HKS Turbo boost controller my car came w/ (help! what is this thing?)

[jsbenami]

My MKIII I bought last month rides pretty sweet. Its got 57k miles, and I am wondering if the HKS electronic valve controller for the turbo boost is after market or even working. It is mounted above the stereo in the center dash of the car. What went there before it was installed if its after market? Thing is, I cannot feel any difference between the low, med, hight buttons on it or when its on manual and its turned up all the way with the knob. There is also a turbo boost guage on the left side pillar. It appears to do much the same thing as the turbo guage built into the Supra dash board. The blue HKS valve that sits in the engine compartment has blue thick latex like tubes hooked up to a vaccum source and two going to the Turbo presumably to control it. It constantly emits this pulse buzzing sounds like its trying to do something and is not able. However the turbo deos engage with a semi loud air sucking sound, and both my guages read about 8 psi when its all spooled up.

On another note, the TEMS controller, is also HKS it sits near the emergency brake, that thing deos not look like an after market thing.....however again press any of the buttons for hard, med, soft ride control.....I don't feel any difference.
Anyone who's had similar things installed I'd appreciate your help so much. I'm not new to Supra's but new to Turbo I am.

[supranerd1987]

TEMS stands for the Toyota Electronically Modulated Suspension, controlling spring rates and damping. The variable spring rates are achieved by changing air pressure in the front and rear compressed air suspension units and the damping is altered by switching between two (Soarers) or three (Celsiors) damping modes in shock absorbers. The electronic part comes into play when these two variables are modulated on-the-go, depending on many conditions. Functions like "anti-squating" on acceleration and "anti-dive" on braking are part of the suspension control program, as well as automatic lowering of high ride height and firming of damping with increased speed.

[bgrieger]

Close, but not really. The full name of the acronym is correct, however, it has nothing to do with air or springs, and certainly does not alter the ride height as it pertains to supras. Damping is altered in each mode by changing the valving in the damper that the oil passes through. The factory had 3 modes - normal, sport and firm. Normal and sport were the factory 2 choices the driver could make, and the firm came on under full throttle accelerations from the line, hard braking over 80kph as I remember, and a certain degree of steering wheel input that I cannot remember off the top of my head.

The HKS controller had 3 buttons as I recall, and one was to override the system and set them to full firm. That my friend is a rare piece that 4 years ago people paid many, many hundreds of dollars to get their paws on. A very neat piece of Supra history, but most people now just get coilovers, as the price of springs, Tokico's and hte HKS controller add up to about that of a Tein Flex setup...if you can find the HKS controller for the tems to begin with.

The reason you don't feel a difference is probably that your dampers need replacement (that cadillac ride is not the way it is supposed to feel). Tokico makes an inexpensive (though the quality leaves a little to be desired) illumina II damper that works with the tems system, and Toyota has them as well. Noone else makes a TEMS compatible damper.

As for the EVC, HKS uses a stepper motor that may or may not be jammed. I don't remember the failure rate being all too high, but it's possible. I'd start by checking to see the vac lines are hooked up per the instruction manual. Look online for the instruction manual. It is possible that the 8 PSI is what it is actually set to, and the instructions will tell you how to set it. If the stepper motor is the problem, you can get replacement stepper motors off of Ebay from time to time, or from an HKS dealer as well, but you would likely be better off just replacing the HKS with something newer, such as a Blitz dual solenoid unit.

[jsbenami]

Thanks for the input, good stuff. The car deos NOT however have that 'Cadillac ride' thank goodness! Its actually somewhat stiff and at first I though perhaps my rear shocks are worn. Now I am not so sure. Perhaps the settings are more subtle and I have to really use the car a little bit more to actually feel the difference. I was however spoiled with the cadiallac ride by my 1985 Celica Supra. Its in good shape suspension wise but much less sporty and aggressive than the MKIII.

I believe that stepper motor is jammed, it deosn't sound right to me. Perhaps I'll replace the whole shbang when I've enough cash. But the only 2 things I care about it for now till I get the other things done like my expensive valve adjustment done and timing belt....is that I get my 8psi of boost and the Turbo is really working.
So the HKS EVC Tubo Boost Controller is definitley an aftermarket thing, but the HKS suspension is not I gather.

[bgrieger]

The HKS TEMS controller (the thing with the buttons) is aftermarket. The original TEMS switch in that location is a 2 button affair.

Toyota did not install any of these goodies from the factory.

The ride should quite noticably change from soft to full firm. If not, the shocks are not what they used to be, or the prior owner hooked up the controller wrong somehow.

[Jeeves]

Personally, even with brand new TEMS Struts, I've found TEMS to be almost worthless and a waste of money. When I do the struts again, I'll be going with the non-adjustable Tokico Blues most likely.

I can't believe people pay the huge amount for the HKS TEMS Controller. To me it's more bragging rights than function.

[jsbenami]

Agreed, I feel maybe a tiny little difference when I nail it off the line, and when I slam on the brakes on dry pavement. Otherwise I barely can tell if they are even working.

[bgrieger]

Agreed, the HKS tems controller is a bling part that is only desirable for it's rarity...I ditched TEMS for much more functional Tein coilovers a few years back, and would do it again in a heartbeat. Maybe one day I'll have done everything I want to the car and I'll get the EDFC for them too (basically a TEMS controller for the 16 way adjustible dampers...allows side to side or end to end independant adjustments etc).

Bob

[Jeeves]

I would rock a set of TEINS so hard if I had the option. Damn being poor and owning a mk3...

[bgrieger]

In the immortal words of Ferris Buller - "...If you have the means, I highly recommend it".

On the upside, Tein now has the SS graded coilovers. Basically a replacement for the discontinued HA, they come in at ~950, giving the price of spring/shock combos a run for their money. Even have IMO better spring rates than the Flex setups do.

[jsbenami]

Ok, now that I've had this car for a bit I've started to figure out this after market turbo boost controller. I've measured it with the aftermarket guage that can read past 8 psi and I've found that my settings are as follows:

low = about 6 psi boost
high = about 8-10 psi
manual with the dial cranked about 15!

I know this has probably been beated with a stick too, but how much past the normal conditions 8 psi boost can the car safely attain? I realize the higher you go the more risk to the bearings, and head gasket. Obviously it can do the 15 w/o blowing up, but I would think that should never be used or used once or twice a year. I'm probably going to do most of my daily driving in the 6 psi range. One thing I've learned with a turbo is that just about any light car with 150+ hp is going to pull ahead of you off the line at a stoplight or the track until your turbo boosts up, then you will probably pass. First gear stinks, this car requires allot of RPMs then it starts flying.
Of course I was spoiled as I used to have an NA 98 Camaro SS with 320 hp so maybe that's just the impression I'm getting. However the payoff in handling with the lack of the solid rear axle and smoothness of the suspension and engine is quite nice. If my 92 had the throttle responsiveness of my 85 Supra and the power of the turbo too that would be heaven!

[bgrieger]

Low - stock wastegate spring. Should be 6 psi. High appears to work. It is settable though, so that was the old owner's version of high. The car should have hit fuel cut at around 12-13 PSI. No fuel cut, you have a leak in the accordian hose, or a lexus AFM in place, or the gauge is wrong.

Now, up to fuel cut is considered quite safe to do all day long. Anything more is where stock parts begin to break. You might consider an HKS sport catback (stock appearance, quiet, but 3 inch flow), a megan or other downpipe, a walboro or just a new Toyota fuel pump and a K&N filter if you only intend to run under or up to fuel cut. Would net you upwards 250-275 rear wheel, and feel much like the Camero did on the highway.

[Jeeves]

Originally Posted by bgrieger

Low - stock wastegate spring. Should be 6 psi. High appears to work. It is settable though, so that was the old owner's version of high. The car should have hit fuel cut at around 12-13 PSI. No fuel cut, you have a leak in the accordian hose, or a lexus AFM in place, or the gauge is wrong.

Now, up to fuel cut is considered quite safe to do all day long. Anything more is where stock parts begin to break. You might consider an HKS sport catback (stock appearance, quiet, but 3 inch flow), a megan or other downpipe, a walboro or just a new Toyota fuel pump and a K&N filter if you only intend to run under or up to fuel cut. Would net you upwards 250-275 rear wheel, and feel much like the Camero did on the highway.

At the same time I ran 9psi w/mods and popped the head gasket.