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Thread: Changed VSS and now running on 4 of 6 cylinders

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    Changed VSS and now running on 4 of 6 cylinders

    Hello everyone,

    Last weekend I swapped out my VSS, completed Sunday night.
    Buttoned it all up Friday/Saturday. Started it and it ran rough...

    Checked for Vacuum leaks, found one. The tab on the TB was pointing up instead of to the firewall. Sprayed with copper gasket and reassembled correctly. Vacuum leak was gone. Still rough idle.

    Checked spark plugs, brand new because of the VSS swap. 3 and 6 look like they never fired and 3 was 'wet'
    Checked spark, nothing from 3 + 6 coil. Swapped coil with another that was producing spark, 3+6 still not sparking but the one that was trying to spark them was sparking on the other cylinders.
    Came on here and chatted with Coop for a while, last night and today.

    removed the PTU and I am testing it right now, following:
    Stealth 316 - Power Transistor Unit

    Now when I test without voltage I get 46K ohm resistance. Apply voltage and test and I get -2.72 M Ohms. Is this because the voltage is applied and opening the transistor?

    Thank you in advance for you help.

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    Stealth owner since '91 Feedback Score 0 Steve '92ES's Avatar
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    Double check your Cam sensor, make sure it's plugged in tight and give the wires a good shake.
    The wires can become brittle with age and break. Also make sure you didn't disturb the reluctor ring (the "ninja star thingie") while you were in there, especially if you took the cams out.

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    Appreciate that, just read a posting that said that the 3 and 6 are off when the cam sensor is off. MAybe I have incorrect timing O.O Checking again in a bit

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    Forum User Not Verified Feedback Score 2 (100%) RealMcCoy's Avatar
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    Quote Originally Posted by Fletch View Post
    Appreciate that, just read a posting that said that the 3 and 6 are off when the cam sensor is off. MAybe I have incorrect timing O.O Checking again in a bit
    If the crank and cam sensors are out of phase, the ECU will get confused and start dropping coils... definitely worth checking out.


    Real Performance Automotive (541)816-4500 www.FB.com/RealPerformanceAuto

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    O.k. Timing is dead on. Cams and crank are at the marks.

    Looking up how to test if the Cam PS is faulty.

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    Tested the harness.

    Pin 3 is getting 11.6vdc
    Touched pin 2 and the other lead was touching the ground on the firewall, no continuity.
    Pin 1 no voltage.

    So where does this connect on the other side of the engine bay, once it goes through the injector tunnel?

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    Forum User Not Verified Feedback Score 2 (100%) RealMcCoy's Avatar
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    The following applies to both the cam and crank sensors: The red wire should carry 12v to the sensor, the black wire should be grounded, (you should be able to touch a simple test lamp between the red and black wires and have it light up) the blue wire with some variant of a stripe should carry the 5v reference from the ECU. You should see 5V on that circuit with the connector unplugged from the sensor with the key on, as well as with the sensor plugged in and the signal wheel is not within the sensor. When the signal wheel passes through the sensor, it should pull the 5V reference to ground. You should be able to see this with your meter while turning the motor over by hand.

    Did you verify the crank gear signal wheel didn't get damaged? and is still lined up? the notch on the wheel should line up with the notch on the gear:


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    Mine does not look like that one
    the blade is a little forward on mine. When I took it off it is the same position that it is in now.

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    Here is a quick shot of mine.


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    so the timing is two teeth off?

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