87 S10 blazer TPS check


Old 09-25-07, 10:39 PM
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Join Date: Feb 2007
Location: new york
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87 S10 blazer TPS check

I have an 87 Chevy s10 blazer 4x4 with the 2.8L v6 I have been having hesitation problems with her. I checked the TPS with an ohm meter according to Haynes Manuel. It says that the ohms reading should go up as the throttle is opened. Mine does just the opposite it's high when closed & goes up when opened? I even took my probes from my meter & reversed them but still got the same reading. Which is just the opposite than the book says & many web pages say. Does this mean I have a bad TPS?. Has anyone heard of this any information would truly be appreciated!. Thank you!
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Old 09-26-07, 03:49 AM
Join Date: Dec 2001
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sounds like the manual is wrong as resistance should go down as the throttle is opened, however they are probably most commonly tested by checking the voltage with the key on and the tps connected the voltage should increase as you open the throttle.
Old 09-26-07, 03:17 PM
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Off Google:

"Throttle Position Switch - Information, Troubleshooting ...This will test the idle speed contact. With the throttle closed, the ohmmeter should read zero (0) ohms. With the throttle open, the ohmmeter should read ..."

Interestingly, this snippet from a long description on the TPS and testing, it says the quote above, - but down (or up) one paragraph it says the opposite when testing between a couple other contacts.

So maybe it has to do with exactly what test on what contacts you are performing!

[Note that in first paragraph quote, where the 3 dots are at end of sentence, the article says "infinity".]

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