Has anyone been able to resolve the "hunting" that occurs under light throttle with the purple dragon torque convertor installed?

I have adjusted the TPS and TV cable which reduces but does not eliminate the problem. It is somewhat anoying as the engine will jump and down about 500 rpm until a higher speed satbilizes the hunting.

I was told that there is nothing that can be done as it is because the size of the convertor is smaller, but I find that rational difficult to understand or believe.

If you are consdisering the torque convertor mode, make sure you are aware that this may occur, as "normal drivebility" as claimed is simply not the case.

By the way, this is the SECOND purple dragon I have put in and they both caused the transmiision to act this way. The factory unit does not.

Any input is appreciated. Thanks!

93 SC400

 

WHo diagnosed the problem as being TC related? I have the purple Precision industries TC from Swift, and have never had any problems like you described. Are you sure its not ignition related?

Sounds fishy to me, are you sure they didn't mess something up when installing the TC?

I'd look into it a little more closely.

Keith

 

Heh, I was getting worried there as I am interested in the TC. But hey, what does he mean "the hunting?" Are you sure it's not the usual that you get when high stall TC?

 

Actually Keith, I explained the situation to the gentleman who is selling the ECU upgrades (Chris), and that was his reply to me (convertor size). I was hoping the ECU upgrade would have some way of controlling the shift/overdrive engagement points.

I am able to get most of the hunting out by adjusting the TPS potentiometer, but I am not sure where the ideal setting is. I am wondering if the TVS cable needs to be fiddled with as well. There is absolutely nothing wrong with my ignition, that I am sure of. The problem only occurs when the gas peddle is backed off, and you are at a lower speed, say 40mph. The tach will bump up and down about 500 rpm until the tranny or convertor "stabilizes". Maybe the CPU needs to "learn" for a few hundred miles, but the problem is only at lower speeds, and only with light or no throttle. A little more pressure on the throttle clears it right up.

Thanks for you input though, someone must have crossed this bridge before..... until then, I will just need to keep fiddling with the TPS and/or TVS cable.

Bob
93SC400

 

Yeah, I have always noticed cars that do that. We have a Maxima, and it's not the most "dialed in" car on the road.. it tends to hunt for the right gear under certain conditions, always has. I personally won't install a torque convertor on my car because I don't really want to spend the money on it, I don't use it as a drag racer, and I just don't care that much. I have enough trouble already with the tires burning during my normal (if you can call it that ) driving. And I have 18x9.5 inch rear wheels!
Problem is that once you start really messing with the internals of a car like that you end up sacrificing the tuned nature of the car, which is what gives the Lexus a big advantage over other makes.

 

not sure if this is the same as your "hunting" but if i'm driving up a slight or large incline at 40mph, with the overdrive off, and the accerelation stable to keep 40mph, my car seems like it want to shift (by shift i hear it and i feel a slight kick down and up though no change in rpm). it's only slight so maybe by putting in the tc, it amplified what was already stock? oh yeah, my auto transmission is stock.

 

928, who did the converter install? I would not consider that to be normal for the Precision converter. I can see how the throttle valve cable would affect your 'hunting,' but the throttle position switch won't directly affect what gear the trans chooses, so if that seems to be lessening the condition, I would look further into that as opposed to the trans itself. Also, a word of caution. The TV cable affects line pressure within the trans, and playing with it too much can damage the unit, take it back to the installer and have him make it right. If you want, you can reach Precision at 901-466-0267 www.converter.com webmastr@converter.com