The short answer is yes, low compression will show up first in difficulty
starting. Compression is an easy thing to measure, and tells a very large
percentage of the whole story about your engine's condition. As an example,
I offer my 300,000 Mi + "Mahogany" 81 Imperial - even at the end of life,
it drove perfectly, burned no oil, and was fairly smooth and quiet, but it
did have a somewhat rough idle. It also would emit some oil smoke when
started if it had not been driven for a week or so. It showed no
deterioration in MPG or performance that I could detect. It was a tired
looking car when I bought it, in 1988 or so with about 130,000 on it, but it
was supremely comfortable (cloth seats in the 1981 only style loose pillow
design) and I drove it everywhere for about 12 years.
It became harder and harder to start - finally to the point that I began
carrying a few ounces of gas with me when I was going anywhere. The
compression was in the 90-110 range on 6 of the cylinders, and 40 on one, 70
on the last one - signs of a very tired engine (which I already knew, of
course). I sold that car in 2002 (as a parts car) to another collector -
he is in Finland and I have not had a report as to what he did with it - but
he had a much nicer one so I suspect it hasn't been driven since. I did tell
him how to start it, though.
If you put a pressure gauge on the fuel inlet to your HSA (the smaller of
the two metal lines), you can measure the fuel available for starting. You
should see about 12-14 PSI there when the purge cycle is occurring. You
should also see a squirt from the fuel nozzles above the butterfly throttle
valves. If you have the fuel there, the car should start right up. If it
doesn't it's time to start looking for another cause.
I assume your plugs, wires, cap, rotor etc. are all in great shape. As you
probably know, there has been a reported high failure rate of the reluctor
coil in the distributor which has caused many high temperature running
problems, but I'd not expect this to cause only a starting problem - if the
pickup is failing, that would also cause your engine to stop anytime, not
just when starting.
Dick
>From: "Dick Benjamin" wrote: snip
>If you have not done so, I think it's time to check the compression on this
>engine.
Why do you think I should run a compression test? The car runs fine and
doesn't burn oil. It just takes some time to start. If you have been
driving it and shut it off for a second or two it will usually start
immediately. Only two big problems I had were on HOT days after a stop of
between a half hour and an hour. For these reasons and the aftermarket fuel
pump sucking fuel UP through the inactive in-tank pump, I suspect a fuel
line problem. Would compression affect the starting, but let it run this
well?
Thanks again,
Rob
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