Was looking into replacing some of the sensors on the 87GT (which are all original except for TPS and EGR) but was wondering if the aftermarket ones are better than the "OEM" ones. I know alot of companies make parts for the "OEM" parts. I wanted to replace the O2 sensors, look into the ACT sensors, and maybe pick up another TPS becuase the "OEM" one I have now I can't set it to where in needs to be on the volt meter. The car has around 80,000 so with the age and miles combined I'm sure it's due. That and the car ran very rich last summer.
Experiance with sensors
- Thread starter CRASH7772
- Start date
i play it by ear with sensors. some stuff like TPS (i know you already did yours) and TFI seem to have the least problems when using an oem unit.
others i play it by ear. if it is really expensive for the oem sensor, i use parts store stuff. also, if it can kill the car (TFI, etc) i get good ones.
for running rich, really check out the O2's (Bosch replacements seem to work well), the ECT (engine coolant temp sensor), ACT, etc. a DMM used to test them cold and then hot will tell you what gives. the Probst manual is awesome for testing these things (i dont have it, but i have excerpts). when i need more than is available in here and in Haynes, i will spend the 20 bucks on one.
good luck.
others i play it by ear. if it is really expensive for the oem sensor, i use parts store stuff. also, if it can kill the car (TFI, etc) i get good ones.
for running rich, really check out the O2's (Bosch replacements seem to work well), the ECT (engine coolant temp sensor), ACT, etc. a DMM used to test them cold and then hot will tell you what gives. the Probst manual is awesome for testing these things (i dont have it, but i have excerpts). when i need more than is available in here and in Haynes, i will spend the 20 bucks on one.
good luck.
Well if you see in my sig, I'm getting ready to swap intakes and though I might just replace some of the sensors that would be easier to get to during the swap. I'm pretty sure the O2's are shot and alot of people seem to like the Bosch O2 sensors. Thanks for the input......
No need to replace the ACT or ECT - they are thermistors and they are good or they are bad. Test with and ohmeter and varying water temps like mentioned.
FYI here's the table for ACT & ECT sensors...
Pin 25 ACT signal in. at 50 degrees F it should be 3.5 volts. It is a good number if the ACT is mounted in the inlet airbox. If it is mounted in the lower intake manifold, the voltage readings will be lower because of the heat transfer. Here's the table :
68 degrees F = 3.02 v
86 degrees F = 2.62 v
104 degrees F = 2.16 v
122 degrees F = 1.72 v
140 degrees F = 1.35 v
158 degrees F = 1.04 v
176 degrees F = .80 v
194 degrees F = .61
Ohms measures at the computer with the computer disconnected, or at the sensor with the sensor disconnected.
50 degrees F = 58.75 K ohms
68 degrees F = 37.30 K ohms
86 degrees F = 27.27 K ohms
104 degrees F = 16.15 K ohms
122 degrees F = 10.97 K ohms
140 degrees F = 7.60 K ohms
158 degrees F = 5.37 K ohms
176 degrees F = 3.84 K ohms
194 degrees F = 2.80 K ohms
The ACT & ECT have the same thermistor, so the table values are the same
Pin 7 ECT signal in. at 176 degrees F it should be .80 volts
Pin 25 ACT signal in. at 50 degrees F it should be 3.5 volts. It is a good number if the ACT is mounted in the inlet airbox. If it is mounted in the lower intake manifold, the voltage readings will be lower because of the heat transfer. Here's the table :
68 degrees F = 3.02 v
86 degrees F = 2.62 v
104 degrees F = 2.16 v
122 degrees F = 1.72 v
140 degrees F = 1.35 v
158 degrees F = 1.04 v
176 degrees F = .80 v
194 degrees F = .61
Ohms measures at the computer with the computer disconnected, or at the sensor with the sensor disconnected.
50 degrees F = 58.75 K ohms
68 degrees F = 37.30 K ohms
86 degrees F = 27.27 K ohms
104 degrees F = 16.15 K ohms
122 degrees F = 10.97 K ohms
140 degrees F = 7.60 K ohms
158 degrees F = 5.37 K ohms
176 degrees F = 3.84 K ohms
194 degrees F = 2.80 K ohms
The ACT & ECT have the same thermistor, so the table values are the same
Pin 7 ECT signal in. at 176 degrees F it should be .80 volts
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