VVT (phaser) tips for testing on your spider

["Damien Gaboury" <dgaboury@domain.elided>]

I week ago, I tried to got some info about the VVT on the archives. I was
quite disappointed. That device on my newly bought spider 86 was broken,
electronic device (some resistances, diodes and transistors) was exposed and
two of the three wires were disconnected from the circuit.



So, I gained information from the CD-rom of the car (Mitchell) and I fixed the
problem during the week-end. Here are some tips to check easily if that device
works on your car.



It should be mentioned that the VVT engages only at full throttle and thus, it
is not real variable valve timing controlled by RPM.



First, locate the VVT solenoid device: it is at the front of the engine head,
passage-side, very close to the radiator. It is a round plastic device with
electrical wires mounted on an aluminium part, fixed with 3 hex crews on the
motor head.



1)      Checking if the electronic device works: Turn the ignition key in
order to put all electrical active on the car (don't start the engine). Lift
the throttle at it maximum and look inside the small hole in the aluminium
part on the solenoid. You should see a small rod pushing inside the head. You
can repeat that lift up and down of the throttle to see the solenoid
operation.



2)      Checking if the mechanical device work: two ways here. A) Remove the
plastic device on the solenoid. Quite easy, unscrew the clipping screw and
pull the plastic device out along the axis of the solenoid. Now, there are 2
pins going to the solenoid. Start the engine, at idle, put a 9 volts battery
on the two pins in order to activate the solenoid. The engine should start to
idle roughly because the cam advance is too much. If so, the internal VVT
mechanical device works. B) Remove the three hex crews in order to remove the
solenoid assembly. Put back the crews in place (just in case, because there is
some oil on the crew). Do the same test at idle, by pushing with your finger
the rod inside the motor head.



3)      Finally, check that your device works when you floor the accelerator.
Have someone to floor the accelerator while looking at the solenoid.



As a final world, there is an electronic device associated with the solenoid
because the signal is too low to active the solenoid it-self. The signal from
the throttle body switch comes from the ECU. It is an 8 volt low amp signal.
The electronic device at the solenoid is a voltage-ampere amplifier. This is
why there are 3 wires at the solenoid: green wire is 12 volts, yellow is
signal from the throttle body switch and black is ground. For further test,
you can disconnect the wires from the VVT device easily, follow the wire and
there is a connection.



Hope this will help someone



1986 Spider veloce

1993 audi quattro sport

____________________________________________________
Damien Gaboury, PhD
Scientifique de recherche
Consortium de Recherche en Exploration Minirale (CONSOREM)
Universiti du Quibec ` Chicoutimi
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