82 CTS Sensor

big2bird 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.

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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.

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There are 2 gnd wires on the harness from under the hood to the ECM. 1 gnds to the front of the intake, and the other under the air solenoid switch. Both ground to the intake. The intake has been painted and possibly causing some problem. It is either Aluminum or Magnesuim, I'm not sure which. Anyway a poor conducter. IT would be easy to attach a ground to the back of the alternator that runs to the battery thru the frame. I don't think this would cause a problem, what do you think. This is a #6 wire.

Checked the TPS out. Ground is 1ohm, 1 is .5 megohm, and 1 is 1.4K ohm. Checked both grounds on intake to alternator ground at 1.6 ohms.

Clean up the ground terminals on the manifold and air switch. Bare metal with star washer is best. Also, give me the part# of the CTS you are using. I'll cross it to make sure it is correct. Should be same as 81.
The #6 ground wire should NOT be necessary, but can do no harm.
How is the engine gound strap on the pass side near the motor mount? Clean with a star washer?

CTS part # Duralast SU109. Made in Mexico. I trying cleaning up the bolts tommorow. The wifes about to kill me from running in and out the door.

If anyone comes up with anything else, I will try it in the morning.

Thanks for all of the help tonight.

SU109 is correct. $15.00 is not bad. GM sensor is 10045847. It's alot more $$

I went by O'Reillys this morning and picked up 1 made in the USA. It was a Borg Warner. I went by Autozone with a VOM and measured the resistance of the SU109, it measures from 2700 ohms to 3200 ohms (3 different sensors ). O'Reillys measured 3000 ohms at 70F. Service manual said it should be 4100 ohms at 70F.

Could this have anything to do with my problem?

Dirtbuster1 said:

I went by O'Reillys this morning and picked up 1 made in the USA. It was a Borg Warner. I went by Autozone with a VOM and measured the resistance of the SU109, it measures from 2700 ohms to 3200 ohms (3 different sensors ). O'Reillys measured 3000 ohms at 70F. Service manual said it should be 4100 ohms at 70F.

Could this have anything to do with my problem?

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I doubt it very much.

Found the Problem

BB & TT,

I found the problem by luck. I got mad and cut the connector off. Checked it with the VOM, and it checked ok. I plugged it into the sensor and check it with the VOM and it read 2.8 meg ohms. I checked the leads to the plug again, and it was ok. Checked the sensor 3100 ohms. While cleaning the plug again, I noticed that the holes for the plug were larger than the pins on the sensor. :banghead: I guess that the original plug had larger pins than the Duralast sensor. Closed the plug holes up and problem solved.

It's usually the easy things that we miss, what a DA I was.

Thanks for the help. Now I have to repair my speedometer so that the IAC motors can reset themselves. It seems to be a bit sluggish at times without them working.


Thanks

BB,

I'm lucky that I found the problem. I was contacting Delta for a ticket from CA. to Ga. With the new fuel prices, that would have cost a lot.

It would have been nice to meet you anyway.

Thanks,

Herb

Dirtbuster1 said:

BB & TT,

I found the problem by luck. I got mad and cut the connector off. Checked it with the VOM, and it checked ok. I plugged it into the sensor and check it with the VOM and it read 2.8 meg ohms. I checked the leads to the plug again, and it was ok. Checked the sensor 3100 ohms. While cleaning the plug again, I noticed that the holes for the plug were larger than the pins on the sensor. :banghead: I guess that the original plug had larger pins than the Duralast sensor. Closed the plug holes up and problem solved.

It's usually the easy things that we miss, what a DA I was.

Thanks for the help. Now I have to repair my speedometer so that the IAC motors can reset themselves. It seems to be a bit sluggish at times without them working.


Thanks

Click to expand...

Herb. It's an easy miss. The later replacement units from GM come with a different connector. GM part # 15306187. I have a NOS spare. PM me and I'll send it to you.

Sorry I missed all the fun. Glad to hear the problem was found. It is a well known fact that the connectors and their interconnects are the primary cause for electronics failure. We go to great lengths to design out as many as we can to reduce cost and enhance reliability on today's military weapons.
One question though. I do not understand how a loose sensor connection resulted in a blown CTS sensor. Are you sure they were toast? If not, I bet that de-railed some guys thinking. :lol: If so, you had more going on than just a loose connection.

Bullshark

The 1st sensor failed. I measured the resistance on it verses a new one. The 2nd sensor probably was ok, but I assumed :quote: it was bad also. The 3rd sensor drove me to drinking. That's when I called in the troops. I cut the pigtail off and installed male & female plugs. When I checked them with the sensor installed it showed 2.8 meg ohms. When I checked the pigtail wires by one by one they were good. It's when I went to install the 4th sensor I discovered the problem. I ohmed out the new sensor at 3k ohms, then connected the pigtail. Out of curriousity I checked it again, and it was basically open. While cleaning the pigtail I noticed that the pin holes were larger than the sensor pins. I tought " no way ". Sure enough the connector went on & never touched the pins on the sensor. I closed up the connector holes & everything was ok.

This problem solved, on to the next!

Long week & story