924Board.org

chris79 · Joined: 29 Jan 2014 Posts: 551 Location: milan

Ciao,

da qualche tempo ho la 924 ferma.

Premetto che ho controllato già praticamente tutto e il problema sembrava essere il distributore di carburante k-jetronic.

Ultimamente però l'ho sostituito con uno revisionato ma ho ancora lo stesso problema.

In pratica la benzina arriva al distributore costantemente, le pompe funzionano, inizialmente la benzina arriva agli iniettori e il motore resta acceso per qualche secondo. Dopo un po di tempo la benzina continua a arrivare al distributore però non esce più dai fori che portano agli iniettori (l'ho verificato allentando le viti sopra la testina) ?

Come mai? Ero sicuro dipendesse dal distributore.

924RACR · Posted: Sat Aug 02, 2014 12:03 am Post subject:

Courtesy of Google Translate...

chris79 · Joined: 29 Jan 2014 Posts: 551 Location: milan

anyone have any ideas?

924RACR · Posted: Sat Aug 02, 2014 10:15 pm Post subject:

Was hoping someone else would jump in here too...

When the engine will run only for a short time, then die, usually this indicates that it is running from fuel provided by the cold start injector, not the fuel distributor. Of course this matches your observation, no fuel coming from fuel distributor.

Can you get it to run a bit if you hold down the accelerator?

The replacement distributor, is it a used part or new? You used the word revisionato - maybe the translation is not accurate for technical terms, could the mean a part which is used but rebuilt (refreshed, given new seals and cleaning)?
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

chris79 · Joined: 29 Jan 2014 Posts: 551 Location: milan

no but initially I verified that the fuel came from its distributor, in fact loosening the screws you could see that the fuel pressure was fine, then after some time he is not out more. It 'very strange because at the gas station and probably get back all in the fuel tank.

924RACR · Posted: Sun Aug 03, 2014 12:23 am Post subject:

No... this is not a refreshed distributor?

Has the car been running until recently, or has it been parked for years?

It is very common that when one of these cars is parked for years that contamination (dirt, rust, etc) is in the fuel tank and is pumped into the fuel distributor, which prevents it from working properly.

If the car has been parked for a long time, we recommend not just to replace the fuel filter but also to drain the fuel tank (from the hose leading to the fuel pump) and check the quality of the fuel - see if there is rust or dirt. You can maybe do this without completely emptying the tank - though it will be messy - if you have just filled the tank. Just drain into a bucket or gas can.

It is a good sign that you did have some fuel coming out when you loosened the screws. We just have to understand why it does not continue.
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

chris79 · Joined: 29 Jan 2014 Posts: 551 Location: milan

In fact, I do not understand because they do not continue to go out, because the entrance to the head gasoline arrives, I tried unscrewing the nut arrival, it seems to go all in return.

KDJones2000 · Joined: 14 Sep 2010 Posts: 322 Location: Phoenix, AZ

As Vaughn said, dirt and rust is probably clogging your fuel distributors.

Your pumps are working, so fuel is coming to the fuel distributor, then returning to the fuel tank via the bypass. Since maybe the fuel distributor plunger is clogged and stuck, no fuel is coming out of the injector ports.

Clean out your fuel tank, put a new fuel filter just before the fuel distributor, and make sure that your fuel distributor is cleaned out.

Put some new fuel in and see if that fixes your problems.

Good luck, Keith
_________________
1987 924S SPEC car
Team Toofah Racing
1988 944 Turbo S

924RACR · Posted: Sun Aug 03, 2014 2:20 am Post subject:

Well, there are very small holes (orifices) to measure the fuel; it is very easy for these to get plugged with debris.

If you remove one of the lines that goes to a fuel injector, when the fuel pump is running (but engine not turning) there should be just a little bit of fuel coming out. Just very slowly.

Another test: If you remove the injectors from the head and place into glass bottles (you must do this to all injectors at the same time), then (with fuel pump running) push up the air metering plate. All four injectors should spray fuel, and the spray should be a consistent, fine mist. There should be no streams coming out, just mist, at high pressure.

But you must remove all 4 injectors from the head before performing this test; if you do not, you will have fuel filling the cylinder like a puddle, and it will end up in the bottom of the engine and dilute the oil. My Turbo is actually in this state now, and I have to go change the oil now as a result...
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

ThomasJoseph315 · Guest

Fuel Dizzy Plunger stuck closed?

chris79 · Joined: 29 Jan 2014 Posts: 551 Location: milan

before you take the test the injectors should I do so that it comes more fuel from the head, otherwise it is useless. I saw that little fuel coming out and very dirty. Now I have removed the head, I blew air in the head with a compressor and the streets seem free, I try to reinstall it and will update.

ps. 924RACR your 924 is beautiful, just like I would turn my 924

924RACR · Posted: Sun Aug 03, 2014 9:41 pm Post subject:

Cheers, thanks, and good luck!
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

chris79 · Joined: 29 Jan 2014 Posts: 551 Location: milan

I mounted the distributor but it does not work, the fuel does not come out even with good pressure. I think the problem is only the petrol station, probably still too long. I already tried to restore one, but my problem is to use the seal around the metal membrane. I've tried using both products in the picture, but after a short time the seal comes off and the distributor loses.
Now I've decided to open the distributor, you have tips on what to use as a garnish?

KDJones2000 · Joined: 14 Sep 2010 Posts: 322 Location: Phoenix, AZ

i didn't use anything and it sealed just fine.
_________________
1987 924S SPEC car
Team Toofah Racing
1988 944 Turbo S

924RACR · Posted: Sun Aug 03, 2014 11:59 pm Post subject:

What he said - should be no sealant there.

Dan Beckett (Ideola) recently pointed me to some fuel distributor rebuild kits on eBay, with new o-rings as well; fortunately I didn't need them, so I of course didn't save the link... maybe someone else here has?

Edit - OK, found it myself...
http://www.ebay.com/usr/cis-jetronic?_trksid=p2047675.l2559

But I would first try cleaning everything you have with acetone (brake parts cleaner), then reassemble clean, maybe with a little gasoline on the rubber parts to help lubricate.
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype