Out in the Jag over the holiday [US 4th] and discovered what
sounds and feels like a misfire at 3400 to 3600 rpm in all
gears. First noticed on the freeway. Plugs , wires, points,
and other settings are all within normal limits.Plugs and
points have 2000 miles on them and look brand new. Wires test
ok too. I have no idea of what to look at next. New sport
coil less than 500 miles old. All ideas accepted. Thanx in
advance. Allan 69 2+2
Allan:
May I suggest you look at the plugs to see it any clue
as to what one is not working. Check that fuel pump
too! Then the rotor and the dist cap! It may be time
to put that 350 in it, no one has any trouble with a Chev
engine 
(Sorry!)
M.Fisher----- Original Message -----
From: Allan or Judith Mandell agm18@access1.net
To: E-Type List e-type@jag-lovers.org
Sent: Tuesday, July 06, 1999 8:45 PM
Subject: [E-Type] Miss 34/3600
Out in the Jag over the holiday [US 4th] and discovered what
sounds and feels like a misfire at 3400 to 3600 rpm in all
gears. First noticed on the freeway. Plugs , wires, points,
and other settings are all within normal limits.Plugs and
points have 2000 miles on them and look brand new. Wires test
ok too. I have no idea of what to look at next. New sport
coil less than 500 miles old. All ideas accepted. Thanx in
advance. Allan 69 2+2
Allan,
Some ideas,
-
On the distributor is the thumb adjusting screw. If it is screwed too
much clockwise (ie the CB plate plate is thus rotated clockwise) and you
could have a condition where the distributor rotor is too far past the
point on the cap and cannot bridge the gap when it fires. Therefore try
screwing the screw (I believe anticlockwise so that the plate rotates
clockwise a bit. -
Run it so it misfires for a minute then cut the ignition and roll to
a stop. Then check all sparkplugs to see if they all look the same. -
I would put back the old points, plugs etc and see if it goes away.
ie the method of substitution. You may have a points bounce problem (a
sort of resonance. Increasing the points gap or points substitution may
uncover this. -
Does it happen at that rpm regardless of throttle opening and speed
of car ? If so it is definitely ignition. Does the car accelerate
perfectly in each gear and but lag in the rpm band you mention??
If not it is speed related, then one would look to the drive train,
suspension or wheels.
-
I am trying to think of how the fuel system or carbs would contribute
to this and will add more when you reply to 4). Why not take out the air
cleaner and try it out? -
Check compression. One never knows…
This sounds like a tough one.
Dennis 69 OTS
Allan or Judith Mandell wrote:>
Out in the Jag over the holiday [US 4th] and discovered what
sounds and feels like a misfire at 3400 to 3600 rpm in all
gears. First noticed on the freeway. Plugs , wires, points,
and other settings are all within normal limits.Plugs and
points have 2000 miles on them and look brand new. Wires test
ok too. I have no idea of what to look at next. New sport
coil less than 500 miles old. All ideas accepted. Thanx in
advance. Allan 69 2+2
Allan: Suggest you check air and vacuum leaks. From intake manifold to
vacuum tank, fittings more than hoses and then loose nuts on intake
manifold, you may be surprised how loose they can be.
Mike in Phoenix----- Original Message -----
From: Allan or Judith Mandell agm18@access1.net
To: E-Type List e-type@jag-lovers.org
Sent: Tuesday, July 06, 1999 6:45 PM
Subject: [E-Type] Miss 34/3600
Out in the Jag over the holiday [US 4th] and discovered what
sounds and feels like a misfire at 3400 to 3600 rpm in all
gears. First noticed on the freeway. Plugs , wires, points,
and other settings are all within normal limits.Plugs and
points have 2000 miles on them and look brand new. Wires test
ok too. I have no idea of what to look at next. New sport
coil less than 500 miles old. All ideas accepted. Thanx in
advance. Allan 69 2+2
High tension wires always suspect, especially if they’re resistor wires
(non-metallic core with carbon particles, instead of solid/braided
copper/steel). Check inside (and outside) the distributor cap (and coil)
for carbon traces?
Good luck!
Larry Schear
Twin Cam, Inc.
At 06:45 PM 7/6/99 -0700, you wrote:>Out in the Jag over the holiday [US 4th] and discovered what
sounds and feels like a misfire at 3400 to 3600 rpm in all
gears. First noticed on the freeway. Plugs , wires, points,
and other settings are all within normal limits.Plugs and
points have 2000 miles on them and look brand new. Wires test
ok too. I have no idea of what to look at next. New sport
coil less than 500 miles old. All ideas accepted. Thanx in
advance. Allan 69 2+2
Thank you all both on and off the list. Replaced the “new”
plugs and still had the miss. Replaced the “new” cap and
rotor and the miss went away. I cannot see anything wrong
with either piece but they are obviously faulty. Fittings ,
hoses, vacuum lines and manifold were all tight. Allan 69 2+2
Weird. Rather common, but weird. I’ve sen this before, a small
non-visible crack in the cap.
LLoyd
Allan or Judith Mandell wrote:> Thank you all both on and off the list. Replaced the “new”
plugs and still had the miss. Replaced the “new” cap and
rotor and the miss went away. I cannot see anything wrong
with either piece but they are obviously faulty. Fittings ,
hoses, vacuum lines and manifold were all tight. Allan 69 2+2