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TPS acting up. Test light doesn't change

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Old 05-29-07, 08:24 PM
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TPS acting up. Test light doesn't change

Hey guys, I tried adjusting my TPS the other day and when I plugged in the test lamp it showed that it was already set correctly. I messed with the screw and the test lamp still showed up as it was still set correctly.
I am just wondering if my whole TPS was messed up and if I need to buy a new one.
Thanks guys
Old 05-29-07, 09:43 PM
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how do u know its TPS? what symtomps u having?
Old 05-29-07, 10:13 PM
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I am having a really rough idle

I was doing a tune up and plugged the lamp up to the connector and i messed with the screw to see if it was really set correctly or just acting up, and there was no responce to the light. One light stayed on the whole time no matter what
Old 05-30-07, 08:52 AM
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Try this just for giggles and grins. Set your TPS using the resistance method. Engine warmed up ignition off. You should see 1000 ohms plus or minus. Once you've got it set this way, go back and see if only one test lamp lights up. Then, ground your initial set connector and adjust the idle to 750 plus or minus 50. Take the car out for a spirited 15 minute drive and come back and verify the resistance settings. If this doesn't solve the problem, you may have a bad TPS or something else affecting idle like a vacuum leak.
Old 05-30-07, 09:27 AM
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Originally Posted by willardgoobody
Hey guys, I tried adjusting my TPS the other day and when I plugged in the test lamp it showed that it was already set correctly. I messed with the screw and the test lamp still showed up as it was still set correctly.
I am just wondering if my whole TPS was messed up and if I need to buy a new one.
Thanks guys
Definately check your vacuum lines... Make sure they are all on and there are no cracks... The easiest way I have found to search for them being off or cracked is to hold the throttle at about 2k or so and search for a whistling sound... If that does not check out then go through the TPS stuff... Good luck...
Old 05-30-07, 11:07 AM
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Thanks, I know I have a vacuum leak somewhere. I've narrowed it down to around the PS pump. I can't figure out the exact line though. Its kinda frustrating. Would that cause the tps to not respond though?
Old 05-30-07, 11:30 AM
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im having the same problem with my tps, only once adjusted, it shows one light, then i giv it full throttle, and the tps light goes out, but then when i release, its all sparratic, like it sometimes shows both lights lit, or none, or just one... i think it is my tps, but im unsure...
Old 05-30-07, 02:56 PM
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TPS test & set:
Using test lights or voltage at idle readings will get your idle setting perfect, but you could still have a worn out TPS resistor.
-The golden test:
Unplug the TPS connector.
Clip a cheap analog (needle type) VOM on the orange & black pins.
Set it to the 1K Ohms scale.
Hold off the throttle & work the short range TPS plunger in & out.
You should see a smooth sweep from ~0 to ~5K ohms.
Any bad spots or drop outs in the stroke - it's bad & will give fuel cuts at part throttle.
(Before you toss it, try spray contact cleaner between the sleeve & plunger.)
- Then set it:
Find the fast idle (warm-up) cam & push it back so the throttle sits on the hard idle stop.
Adjust the setting to 1K ohms.
While holding off the fast idle cam, open & close the throttle a few times to see that the 1K setting repeats.

The S5’s have a second (long range) TPS that is self adjusting.
You shouldn't have to mess with it.
Its job is to tell the ECU how to run the MOP.
Old 05-30-07, 03:51 PM
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So if i get fuel cuts at part throttle it indicates that my tps is bad?
Is it noticeable when driving?
When I am driving at part throttle, my car seems to jerk up and down rpms.
Old 05-30-07, 03:57 PM
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[QUOTE=SureShot;6992443]TPS test & set:

Find the fast idle (warm-up) cam & push it back so the throttle sits on the hard idle stop.

--

Back when I was a noob around these cars I had trouble adjusting my TPS because of this. The thermo pellet which expands and releases the cam for the fast idle wasn't releasing. I then took a closer look and noticed the throttle plates were not completely at idle.

I hope it's as simple as that.
Old 05-30-07, 06:14 PM
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Originally Posted by willardgoobody
Hey guys, I tried adjusting my TPS the other day and when I plugged in the test lamp it showed that it was already set correctly. I messed with the screw and the test lamp still showed up as it was still set correctly.
I am just wondering if my whole TPS was messed up and if I need to buy a new one.
Thanks guys
Was the engine HOT or was it a cold engine? It makes a difference
Old 05-30-07, 06:30 PM
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Originally Posted by willardgoobody
Thanks, I know I have a vacuum leak somewhere. I've narrowed it down to around the PS pump. I can't figure out the exact line though. Its kinda frustrating. Would that cause the tps to not respond though?
If you *KNEW* you had a problem.... Why did you think to adjust the TPS?

Usually I like to try all of the obvious stuff first before I go messing with something as touchy as the TPS.

Go fix your vacuum leak... THEN start playing with the TPS.
Old 05-30-07, 09:40 PM
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Originally Posted by HAILERS
Was the engine HOT or was it a cold engine? It makes a difference

yeah i did all the steps i needed to.


Now im just going to try to figure out which hose it is, that fan makes it hard to hear the noise though.
Old 05-30-07, 10:03 PM
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Originally Posted by willardgoobody
yeah i did all the steps i needed to.


Now im just going to try to figure out which hose it is, that fan makes it hard to hear the noise though.
Spray starter fluid around where you think the leak is.. if the engine rev's up, thats where the leak is.

Thats one way. The other way is to replace ALL of the hoses.
Old 05-31-07, 08:00 AM
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Originally Posted by willardgoobody
So if i get fuel cuts at part throttle it indicates that my tps is bad?
Is it noticeable when driving?
When I am driving at part throttle, my car seems to jerk up and down rpms.
It's an absolute test. If the meter needle moves smoothly up & down as you work the TPS plunger in & out - it's good.
If the needle jumps around as you slowly move the plunger - it's bad.

link to short video of a good test

link to short video of a bad test

Sometimes spray contact cleaner like CRC QD or 2-26 will fix it.


Another thing that can cause uneven cruise power is a crack in the inlet duct.
It can be squeezed closed when your testing for a leak, then can pull open as the motor works on the mounts under load.

Last edited by SureShot; 05-31-07 at 08:13 AM.
Old 05-31-07, 11:08 AM
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Yeah I'm thinking about just doing all of the hoses, its pretty cheap to get it by the foot from mazdatrix.
Ill try to test it soon. I hope my meter will work for it.
Thanks again guys!
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