924Board.org

[Elrok]

Hi!

As I described in previous topic I have connected the K-jetronic system in my 924. I have tested:

1. The injectors and they spray +/- the same amount of fuel.
2. The 5th injector which sprays the fuel directly to the air inlet.
3. The spark plugs - there is spark.
4. The compression of the engine. It is in accordance with the book.

Everything seems to be ok.

When I try to start the engine there is no effect. The starter is running, I can hear the fuel pump working, engine is rotating, but there is no effect. I even tried to pull the throttle to full open position during start but there was no effect.

I have tried to start the engine by pulling the plate in air flow meter a little up by hand, and than the engine started, but as soon as I took my hand off the plate, the engine stopped working.

I think that the reason can be that the air that flows through Air flow meter is not enough to pull the screw in fuel distributor up so there cannot be enough fuel sprayed so the engine could run.

I have no clue what is the reason and what is wrong. If anyone has an idea I would appreciate any feedback.

[morghen]

Try to start it with engine starting spray.
If it starts and it runs with the spray, then the problem is the fuel pressures.
Probably the WUR.
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https://www.the924.com

[Fasteddie313]

[Elrok]

Ok,

I tested what is going on when i have the fuel pump powered by jumper wire instead of relay.

The pump is pumping the fuel, and even when i pull the plate in air meter full up the fuel does not go through the injectors. In my opinion it goes to the WUR and goes back from the WUR to Fuel tank. I started to think if I connected the fuel lines correctly.

Below you can find the photo and the description:



1. Line going back to fuel tank and the line going back from WUR (smaller hole) and line going back of solenoid.
2. Line going to the input of WUR(bigger hole) and the line going to input of solenoid.
3. Line going from fuel tank and the line going to the 5th injector.


Please let me know if it is connected correctly.

I can say also that when I blocked the output no 2 from distributor the fuel was going through the injectors (however I know that it shall not be done like this).

Thank you for any feedback.

[Fasteddie313]

Maybe that solenoid you have off of the WUR port is stuck open? (might want to just block that for now?)

Also check the fuel pressure regulator valve, that big hex just to the right of your "1", and make sure it is clean and not stuck open..

I don't much like your hose clamps on 2 and 3 though as their is a bunch of pressure there..
Might work for testing but you should eventually upgrade that, and keep a fire extinguisher handy meantime..
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80 Turbo - Slightly Modified

[macBdog]

Yea x2 what fasteddie said. The fuel pressure on these cars is over and above most other cars. Normally, jubilee clamps and barbed connections on carbureted and even low pressure EFI systems are pretty safe.

My experience is that the fuel system on these cars will burst normal hoses and clamps with the result being large amounts of finely atomised fuel everywhere. Nightmare scenario...
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1979 931 with a 350 chev
1973 911E with EFI

[Elrok]

I have already checked the solenoid and it is clesed so this is ok.
What about the pressure Valve? How can I check if it is ok?

When I am looking at this it also does not look safe. So as soon as I will get the engine running i will replace it .

[safe]

I have actually never had a hose clamp fail with a propely sized hose.
Usually you will have to fight to remove a hose thats been there while even without a clamp...

[Witty924]

Hi, I found this post and wondered if you found a fix in the end. I’m experiencing similar problems without being able to start the car.
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Witty924 - Porsche 924 2.0l NA 1984