P0020 and P0021

[Captain Lockheed]

Oh crud, does any one have the figures for them Variocam+?

[JFP in PA]

It is not a single value, it is a curve because the system is variable, from 0 to 25 degrees depending upon the engine operating conditions. 

 

 

 

 

 

 

[Captain Lockheed]

Thanks, I am learning slowly.

Is there anywhere I can get a graph?

Thinking that it is probably a map, with engine speed/load/gear/temps/pressures etc.

If I can I will see if I can plot some of this stuff.

 

Work is currently getting in the way of Porsche time, but it does pay for it.

 

 

[Ahsai]

The easiest is to plot both banks simultaneously amd compare them. Should be quite obvious based on your codes. Durametric can do that but I'm not sure if piwis can. It probably can too.

[Captain Lockheed]

I managed to get the morning off work and had a look at the sensor that JFP and Ahsai recommended, thanks guys.

Wheel off, heatshield off.

Found the sensor.

Took off the connector.

The metal clip that I think should be attached to the tab on the sensor holder, was on the loom but not on the tab.

Looking at the wiring diagram I tried to check continuity and it checked out.

 

[Captain Lockheed]

I can't see how to get the sensor out without dropping the exhaust and I have to get to work.

The clip.

[Captain Lockheed]

The connector.

I didn't short the connector. Or check the resistance of the sensor.

I've put it back together now.

[jl-c]

This is what it should look like, as you say the cable clip is supposed to be part of the sensor retainer bracket.

[JFP in PA]

I would take a close look at the sensor retaining bracket, we see these things snapped off pretty regularly:

 

 

 

 

 

[Captain Lockheed]

Thanks, I didn't have the time to take the exhaust off, so did what I could in the time available.

The muffler and hangar are going to have to come off to get access.

I will bet it sounds great with it off mind .

Idle, both banks.

[Captain Lockheed]

Idle, both banks.

Bank 1

Specified -1.0000

Actual -0.8281

Deviation -1.2500

Bank 2

Specified -1.0000

Actual -1.1875

Deviation 0.1094

 

 

[Captain Lockheed]

With about 3000 revs

Bank 1

Specified -23.3359

Actual -21.7188

Deviation -1.2500

Bank 2

Specified -23.3359

Actual -20.7031

Deviation 0.1094

[Captain Lockheed]

A few more revs

Bank 1

Specified -29.3594

Actual -27.0313

Deviation -1.2500

Bank 2

Specified -29.3594

Actual -30.2344

Deviation 0.1094

 

[Captain Lockheed]

In all of the three above, the difference between the actuals and the specified isn't the same as the deviations?????

The deviations are staying at static values.

I am Confused.

Edited December 2, 2016 by Captain Lockheed
More info

[Captain Lockheed]

2 hours ago, jl-c said:

This is what it should look like, as you say the cable clip is supposed to be part of the sensor retainer bracket.

Thanks that is it, where is the picture from?

[Captain Lockheed]

34 minutes ago, JFP in PA said:

I would take a close look at the sensor retaining bracket, we see these things snapped off pretty regularly:

 

 

 

 

 

I think you are on to something there.

Thankyou.

[jl-c]

Talk to Porschelibrarian for your manual.

[Ahsai]

31 minutes ago, Captain Lockheed said:

A few more revs

Bank 1

Specified -29.3594

Actual -27.0313

Deviation -1.2500

Bank 2

Specified -29.3594

Actual -30.2344

Deviation 0.1094

 

 

These readings look OK to me so it looks like you have an intermittent problem in bank 2, where the spec'ed angle and actual angles were very different in one of your earlier posts. You can just reset the codes and see if they come back.

 

The cam deviations should be fixed (during each drive but they may be slightly different across drives) and solid at all revs. If they fluctuate with the rev, you have a very bad problem.

Edited December 2, 2016 by Ahsai

[Captain Lockheed]

Thankyou. I will take the mufflers off and have a look at the bracket suggested by jfp and jl-c.

[JFP in PA]

34 minutes ago, Captain Lockheed said:

In all of the three above, the difference between the actuals and the specified isn't the same as the deviations?????

The deviations are staying at static values.

I am Confused.

 

 

Which could happen if there was no communications from one or more cam position sensor.

 

 

 

 

 

[Ahsai]

Just so it's clear, the "sensor" you're checking now is not a sensor, it's a solenoid that controls the hydraulic flow to the variocam timing device on the head of the intake cam. The timing device varies the relative phase difference between the crank and the intake cam.

 

The cam sensor that John referred to is actually a hall effect sensor that reads the reluctor on the intake cam.

[Ahsai]

This is where the bank 2 cam sensor is.

 

 

[Captain Lockheed]

Thankyou. You guys are great.

I will check the sensor and wiring to it, on the front of the engine and the brackets and wiring for the two on the cam cover.

[Captain Lockheed]

Work has meant that I haven't yet got to look at the car, the wife uses it as her daily.

The check engine visit workshop hasn't come back, but I am still going to check everything as soon as I get the chance.

 

[Captain Lockheed]

Managed to use the PIWIS to cycle the solenoids and check the wiring. Alla seems good. No obvious damage.

Bank 1

Specified -0.93725

Actual -0.7656

Deviation -0.5938

Bank 2

Specified -0.9375

Actual -1.2500

Deviation 0.0625