924Board.org

[maybeoneday]

Hi Guys,
I was doing a little more work on the 924 today and whilst it got really close to starting it just would not.

I was doing a little troubleshooting and whilst checking fuel delivery I found that the back two injectors were leaking. The injector line on cylinder 1 also makes a whistling noise but it appears to be metering ok and does not leak after the plate drops. Cylinder 2 meters within 5ml of cylinder 1, does not whistle, and also does not leak after the plate drops . whilst cylinder 3 leaks a little after the plate drops for 5-10 secs and cylinder 4 leaks a lot and for at least 10-15 secs after the plate drops.

My thinking was that this was probably just an injector issue and that I should replace them all. However not being 100% about how the whole system functions I wanted to check with someone that knows the system better that this does not suggest a further issue with the fuel distributor, and also if there are any other follow up checks that I should perform now.
Thanks
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1977 924 NA Auto

[ideola]

I would not assume the issue to be with the injector. You need to verify by moving the injectors around. It sounds like #2 is the best and #4 is the worst. So put #4 on the #2 line and see what it does. Continue in this fashion with #3 and #1 injectors. This will tell you which injectors are leaking. Then, take the #2 injector and use it to test the other three lines. This will tell you if there are any issues with the fuel dizzy. Any injectors that turn out to be bad should be replaced. If the problem is with the fuel dizzy, you will need to send it out for rebuild.
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erstwhile owner of just about every 924 variant ever made

[maybeoneday]

Thanks heaps for the test procedure and advice. I carried out the test you suggested and when I put the injector from 4 on 2 it leaked and likewise 4 did not. After swapping them all around it appeared that it was the injectors that were causing the leaking. I was still a little worried about the whistle on 1. it appeared to get a little better with the single good injector on it but it still whistled a little. I will have to replace all the injectors I think as 2 are leaking badly and one of the remaining 2 has a dodgy spray pattern. Only the injector that was on cylinder 2 to begin with and is now on cylinder 1 seems to be ok.

I am still a little concerned with the fuel distributor as I had a few issues with it when running the tests. One that was on particular concern was when I let down the plunger the fuel pump continued to run and the injectors continued to spray. This only happened a few times but it did worry me and I had to tap on the plunger to stop the pump even though it appeared to be closed.

Anyway thanks again.
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1977 924 NA Auto

[!tom]

The pump should always run during this test. In other words, having the metering plate in the closed position should not cause the pump to shut off.
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78 924 NA
5-lug

[maybeoneday]

[scm924s]

Check the centre pin in the fuel distributor is free, standing with old fuel often gums them up. The pin should move up and down easily and drop out under it's own weight, take it out and clean with carb cleaner, and spray plenty up into the hole it comes out of. If that doesn't stop fuel spray with the flap in closed position, then mixture screw is not adjusted correctly
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1984 n/a Ruby Red Metallic
1988 924S Guards red- sold
1986 924S Guards Red - sold
1984 n/a Black - sold
1980 n/a Le Mans#1 - sold
1980 n/a Le Mans#2- sold
1977 Martini - sold

[Ozzie]

If you can get down to your local supercheap auto, pick up some Flashlube carby cleaner fuel additive. a double dose of that to a tank will generally give it a good clean through the fuel system.
I use it regularly.

(I buy my injectors from the USA)
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Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

[maybeoneday]

Thanks guys,
I will check the pin for gummed up fuel and give it a clean and I will pop in to supacheap and grab some additive for the fuel system (I was just there the other day). I have a feeling that the mixture screw may not be adjusted correctly also. My dad used to have a car with the bosch CIS system and the whistle I was hearing on cylinder 1 injector line sounded like something I have heard before when the mixture is set a little high. I wish I spent more time learning this system on his car now! I am guessing that to set the mixture you will have to adjust the screw to achieve the correct pressure difference across the distributor and for this you will need the CIS tester or something similar.

Injectors are bad news, the best price I have been able to find locally is $140 each. That is only $10 cheaper than what I can get 4 for from the US. I think that this price was set in 2001 when out dollar was 40 US cents and they have not adjusted for todays 90 US cents, either that or they are just trying to screw us. I was prepared to pay a little more to get them locally and not have to wait the shipping time but not that much.

I have a few other things to do. I need to check the brakes and flush the fluid, service the trans and change the dif oil. I also want to rekey the ignition so the doors and ignition are on a single key. I guess I can do all this while I wait for the injectors to turn up.

Thanks again
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1977 924 NA Auto

[scm924s]

[Rasta Monsta]

You might send your injectors out for service...about $25 per here.
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[maybeoneday]