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I have noticed that fuel accumulators for '78 - '79 cars are getting harder to find and proces are extreme. While a fuel accumulator for a 911 will cost appox EUR 100, almost he same part for a 928 will cost approx EUR 260 - EUR 360. Ebay sources are e.g. Riga (Letland) but not much else outside the USA. Are there any alternatives like for Mercedes cars? Why are these things so expensive?

Jørn

Hi

They seem to have it at rosepassion. This is in France so shipping is probably less than from US but price as you mentioned quite steep close to 350 euro.
http://www.rosepassion.com/en/cat/92...1-01259/P21763

ROG100

Hard to find but still available - I buy everyone I find 8>)

hlee96

Roger, how much for '78 vin#413?

GlenL

This gave me a chance to use my favorite website:
http://www.bosch-automotive-catalog.com/en/

The Bosch P/N is: 0438170026 and the part isn't used on any cars except the 928.

Searching by that P/N finds multiple vendors with prices down to $185 but a lot of "sellers" who indicate it's not available.

Bosch does make a bunch of fuel accumulators for cars of that era. I assume they're not all CIS but a determined guy could check. RockAuto shows 9 similar accumulators from Bosch for prices under $150 including several for Porkers. If it had the right fittings, I'd put it in if I was saving $350. It's just an accumulator, after all, and not a pressure regulator.

ROG100

Early 78 uses the 0438 170 022 - Porsche part numbers 928 110 197 04/05
And as already said this had a 14mm connection on the bottom for the fuel weep pipe.
So unless you are very **** about originality you can use the 928 110 197 06/07 Bosch # 0438 170 026 and not use the weep pipe.

The difference between the 928 and other more readily available accumulators are the connectors being male v female.

I have both the 22 ($413) and 26 ($438) in stock as supplied by Porsche.

I have 1 x OEM Bosch 26 for $285.

docmirror

Seems like a good opportunity to make up a cheaper alternative with some fuel fittings and crush washers.

James Bailey

Several feet of rubber high pressure fuel line is said to work.....like your garden hose after you turn off the tap at the house if you squeeze the nozzle it still shoots out a stream of water for a moment. The rubber fuel hose expands a bit and holds a pressure reserve keeping pressure in the CIS system to allow for a easier hot start. When cold the ninth fuel injector gest the fire going and the airflow triggers the injection. Some have mounted a push button to turn on the cold start injector anytime they wish which eliminates the need for the accumulator....

dr bob

My feeble/foggy memory of CIS accumulators is that they maintain system pressure above fuel boiling point as the system "cools off" after engine stop. The pump relay in CIS systems generates an initial pump run when the key is turned on to make sure there is adequate fuel pressure prior to starter engagement, then drops out if ignition pulses aren't detected within 5 seconds or so. Virtually any accumulator that can connect to the system downstream of the fuel pump check valve will get the job done. Size matters only if the system likes to leak down either through the check valve or the pressure regulator in the metering unit. Or if the fuel metering unit itself leaks by to the injector nozzles. In this last case, smaller is definitely better.

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Dear Roger,
I remember there is a nut on the top, with a very small hole in it. That is for a weep pipe? And what does # 0438 170 026 do with the fuel or air that comes from the weep pipe from the older version?
Are both versions interchangeable and mount the same way? The air vent/weep pipe (single outlet) mount upards.

GlenL

The accumulator also serves to smooth the fuel pressure as the pump produces it in small pulses.

ROG100

The early accumulator with the "weep" pipe. The pipe just directed fuel to the side of the car. Remember this only happened if the diaphragm in the accumulator ruptured as in Failed. They deleted it in late 79 and I can only guess that this was a cost reduction as the accumulators rarely failed. When they do the fuel just leaks to the ground. Apart from that they are the same.

Most accumulators that I have seen fail was more a corrosion issue.

Ad0911

So if I understand correctly, my car originally was fitted with an accumulator without the side weep pipe, but with a nut with pinhole at the top to release air. This part was followed up in 79 by the accumulator with the siede weep pipe. Does this make the accumulator more dangerous for catching fire when it weeps? I guess the olde one just keeps the leaked fuel in the top part that should only contain air and a spring above the diaphragm

ROG100

Ad - the other way around - early cars were fitted with the extra pipe and it was deleted in early 79 IIRC.

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I am really sorry to bring this subject up again but I want to be sure I buy the right part. It is too expensive to make the wrong choice.

I have noticed that at some point in gtime, the fuel accumulators were fixed upside down. Mine is mounted as in the picture (stole it from other forum). Does this determine the type of accumulator needed?