Gas expansion tank
- Thread starter Henrik
- Start date
On my early model E24 I removed the fuel pressure accumulator from the plumbing, with the original pump, and the engine would not run well. With a better pump this may not be an issue
Are you putting an in-tank pump in?
Are you putting an in-tank pump in?
Technically the evaporation tank is not needed but our environment will thank you if it’s hooked up properly. 
Sounds like you are talking about the one on the pump though, never mind.
Sounds like you are talking about the one on the pump though, never mind.
Ah, I may have mis understood. The expansion tank is only needed to reduce hydrocarbon emissions from tank evaporation. The accumulator I was referring to is the cylinder next to the pump under the car.
If you have a spare expansion tank and activated carbon canister I'd be interested?
If you have a spare expansion tank and activated carbon canister I'd be interested?
I think that canister is an accumulator, if so it’s job would be to remove spikes and dips in pressure, thereby protecting the system from peaks in pressure and especially giving the injectors a near constant feed pressure. I would retain the accumulator in the system.
There is nothing inside the canister that makes it work as an accumulator and that is why I don´t find any good reason to keep it. It is only a can with an inlet and outlet. No bladder with pressurized gas that can smooth out pulsations or anything else. Anyone out there driving without it?
I remember reading that it prevents fuel starvation under hard cornering/braking by having a supply in the cannister. Not sure though.
Honolulu
Well-Known Member
I'm onboard with the idea of the "accumulator" functioning similarly to a "shock absorber" or a "pressure spike filter" and per post #2 above, if you've got it, I'd keep it
Henrik
Sounds like you are going to try it without the canister, we are all keen to know what happens.
If it has no membrane inside then it is not a conventional damper type accumulator, however it will still alter flow characteristics. Empty canister type accumulators are fitted to tractor hydraulic systems to reduce noise for operator comfort.
There was a cost to fit it as standard, so at that time there was a reason, let’s see if you are correct and that with a modern pump it makes no difference.
Best wishes
Sounds like you are going to try it without the canister, we are all keen to know what happens.
If it has no membrane inside then it is not a conventional damper type accumulator, however it will still alter flow characteristics. Empty canister type accumulators are fitted to tractor hydraulic systems to reduce noise for operator comfort.
There was a cost to fit it as standard, so at that time there was a reason, let’s see if you are correct and that with a modern pump it makes no difference.
Best wishes
Well, the downside of this experiment can be a loss of fuel while driving, or at least running rough. The the most comfortable way to avoid it is to buy a new unit
Walloth & Nesch has a new one for 136 Euro so I think I choose that alternative while it´s still available.
Walloth & Nesch has a new one for 136 Euro so I think I choose that alternative while it´s still available.
Rex Kapriellian
Well-Known Member
So you ran it without?
I have not completed the gas pump set up yet. But I bought a new canister from W&N which I will use without the pump mounted on the same bracket. My alternative solution is a newly arrived in tank pump from Tanks Inc. Model PA-4. I use this because my tank must be converted from carburetor to injection. I can also use the old level sender this way. Another advantage is that it will be fewer pieces of hose and joints under the car. This can reduce the risk of gas leaks (very close to the hot exhaust silencer!!)
My car, a 1973 3.0cs, (so its carbed) doesn't have the cilinder under the floor with the fuel line running through it, and it ran great. There were also no provisions to have it mounted, so I think it is originally like that.
Is it just a Csi thing?
And it has been cornered hard enough to eat a set of tires in 3 years over just 15000km....
Is it just a Csi thing?
And it has been cornered hard enough to eat a set of tires in 3 years over just 15000km....
Rex Kapriellian
Well-Known Member
It’s for for injected cars.
Changing these hoses around the tank, pump and accumulator was the least pleasant part of renewing all of the rubber in the fuel system on my car; flat on back on cold garage floor, with fuel dripping around me, I can almost smell it still, nearly a year later [shudder!]
Pretty sure the accumulator is a key part of the fuel system on injected cars, don't know what it does but my E24 ran v poorly (undriveable) without it, not an experiment I feel the need to repeat!
Pretty sure the accumulator is a key part of the fuel system on injected cars, don't know what it does but my E24 ran v poorly (undriveable) without it, not an experiment I feel the need to repeat!
Rex Kapriellian
Well-Known Member
I think it plays a large part in sudden changes in volume requirement, Acceleration, low fuel levels, maybe even lateral forces. The G Body Porsche’s (70’s - 80’s?) with similar Fuel injections have the same component, just looks differentsee
The issue that I’m having that lead me to this thread is the rate of acceleration from 3000 to 5000 RPM Under load.
Fuel starvation?
Timing?
Dirty injectors?
Bad plugs?
Clogged filter?
Weak pump?
Bad accumulator?
The issue that I’m having that lead me to this thread is the rate of acceleration from 3000 to 5000 RPM Under load.
Fuel starvation?
Timing?
Dirty injectors?
Bad plugs?
Clogged filter?
Weak pump?
Bad accumulator?
Attachments
I think that the canister or accumulator is more or less a surge tank that shall keep the fuel pressure constant if the fuel supply is disturbed by a low level in the tank and the pump sucks air. I haven't studied the original tank armature in detail but there seems to be a lack of coaming around the suction inlet at the bottom of the tank to prevent this from happening.
My new in-tank pump have a tray at the bottom so the pump will be feed even if the tank is almost empty and the driver (me) drives like a maniac (Not that often...Only when I have to do some spectacular overtaking to get my adrenaline pumping if I`m getting sleepy).
I would probably delete the canister (surge tank) if I knew about the Tanks Inc. for a while ago.
My new in-tank pump have a tray at the bottom so the pump will be feed even if the tank is almost empty and the driver (me) drives like a maniac (Not that often...Only when I have to do some spectacular overtaking to get my adrenaline pumping if I`m getting sleepy).
I would probably delete the canister (surge tank) if I knew about the Tanks Inc. for a while ago.
Please post a pic of your new pump and fuel sending unit.
Some pictures of the new unit. The installation went well, but the instructions could have been more educational. Cutting the support with a grinder was necessary. Also some of the bolt lengths was not in accordance with the instruction, but it was not a show stopper. In total Iḿ satisfied with the solution.
I could convert an old non FI tank to FI without very much effort and cost. As you can se from the pictures the top flange fits perfectly into the tank curves (4 1/2" diameter cut out needed) I need some more fittings to complete the job. The fuel pump itself is a good brand and should do the job.
The advantage of this solution is that the old level sender is in itś place and work as usual instead of a compromise between a fuel pump armature from a later BMW thatś inserted in the fuel sender position without a sender that is adapted to the depth of the tank.
I could convert an old non FI tank to FI without very much effort and cost. As you can se from the pictures the top flange fits perfectly into the tank curves (4 1/2" diameter cut out needed) I need some more fittings to complete the job. The fuel pump itself is a good brand and should do the job.
The advantage of this solution is that the old level sender is in itś place and work as usual instead of a compromise between a fuel pump armature from a later BMW thatś inserted in the fuel sender position without a sender that is adapted to the depth of the tank.