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Old 04-16-2010, 08:24 AM   #31
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Whatcha thinking Dan? TPS should be able to cause a car to surge at idle (reading too high) and possibly act funky under throttle if it were reading low. I don't have any experience with it causing a stalling etc.
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Old 04-16-2010, 09:28 AM   #32
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The TPS is a potentiometer, and is not at zero at idle, it'* jut above that. If the signal is interrupted and the PCM reads a zero, it will stall. I say put a DVOM on and read the resistance threw the scale and watch for drastic spikes in the readings.
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Old 04-16-2010, 11:20 AM   #33
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I will put my Fluke on it this evening and see if I can get it to act funny.

I have not tested TPS- I'll look it up and try that.
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Old 04-16-2010, 12:12 PM   #34
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If the TPS doesn't read 0 volts and 0 throttle percent at idle, then your TPS has a problem. The TPS should be 0 when there is no throttle pedal being pressed and at WOT it should read very close to 5 volts/100 percent.

The TPS will not stall the car at 0 percent/0 volts. This is the reason for the Idle Air Control valve. It'* job is to meter air around the throttle plate and idle the engine.
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Old 04-16-2010, 12:26 PM   #35
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Thanks Bill and Dan- After reading a lot more 'm grasping these relationships and interactions.
I guess it'* time I learned about modern day induction- It aint no Holley pumper or Mikuni flat slide--- but oh do I wish

With the help you guys have given me, and all the sticky diagnostics with pics from Dan I WILL get this whipped. Can't wait to share the solution.

Thanks again.
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Old 04-16-2010, 03:35 PM   #36
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When you do test the TPS, use volts...not ohms. I took a look it this morning and was going to discuss that write up with Dan later when we had a little time.
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Old 04-16-2010, 07:44 PM   #37
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OK, just finished up doing some tests-
TPS- V test= chk
TPS pot test= chk. at idle .987r climbs smoothly to somewhere around 4. Tried several different driving methods such as mashing the throttle- dropping it from wot- normal simulated driving.
Here'* the problem though- my testing results could be as intermittent as my problem. Today it was trying several times to stall. Several times no problems. But other than trying it for 30 minutes (which I may do) it checks out smooth with no spikes, dead spots.
MAF power test=chk
AIC I don't see much of a tst on. I was able to find voltage across two different wires that was the same. My DIC said 13.5v I got 10.25 or so on the AIC plug w/key on. I was looking for a R across the pins on the IAC itself to no avail.
right now I'm about ready to go buy an AIC and try it.

Wish I could have found something! I also checked for loose wires during the V test on the plugs. I held the plug stationary and did the wire wiggle on them- got excited a couple times! but no, it was moving probes.

I wish I had a scanner- maybe I should just buy one and be done with it- big bucks aren't they?

So what kind of beer yall like?
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Old 04-16-2010, 07:47 PM   #38
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Quote:
Originally Posted by BillBoost37 View Post
When you do test the TPS, use volts...not ohms. I took a look it this morning and was going to discuss that write up with Dan later when we had a little time.
I set to resistance and tested across the pins while moving the throttle while plug was out- Your saying I should switch to V? I'll try it-don't get it but I'll try it.

I'm not getting it----- nothing
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Old 04-17-2010, 01:35 PM   #39
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Sensor/System
  • Check for conditions which cause an incorrect idle speed.
    • Any throttle body tampering, excessive deposits, or damage
    • A restricted air intake duct or a dirty air cleaner element, refer to Air Cleaner Element Replacement .
    • Check for a large vacuum leak.
  • Check the throttle position (TP) sensor and the related wiring. Refer to DTC P0123 Throttle Position (TP) Sensor Circuit High Voltage .
  • Check the EGR system:
  • Check the PCV valve for proper installation. Refer to Crankcase Ventilation System Inspection .
  • Verify the correct operation of the PNP switch by comparing the transaxle range switch input with the vehicle in drive and the gear selector in drive or overdrive.
  • Check for the following conditions:
    • Check for bent harmonic balancer interrupter rings.
    • Check for a damaged crankshaft position (CKP) sensor.
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Old 04-17-2010, 01:39 PM   #40
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A scan tool would be helpful for testing TPS
Check for the following conditions:
  • A faulty connection at the PCM--Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Use a corresponding mating terminal to test for proper terminal tension.
  • Inspect the wiring harness for damage. If the harness appears to be OK, observe the TP sensor display on the scan tool while moving connectors and wiring harnesses related to the TP sensor. A change in the display will indicate the location of the malfunction.
  • A malfunctioning TP sensor--With the key ON and the engine not running, observe the TP sensor display on the scan tool while slowly depressing the accelerator to wide open throttle. If a voltage over 4.71 volts is measured at any point in normal accelerator travel, replace the TP sensor.
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