A 944 LIVES AGAIN
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‘We have an excellent working relationship with Bosch in Germany’ 37 porscheclubgb.com
I knew, as soon as my 1985 944 finally burst into life again this summer, that I had a problem. Essentially one of its four fuel injectors appeared to be completely blocked. What to do about it, though? I had three spares, but they might have been no better. Best have the original ones cleaned and overhauled, then. If that didn’t work I could use one of my spares, and hope that it either worked as it was, or else responded to the same treatment. At least the next part of the question – where to go – was easily answered. I had first encountered Bushey, Hertfordshirebased ASNU in 2002, and even then quickly realised they knew more about this fascinating aspect of engine performance than I could ever hope to. Phil Ellisdon kindly agreed to run all four injectors through his standard test routine, and my ‘diagnosis’ was proved correct: there was no fuel squirting out of number three. Interestingly, though, within a few seconds it began to work, no doubt as a result of the cleaning fluid passing through it, but all four spray patterns were all over the place, and the total fuel delivery ranged from 50ml per minute (number two) to just over 70ml (number four). In the event even number three finally managed 65ml. Phil removed first the upper and lower ‘O’-rings, and then the tiny filter basket at the upper end of each injector. These were followed by the pintle caps and insulating washers. Next step was to connect the units to the same flying leads that had enabled them to be pulsed open and shut during that spray-pattern and flow test, place them in some clean fluid in the ultrasonic tank, and let the machine get on with the job. Within a few minutes we could see the tell-tale foaming inside the inlet port of each injector, and by the time the machine had switched itself off the fluid was brown and opaque. Phil fitted new pintle caps, filter baskets and ‘O’-rings (the insulating washers could be used again), and then it was back to the test-rig to see how the injectors behaved now. All four of spray patterns were now pretty much identical, and likewise the total flow. But two of the injectors – numbers one and four – now had catastrophic leaks from somewhere between the nozzle body and the outer casing. ‘That’s remarkable,’ said Phil. ‘I have been working with these units for 30 years, and I have never seen that before. These injectors cannot be used again.’ Fortunately I had taken with me those three spare injectors – of largely unknown history and provenance – and two of those, stripped, cleaned and rebuilt, made perfect substitutes. Back on the rig, all four flowed and sprayed just as they are meant to, and back on the car they are now delivering the instant starting, quick throttle response, and metronome-like tickover, that before I could only dream about.