Gregg K

I'm wondering if this is a valid test. After running the car, I pulled the inlet to the WUR, and pressurized fuel was found. I am guessing that the WUR gets fuel directly from the source to the fuel distributor. So seeing pressurized fuel at the inlet to the WUR would be an indication that things upstream are functioning?
And if so, is it now time to start looking at injectors as the source of my three second start ups?

Dennis Wilson

Gregg,

If the accumulator diaphram is bad there will be fuel in the single outlet side of the accumulator. If you have fuel in the return line, try capping the outlet to see if that will stop the bleed down. If it fixes the problem, replace the accumulator. If not, replace the accumulator and the check valve. If no fuel is in the return line, replace the check valve. BTW some accumulators have had the return line removed and the outlet permanently capped.

Dennis

Gregg K

Thanks. My first thought was to check the other side of the diaphram. I mean, how else could the thing fail. Duh. I thought it vented to air, so I'd actually see gas on the ground. Guess the designers were smarter than that.

Cobey

editted for my ignorance

If the diaphram is bad, as in Dennis' example, fuel can shoot right out of the top of the single outlet. That [b]is[b] and air vent for the diaphram when it moves up and down inside.

I'm not sure how you could check if the diaphram was stuck in place. You would probably have poor starting I think.

TAREK

just curious...what are the symptoms?

Gregg K

It always takes 3 seconds of turning before the engine fires, hot or cold. Hey, I saw your 911 post. Looks like they have similar systems. BTW, I pulled the pump, and the check valve appears to work. At least with "mouth" pressure. It may leak under higher press, but I kind of doubt it.

Dennis Wilson

If the diaphram on the accumulator is ruptured, you will have a slow cold start and a difficult or no hot start situation. The bleed down will be pretty rapid. Slow bleed downs are usually associated with leaking injectors or a partially clogged check valve.

Dennis

Steve J.

Reckon I need a new one? Hope the inside doesn't look as bad as the outside! Symptom - Will not start when warm unless I wait a few minutes and try again. Then it starts no problem. Looks like the PO inserted what appears to be a check valve in line. And just where does that bottom line from the accumulator go?

Minus000

Replace it ASAP. I bought a 78 924 that had sat for a short awhile. After using it as a daily driver I started having problems starting the car and in the end, the accumulator ruptured so each time I let the car sit, fuel sat in the bottom of the accumlator and then rust from there was distrubted into my WUR/Fuel metering head and injectors. So far I have had replaced the WUR and Metering head and have injectors and seals coming. Its a **** off.

Cobey

Steve, I think you really need to replace that guy! I don't know where that other line goes though. Mine didn't have the line, though the original accumulator had a place to attach one. It is hard to determine using the PET CD, but I think it might go back into the tank.

Is that picture upside down?

Steve J.

No, that's how it's oriented. It's in front of the right rear wheel. That bottom line is called the "fuel leakage line" in PET5, but it's not clear where it goes. Guess I'll find out. I notice a lot of fuel accumulators don't have the fuel leakage line. I'm wondering if just about any fuel accumulator that looks similar and has the right fittings would work? Replacements are pricey (~$135) but every now and then I see one on eBay for a VW, BMW, etc. that looks like it might fit.

Cobey

Well, here is the problem Steve. All the new ones that I have seen do not have that connection. The one I picked up didn't, and serverl foks here told me it didn't matter.

You could get a used one from 928Intl for $50. If you call them, they can probably look to make sure that they are the older style with a fitting a the top.

Gregg K

I'm wondering if this is a valid test. After running the car, I pulled the inlet to the WUR, and pressurized fuel was found. I am guessing that the WUR gets fuel directly from the source to the fuel distributor. So seeing pressurized fuel at the inlet to the WUR would be an indication that things upstream are functioning?
And if so, is it now time to start looking at injectors as the source of my three second start ups?

Sean79 5spd

There is a leak test procedure in the CIS portion of the workshop manual (page 25-11) . The test requires a pressure guage. I think the procedure is designed to check for systems leaks and operation of the fuel check valve and accumulator.

Sean

Vilhuer

My memory might fail me as it was months ago when we last fought with accumulator on relatives '78 Euro. Anyway, I think that leakage line goes to expansion tank, above in same right rear wheel housing. There is two connections at the front of the tank, up high and impossible to see without taking tank down. Accumulator line goes to lower one. Top connection is for breather line, all the way back to middle of rear bumber and down to ground. In our experience it's not worth saving by buying used accumulator. Standing unused and dry for long time don't seem to improve them. One that we tried made all sorts of funny noisees like loud banging when membrane moved under fuel pressure. We even got nice fountain back there when it desided to quit for good and there was just breather cap, no leakage line to leak to. I think any similar sized accumulator will do. Bosch probably did only few designs for different capasity systems.

Regards,

Erkka
1992 928 GTS 5-speed and no CIS
Oak Green Metallic 22L
Classic Gray MX