Hi all,
I posted a while ago about a strange state that my TR3a would get into after a
thorough warm up. It runs fantastic when I first start up and run around for
at least 15 or 20 minutes. Not exact on the time, and I don't think it is
always consistent anyway but definitely this 'strange state' occurs well after
the car is warmed up.
What happens is it is as if it is running on only one or maybe two cylinders
which allows me to limp home but constantly scanning the side of the road for
possible emergency pull offs. Having experienced a mechanical fuel pump
failure on another old friend of mine ('63 Tbird) this seemed very familiar.
I'm thinking the fuel pump is going and it's being kind enough not to strand
me on the road. So I replaced with an electric fuel pump and after a few
unrefreshing petrol showers while rolling around in the fall leaves and fallen
oil it is working like a champ. Plenty of gas is getting to carbs. So someone
suggested a stuck float valve or a maybe a SU piston that was sticking. Took
apart both carbs last night and everything looked very kosher. Of course I
cleaned out all passages for good luck as long as I was there.
Now I am begining to think about ignition stuff. Popped off the distrib cap
and was kind of surprised to see that it wasn't all that clean in there. I
have a Petronix ignitor that I put in when I got the car and it has been
working fine since then. There was some corrosion showing on the rotor cap (I
think that's what it is called). The thing that is plastic and conductive and
swings around just inside the distrib cap and actually distributes the juice
to the spark wires. I cleaned that up as best I could with some 600 emery
cloth. Looks pretty shiny now and I am sure this won't hurt even if its not
the problem. Also touched up the 4 contacts that this rotor arm touches. They
were a little off color but not too bad. The distrib cap, wires and coil were
new with the Petronix ignition stuff so we are only talking a few hundred
miles on them.
In the course of replacing the mechanical pump with the electric I can testify
as a reluctantly soaked witness that there are no blockages in the lines. One
thing I am kind of grasping at straw with is the rubber hose that comes from
the bottom of the tank to the hard line on the chassis. I have not replaced
that and am wondering if it might be collapsing and shutting off the fuel
under certain conditions (like when its hot?) but otherwise working fine. I
haven't looked at it too closely but has anyone replaced that part recently?
It seems that it would be very difficult to get to the tank side of whatever
that hose connects to to replace it.
The carb side is obvious.
I haven't had a chance to drive the car since I did the carb distrib cleaning
but I don't have real high hopes that I have dealt with this problem yet. One
thing that makes this even stranger, to me at least, is that when it first
started happening (and remember this was before the electric pump came on the
scene) it would only occur in the higher gears and when I was moving along
pretty briskly. The 'low end', starting from a stop, did not seem to be
effected.
Most recently though, like yesterday, the opposite has occurred and it is
running in 3rd and 4th like a sled on snow but apparently starving for
something, or shutting down cylinders in the low end when I am starting out in
1st or 2nd.
Any ideas, thoughts, scathing rebukes or harsh criticism would be most
welcome,
Thanks much,
Jim Lee
|