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Registered
Join Date: Sep 2007
Posts: 6
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1990 964 C2 on start, poor idling/throttle response
yesterday AM, On start up the idling was balky and engine stalled several times. After warm up things improved but the throttle response was delayed and never produced the usual power. After driving some then parking and shutting off the ignition I restarted an hour later. The engine ran better but still hinting at trouble. After shut down and subsequent restart it bucked and sputtered then died. No point in flogging a dead horse. I have experienced similar problems over the years with other makes. This sort of thing in the past has pointed to closed points, faulty coil, clogged fuel filter. That sort of thing, while I have owned a few Porsche's over the years I've never had to "learn" them and have some catching up to do. I'm more familiar with the older stuff..
I got a set of factory manuals for the 964 but I'm getting the feeling they are woefully incomplete. Any how "Thanks in advance" for any suggestions on repairs or reading materials. Scott |
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Moderator
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Here's my checklist:
1) DME 2) Fuel Filter 3) Airflow Sensor My vote's number 3; but very interested to see if AF Juvat or Bill Verburg have a more informed opinion.
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Don Plumley M235i memories: 87 911, 96 993, 13 Cayenne |
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Registered
Join Date: Sep 2007
Posts: 6
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1990 964 C2 on start, poor idling/throttle response
yesterday AM, On start up the idling was balky and engine stalled several times. After warm up things improved but the throttle response was delayed and never produced the usual power. After driving some then parking and shutting off the ignition I restarted an hour later. The engine ran better but still hinting at trouble. After shut down and subsequent restart it bucked and sputtered then died. No point in flogging a dead horse. I have experienced similar problems over the years with other makes. This sort of thing in the past has pointed to closed points, faulty coil, clogged fuel filter. That sort of thing, while I have owned a few Porsche's over the years I've never had to "learn" them and have some catching up to do. I'm more familiar with the older stuff..
I got a set of factory manuals for the 964 but I'm getting the feeling they are woefully incomplete. Any how "Thanks in advance" for any suggestions on repairs or reading materials. Scott |
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Sports Purpose 911 Driver
Join Date: Mar 2002
Location: La Jolla, CA
Posts: 4,368
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sounds like a sensor issue leading to a timing problem.
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James Shira R Gruppe # 271 1972 911 Coupe 3.8 RS ‘nbr two’ 1972 911 Coupe 3.2 TwinPlug MFI 'Tangerina-Jolie' 1955 356 Pre A Coupe ‘old red’ 1956 356A Emory speedster build in progress |
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Registered
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Sounds like one side of the twin plug ignition system failed. Disconnect the plug from one of the Bosch ignition modules on the left side of the engine compartment, start it up and see how it idles. Turn it off, plug it back in and unplug the other one and repeat. If it idles different or doesn't start, you need to check the coils, distributor belt, wires, or even the ignition modules.
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Registered
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+1 on the secondary dizzy not producing a spark. If the car won't start if one or the other plugs at the ignitors are disconnected you probably have a bad belt inside the distributor.
Does your car have the ventilation kit installed? It is a little rubber tube that runs from the fresh air hose (connected to the electrical engine fan) to the distributor base. Its purpose it to vent the ozone produced by the sparking in the caps. Ozone is responsible for premature belt failure on 964 NA cars. The belt becomes brittle and rips. Cheers, Ingo
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1974 Targa 3.6, 2001 C4 (sold), 2019 GT3RS, 2000 ML430 I repair/rebuild Bosch CDI Boxes and Porsche Motronic DMEs Porsche "Hammer" or Porsche PST2, PIWIS III - I can help!! How about a NoBadDays DualChip for 964 or '95 993 |
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