I seem to be having an intermittent problem with my '73 450SLC.
From time to time, the engine will stuble badly, but it will only
last for a few seconds then the problem goes away as quickly
as it strated. I've ruled out an ignition problem, so I think the
problem may be in the fuel injection system.
I do not have a manual that covers the engine. There must be a sensor
that tells the injection system the postion of the crabkshaft. I sure can't
it! Sure would appreciate some help.
Your EFI injection timing is controlled by the trigger points in the base of the
Highly unlikely that they are your problem. There are 4 sets of points in the
group. They send a
signal to the ECU behind the glovebox. Each triggers a pair of injectors. The
injectors are paired
as follows: 1 + 5, 2 + 7, 3 + 6, 4 +8. The cylinders are 1-4 on the pass side,
5-6 on the drivers
side, on a US LHD car...
The usual sign of bad trigger points is oil getting on 1 set and you lose 2
For an intermittant stumble on a take-off from idle, I would highly suspect the
EGR valve. Do you
have one? It will be on the top of the drivers side exhaust manifold. It is
vacuum controlled thru a
transducer that gets water in it. I would disconnect both vacuum hoses going to
the EGR valve and
plug both hoses. Drive it for a while and see if it corrects the stumble.
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