TOXNER

I just purchased my first 930. It is an 85 grey market car. The previous owner was a very nice fellow who told me straightforward that the car did not run like it should. In second gear it starts missing at about 4800rpm. The boost guage is pegged. I do not know how accuarate the boost guage is. The engine appears to be a stock euro model with 123,000 miles on it. Any suggestions as to where to start looking? Thanks.

Tom Oxner

PorschePhD

You sure it is just in second? It could be there is enough load to cause the clutch to start slipping there. Otherwise you will need to open the tranny to inspect. It will be costly if it is second gear. Something will have had to come apart for that.

911rudy

Are you talking about the engine missing while in second gear or do you mean the drive train is missing, (Slipping), in second gear? If it is only missing in second gear, (Engine), then it could be several things from a bad spark plug, bad or cracked injector loose wire etc. If you mean that the drive train is slipping or grabbing then you are in for some major work unless the clutch can be adjusted. You need to clarify your question a little bit more.

TOXNER

If I am driving at an RPM below where boost comes in, the car seems to run OK. When I floor the throttle in second gear, the boost comes on, but when the engine reaches approximately 4800 rpm, the engines starts to misfire. It still accelerates, but not as quickly. It probably does this in first gear also, but the mechanical advantage makes it much less noticeable. The clutch does not seem to be slipping (this would also probably be more noticeable in gears 2-4 than in first). The second gear synchros need to be replaced in the trans. I am trying to get a little more diagnostic information on the engine condition before I remove the engine and trans to rebuild the trans. Thanks for your help.

Tom Oxner

TOXNER

I did not mean to imply that this condition exists only in second gear. It probably also exists in third and fourth, but I have not had the opportunity to drive the car enough to get the rpm's to that level in third or fourth. In the limited time I have had the car, I have only gotten into the boost heavilt in second gear. Thanks for your help.

Tom

srf506

I'll bet your clutch is slipping in 2nd gear at those torque levels. At 123,000 miles, assuming its the second clutch, it would have about 60k, or maybe more, miles on it. It probably needs a repair/replacement. especially if the car has been driven in the "sportier" RPM and boost levels.

Mo Mia

if the clutch is slipping, the car will keep revving but with no proprtionate increase in speed. i would get a mech to have a look at the basics b4 stripping $$$. maybe you get lucky and its a spark plug or lead issue. good luck

TOXNER

The engine will not rev past 5500 due to the misfiring. If the clutch were slipping, the engine would rev faster than normal.
Tom

FONNE

My 1982 930 with alot of milage behaved in a similar way when the boost came in, maybe not that bad, but anyway in a similar way. It was a snapped cylinderbolt - common af what I heard, and I now replaced all of them and got a complete rebuild of the engine at the same time.

/Peter, Sweden

srf506

If its RPM limited then I'd start looking at the overboost cut-out, manifold and injector leaks and obviously the ignition system. Also, has anyone messed around with the wastegate? Maybe you have too big a spring(s) in it that's allowing you to overboost?

Last930

As it's a new car to you always look at the simple basic things 1st. Try new plugs ,cap, rotor, and check out the plug wires - I had the same problem with my '79 930 and it went away after I replaced the 27 year-old original ignition harness.