82 CTS Sensor

Dirtbuster1

Dirtbuster1

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Joined
May 13, 2008
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Location
Georgia
What would cause a CTS sensor to keep going bad. I just changed it 2 weeks ago, and its bad again. :confused:

Help
 
corroded conenction, are you using the old mushroom style connector with the tan colored cover or a weatherpack sensor? If the first, get the weatherpack type (TPI and later), the range is the same. Make sure you get the sensor with pigtail (black/yellow wires), the non weatherpack (stock) style corrodes over time, giving way too much resistance over the connection and a false cold reading and severely rich running.

If you just changed it, it won't go bad that quick unless there's moisture in the connction or maybe dirt. Check that out (check the harness side of the connector)
 
TT,

It has been changed over to the weathertite style. The last one lasted 1 hour maybe. It seems to go to 28K ohms or higher. 1 ohm cold, or new.

Sounding dumb, I was working on the car earlier when I got a call. I was checking codes and it showed a code 15. Car was running ok. I forgot about the code key, and left it in while I cranked it up. Could this cause a problem?:huh:
 
The normal range should be:
[tr][td]T (°F)[/td][td]R (Ohms)[/td][/tr][tr][td]210[/td][td]185[/td][/tr][tr][td]160[/td][td]450[/td][/tr][tr][td]100[/td][td]1800[/td][/tr][tr][td]70[/td][td]3400[/td][/tr][tr][td]40[/td][td]7500[/td][/tr][tr][td]20[/td][td]13500[/td][/tr][tr][td]0[/td][td]25000[/td][/tr][tr][td]-40[/td][td]100700[/td][/tr]


Leaving the ALDL grounded will put it in special mode, the CEL will flicker fast in open loop and slow for closed loop (fast = probing o2 sensor for signal other than ... I think it was 3.2 V, slow is a cross count, each time mixture passes stoichiometric lambda = 1 the lamp goes on/off)
 
I don't remember the light flickering, or going on or off. Service manual says if you get code 15, short the white wire to the black wire. That would be 1 ohm. I measured a new sensor at 70F, and it was 1 ohm. Car runs great like this. Could something else be going on? I am currently not getting any codes.
The car is not running rich.
 
More CTS Problems

Blown another sensor. Somethings going on. Code 15 again. I checked the connector again, and it checks out ok both hot & cold. Ohm out the sensor, and I'm getting 2.8meg ohms. Pretty much open. I have even hooked up 2 ECM's!

Is there a major difference in quality of these sensors? I have no clue in what to do next. I have traced wires, checked grounds, & drank plenty of beer while scratching my head.

Help
 
Dirtbuster1 said:
Blown another sensor. Somethings going on. Code 15 again. I checked the connector again, and it checks out ok both hot & cold. Ohm out the sensor, and I'm getting 2.8meg ohms. Pretty much open. I have even hooked up 2 ECM's!

Is there a major difference in quality of these sensors? I have no clue in what to do next. I have traced wires, checked grounds, & drank plenty of beer while scratching my head.

Help
Click to expand...

If you are burning out sensors, they are passing too much current.
1) Wiring fault causing too much current flow
2)ECM fault, causing too much current flow
3)You have the fan switch and CTS mixed up.
 
big2bird said:
Dirtbuster1 said:
Blown another sensor. Somethings going on. Code 15 again. I checked the connector again, and it checks out ok both hot & cold. Ohm out the sensor, and I'm getting 2.8meg ohms. Pretty much open. I have even hooked up 2 ECM's!

Is there a major difference in quality of these sensors? I have no clue in what to do next. I have traced wires, checked grounds, & drank plenty of beer while scratching my head.

Help
Click to expand...

If you are burning out sensors, they are passing too much current.
1) Wiring fault causing too much current flow
2)ECM fault, causing too much current flow
3)You have the fan switch and CTS mixed up.
Click to expand...

Just checked CKTS 452 & 410. There is 5.23 volts. CKT 410 has 3 ohms to ground. CKT 452 has 2.3K ohms( I think ). Have tried 2 ECMS. The fan switch I think you are refering to goes to electric fan on passenger head. OK

I am sitting racking my brain.:bonkers: Could ECM not be ground thru the frame? My 2nd ECM is just sitting in the storage compartment. Only hooked it up for verifiying codes between the two.
 
Frankly, I don't have a schematic for an 82. All I CAN tell you is these sensors are designed to give you a variable 'voltage", while carrying virtually zero current. If they are rapidly burning out, their peak let thru current carrying capacity is being exceded.
Hopefully, Bullshark or TT will see this thread.
You could try this. Place a VOM on milliamp scale in leu of the sensor, or in line with a 1 ohm resistor, and see just how much current is going thru there.
 
Thanks for the help!

Got 5.25 milliamps with no resistor. Not much current. I think there might be a schematic in the download section if you don't have much to do. TT'S probably sleeping about now.
 
Nope, wide awake & right here :)

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It uses the same gnd as the TPS, well there may be a problem right there. Check again but with the throttle open, maybe that's the problem.
 
TT,

What do you suspect the problem might be. Best I can tell is that the CTS, TPS, & Map sensor have the same 5volt reference signal with CKT 452 being the common thread. I understand what the CTS does, but what would make it continue to blow unless it is just poor quality from AutoZone. I talked with someone from O'reillys earlier, and he suggested that the problem could be coming from electrolosis. Is this possible?
 
Like bird says, too much current through it. Maybe there's an internal short in the TPS?
 
Twin_Turbo said:
It uses the same gnd as the TPS, well there may be a problem right there. Check again but with the throttle open, maybe that's the problem.
Click to expand...

I picked up on that too. The 81 has both sensors go home.;)
His loose mounting of the ECM should NOT be a problem, as it's ground is in the ECM harness connector. Starting the car with the diagnostic terminals shorted would also not cause a CTS to blow.

As TT has stated, the TPS sensor may have a fault to ground, or the engine to ECM ground wire may be lifted/bad.

All the sensor wires are 1-5 volt with negligable current levels.

The output side of the ECM carries larger current values, and drive the relays/injectors, and what not. A ground fault COULD cause excessive current thru the sensor wires.

I suspect a bad ground/faulty wire/connector.
 
Twin_Turbo said:
It uses the same gnd as the TPS, well there may be a problem right there. Check again but with the throttle open, maybe that's the problem.
Click to expand...


Wasn't sure how you wanted me to check. With engine running or off. Off test does not have any change on volts, amps, or resistance when going to wide open. This was with the VOM connected to CKT 410 & 452.
 
Dirtbuster1 said:
Twin_Turbo said:
It uses the same gnd as the TPS, well there may be a problem right there. Check again but with the throttle open, maybe that's the problem.
Click to expand...


Wasn't sure how you wanted me to check. With engine running or off. Off test does not have any change on volts, amps, or resistance when going to wide open. This was with the VOM connected to CKT 410 & 452.
Click to expand...

Unplug the tPS, and check for resistence to ground. Each of the 3 terminals. Should be isolated.

Also, see that the ECM to engine ground is good/connected. 81 it is on the carb base. Don't know about 82. TT?
 
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