In Tank Fuel Pump

[02coastie]

I have weber downdrafts right now on my '74. The engine, however is a later model with no mech fuel pump provision. I'm currently using an electric pump like this:

It is now starting to crap out on me, particularly when the engine gets warm in traffic. It may just be getting old, or perhaps it's because it's currently mounted to the engine block... Anyway, after a momentary failure yesterday caused me to back up tunnel traffic (sorry Alameda!), I'm looking to replace it. Rather than putting the same set up back on, I want to move to an in tank setup. I intend to use the low pressure feed pump from an early E24/E28, which I understand will drop right in. Not only will it be quieter, but it will make swapping in a high pressure pump a quick job if/when I decide to go EFI.

A few questions:
1.) Can any one confirm/deny that the early E24/E28 pumps are drop ins? I've seen a few posts to suggest they are, but nothing definitive.
2.) Since I have a later car, what are the chances I have untapped wiring already in place to run the pump? (ie did CS/CSI cars share the same harness)
3.) If no to #2, any recommendations on where to tap an ignition hot source near the rear of the car? If not a large enough gauge, I'll run a new circuit/relay for it.

Thanks!
-Lloyd

 

[aearch]

ger a new 3 series ill show you mine

 

[02coastie]

ger a new 3 series ill show you mine

Isn’t the 3 series pump high pressure? The one I pulled from an E30 318is for my 2002 is...

 

[HB Chris]

Don will chime in with an aftermarket solution but all BMW pumps are too short and you will need to lengthen it and use the new integral sending unit. I used the 318is pump, there was no existing wiring. The new sending unit is shorter as well so fuel gauge will read lower than it really is. My relay is above the glove box and I ran the wire down passenger side of the coupe to the trunk.

 

[sfdon]

Kim at Williams welding on blanding will weld your pump unit to right length
The 5er unit is 15 % too short

 

[Mike Goble]

Kim at Williams welding on blanding will weld your pump unit to right length
The 5er unit is 15 % too short

What do you use for a sending unit? The e24/28 units fit perfectly in an e3.

 

[sfdon]

I tried to look it up for you but got a special message...

RealOEM.com
You have accessed our pages too fast and you didn't pass the human test.

As a result, your access to this site has been suspended.

We will investigate this incident and restore your access as soon as possible.

IP 54.241.149.95

 

[rsporsche]

as Chris mentioned, the 318is sending unit works great for fuel injection, as it has two gas line connections - 1 for delivery / 1 for return fuel. the e24 in tank pump works fine. the downside of the 318is pickup / sending unit is that it doesn't reach the bottom of the e9 gas tank and must be extended. i think there is a post from sfdon that shows how you have to extend that piece.

if you are using carbs, you don't need the return fuel line. what i don't know is if the e24 in tank pump delivers fuel at too high of pressure for carbs.

 

[sfdon]

And keep in mind we all used the Vega pump... 30 bucks

 

[Mike Goble]

as Chris mentioned, the 318is sending unit works great for fuel injection, as it has two gas line connections - 1 for delivery / 1 for return fuel. the e24 in tank pump works fine. the downside of the 318is pickup / sending unit is that it doesn't reach the bottom of the e9 gas tank and must be extended. i think there is a post from sfdon that shows how you have to extend that piece.

if you are using carbs, you don't need the return fuel line. what i don't know is if the e24 in tank pump delivers fuel at too high of pressure for carbs.

I use the in-tank VDO lift pump from the early 2 pump systems found in the early injected engines. It provides about 3# of pressure, works great with Webers.

 

[Markos]

I use the in-tank VDO lift pump from the early 2 pump systems found in the early injected engines. It provides about 3# of pressure, works great with Webers.

Hi Mike,

Do you think this pump has enough volume for
triples? Do you have a part number?

 

[Mike Goble]

Hi Mike,

Do you think this pump has enough volume for
triples? Do you have a part number?

I would think that triples don't require a lot more gas than doubles, you can only run so much gas into each cylinder.
You can't buy the pump by itself. I get mine from the boneyard, and they have been very reliable, one failure in 9 years.

 

[Gazz]

I tried to look it up for you but got a special message...
RealOEM.com
You have accessed our pages too fast and you didn't pass the human test.
As a result, your access to this site has been suspended.
We will investigate this incident and restore your access as soon as possible.
IP 54.241.149.95

Yeah I'm getting this as well. It does work if you go slowly but it's frustrating.

So here we are then, machines telling us that we don't pass the human test.

 

[02coastie]

Thanks everyone. So if I'm understanding correctly, early E24/E28 "lift pumps" ie two pump systems are largely plug and play with the exception of the pickup tube being slightly short. And thanks Don for the reminder of the Vega pump. That confirms what I read on another forum. Off to the pick n pull to see what I can find!

 

[Mike Goble]

Thanks everyone. So if I'm understanding correctly, early E24/E28 "lift pumps" ie two pump systems are largely plug and play with the exception of the pickup tube being slightly short. And thanks Don for the reminder of the Vega pump. That confirms what I read on another forum. Off to the pick n pull to see what I can find!

Good luck with that. I would consult Row52 for suitable donors before trekking out there. Not many donor cars out there.

 

[Drew20]

My 1981 635CSi had the low pressure in tank pump and a high pressure pump by the diff, but I think E28 based cars had a high pressure in tank pump only, like E30s I think

Also my 1988 golf gti had a low pressure in tank pump, but a very different sender I would guess

 

[HB Chris]

Any BMW in tank pump you buy will be short as stated, and, you will need the sending unit that fits inside it which will also be short. Buy a single high pressure pump, why go with two.

 

[Markos]

Any BMW in tank pump you buy will be short as stated, and, you will need the sending unit that fits inside it which will also be short. Buy a single high pressure pump, why go with two.

I thought we were talking about low pressure pumps and where to get them...

 

[Stevehose]

Carter 4070 is a great pump for triples. No in tank to deal with.

 

[HB Chris]

I thought we were talking about low pressure pumps and where to get them...

Not sure if he is going to use the lift and main pumps, lift alone won’t work I don’t think.