tone40

I had 2 minor issues with my '88 911.

(a) My headlights flicker when at idle.

(b) My car did not hold a steady rpm smoothly. It had good power, but I felt like I had to force it to rev. Did not miss. Most evident when I lifted off throttle. Poor transition from acceleration throttle position to steady throttle position. I thought that it might be an exhaust restriction.

So I figured I would clean the ground connections to address the flickering lights issue. I got out my Bentley manual and cleaned all the grounds that were readily accessible (next to fuse box, at the battery, behind the fuel filter and on the intake manifold).

I also removed my air filter, just to see if the filter was clean. The filter was pretty clean for ~7K miles on it. I tapped it a few times and no appreciable amount of dirt was evident. Connecting the back lower clip is a real PITA!

So I drive it last night and this morning. To my surprise, the rough steady rpm issue is gone! The car seems to rev easier/smoother as well. The headlights still flicker.

Could the ground cleaning have improved the rough idle? Or, did the elimination of the minor amount of filter dirt greatly enhance the air delivery? Or, I wonder if the back clip was not on correctly before causing too much air for the intake air system.

Any suggestions? I knock on wood that I improved the running condition.

Edward

I would guess that yes, getting a good ground would aid the DME (and maybe even the fuel pump) do its job. I would doubt that the air filter did much. Yours was clean and I've had some pretty nasty-looking filters in the past (other non-p cars) and changing only the filter did little in terms of drivability. Congrats, though. Enjoy it!

Edward

sharky47

The 944 series can benefit greatly from cleaning all the grounds - solves a lot of wierd problems.......

Peter Zimmermann

I respectfully suggest that you get to the bottom of your flickering headlight problem - that is something to be concerned about. You will probably find that you have a alternator/regulator problem. Warm the engine for a few minutes, and place the leads of a volt-ohm meter across the battery terminals. You should get a reading of approximately 13.3 - 13.6 volts at idle, and a reading of about 13.8 to 14.1 volts at a steady 2500 rpm. Check it soon!
Pete
FYI: If you remove the air filter and its cover your engine will still use the same amount of air, the only thing that changes is filtered air or unfiltered air. The mixture won't change.