Changed VSS and now running on 4 of 6 cylinders

**Fletch** · 07-17-2011, 07:04 PM

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.

**Steve '92ES** · 07-17-2011, 07:51 PM

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.

**Fletch** · 07-17-2011, 08:16 PM

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

**RealMcCoy** · 07-17-2011, 08:21 PM

Originally Posted by Fletch

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.

**Fletch** · 07-17-2011, 09:22 PM

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

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

**Fletch** · 07-17-2011, 09:35 PM

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?

**RealMcCoy** · 07-17-2011, 10:03 PM

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: