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2G Throttle Position Sensor bad?

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SPEEDY

20+ Year Contributor
614
0
Apr 7, 2002
Asheville_NC
OK... I just had my computer scanned for a check engine light that kept coming back on everytime I reset the computer thinking it was because of my test-pipe. It said the TPS was bad. So... now as I type I'm on the hunt down for one, but anyways the question that I have is, what is the effects of continuing driving the car with TPS being bad? Will it hurt anything severe or what? Thanks!!!!
 
If the TPS is bad and the voltage is off . It will affect your idle and overall drivablility since it is not measuring the throttle posistion correctly.
 
Originally posted by L2RTSiAWD
If the TPS is bad and the voltage is off . It will affect your idle and overall drivablility since it is not measuring the throttle posistion correctly.

But... is it a type of failure that if I were to keep driving the car, that the car would completely break down and leave me walking. I mean I definately don't want to take the chance if it were to leave stranded on the side of the road somewhere. Thanks!!!

On a side note...my a/f ratios are definately acting strange, I have the blue wire mod on my s-afc and my volts sometimes register and sometimes they don't, or they are very low or erratic.

My O2 sensor is brand new. I put in a brand new one when I did my turbo swap back last February.
 
Last edited by a moderator:
Originally posted by mitsutuner
this sounds a lot like the crankwalk problem, has you motor been redone yet to fix this? gregorio
What do you mean crankwalk problem? This isn't about crankwalk.

My check engine light was scanned and it gave a P0120 code which is a TPS malfunction. It says here in my Chiltons manual that the TPS is an electrical resistor which is activated by the movement of the throttle shaft. It is mounted on the throttle body and senses the angle of the throttle blade opening. The voltage that the sensor produces increases or decreases according to the throttle blade opening. This voltage is transmitted to the ECU where it is used along with data from other sensors to adjust the air/fuel ratio to varying conditions and during acceleration, deceleration, idle, with wide open throttle operations.

This would probably explain why my A/F ratios are acting funky. But I still want to know if it will leave me stranded or do some kind of major engine damage if I were to keep driving it till my other TPS gets here.

My EGT's are very normal 850c at the top of third, and I'm currently running about 18 to 19psi on my FP Big28.
 
Last edited by a moderator:
I don't suggest boosting at all till you fix it. Normal driving should be ok for a while. It has nothing to do with CW so don't worry.
 
sorry if I threw you off with the crankwalk, just a wild guess based on my limited 2g expereince,which is what I read on the web, and what I read is that the TPS tries to control idle speed in conjunction with the speed sensor, which is located next to the crank pulley and it malfunctions when the crank moves laterally in the block-the crankwalk problem. To find out more, google search "dsm 4g63 crankwalk", a 2g phenomena resulting from sloppy mitsu manufacturing process--gregorio
 
Originally posted by L2RTSiAWD
I don't suggest boosting at all till you fix it. Normal driving should be ok for a while. It has nothing to do with CW so don't worry.
Thanks for the info and advice.

Originally posted by mitsutuner
sorry if I threw you off with the crankwalk, just a wild guess based on my limited 2g expereince,which is what I read on the web, and what I read is that the TPS tries to control idle speed in conjunction with the speed sensor, which is located next to the crank pulley and it malfunctions when the crank moves laterally in the block-the crankwalk problem. To find out more, google search "dsm 4g63 crankwalk", a 2g phenomena resulting from sloppy mitsu manufacturing process--gregorio
No problem! Thanks.
 
hey mine is bad too and someone told me that i have to replace the throttle body with do i really need to do that
 
I have that same problem:

P0120: Throttle Position Circuit Malfunction
Probable Causes:
- Throttle Position sensor failed or maladjusted
- Open or shorted throttle position sensor circuit, or loose connector
- Closed throttle position switch ON malfunction
- Closed throttle position switch signal wire shorted
- Engine control module failed

The weird thing is, this didnt go on until I installed my Dejon Tool Upper *L* & *S* (from throttle body to smic), cone filter, hks ss bov (vented to atsmopshere at the moment). At first it never went on, but after doing one hard run, going past 4000rpm in first gear.. the moment i shifted, the CE light went on. Weird, i dont know how those mods can make the TPS CE light go on.

I still have 200 miles left until my warranty is over. I'm planning to bring it to satan, but now i have mods. don't know wat to do. and i dont want to put all the stock ic pipes back on. grrr

wat to do, wat to do.
 
i'm not sure how to quote, but to answer speedy's first question, a bad TPS could give fluctuating pedal readings despite constand throttle position. when i bought my 91 the bad TPS would cause occasional rich shots of fuel. the entire car would buck like the misfire from hell, and i was sure something expensive was violating something even more expensive in the engine. tsall good now though, the TPS was an easy fix.
 
Originally posted by markmakeitso
i'm not sure how to quote, but to answer speedy's first question, a bad TPS could give fluctuating pedal readings despite constand throttle position. when i bought my 91 the bad TPS would cause occasional rich shots of fuel. the entire car would buck like the misfire from hell, and i was sure something expensive was violating something even more expensive in the engine. tsall good now though, the TPS was an easy fix.
Thanks for the info! My car hasn't started bucking as of yet, but at idle it has a mis-fire here and there that bugs the crap out of me. I hope this cures that problem also. I know it will cure the CEL problem, but I'm hoping this mis-fire I get at idle every now and then will go away to. I've been thinking the TPS has had something to do with that problem, even though I had this little mis-fire problem before my CEL came on. I'm thinking that this has been a slow process of the TPS going south on me since I had the mis-fire problem before the TPS actually got bad enough to trigger a CEL.
 
My car did the same mis-fire deal, then the Check Engine Light would come on. I cleaned the TPS and it seemed to do much better. It stopped mis-firing, but every once in a blue moon the CEL will turn on for a few seconds (but the car will act completely normal, turbo and all). Can't hurt to try cleaning it before shelling bucks out can it?
PS-Is the TPS a common problem for 1g Eclipses? And what else is common
 
Originally posted by Fishe
My car did the same mis-fire deal, then the Check Engine Light would come on. I cleaned the TPS and it seemed to do much better. It stopped mis-firing, but every once in a blue moon the CEL will turn on for a few seconds (but the car will act completely normal, turbo and all). Can't hurt to try cleaning it before shelling bucks out can it?
PS-Is the TPS a common problem for 1g Eclipses? And what else is common
Well....my car is a 2g so I really don't know for sure if it is a common problem or not with the 1g's. How or what did you use to clean the TPS with? Thanks!!
 
Originally posted by talonjunkie
hey mine is bad too and someone told me that i have to replace the throttle body with do i really need to do that
I personally wouldn't think that you would have to replace your throttle body in order to change a TPS sensor out. Atleast it doesn't look that way in my cheesy Chilton's manual.
 
Originally posted by SPEEDY
I personally wouldn't think that you would have to replace your throttle body in order to change a TPS sensor out. Atleast it doesn't look that way in my cheesy Chilton's manual.

you don't have to replace the throttle body. the TPS is held on by two screws. the only thing is that one of them is hard to get to because of the fuel rail blocking access to the lower one.
 
Originally posted by RamenPride


you don't have to replace the throttle body. the TPS is held on by two screws. the only thing is that one of them is hard to get to because of the fuel rail blocking access to the lower one.
Agreed! Our 4g63 motors just have an electrical connector and two phillips head screws. I'm not to familiar with the Talon ESI motor setup, but I still wouldn't think that Talonjunkie would have to replace or remove his throttle body just to swap out the TPS, unless of course it makes the job easier by doing so.
 
Fishe said:
My car did the same mis-fire deal, then the Check Engine Light would come on. I cleaned the TPS and it seemed to do much better. It stopped mis-firing, but every once in a blue moon the CEL will turn on for a few seconds (but the car will act completely normal, turbo and all). Can't hurt to try cleaning it before shelling bucks out can it?
PS-Is the TPS a common problem for 1g Eclipses? And what else is common

just ran into this problem. how can i clean it? i need details on where to clean and what to clean it with. thanks.
 
Nayr747 said:
Here's how to clean it: http://www.plymouthlaser.com/tbody.htm :thumb:

Edit: Sorry, thought you were talking about the throttle body. Also, does anyone know where to get a new TPS and how much they are?

Classifieds..anybody fully parting out their car. DSMTrader, or I'd suggest Mitsu. Graveyard. They usually have pretty much any part. I got a TPS from them for 25 bucks. Used, but it works.
 
I have the same idle problem, strated last year. I've replaced parts, TPS and o2 sensor, but didnt work. When I replaced the TPS, it acually made the idle worse, to the point where I couldnt even drive the car. I removed the TPS and have been driving it since, havent had any problems, other than high idle and the occasional stalling.
Jason
 
Nayr747 said:
Not to hijack this thread but does anyone know an easy way to remove the electrical connector from the TPS on 95-99 engines? I can't get the bottom clip off. :cry:

Just take like a screwdriver & push the tip into the metal clip to kinda lift it up while you pull the harness off.
 
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