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Post by Sir Trevor on Feb 23, 2006 16:23:31 GMT -5
Never disturbed the MAF. IT is mounted almost at the throttle body. I only had to take the piece off that was mounted over the radiator.
And I was having this trouble before I took the air cleaner off the throttle body, and I left the MAF connected.
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Post by bunbun / Hank on Feb 23, 2006 16:31:38 GMT -5
CODE 22.TPS circuit signal voltage low: Check for sticking or misadjusted TPS. Check all wiring and connectors at the TPS and at the ECM. By monitoring the output voltage from the TPS, the ECM can determine fuel delivery based on throttle valve angle (driver demand) A broken or loose TPS can cause intermittent bursts of fuel from the injector and an unstable idle as the ECM thinks the throttle is opening.
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Post by Sir Trevor on Feb 23, 2006 16:37:03 GMT -5
Yep The problem is the reference signal voltage is too low. It's supposed to be .5 volts, but I am only getting .122 volts. And I've checked it all the way back to the firewall, so there isn't a short in the wire under the hood. I'm hoping it's a bad connection at the computer. Otherwise the only thing I can think of is that the computer isn't putting out the correct amount of juice, which is a big oh-no.
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Post by bunbun / Hank on Feb 23, 2006 16:41:16 GMT -5
To check the operation of the TPS, connect the positive probe of a high impedance digital volt meter to the center terminal of the TPS (dark blue wire) and the neg. probe to the TPs ground wire, which will be either black or black with an orange stripe. Turn the ignition switch to the ON position (don't start the car). With the throttle in the closed position (idle), the volt meter should be approx. 0.45 to 1.25 volts. Now open the throttle completely and check the voltage. it should read approx. 4.5 volts. If the TPS does not respond as described, replace it.
So there ya have it. Hope this helps. HANK.
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Post by Sir Trevor on Feb 23, 2006 16:44:18 GMT -5
The problem is, that it isn't getting that much voltage to the TPS. There should be a mention of doing a reference voltage test. Which is what is failing. Where you test the wiring itself. The TPS isn't getting enough voltage to operate correctly.
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Post by bunbun / Hank on Feb 23, 2006 16:58:47 GMT -5
Trevor. Whole bunch's of info coming your way. Again I will break it down into small segments as I DON'T want to lose the whole damn thing again.
ECM. Located in the passenger compartment on the passenger side, under the instrument panel. Remove the right side under dash insulating panel and or glove box to gain access to ECM.
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Post by bunbun / Hank on Feb 23, 2006 17:08:08 GMT -5
TPS have their own types of driveability symptoms. The most common symptoms of a faulty sensor is hesitation or stumble during acceleration. The same symptom of a bad accelerator pump in a carburetor engine. There are basically two voltage checks you can make to test the TPS( it is best to have the correct wiring diagram for the car.
First test is for the presence of voltage at the TPS sensor supply wire with the ing. key ON. The TPS cannot deliver the correct signal without the proper supply voltage.
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Post by Sir Trevor on Feb 23, 2006 17:11:44 GMT -5
Yep, that's the one that is failing.
And thanks. I found the computer. Now I just have to finish tearing the dash apart and checking connections.
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Post by bunbun / Hank on Feb 23, 2006 17:15:57 GMT -5
You can determine the function of each wire by probing each one with a volt meter and checking the different voltages. the voltage that remains constant when the throttle is open and closed is the supply voltage. if there is no voltage at any of the wires, there is probably an open or short in the wiring harness to the sensor.
The second check is for the proper voltage change that occurs as the throttle opens and closes. As the throttle goes from closed to wide open the voltage at the signal wire should increase smoothly from 1 volt to 5 volts.
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Post by bunbun / Hank on Feb 23, 2006 17:24:21 GMT -5
An alternate method for checking the range is the resistance test. Hook up an ohmmeter to the supply and signal wire. With the ignition key OFF, slowly move the throttle thru the complete range observe carefully for any unusual changes in the resistance. (the change should be smooth) as it increases from low to high.
I'm beginning to think I'm the medieval CLICK & CLACK! hope this helps. keep me posted and I'll send along any info I think might be of Help. HANK
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Post by bunbun / Hank on Feb 23, 2006 23:06:11 GMT -5
Trevor...One last thought before I call it a night. Maybe you have already done this but if not...If you have accessed the ECM take your ohmmeter and connect one probe to the supply wire at the ECM end of the harness and the other end to the harness at the TPS end and see what the resistance is. If you are only getting .122 volts going into the TPS you gotta have a lot of resistance somewhere in that wiring harness. A badly corroded connection or something along those lines. Or else the ECM itself just took a crap on ya. Good luck in your battle with Sir Buick. I hope you win soon, before the weather turns bad on ya again. HANK.
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Post by Sir Trevor on Feb 23, 2006 23:18:32 GMT -5
That's why I am hoping it is the connection at the ECM. I took a voltage reading of the wire at the firewall and it is still .122 , so there isn't any problem with the wire under the hood.
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Post by bunbun / Hank on Feb 24, 2006 7:35:39 GMT -5
Trev...I spent some time going over the wiring diagram and it shows 3 wires coming off the TPS. They all run to the ECM. You have a BLACK, which is the ground. A DARK BLUE which is marked as TP sens in. and a GRAY which is marked as 5 volt ref.
If you're lucky you have a bad ECM. It might be a bit expensive to replace it ( you might want to consider a used one from the bone yard) but that has to be easier than replacing the wiring harness. Although you maybe could bypass the offending wire if that is the cause of your problem. From past experiences with wiring problems, look closely at the plug in connectors as that is where the trouble usually is. But that is not to say the wire could not have gotten "pinched" in the middle somewhere. Good Luck. HANK
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Post by bunbun / Hank on Feb 24, 2006 18:08:40 GMT -5
Sir Trevor...How goes thy mortal combat with Sir Buick? have thee vanquished thy foe and emerged victorious, or does the fight go on?
They say no news is good news. And we have not heard from you yet today, so I hope that is a good sign.
HANK.
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Post by Sir Trevor on Feb 24, 2006 20:07:11 GMT -5
Been busy tearing things apart. Now it really makes no sense to me. I located the wire where it comes out of the computer. Even verified I had the correct one by pulling the plug out and testing for continuity between that wire in the plug to the wire on the TPS. Plug it back in, turn the key on and check the wire for voltage (which lead to sticking the probe into my finger a couple times of course ) Anyway, it reads 12 volts Now I am trying to figure out what the heck is going on. How can I have 12 volts output, only .122 volts at the sensor, and I am looking for .5 volts.
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