gear_grinder

iTrader: (4)

Hi, ive got a 87 turbo. i was checking/adjusting the TPS due to some idle/running issues. my TPS is within spec at WOT (5.3K ohm or 5.4v), but sits at about 3k ohms or about 3.5v @ closed. The car has emissions blocked off and thermowax removed and i have the adusting screw turned as tight as posible to try and bring the TPS into spec at closed throttle.

is my TPS out of spec? thankyou!

PS, i'm waiting for my intake pressure tester to come in the mail (should be here tomarow)

ifryrice

I generally aim for 1k ohms, move the plunger on it by hand and see if the sensor itself will read low enough. Is your throttle plate stuck open at all or is everything closed properly?

gear_grinder

iTrader: (4)

if you move the plunger by hand, you can get it to 1kohm or about 1v.

the throttle is closed, not stuck open in anyway, and the adjuster is maxed.

ifryrice

Has it worked previously at all or always been this way? Could be a bent linkage

calpatriot

If you can get to 1k ohm by moving it by hand, sounds like the sensor is ok but the linkage is out of whack.

Tell me about this intake pressure tester you are getting?

gear_grinder

iTrader: (4)

the pressure tester is unrelated to this thread about the TPS, but i've been in a long drawn out battle to get my car to idle and run properly. the culprets are ether the TPS or a vac leak somewhere due to the way the car acts.

i bought the pressure tester from "silicon intakes"

the car acted normal at one point with a "bad" tps (8kohm @ wot)

ifryrice

If you're sure the plates are proper, then just bend the linkage to get it in range. I've had to do that on a couple of fubar'd vehicles. (Make sure the sensor itself didn't get pushed back out of it's bracket causing it not to contact fully).

HAILERS

On a more or less stock car the engine needs to be hot to set the TPS. Has to be HOT due to the water thermowax will hold the linkage open a bit til the water gets hot.

Linkage being held open a bit also means the TPS will be having its plunger pushed in a bit til the water gets hot.

This minor problem can be overcome by lifting up on the linkage/screw that rests on the water thermowax's piston, which in turn makes the throttle linkage go full closed..........which in turn lets the TPS piston extend more. Moer TPS plunger extension means the voltage output will decline a bit.

A cold engine's TPS will read somewhere in the 2-3vdc range (that's a General figure), but once the engine gets fully hot, the TPS will read approx one volts dc if set right.

See the attached jpg for the place to Lift up on to fully close the throttle linkage on a cold/warm engine.

That Might be your problem, might not be your problem.

The second jpg shows the throttle stop screw and the Gap that exist b/t the stop screws end and the throttle linkage. That gap will close when the engine gets hot OR you lift up on the linkage in the first jpg attached.

When the gap closes, then the linkage and throttle plates are fully closed and the TPS can now be set right.

ifryrice

You silly goose.... slackin' in your old age! (Good info, btw, can't tell you how many times i've seen people forget that)

gear_grinder

iTrader: (4)

i will take a vid if i get time, and show you exactly what i mean.

just startn

iTrader: (33)

Hailers, seens how this is the most recent tps thread....

My microtech screen says the tps is open 20%. my throttle is all the way closed and my tps is all the way closed. i noticed it today, i haven't really messed with it to much

ifryrice

Recalibrate it. (Once warm, unless thermowax removed, of course.)

HAILERS

Some aftermarket devices show/display the percent TPS differently.

A Zeitronix display Will show it a zero percent at idle and foot off the gas, when the TPS is set right.

A RTEK2.1 will show it as 20% at idle and foot off the pedal and TPS set right.

Frankly I forget what my SAFC showed the TPS percent at when set right and foot off the pedal.

What it is, is that your TPS has a voltage range of 1 to 5 vdc. One volt is what percent of 5??? It's 20% of 5 is the answer.

A properly set TPS on a stock RX7 ECU is set to output 1vdc. So you can see where the 20% figure comes from.

MIcroTech might and probably is looking at the TPS in that fashion...i.e the TPS has a voltage range of 1-5 vdc and when set right is set to 1vdc, therefore it's at 20%.

Something like that. Always remember, if you have the water thermowax on the throttle body, that percent figure will read high til the engine water temp gets up to operating temp. That high reading is normal and is reading right due to the cold engine temp.

ifryrice

They have a calibration that you can trigger which sets 0% at the lowest read voltage, and 100% to the highest read voltage rather than using a static translation. It's been a while and I forgot how to reset it, but it's in the MT manuals.

dennis blackstone

if your tps is set at 1300 what are the ill effects

HAILERS

I'd inquire on the MicroTech forum. I know zip about MicroTech. I just know about the stock ECU and the RTEK2.1 and some memory of the SAFC and a lot about the Zeitronix.

I think you question is MicroTech peculiar as post #14 says.

On stock, I've see something like .9vdc to 1.1vdc and no ill effects. I don't do the ohm it out bit myself, but the ohms figures should about match those two vdc figures.

john ward

iTrader: (7)

tps cal in options screen. hit mode scroll up or down to zero

HAILERS

You might remember, that on a series four car, the TPS is at 100% just at the point the secondary throttle plates JUST start opening.

That's a loooooooooong time before actual full throttle is achieved. Something like only 18* PLA.


I don't know if MicroTech takes this into account ...or not.

gear_grinder

iTrader: (4)

im not worried about the WOT on my car, its the fact that it sits at 3kohms at closed throttle (IE 60% if you go by the 1v=20%)

HAILERS

I don't know about the rest of the series four TurboII cars built, but on mine, when you screw the TPS screw clockwise the TPS plunger EXTENDS making the output go UP.

That's in reference to these words "i have the adusting screw turned as tight as posible to try and bring the TPS into spec at closed throttle."

Personally I'd connect all plugs.............backprobe the green/red wire on the harness side of the TPS connector with a digital meter on dcvolts............unscrew the TPS screw til it's almost falling out............key to ON and then turn the screw clockwise til the TPS output is one (1) vdc. Then put up for the night and watch the boob tube. Done


Maybe before doing the above, back off the TPS screw, then screw it in while watching the plunger of the TPS. It WILL extend. Just like stepping on the gas pedal.

just startn

iTrader: (33)

My screws unscrewed as far as it can go and the plunger is all the way in as far as it can go. my microtech has always has been at 20% but something about it just clicked in my head as to why it's 20%. Im going to have to post it on the microtech forum.

gear_grinder

iTrader: (4)

um, mine tightens and pushes the stoper farther into the button on the TPS

HAILERS

I've three cars and numerous spare throttle bodies, and the way things work is:

Turn the TPS screw clockwise and the TPS plunger extends causing the voltage output to go UP.

Turn the TPS screw anti clockwise and the TPS plunger goes back into the TPS housing more and the voltage output declines.

That's for a series four TPS. RX-7. Turbo.

just startn

iTrader: (33)

correct

hypestar1983

i think the safc does the same thing on my car and it reads 0% with pedal off and car warmed up, and it reads a low throttle percentage when dead cold until warmed up. 88 non turbo.