Good Morning Folks,

I'm having a very minor issue but i'm very new to this car so I want to get some second opinions.

My car runs fine and idles fine, it is however throwing a check engine light when idle. Pulled the code which pointed me to the TPS.

Found if I put my foot on the throttle just the littlest bit the light goes out. Checked the service manual for the expected resistance on the switch and i'm getting lower than documented readings from my multimeter.

Could the lower than documented resistance levels indicate that my TPS is starting to go back? The service manual says that resistance increases as you press the throttle so i'm thinking this is why a slight press of the throttle makes the light go out.

BTW, doing a throttle adjustment didnt seem to effect the check engine light in anyway.

--m

 

on S5's, if you have TPS problems, that generally means the TPS is going bad. You can adjust it as much as you want, but you'll still have minor drivability problems that you wouldn't have with a fully functioning TPS.

 

Yeah I figured as much. Checked Mazdatrix and they want 360 bux for a new one. Holy Cow.

 

Yeah, the S5 TPS's are hella expensive. Check on these forums and on EBAY and you might be able to find a used one that's still fully functional.

 

If the car is not exhibiting any other obvious symptoms and is running fine. just drive it. The TPS is not a particularly critical part as long as the engine is running fine.

 

can someone confirm on this? i too am having the same problem and want to know if its just throwing a CEL because the tps is not in spec. like he said, if there is little pressure on the tps the light goes away. i confirm this when i gave the tps button a little push enough so that when i let go its compressed just a bit so that the light goes away. i also dont ave this problem all the time (like when i let off the gas fast) and i have no hesitation at all throughout the rpms. does this still mean bad tsp or do we need to adjust elsewhere?

thanks

 

But not on S4's? The S5 TPS is the same as the S4, only there is two plungers instead of one.

 

The S4 is basically an on/off switch. Either the throttle is closed or it is open. The S5 is a combo on/off switch and full range TPS. It sends a different signal through out the whole range of the throttle opening.

The second plunger on the S5 is compressed gradually. The first is just like the S4.

BC

 

if a CEL light is coming on, then your TPS is probably bad.

When I say minor problems, I mean light bucking and/or light pulsing of the idle. If you're tripping CEL lights, something's off.

 

My brand new TPS does the same thing, never throws a CEL when I'm on the gas, but soon as I let off the gas and using the motor to slow down the car coming to a stop or going down a hill, the CEL comes on. I checked the code and it is the "full ranged fixed at 20%" TPS error code. I haven't really tried to dial it in with a multimeter, becuase I'm not really sure how to do it. I done the light thing and I always have at least one light on.

I have no other CEL light other than the TPS, so I just said whatever and been driving it that way for a month with no issues...just drive it.

 

take your TPS off. Does it have any sticking issues on the full sensor?

 

a trick i used on my 87 glx when the tps was on the way out.
go to your local electronic store and get some pot cleaner, i use cailube blue.
give it a shot in the side of the plunger on the tps, move the plunger through the full range f or about 30 sec, let sit for a couple of minets, reinstall.
my tps was completely hooped, but this trick got me around for a couple of days.
i use this stuff when i am doing mantinence on my mixing board, works great on the faders, if they have been getting dirty and scratchy, it makes them sound like new. a tps is a linear pot just like a fader, so what the hell.

 

If the TPS readings are out of spec, then the TPS is bad, thats what specs are for.

You can certainly run it with a bad TPS if you like, but I always hate that kind of non-solution. I can't tell you how to spend your money, but personally if my TPS is broke, I fix it.

If the TPS has a dead spot, it could lean out if the ECU is "seeing" a closed throttle when it really isn't. How do you really know how bad the TPS is, unless you get an ocilliscope on it, it could be tough to get an accurate look at what the ECU is "seeing" from the sensor.