twentyfouroz
New Member
- Joined
- Jan 8, 2021
- Messages
- 7
- Reaction score
- 6
- Points
- 3
- Age
- 54
- Location
- Adelaide
- Members Ride
- VY and VX wagon
Last Tuesday my VY wagon just stopped dead, no sputter or cough, just immediate loss of power and a coast to a stop. It was a hot day, and my instant assessment before I'd even lifted the bonnet was the Crank Position sensor. I tried to crank it, but no go, so I let it sit for 20 minutes then poured some water around the harmonic balancer( yup, it's a, Ecotech right of passage, isn't it? 
) and tried again. With no joy I caved and called the RAA, and they arrived about 40 minutes later. The mechanic also tried the cold water trick to no avail, so he plugged into the ODB port for a look see. I had no engine warning on the dash, but he said the code indicated a CPS failure. Since that's kinda what I was expecting, I just accepted that to be the case. Got it towed, and that night I pulled the fan, and then pulled the balancer.
Early the next morning I picked up a new CPS and a new CAS from my local old school parts store, raced home, and fitted them. I had it all back together in an hour and was all set to head off to work... but I was going NOWHERE. With everything replaced and plugged back in, I still could not get it to kick. At that point I decided I'd swap the Ignition module and coils over with spares I had on my old cooked engine, to see if it made any difference... it didn't. I then decided to see if the Fuel pump was running, so I pulled the relay and bridged it, and it definitely was running. I then swapped over the ignition relay as it might have been an easy win, but no joy. Called a mechanic mate who owns the same model wagon, and he laughed and told me he'd had one brand new Crank Position sensor out of the box DOA, and another that lasted 2 days. So I pulled everything off again and swapped the CPS and CAS for the ones off of my old motor. Put it all back together... still no kick. This morning I pulled the balancer and the shroud. then undid the bolts for the CPS and the CAS. I then got a multimeter and a pin into the rear of the plug on the CPS, and tested for 12V and 3x and 18x pulses by waving a screwdriver through the gaps. I could see the voltage dropping from 5.5 to 0 whenever I tickled it. I then did the same with the CAS and a fridge magnet, and it behaved as expected. So at the point I was convinced that both sensors were getting 12V from the ignition module, and both were sending pulses back. Here's where it gets weird.
Going off this guide, the pins on either side of the Ignition module plug fastener are the 3x and 18x pulses. I plugged my MM into the back, and if I slowly turned the crank ( long arm and socket on the balancer bolt ), I could see the volts going up to 5.5V, down, up, down as I turned the crank for the 18x. On the 3x pin though, it never dips... just stays at 5.5V the whole time. Now, had it just stayed at 0v I'd maybe look for a short to ground on that wire, so in this case you'd maybe conclude it was open between the Ignition module and the CPS... but I get continuity if I test it unplugged. That has got me wondering if something on that input has fritzed in the ECU, like a protection diode or something.
Before I go THERE though, has anyone seen anything like this, an immediate shutdown and subsequent no start that was NOT caused by the Crank Position Sensor, Cam angle sensor, the igniton module, the coil packs, or fuel? This one has me scratching! Thanks in advance for your insight.
) and tried again. With no joy I caved and called the RAA, and they arrived about 40 minutes later. The mechanic also tried the cold water trick to no avail, so he plugged into the ODB port for a look see. I had no engine warning on the dash, but he said the code indicated a CPS failure. Since that's kinda what I was expecting, I just accepted that to be the case. Got it towed, and that night I pulled the fan, and then pulled the balancer. Early the next morning I picked up a new CPS and a new CAS from my local old school parts store, raced home, and fitted them. I had it all back together in an hour and was all set to head off to work... but I was going NOWHERE. With everything replaced and plugged back in, I still could not get it to kick. At that point I decided I'd swap the Ignition module and coils over with spares I had on my old cooked engine, to see if it made any difference... it didn't. I then decided to see if the Fuel pump was running, so I pulled the relay and bridged it, and it definitely was running. I then swapped over the ignition relay as it might have been an easy win, but no joy. Called a mechanic mate who owns the same model wagon, and he laughed and told me he'd had one brand new Crank Position sensor out of the box DOA, and another that lasted 2 days. So I pulled everything off again and swapped the CPS and CAS for the ones off of my old motor. Put it all back together... still no kick. This morning I pulled the balancer and the shroud. then undid the bolts for the CPS and the CAS. I then got a multimeter and a pin into the rear of the plug on the CPS, and tested for 12V and 3x and 18x pulses by waving a screwdriver through the gaps. I could see the voltage dropping from 5.5 to 0 whenever I tickled it. I then did the same with the CAS and a fridge magnet, and it behaved as expected. So at the point I was convinced that both sensors were getting 12V from the ignition module, and both were sending pulses back. Here's where it gets weird.
Going off this guide, the pins on either side of the Ignition module plug fastener are the 3x and 18x pulses. I plugged my MM into the back, and if I slowly turned the crank ( long arm and socket on the balancer bolt ), I could see the volts going up to 5.5V, down, up, down as I turned the crank for the 18x. On the 3x pin though, it never dips... just stays at 5.5V the whole time. Now, had it just stayed at 0v I'd maybe look for a short to ground on that wire, so in this case you'd maybe conclude it was open between the Ignition module and the CPS... but I get continuity if I test it unplugged. That has got me wondering if something on that input has fritzed in the ECU, like a protection diode or something.
Before I go THERE though, has anyone seen anything like this, an immediate shutdown and subsequent no start that was NOT caused by the Crank Position Sensor, Cam angle sensor, the igniton module, the coil packs, or fuel? This one has me scratching! Thanks in advance for your insight.
