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Problems with 924 -79, does not start/run properly

 
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Holke  



Joined: 06 Oct 2010
Posts: 5
Location: Sweden

PostPosted: Wed Oct 06, 2010 5:27 pm    Post subject: Problems with 924 -79, does not start/run properly Reply with quote

Hi!

I just bought a porsche 924 -79. I saw it when i was visiting a friend, and it has been standing under a tree for about 10 years. I asked the old man who owns it if I could buy it, and we made a deal.

I towed it back home, and started to work with it. Cleaned it up and bought a new battery etc. But, i cant get it to run properly, when i start it it runs "OK" for about 5-10 sec but then it dies. If I push the throttle while starting it he will run very "bad" misfiring etc, and then die.

Sparkplugs are ok, i emptyed the tank, filled up with new gas. I also flushed the fuelsystem, i unscrewed the banjo coupling from the fuel distributor, and let the fuelpump run until i had about 5L of gas in a box. And the sensor plate moves perfect.

This is a video with the car, when we are trying to start it:

http://www.youtube.com/watch?v=eRnAsiTrYm8

Sorry for the crappy quality and others "mistakes" made...

What should i do?

Regards,
Andreas
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gerben1986  



Joined: 13 Mar 2008
Posts: 232
Location: The Netherlands

PostPosted: Wed Oct 06, 2010 7:54 pm    Post subject: Reply with quote

What is the status of the injectors?
And if you unscrew the fuellines after the fuel distributor (towards the engine), is there any fuel coming out?

Do you smell fuel after the engine dies? In that case he could be to rich...

Also check if the airintake lines have gaps in it. If there is "false air" in the system the engine wil not run as it is supposed to do. Check also if the carterbreatherhose (is this the right name for it?) from the oilpan to the airsystem is not leaking.

Btw, do you have a Haynes or workshopmanuel at hand? I guess this problem should by described there.
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968rz  



Joined: 21 Aug 2006
Posts: 537
Location: S. E. Wisconsin

PostPosted: Wed Oct 06, 2010 8:40 pm    Post subject: Reply with quote

Maybe a stuck piston in the warm up regulator.
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Rick
79 924 coupe Petrol Blue 3spd auto (wife's DD)
93 968 coupe Amazon Green 4spd Tip (my DD)
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bnoon  



Joined: 12 Oct 2009
Posts: 607
Location: West Des Moines, IA USA

PostPosted: Thu Oct 07, 2010 5:26 am    Post subject: Reply with quote

Judging from your video, you have a plugged WUR (Warm Up Regulator), though there is no "piston" in the WUR as 968rz mentioned. It's a flat metal diaphragm to operate control pressure (spring loaded with a bi-metalic strip too).

To check if it's the WUR without buying a CIS fuel system tester, take the black rubber boot off of the air meter and open/move the air meter by hand a little bit as you're giving it throttle as someone else cranks the key. I'll bet your air meter tries to open when it first starts, but as the control pressure builds it pushes the air meter closed again, causing it to die.

If that's not the case, you may have an overall pressure issue that could be the dizzy or the high pressure pump... or a total clog on the in-tank pump filter.
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'80 924 Turbo - SOLD!
1986 Porsche 944 Turbo - SOLD!
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Holke  



Joined: 06 Oct 2010
Posts: 5
Location: Sweden

PostPosted: Thu Oct 07, 2010 4:24 pm    Post subject: Reply with quote

Hi

Thanks for answering. Where is the WUR located? I will test this as soon as i get back hom from work. Btw, fuel pressure is ok i guess, i had 9,6 bar just before fuel filter. When pump was turned of it slowly dropped to 4,3 bar. Fuel filter did not look good, have ordered a new one and will change this afternoon.
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Holke  



Joined: 06 Oct 2010
Posts: 5
Location: Sweden

PostPosted: Fri Oct 08, 2010 5:31 pm    Post subject: Reply with quote

Changed fuel filter, and lifted plate while friend was cranking engine. Still does not start, and it got very much fuel, totally drowned. And i also checked cold start valve and itīs ok. Next step, checking injectors?
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bnoon  



Joined: 12 Oct 2009
Posts: 607
Location: West Des Moines, IA USA

PostPosted: Sat Oct 09, 2010 1:14 am    Post subject: Reply with quote

Don't lift the plate while he's cranking, only lift the plate a tiny bit to keep it running once it's already started. Only like a mm or so at most at idle, then you should be able to rev it too if you open the throttle and lift the plate to give it gas at the same time.
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'80 924 Turbo - SOLD!
1986 Porsche 944 Turbo - SOLD!
Porscheless
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Holke  



Joined: 06 Oct 2010
Posts: 5
Location: Sweden

PostPosted: Sat Oct 09, 2010 6:42 am    Post subject: Reply with quote

Ok, so we tried doing as you say, and we got the engine running! Had it running for like 60 sec, really hard timing fuel/air manually, haha and i took the wur off the engine, pulled it apart and put the part with the hoseconnection in My ultrasonic cleaner, hope it Will function when cleaned and reassembelled.
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Holke  



Joined: 06 Oct 2010
Posts: 5
Location: Sweden

PostPosted: Fri Oct 15, 2010 4:07 pm    Post subject: Reply with quote

After knocking the pin a bit (on the wur), it now runs a bit rich, but i will adjust that. Thanks for helping me out!
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