CUTLASS Replace TPS or Carb?

Eddie Cutlass

Eddie Cutlass

Not-quite-so-new-guy
May 3, 2020
46
18
San Diego
So I noticed the check engine light only comes on after the car has been warmed up. Wether it’s idling in Park or driving down the street, no check engine light until motor is warmed up...the light is also off for a few seconds each time I start the car afterwards, then comes back on.
Would the rotted out A.I.R. tube cause the ECM to throw the code? Or possibly the O2 sensor? Thanks again!
 
69hurstolds

69hurstolds

Comic Book Super Hero
Supporting Member
Jan 2, 2006
3,879
113
The O2 sensor could, but I believe that's a Code 13 if the sensor isn't doing right.

The Code 21 won't set until you get to operating temperature. While the engine is warming up, you're usually on fast idle which has the throttle blades open a bit more, thus a higher voltage signal from the TPS, so the ECM doesn't bother to look at it until it gets the signal from the coolant sensor that the engine's up to temp. So at least the ECM's getting the "coolant is warm enough" signal. There are other codes as well that only flip on when the engine warms up. And others come on immediately whenever they see the malfunction, regardless of temperature.
 
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Olds G's

Olds G's

Not-quite-so-new-guy
Apr 6, 2020
39
18
CT
This is such a great thread! I've learned quite a bit from checking back from time to time. 69hurstolds is absolutely correct by reinforcing the need for true shop manuals. Also very helpful is the Electrical Troubleshooting Manual. As noted previously, be sure it covers your Cutlass specifically. This 1984 version happens to cover all Oldsmobile series for 1984.
20200522_122733 (1).jpg
 
jiho

jiho

G-Body Guru
Jul 26, 2013
658
43
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jiho

jiho

G-Body Guru
Jul 26, 2013
658
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jiho

jiho

G-Body Guru
Jul 26, 2013
658
43
I'm wondering about those stripped/crossed wires you found. "Red or pinkish" I think you said. Depending on what those wires are, it's possible something got overloaded in the ECM? Or the TPS? The TPS doesn't have any wires that could be confused for red or pinkish. But it does have a gray wire, which might look red or pinkish from oil/dirt/rust etc.

Is it possible you could get snapshots of those two wires and what they plug into at the connector end(s)?
 
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Eddie Cutlass

Eddie Cutlass

Not-quite-so-new-guy
May 3, 2020
46
18
San Diego
I'm wondering about those stripped/crossed wires you found. "Red or pinkish" I think you said. Depending on what those wires are, it's possible something got overloaded in the ECM? Or the TPS? The TPS doesn't have any wires that could be confused for red or pinkish. But it does have a gray wire, which might look red or pinkish from oil/dirt/rust etc.

Is it possible you could get snapshots of those two wires and what they plug into at the connector end(s)?
Yes, two wires were faded red and brittle plastic. I didn’t even think of tracing the wire to see what it plugged into 🤦🏻‍♂️. I ordered shrink tube and wire loom so i can patch up damaged wires. I’ll take a picture tomorrow. I’m now hoping that’s the Code 21 issue. Excuse the late response.
 
R

Rodsridess

Not-quite-so-new-guy
Oct 1, 2018
5
3
Hey guys, wondering if y’all could give me a few pros and cons on either replacing the TPS or replacing the whole carb? I’m pulling a code 21 (faulty TPS). Car is a 1985 Cutlass supreme 307 Olds V8. Thanks in advance!
Should be 0-5v on the two wires. Use sewing needles to Peirce the wire so you can clamp on alligator clips and volt meter. Turn the key ON...Slowly opens the throttle...0-5v positive
 
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