is my TPS sensor bad or going bad ?

8

85cleangtvert

Member

May 19, 2005

103

1

18

Oct 10, 2005

#1

• Oct 10, 2005

• #1

sometimes when i start my 88 5.0 sitck, it will run way to fast. around 2 rpm...when usually it is around 1. it is tuned correctly because I just set the timing and fuel the other day, and it was running good after i did that. I also cleaned the IAC. the problem seemed to go away. but still sometimes it does it as it did tonight, and seems to be getting worse. it still drives good but it is like it is driving it self and needs to calm down, but wont. the idle will just go up for no reason. up to 2 1/2 rpms... i have read that this could be a bad tps. i tried to set it the other day. I got it as close to specs as I could, which was about .89, I couldnt get it to go any higher. what do you guys think?

 

LX302

Stanger

Founding Member

Feb 29, 2000

728

6

19

Bethlehem PA

Oct 10, 2005

#2

• Oct 10, 2005

• #2

Did you clean the throttle body? That might be giving you the rpm hangup.
.89v is fine unless you want to elongate the slots on the sensor. But did you do a sweep test when you were checking the TPS? You want to open the throttle when you have the voltmeter hooked up, and see if it incrementally goes up around 4.5V., but my bet is in the throttle body or the engine harness connectors. Disconnect them and clean and use di-electric grease before reconnecting.
I'd also scan for codes while your under the hood.

 

1

1990 HOSS

Member

Oct 9, 2005

53

0

6

Carnesville, Ga.

Oct 10, 2005

#3

• Oct 10, 2005

• #3

I read somewhere the other day on the internet where you can drill out the holes a little to allow more adjustment of the TPS.

 

srothfuss

Last night I stabbed the same guy 7 times in a row

Oct 17, 2004

1,796

3

0

Woodward Ave.

Oct 10, 2005

#4

• Oct 10, 2005

• #4

Symptoms of a bad TPS:

When you lift off the throttle, the RPM's increase as you shift.

When you are costing to a stop / stopped your idle hangs above it's normal setting

A true indicator: If you experience these two problems and simply turning off the car / and back on cures it... than the TPS is suspect.

 

8

85cleangtvert

Member

May 19, 2005

103

1

18

Oct 10, 2005

#5

• Oct 10, 2005

• #5

yes, i cleaned the throttle body the other day when i was tuning up the car. it looked good and opened and closed nicely with no hang ups. the tps went up to 4.30 maybe higher but it looked as if it was working cool. where are the engine harness connectors? why would it be them? i have scanned for codes and i really hate the beeping code reader we have. i have been meaning to buy one that shows it digitally. my car throws codes so i need to check that out.

 

8

85cleangtvert

Member

May 19, 2005

103

1

18

Oct 10, 2005

#6

• Oct 10, 2005

• #6

id say yes to those symptoms, except turning off the car and restarting it doesnt always get it to go away, but often makes it better or more tolerable to drive. and i also just bought a code reader (digital) for 35 bucks so I should be getting it in the mail this week some time hopefully.

 

jrichker

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Mar 10, 2000

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Dublin GA

Oct 10, 2005

#7

• Oct 10, 2005

• #7

See http://www.members.tripod.com/sparkplugs/idle.htm for some help on your surging idle.

This site points to bad TPS sensors as being the culprit in the surging idle that goes high and sticks until you shut off the engine.