Testing TVIS

[ee904age]

Is there any way other than by ear to tell if TVIS is working properly? My car doesnt seem to have the same take off at 4500rpm or even down low for that matter as it used to.

I wedged my arm down the back of the manifold and touched the actuator arm whilst revving to what sounded like about 5500rpm, (i cant see the tacho from under the bonnet!) and it didnt move.

There are no vacuum leaks so the only thing I can think of is the ECU isnt triggering it. Is there any way of confirming this??

Cheers
Shay

[CozmoNz]

Is there any way other than by ear to tell if TVIS is working properly? My car doesnt seem to have the same take off at 4500rpm or even down low for that matter as it used to.

I wedged my arm down the back of the manifold and touched the actuator arm whilst revving to what sounded like about 5500rpm, (i cant see the tacho from under the bonnet!) and it didnt move.

There are no vacuum leaks so the only thing I can think of is the ECU isnt triggering it. Is there any way of confirming this??

Cheers
Shay

is the car fitted with a poddie?

youll hear the difference quite easily.. its a defentite noise difference. Performance wise i guess youd feel above 5000 drop off.... no continiuation of accel.

get ur buddy to rev it to 6000 or something from inside the car, while you have your arm on it (you may have been revving it to 3,000) cars sound much louder with the bonnit open (dependant on intake and such etc obviously).

[Twolitre]

By default the TVIS butterflies are open so it is possible that they're open because of a problem. I've seen a rooted tvis diaphram on a 3S leak and not staying closed with vacum so have a look under the intake manifold and see if the rod moves and closes when an assiatant starts the engine, if you can't see it then put your hand under the manifold (obviously when cold) and feel if the rod pushes out from the diaphram to close the tvis butterflies when under 4500Rpm
If nothing seems to be happening then check for vacum leaks around the tvis system or remove the manifold altogether and replace the faulty parts.
Having said all that a lack of low down torque could be a result of incorrect ignition timing so might pay to check that first.

[kingcorolla]

the 18 pin plug on the ecu, locate number 10 pin (bottom left corner). This is the pin for the TVIS curcuit. Test for power with a multimeter, there is constant power at this pin when TVIS is shut, and the ecu open curcuits to open the butterflys. You could also check for power on the TVIS solenoid, but will be difficult due to the FWD layout.

Also, are all the TVIS hoses connected correctly? Ive gotta pic to show the hoses correct location if you need it.

ALSO, when i pulled my 4age apart, i found my butterflys were stuck shut due to all the oil/gunk. They were pretty stuck, like, almost unmovable by hand This could be the case.

thats if it is the TVIS...

[Caveman]

Turn the car off. TVIS butterflies open. Turn the car on and idle. TVIS butterflies closed.

If you can feel the accuator working/moving while the car turns on its working. Wheather its being switched at 4500RPM or whatever take off the plumbing to the trottlebody and rev to about 5000RPM. You should here a difference.

I suspect mine is screwed so im taking off my head (to do other repairs as well). I have very little torque at 2000RPM. I was tempted just to spray CRC down the manifold but thought I should do it properly.

[Twolitre]

Ok after reading you post properly this time you say you've already checked the tvis, have you checked to make sure the tvis vsv is still plugged into the loom and that all the vacum piping is still correctly attached and in order?
You could always get a longer piece of vacum pipe and attach it to the nipple on the back of the diaphram and suck through it, pinch the hose and see if it moves the rod and holds it, if not then it'll be rooted and will have internal leaking seals and need replacing with a non leaky one

[ee904age]

OK, the actuator arm doesnt move when starting it, so I assume TVIS is open. However when I connect the diaphram directly to the manifod (bypassing vac tank and switch) the butterflies slam shut(?) when started. From that I take it the diaphram is OK.

The vac tank is just a one way valve right? if so it is working fine also.

If anyone has a diagram of how it all SHOULD be connected or even draw me a picture in paint it would be great 'coz I had one but cant seem to find it!!

PS. If you draw a pic please show the 'flow' of vac so I know which way all hoses should be around. EG the tank has a straight and a right angled in/outlet please show what is what.

Thanks heaps
Shay

[kingcorolla]

[ee904age]

Cheers for the kingcorolla, the two hoses on the switch were the wrong way round but its still not closing!!!

This things really startin to get on my nerves!

Tested for continuity on the plug goin to the switch, nothing on one pin but on the other I got continuity at low rpm and then broke contact at high rpm. Is this how it should be??

I dont think its anything electronic but its worth a shot.