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Topic: 1982 crossfire tps

in Forum: C3 Engines

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1982 crossfire tps (1/6)
9/2/09 11:16am

mitch
Former Member
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STEGER, IL - USA

Vette(s):
1982 Charcoal T-Top Charcoal int. ,1977 LIGHT BLUE T-TOP DARK BLUE INT.

Joined: 9/25/2007
Posts: 128

On the 82 we are gitting code 22 from the computer. Whick is TPS circut open. I am getting 5.36 v on the circut when it is closed, all data says it should be less thank 1v closed. we are getting over 10v when throttel plate is open, all data says should max out at 5v. Any ideas as to what may be going on. thanks in advance Mike.

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1982 crossfire tps (2/6)
9/2/09 1:17pm

Adams' Apple

Lifetime Member
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 20128

The TPS should have less than 1volt closed...usually you'll see around .70 or so at closed throttle.
At wide open, you should see around 4.5, or whatever the reference voltage is, usually 5 volts.
So, with the connector unplugged, you should see 5 volts(or close to it) on one terminal(key on, engine off). One terminal should be a ground, and the other terminal is the signal going back to the ECM(signal return). If you have a 5v reference, and a good ground at the connector, plug it back in, and test the signal return voltage, which will be the other terminal. At closed throttle, the TPS grounds the reference voltage, bringin it down to around .70 volts, and that voltage will(should) raise as you move the throttle up to WOT, giving a final reading of around 4.5.
If the return signal does not read correctly, the TPS is bad, BUT....you have to make sure there is a good 5v reference, and ground first.
There's no way to have anything over 5v on the TPS at any time unless something is shorted to power in the circuit....or possibly the ECM is bad...

hth

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1982 crossfire tps (3/6)
9/2/09 1:54pm

mitch
Former Member
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STEGER, IL - USA

Vette(s):
1982 Charcoal T-Top Charcoal int. ,1977 LIGHT BLUE T-TOP DARK BLUE INT.

Joined: 9/25/2007
Posts: 128

Have 5.1 v when you test between the + and - on the harness off the tps. the signal wire has nothing so one would assume the tps is bad. Thanks agian for your help.

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1982 crossfire tps (4/6)
9/2/09 9:44pm

Adams' Apple

I still don't understand where the 10v is coming from. You have a 5volt reference, and a ground...where the heck did the 10v come from? That's just weird!

The TPS can't make voltage....
Perhaps you have a ghost in your machine.

Let us know how it reads with a new TPS.

______________

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1982 crossfire tps (5/6)
9/2/09 9:49pm

kstyer

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CUYAHOGA FALLS, OH - USA

Vette(s):
1975 C3 Red, T-Tops, Black Interior. All I need is time and money! Getting there!

Joined: 12/2/2003
Posts: 6424

Double check your grounds, not just the TPS ground, but from the engine and the computer as well. That 10 volt is just too odd.

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1982 crossfire tps (6/6)
9/4/09 3:29pm

mitch
Former Member
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STEGER, IL - USA

Vette(s):
1982 Charcoal T-Top Charcoal int. ,1977 LIGHT BLUE T-TOP DARK BLUE INT.

Joined: 9/25/2007
Posts: 128

Ok, still waiting on parts. Napa had one for $53 but will take 3-5 days to get here. My multimeter is auto ranging and was switching to milivolts. thanks for the help guys.

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