fit the new pump and add a return line or making it fit somehow. My worries will be, would it deliever enough fuel for the S54?

Does anyone have experience with this that can shed some insight?

[WannaBe30]

I didn't take pictures I don't think but should be plug and play

I also cut a piece of the bracket and just bent it back to hold it




Sent from my iPhone using Tapatalk

[jink0619]

I didn't take pictures I don't think but should be plug and play

I also cut a piece of the bracket and just bent it back to hold it




Sent from my iPhone using Tapatalk

Your pump is different then on my m3, Ive replaced a late model pump before and it's simple, on the pump assembly there is a positive and negative wire so would just have connect them together but on the early models, there's no connector for the ground, it grounds to the fuel assembly, which makes me very curious to how it would work. My other problem and concern is if the new pump will work well with a two pump system, signs.

[FredK]

I believe the M3, as well as early E30s, had a dual pump system, where the in-tank was a low-pressure (high volume) lift pump, and the second pump underneath the car was the high pressure pump.

I don't think the car will run right if you put a high pressure pump in the tank, while retaining the E30 high pressure pump.

I am not sure what the solution to your problem is, because I'm uncertain as to how the pump plumbing is in early cars.

[nando]

unless you want to swap to a newer tank and single pump, it might be better to get a new stock lift pump and use a higher output external pump instead.

you could use the high output internal pump + a stock high pressure external pump, but that would be way overkill. Essentially what that will do is make the external pump a lot more efficient and it will flow a lot more fuel than you need.

[328ijunkie]

E30 M3 and late model 318s are just like <=87 325i/e's Little POS lift pump (high flow low pressure) in tank and high pressure low flow external where late models have fuel filter...

[nando]

the 318is has a single in-tank pump though

the dual pump setup is actually more efficient but it seems like they have more starvation issues due to how the tank is designed.

[328ijunkie]

the 318is has a single in-tank pump though

the dual pump setup is actually more efficient but it seems like they have more starvation issues due to how the tank is designed.

Sorry meant to say 318 retains early/small tank, although does have single pump

[jink0619]

Thanks for the responses guys, man what a headache!!! I really don't want to replace the tank to go single pump. So if I can't put a high pressure pump intank, then would replacing the external pump with something with higher pressure work? I think walbro makes an inline pump so what intank pump could work with it?

[jink0619]

I believe the M3, as well as early E30s, had a dual pump system, where the in-tank was a low-pressure (high volume) lift pump, and the second pump underneath the car was the high pressure pump.

I don't think the car will run right if you put a high pressure pump in the tank, while retaining the E30 high pressure pump.

I am not sure what the solution to your problem is, because I'm uncertain as to how the pump plumbing is in early cars.

After farther research, there are some options I can go with that will allow enough fuel pressure for the s54@5bar. This is just for cars with Duel Fuel Pumps, The late models just need to replace the intank pump.

1-keep intank stock and replace external pump with a inline Bosh004 or walbro
2-replace intank with a high pressure pump and delete external pump
3-replace early model gas tank with late model and convert to single pump

I'm going with option 1, because the intank pump is used as a lift, lifting up fuel for the external pump, I'm deciding to leave it alone and replace the high pressure external pump to a inline Bosh004 which is a direct fit. Now just hoping for no fuel starvation and finally headaches over and can continue with swap.

Edit* Im wrong about the Bosh004 being a direct fit, you will need to find two fittings one being an 8mm 5/16" and 18mm 1/2" I found them on EBay.