Advanced timing

[WyrTwister]

Just finished watching this video . Car was running bad . Eric pulled the codes , one of which was cam / crank correlation error . Put the scope and compared the wave pattern to a known good he found on the internet . Discovered one was advanced something like 30 degrees from the other .

Evidently the cam phaser is operated by engine oil being used as a hydraulic fluid . He tested the servo / solinoid that applied oil pressure to the cam phaser . It clicked . Texted the other . It did not click , even though the coil was drawing current .

This is exactly why I change the oil / filter ( full synthetic DEXOS ) twice as often as the guess-o-meter indicates . Do not want things like this stopping up / sludging up / freezing up .

https://www.youtube.com/watch?v=aWJLUzqK0r0&t=3s

 

[Linctex]

I just never buy any VVT equipped vehicles.

Done.

 

[Snagglefoot]

I like the VVT in my 6 liter Chev Suburban. Between it, the cam and the head design, the engine produces 300 to 380 ft lbs of torque between 1000 and 6000 rpm. And the system currently has 180,000 miles. No problems so far. That motor is a horse!

 

[vssjim]

Originally Posted by Linctex
I just never buy any VVT equipped vehicles.

Done.

I got to tell you lots and lots of cars and trucks have VVT going back to late 90's

 

[Silk]

Earlier than that - my 1990 Nissan NX Coupe had VVT. GA16 DE.

 

[Diesel12]

I have a VVT car with 225K and have never changed a cam phaser. Maintenance is key.

 

[StevieC]

Originally Posted by WyrTwister
Just finished watching this video . Car was running bad . Eric pulled the codes , one of which was cam / crank correlation error . Put the scope and compared the wave pattern to a known good he found on the internet . Discovered one was advanced something like 30 degrees from the other .

Evidently the cam phaser is operated by engine oil being used as a hydraulic fluid . He tested the servo / solinoid that applied oil pressure to the cam phaser . It clicked . Texted the other . It did not click , even though the coil was drawing current .

This is exactly why I change the oil / filter ( full synthetic DEXOS ) twice as often as the guess-o-meter indicates . Do not want things like this stopping up / sludging up / freezing up .

https://www.youtube.com/watch?v=aWJLUzqK0r0&t=3s

Yeah that was something eh? 200 micro second discrepancy between the old and new sensor according to Eric but it didn't really show up in the waveform at a glance. It was enough for the ECU to set off the misfire counter even though the engine seemed to have no driveability problems.

The only thing I have seen in the past is completely dead crank sensors or where it won't pull the voltage right to ground but say 1 volt above ground and this can cause intermittent misfire or intermittent no start but never did I see something like this. The dead giveaway on these if the vehicle is still operating is the misfire seems to move between all the cylinders where the voltage isn't being pulled down completely.

I watched another video yesterday on ScannerDanner where he had a 2000-ish Dodge Ram and the camshaft sensor would stop working when it was hot and this would cause a no-start situation when the vehicle was hot but would start fine when it was cold. If you never shut the vehicle off it would continue operating just fine all day. The reason that was a problem was because the ECU couldn't synchronize the Cam and Crank during start-up so it would never fire the spark plug, but once it was running it didn't care if the cam sensor disappeared because it had the crank signal. (This engine didn't have VVT). I thought that was interesting... https://www.youtube.com/watch?v=Uk-GqHpOKAY