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Re: quattro-digest V4 #2358
> Except for this one baffling behavior. At 4800 RPM, in first,
> second or third (I haven't found a long enough road to get up
> to 4800 in fourth or fifth), the engine acts as though all the
> pistons have come loose and are about to fly out of the block.
> Shifting into the next higher gear returns to the smooth, fluid
> transfer of power to the drive wheels, but it seems that the
> car is just getting started when it bucks and jerks. The owner
> opined that it's the rev-limiter kicking in at that RPM, and
> that the tach is reading low. Sounds improbable to me, but...
Yep, seen that one before.
Someone has replaced the fuel pump relay and used one for a four cylinder car.
They look the same, BUT, the rev limiter is built-in to the fuel pump relay. One pin on the
relay goes back to the coil and "counts" ignition pluses. Then kills the fuel if it sees too many.
A five cylinder car has 20 percent more ignition pluses per rev then a four cylinder. The
limit should be about 6200 rpm. The four cylinder relay thinks your going too fast and shuts off the fuel
before 5000 rpm.
Just put the right relay in there (in the little box under the dash-drivers side) and you should be all set.
'86 4000 CS Quattro