QuestionHi, and thanks in advance for your help. I need to test my TPS. My vehicle is a 1997 Chevy Blazer LS, 4dr, 2wd, 4.3L Vortec, AT. I was able to find some info, but it said how to test tps with 3 wires, mine only has 2 wires. Reason for testing; poor performance, poor fuel economy, weird trans shifting...
AnswerHI ANDY, ONE WIRE SHOULD HAVE A 1 TO 5 VOLT REFERENCE FROM THE PCM AND THE OTHER SHOULD BE A 12 VOLT SUPPLY. GROUNDS THROUGH THE CASE. I DO NOT FEEL YOUR PROBLEM IS IN THE TPS..HAVE YOU TUNED THIS ENGINE RECENTLY ??? USUALLY WHEN A TPS GOES BAD IT BOGS DOWN AT TAKE OFF OR A FLAT SPOT AT SAY 30 MPH OR SO..THIS IS THE NORM FOR A TPS. IF IN FACT YOU FIND IT IS BAD,REPLACE IT AND TURN THE IGN ON,THROTTLE CLOSED ALL THE WAY AND SET THE REFERENCE SIGNAL TO .5 VOLTS WITH A VOLT METER.IF NOT THE TPS,,,I WOULD CK THE MASS AIR FLOW SENSOR FIRST JUST UNPLUG IT AND SEE IF THE RUNNING ISSUES GET BETTER,NOT PERFECT BUT BETTER. IF SO THE MASS AIR FLOW IS THE FAULT. HAVE YOU CHECKED FOR ANY CODES IN THE SYSTEM YET ?? THAT WOULD BE MY FIRST STEP. HOWEVER YOU WILL STILL NEED TO DO THE MASS AIR FLOW TEST LIKE I SAID BECAUSE MORE TIMES THEN NOT THE PCM WILL NOT SET A CODE FOR A FAULTY MASS AIR FLOW. YOU WOULD NEED A SCAN TOOL THAT CAN GIVE YOU DATA READOUT TO CK THIS.. THIS MAY ALSO CAUSE LATE SHIFT POINTS...[[[POOR FUEL ECONOMY >>> PLUGGED AIR FILTER OR FAULTY O2 SENSORS,,]] THIS WILL HAVE A CODE FOR IT...DO NOT FORGET TO REPLACE THE FUEL FILTER AS WELL IF YOU HAVE NOT ALREADY..LET ME KNOW IF YOU HAVE ANY CODES OR GET BACK TO ME WITH MORE INFO..GOOD LUCK,,,TOM.
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PS,HI AGAIN ANDY,I AM AT WORK AND I THOUGHT I WOULD LOOK THIS SYSTEM UP AND ALL OF MY COMPUTER SOFT WARE IS TELLING ME THIS YEAR BLAZER HAS A 3 WIRE TPS SENSOR NOT 2. DID YOU CK THE HARNESS AND TPS SENSOR TO MAKE SURE A WIRE DID NOT BREAK OFF ???
