Geoff---I'll take at shot at this one..
First off, let's eliminate the MSD6-A for now, by converting back to the
stock ignition. You don't have to remove the MSD, just use the "Purple"
jumper wires that allow one to connect the MSD wires at the coil to the
stock ones that should be "insulated", right next to them. If you saved
your instructions, it'll be easy enough. Write back if it's not.
When you jumper out the MSD and back to points only, the timing will
need to be reset.
With the vacuum retard disconnected, set it at 10 deg. BTDC with the
engine idling as close to 900rpm as you can get it.
While the MSD is a very reliable unit, they don't last forever. (I got
around 100,000 miles out of my first one). Yours acts just as mine did,
with the cutting in and out, backfiring, etc. The unit, I was told later
by the foks at Autotronics, "was fried".
If the engine still doesn't run right, even with the MSD disconnected,
there could still be an issue with what is going on under the dist. cap.
At this time, it is necessary to look at the wires and points, rotor and
cap (for cracks), and see if the timing advances with engine speed.
Let us know!
Dick
'73
From: gameparker@bellsouth.net(<gameparker6Acting Completely Crazy -
Who's Up to this Diagnostic Challange?
O.k. - Here goes nothing.
Had to drive the 6 all week because F150 was in the shop. Performed
flawlessly all week. Left it out in the rain one night because I had to
stay at work and witness a 350 cubic yard concrete placement. Anyway, it
started right up the next day with a little choke for a minute or two as
it always does. Leaving from work, there were a few collegues looking to
be impressed so I gap it a little and take first up to about 6000 rpm
which for me is also quite a common practice. Two minutes later there
was a miss, then another then the engine wants to cut out at lights. I
limp it home feathering the choke to keep it running and I see that the
fuel filter is very empty, even though the tank is full. I suspect the
pump, get and install a replacement with no change in the symptoms. The
symptoms, BTW, are unusually inconsistent - the car never wants to start
and when it does, it's only with the choke fully on. It'll run somewhat
O.K like this for anywhere from a minute to 10 mi! nutes and then just
cut out. Sometimes there is a backfire from my SU's but the bowls are
full and the float needles are clean and operational. Testing each and
every one of the plug wires suggests that all plugs are getting ample
consistent spark from the MSD 6A. No broken valve springs and
compression is 155-165 across all 6 cylinders (head is shaved). Timing
is another issue - never my forte, I can get the engine to remain
running by rotating the dizzy all the way to the right and disconnecting
the vacuum retard. It was running rally badly when I discovered the
dizzy changes things - lots of black and blue smoke, an obvious miss
from one or more cylinders and a knock then seemed to come from the
motor and the exhaust. Speaking of the exhaust, the sound is terrible
and sound like I am running an open pipe. Checking the timing once the
dizzy was rotated to the right with the retard disconnected showed 4
ATDC. Attaching the retart puts it about 12 ATDC.
HELP PLEASE - spent the whole day with nothing to show (except for the
timing epifany). Cheers,
Geoff Parker
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