[ OUR CARS ] 1985 Porsche 911 Carrera 3.2
The intermittent rough running of Stewart’s 911…
Owned by Stewart Perry (c/o classic.cars@bauermedia.co.uk)
Time owned Ten years, seven months
Latest/total miles 550/120,473
Latest/total costs £600/£41,776
Previously Defensive driving course for Kim
The 911 just completely died on the freeway and is going home on a tilt tray,’ came the call from my brother Ross, who had been using the 911 for his 15-mile daily commute. My 911 had been a pillar of reliability for years, never once giving trouble, so this came as a surprise.
Annoyingly, back home, the car started and ran perfectly as if nothing had been wrong. The age-old question of ‘is it fuel or spark?’ certainly applied… Ross mentioned that it felt like the car was running out of fuel before it stopped. I knew the fuel pump was the 120,000-mile original part, so replacing it was a good first step and I even had a spare.
With the new pump installed, I did some local trips and things seemed back to normal, perhaps with a very slight and occasional rough idle. A few weeks later, we decided to take it for a proper run into the hills, but we never made it. Once again, the Porsche came home on a tilt tray, and once again, after cooling down, the car ran normally.
At this point, all bets were off. Ross spent many hours checking components using his extensive knowledge and the Bentley Porsche 911 Carrera Service Manual. Every electrical check yielded no categorical answers, not even a hint.
…has led to much head-scratching for him and Ross
With no answers and no trust in the car’s reliability, we were stuck. There was talk of taking it to a professional. Then it hit me – why don’t we just throw parts at it? Initially it seemed silly, not knowing what was wrong, but the more we discussed it, the more sense it made. Given the reasonable prices from Pelican Parts in the US, I could replace a lot of 120,000-mile, original parts for less than a few hours at a workshop.
So, I ordered a distributor cap, rotor button, spark plugs, coil, and fuel filter.
Still the problem persisted. A friend who’d owned an Eighties Mercedes suggested crank angle sensors, having had a nearly identical issue. Once installed, over the next few weeks the issue didn’t return.
With a big Porsche rally coming up, I wanted to be certain of its reliability. That weekend, we were heading to the Retrospeed Wilby Park Sprints. I asked my wife Kim to bring the 911 as a shakedown run, and my daughter and I towed our caravan with my Ford Falcon XB GT.
The run up was smooth. Kim even took the 911 for a few laps of the track. But 20 miles from home, she pulled over; it wasn’t running right. Frustrating. We pushed on; it still ran, albeit roughly. I replaced the spark plug leads, not cheap at AU$500 (£240)! The rough running vanished. The 911 has returned to being the pillar of reliability it has been for the past decade and is back in semi-daily use.
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