OK, SO it seems that I most likely am experiencing the dreaded failure of my VTC assemblies. But VTC's be damned, I am going to be with this car for many years to come.

So I have some questions about the VTC functions as far as performance is concerned.
I know that the VTC is on at low RPM in order to Increase power, but when the VTC ground Fix is used they are permanently off, causing a drop in low end power.

Question #1: I seem to have gathered that a Timing advance will fix the low end loss, but since the timing advance is permanent will this cause a decrease in power at higher RPM's?

Question #2 The JWT ECU advances the Timing from stock as part of the modified programming so would this mod effectively negate the loss associated with the VTC failure while still giving a good increase in power?

Question #3 If the VTC's do go out completely, does this have any harmful effects on the rest of the engine?

once again thanks for any answers provided!

 

I can't comment too much on the VTC grounding, but the timing advance shouldn't mess up your stock power too much. On my old engine I had it set at 20 BTDC, and just made sure that I put good gas in it. I just have my new engine's timing set at stock (15) and I notice a little less power but more smoothness. Basically it just adds power. I think that if your VTC's are disabled that the timing advance is just replacing power lost. If two cars, one having grounded VTCs, both had advanced timing the one with the operating VTC's would be faster. Timing advance is actually more effective at higher RPM, but it should help your torque as well.

I don't know at all how that would affect your JWT ECU if you grounded the VTC's, but I think it is adjusting the air fuel map according to the RPM, and it doesn't take into account whether or not the VTC's are functional. I don't know how the JWT is advancing the timing but you can adjust the crank angle sensor using a timing light anyways. I guess you would want to make sure that your timing isn't too far advanced so you don't start knocking and get the knock sensor to shut the party down by retarding the timing.

VTC's shouldn't cause any major engine damage, it might dirty your oil faster, but they will get annoying as hell(rattle, rattle)until they are fixed one way or another.

my $.02

 

I swear I remember being told that the JWT ECU advances the timing, but I could be wrong of course.

Any more input anyone?

 

I am sure that your JWT is advancing timing, I just didn't know exactly how it was doing it (i.e. advancing it 5 degrees accross the board or only advancing it at higher RPM....

 

Yes the JWT advances the timing. If you get one DO NOT ADVANCE THE BASELINE TIMING! You will end up w/ way too much advance. The timing mod you can do just advances the baseline timing reference but the JWT actually alters the timing curves.