Accumulator Question

[Dave Taylor]

I have a '74 2.7 and it's been running without a connection on the bottom of the accumulator. I bought it this way, but lately I've been wondering if there should be something connected here. On a diagram of the later cars this is connected to the return line to the tank. I've never seen gas come out there.

Should I put in a Tee in the return line and connect this up just to be safe?

Thanks, Dave

[Dave Taylor]

....bump....

[al lkosmal]

I'm interested in the answer to this, as well. Bump for Dave

[Dave Taylor]

OK, there must be someone out there that knows how these things work....

[Gunter]

I believe that the 2.7 had an accumulator with only 2 connections and the later SC's had 3. The bottom one was meant to return any potential leak to a T in the return line.
You may have a later accumulater installed? Give me the Bosch number and I'll tell you what you have.

[Dave Taylor]

Hi Gunter,

Here's the part number off the top:

0438 170005

I'm thinking you're right and it's from another model since it wasn't connected at the bottom and there's no tee back to the tank. I may install one or cap the bottom.

Thanks, Dave

[al lkosmal]

Dave & Gunter,
My 77 has the accumulator with the return line, as well.

Al

[Gunter]

0438 170 005 is for 1980 SC
0438 170 015 would be correct for 1974
0438 170 009 is for 1977
Just put a plug on the bottom?
I am not sure how much difference there is between accumulators

[pjv911]

Guys, the bottom line fitting is there to route fuel back to the tank(via return line) in the event the diaphram ruptures inside the accumulator . The principle of the accumulator is kinda like a backup capacitior but instead of storing voltage it stores pressure. It also serves to dampen pressure pulses from the fuel pump . This gives the injection a steady even flow of fuel.
As far as I have seen the first year (for 911 cars anyway) a return line was used was in 1978 starting with the SC cars.
For what its worth if a bottom fitting on an accumulator is not hooked up then its a good working unit provided fuel is not pouring out. It is however very unsafe to have it open like that since these do go bad after 20 years or so . Its just a rubber diaphram backed with a spring.
Im fairly certain since your car does not have the line to attach to it , you could just cap it . Best thing to do is install the correct accumulator.

One more thing comes to mind about these accumulators. When they go bad they cause an extended crank starting problem very similar to when a fuel pump check valve goes bad. Ive also found throttle responce to lag as well .

Kurt Williams

[Dave Taylor]

Thanks everyone.....to be safe I'm definitely going to cap it for now, but replace it with the correct one soon.
Dave