Continued engine missing problem
Thread Starter
Racer
Joined: Sep 2002
Posts: 293
Likes: 1
From: Prather, California: somewhere in the middle of the State
Continued engine missing problem
My wife's '91 C2 cab has been giving me fits. I would do one thing to try to easteregg the problem of stumbling and missing and it would run great. The next day, it would beback to it's old problematic self. After all the standard things have been done to solve the C2 from missing and stumbling (tune up, coils, DME relay, coils, fuel filter) I finally gave up and today took the car to a Porsche mechanic. After reading fault codes and putting the car on a diagnostic machine, I was told that the Hall Effect sensor on the primary distributor is providing erratic signals. Sometime it provided steady signals. Other times it was just providing a mish-mash of signals. The only solution, I was told, was to buy a new primary distributor. Has anyone had a similar experience? The price for the new distributor is around $800 US. Then there is labor. Ouch! Is there anyway that the sensor can be replaced without buying the entire distributor? FYI I have 128,000 miles on the car.
Technical Guru
Rennlist Member
Rennlist Member
Joined: May 2002
Posts: 8,138
Likes: 122
From: USVI
Its very simple to remove the old hall sensor the problem is I don't know of anyplace that sells replacements. When I had the same code which caused stalling whenever I came to a stop I just cleaned the 3 pin contacts and reconnected everything. I'm not sure if you can reach the contacts without removing the distributor (not a big deal) but its worth a try. If that doesn't work I would check the 3 wires that connect the hall sensor to the connector (internal to the distributor). Hall sensors have no moving parts so there is not a whole lot that can go wrong.
Race Car
Joined: May 2003
Posts: 4,229
Likes: 102
From: SoCal
The problem you describe is typical of a 964 engine with bad or poorly connected
spark plug wires. The 964 ignition system when not functioning properly can cause
RFI noise which affects the DME control unit. The fault code does come up as the
Hall sensor when in fact it maybe the ignition wiring/connectors.
You are aware that the 964 engine will run without the Hall sensor which is used
for the sequential injection mode and knock sensing. Therefore, you can disconnect
it for troubleshooting. Avoid replacing the Hall sensor until you're sure of the problem.
spark plug wires. The 964 ignition system when not functioning properly can cause
RFI noise which affects the DME control unit. The fault code does come up as the
Hall sensor when in fact it maybe the ignition wiring/connectors.
You are aware that the 964 engine will run without the Hall sensor which is used
for the sequential injection mode and knock sensing. Therefore, you can disconnect
it for troubleshooting. Avoid replacing the Hall sensor until you're sure of the problem.
Thread Starter
Racer
Joined: Sep 2002
Posts: 293
Likes: 1
From: Prather, California: somewhere in the middle of the State
Lorren
What an interesting post. I will take it to my mechanic early Monday morning and have him check it out. I can certainly put off the replacement of the distributor since he did not have it in stock. Thank you for the advice.
What an interesting post. I will take it to my mechanic early Monday morning and have him check it out. I can certainly put off the replacement of the distributor since he did not have it in stock. Thank you for the advice.
