engine trouble

[bruceb]

Hello board needsome help

I Have just serviced my 83 sc. It had been running fine with no problems. For the service I used the standard Porsche service kit but additionally had the CIS injectors flushed by a Bosch service agent. Well the car initially ran OK but with a small misfire at low revs and load. The car has always been a little rough at low revs since the installation of SSI exhaust a few years ago so I ignored the new misfire and went for longer run out. The car did 60 miles on the motorway with no problems and plenty of power. Only when turning off onto slower roads did the car really start to complain about accellerating below 3000rpm. A few miles later the car was down to five and then four cylinders and I just made it to a friends house. The car is running just but really rough and cannot be driven on the road so I had to abandon it and catch a train home!! I am going to have to phone the nearest Porsche agent to the fix the car sometime early next. Anybody got any home fix ideas befor the dreaded wallet wilting visit to the Porsche agent!

Thanks

Bruceb

[jester911]

When you say "kit" what all was included? Did you change plugs? Sounds like a problem I had with spark plugs.

[Early_S_Man]

Hi, Bruce, and welcome to the board!

How warm was the weather on your 60 mile ride ... 30° - 35° C??? Could be a failed Beru spark plug connector causing your miss ... if the weather was hot ... 85° - 90° F is warm enough to cause a misfire in a cylinder where the internal resistor in the Beru connector has gone open.

Check all of your spark plug wires for end-to-end continuity in the nominal 3000 - 4000 Ohm range with a multimeter. I also recommend a 'shake' test where the connector is held firmly to the test leads and shaken vigorously ... but don't bang or hit it against anything while doing the test! Intermittent Beru's have been found by multiple board members, but it may require an assistant to keep the test leads connected while doing the test. It is easier to test the connectors when they are off the wire during a replacement procedure for the Neoprene/Hypalon wires, but I don't recommend unscrewing them during a routine test, as the act of removal can loosen the crimped brass threaded end on the wire.

Good luck!

[bruceb]

Guys

thanks for the replies, the standard sevice kit included plugs air and fuel filters, I changed the plug leads and caps and distributer cap and rotor arm with new parts about a year ago, could they go wrong so quick? (2000miles) I will get them checked again before calling the agent,

Bruceb

[bell]

sounds like it's "fouling out" due to not enough spark or faulty beru's........what brand/part number plugs were used? maybe they're too cold of a plug.....
my .03

[bruceb]

New plugs are Bosche W3 CC same the old ones, they were also the prefect book colour for a used plug so I guess the engine was running just fine before my home service efforts, the mystery deepens

Bruceb