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924 CGT Sputtering

 
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bgravolet  



Joined: 18 Sep 2014
Posts: 2
Location: New Orleans, Louisiana

PostPosted: Thu Sep 18, 2014 2:06 pm    Post subject: 924 CGT Sputtering Reply with quote

Hi, I hope you all can help. My 1981 CGT has been at the Porsche dealer since March. I was driving the car and it started cutting out around 4800 rpm and then died and would not restart.

Since then the fuel tank has been cleaned out and lined, the wur replaced, the fuel head rebuilt, valves adjusted, fuel accumulator replaced and the fuel head shimmed to raise the fuel pressure. Also replaced the waste gate with one from Freisinger. Prior to that I replaced the plug wires, plugs, rotor and distributor cap along with the timing belt.

I went to visit the car today and it is idling roughly, the steering wheel is vibrating and under acceleration it is sputtering at 4800 rpm and won't accelerate further unless you lift your foot off the throttle, press the pedal again, then it will accelerate beyond that. Get near 4800 rpm and it does it all over again.

Any ideas? Any help would be appreciated as I would like to get the car back.

Thank you all in advance,
Ben
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CÚdric  



Joined: 27 Aug 2004
Posts: 1976
Location: Sweden

PostPosted: Thu Sep 18, 2014 2:28 pm    Post subject: Reply with quote

Sounds like misfire, Check all the connections in the ignition system, especially the big harness to the ignition box under the dash. Could also be the ignition module on the front wing, i had severe problems with my ignition, sometimes the car just sputtered and died. Replaced it with a standard part from a volvo 740, solved the problem.
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9xx  



Joined: 18 Jun 2006
Posts: 627
Location: Jarvenpaa, Finland

PostPosted: Thu Sep 18, 2014 3:07 pm    Post subject: Reply with quote

Here you can see the harness connection Cedric mentioned. It is sort of behind the radio.

http://www.924.org/techsection/5ignition.htm


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Mikko

All gone: 931 '82 Alpine White, original option "220" G31 with LSD + 3 x 944
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morghen  



Joined: 21 Jan 2005
Posts: 8167
Location: Romania

PostPosted: Thu Sep 18, 2014 3:14 pm    Post subject: Reply with quote

First look for air leaks.
Hook up a wideband sensor & gauge and take that on your test drives. Monitor the AFR values.

I get that sputtering and wont rev unless i take off the foot of the pedal and gently press it on my GTS wannabe car when its cold outside and the engine is cold. Once it warms up (a couple of minutes) everything is fine...but while cold the AFR is very lean, it sputters and wont rev under load. idle is nice and smooth tho.
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Ruby-sh 924
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Gijs937  



Joined: 02 Jul 2014
Posts: 24
Location: Netherlands

PostPosted: Fri Sep 19, 2014 8:07 am    Post subject: Reply with quote

Check ignition module, and another issue can be a loose wire from cranksensor.
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 1973
Location: Somerset, UK

PostPosted: Fri Sep 19, 2014 8:53 am    Post subject: Reply with quote

Overboost switch cutting fuel pump relay? Earth the wire onto the engine and drive again.

Is the tachometer going mad whilst misfiring? If so check the quality of green wire off the coil to fuse board and FPR
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
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Then www.924board.org/viewtopic.php?t=31252
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griffinbilt  



Joined: 23 Nov 2010
Posts: 31
Location: Flora Indiana

PostPosted: Fri Sep 26, 2014 11:19 am    Post subject: Reply with quote

Send the fuel dist to larry Flecher in Fairhope,Al.
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Gijs937  



Joined: 02 Jul 2014
Posts: 24
Location: Netherlands

PostPosted: Fri Oct 10, 2014 4:33 pm    Post subject: Reply with quote

@brgavolet: any update? Problem solved?
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bgravolet  



Joined: 18 Sep 2014
Posts: 2
Location: New Orleans, Louisiana

PostPosted: Wed Nov 12, 2014 7:54 am    Post subject: 924 Carrera GT Update Reply with quote

Sorry for the delay in answering.

I just go the car back and it runs very, very well. Turns out the rebuilt warm up regulator I purchased was bad. Larry Fletcher had previously rebuilt the fuel distributor so I had him redo the WUR. I didn't know about Larry when I had the first one rebuilt but I won't have anyone else work on the injection from this point forward!

I bought the car from Belgium and had to spend a small fortune on it but finally it is close to being done!

The problem I have now is there is a small fuel leak somewhere near the top of the tank. Do you guys know if this is common? Seems to be in 944s.

Thank you all again for all the help.

Ben
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morghen  



Joined: 21 Jan 2005
Posts: 8167
Location: Romania

PostPosted: Wed Nov 12, 2014 4:42 pm    Post subject: Reply with quote

Pull the carpet and soundproofing carpet and look for the trace of it.
IIRC it can be the fuel level reader seal or some hoose/gasket that connects the filler hatch to the tank.
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Ruby-sh 924
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Rasta Monsta  



Joined: 12 Jul 2006
Posts: 11378
Location: PacNW

PostPosted: Thu Nov 13, 2014 2:51 am    Post subject: Re: 924 Carrera GT Update Reply with quote

bgravolet wrote:
The problem I have now is there is a small fuel leak somewhere near the top of the tank. Do you guys know if this is common?


More than you want to know can be reviewed HERE.
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Toofah King Bad

  • Red (1987 924S) - Pro44/Spec944
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!tom  



Joined: 28 Aug 2006
Posts: 1898
Location: Victoria, BC Canada

PostPosted: Thu Nov 13, 2014 4:26 pm    Post subject: Reply with quote

And my experience HERE.
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78 924 NA
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CÚdric  



Joined: 27 Aug 2004
Posts: 1976
Location: Sweden

PostPosted: Thu Nov 13, 2014 9:07 pm    Post subject: Reply with quote

Is the CGT tank 84 litres? how big is that fuel tank physically? The regular 931 fuel tank is easy to take down, you can slide it behind the gearbox so there is no need to remove it.Its a good exercise anyway to change all the tubing and seals around the tank, they are quite old by now...
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Gijs937  



Joined: 02 Jul 2014
Posts: 24
Location: Netherlands

PostPosted: Sat Nov 15, 2014 9:28 pm    Post subject: Reply with quote

Fueltank has capacity of 85 LTR
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