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It was intermittent, sometimes it did it, sometimes not.
Oh dear, the Camshaft Adjuster is playing up. The suspect part looks like this....
There is a quite a long running bulletin on this TPI 2009810/19, dated 09.11.11. and the Cold Start-Up Rattle for 2 to 3 seconds. The problem can affect 160PS engines upto serial number CAV 213442. My engine serial number was within the production range
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The Camshaft Adjuster at start-up adjusts the inlet camshaft to speed up engine warm-up by overlapping the valve timing to keep some exhaust gases in the cylinders. Hence the funny "dieselling" sound during the initial running of the engine when cold started. This is to cut down engine emissions rapidly. This the negates the need for an EGR valve (Exhaust Gas Recirculation) to be fitted externally to the engine.
This is how the system works..... (Forget it isn't VW, VTC is exactly the same)
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The bulletin indicates the job requires about 6 - 8 hours of labour time and the right side of the engine taken apart to get the Adjuster off the Inlet Camshaft. As mine was intermittantly happening, it had me thinking........ Don't want the engine ripped apart.
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So a bit of searching around found the W8 engine in the Passat had a similar problem, the difference being, they were also finding engine ECU fault codes which I didn't have. But they had located the problem down to the Camshaft Adjuster Solenoid Control Valve. So I decided to investigate and follow their solution........
What prompted me that it may be the Camshaft Adjuster Solenoid Valve is that my Scirocco only does 5 miles journey's each way, each day. So the oil temperature never exceeds 70'C and the oil gets very dirty as a result (Hence my mid-service period oil change last year and again in 3 weeks time at the end of April - 1.4TSi Intermediate Servicing)
The Camshaft Adjuster Solenoid Valve was known to the W8 owners to be sticking. So I decided to follow their solution........
The Camshaft Adjuster Solenoid Valve, part number 03C 906 455A is located here on top of the right side of the engine under the engine cover....
The component looks like this.....
Firstly I thought I would tackle it with VCDS Output - 03 tests in the Enginer ECU section [Camshaft A (Intake) Position Actuator (N205)] which exercises this Solenoid Valve for as long as the test is set running (No engine running, ignition ON only). Gave it about 30 seconds of clicking on top of the engine. Hmm interesting, this had an improvement but it wasn't curing it.
So next, off with the Engine Cover and disconnect the electrical connection. Using a pair of VW repair wires from my VAG electrical repair box, I insulated the one of the end fittings (connectors) and connected up.
With the engine switched OFF, I then connected a 9 volt PP3 Battery to the VW repair wires and exercised the Solenoid Valve, by pulsing the connection. Hold one wire end to the Battery negative while dabbing the other wire on the Battery positive terminal. 1/8th of a second ON, 1/2 of a second OFF.... tick, tick, tick.......
The Valve could be heard ticking. The engine start -up improved again but still not perfect.
So as with the W8, it looked like using 12 volts from the car battery was needed to push/pull the valve to remove the sticking. The Camshaft Adjuster Solnoid Valve has a resistence of 7.4 Ohms and at 12.25 volts from the battery that meant 1.66 amps would be flowing in the wires. I thought using the car battery was a little different from using a small battery like the PP3. So it called for a proper tool to be made.
So I bought at connector body that fits the Camshaft Adjuster Solenoid Valve's electrical connection. The parts needed are:
Connector body - 1J0 973 702, £2.05 + VAT
VW Repair Wire - 000 979 131E, £1.99 + VAT (Cut in half to make two short wire ends.)
Then crimp on extension wires to reach over to the Scirocco's car battery.
Here's the initial tool with extension wires crimped on to reach the Scirocco's battery.....
And finally tidied up to look like this.........
When connected up, now was all safe not to damage the Camshaft Adjuster Solenoid Valve's electrical connections, had to be at a replacement cost of £78.01 + VAT for the Valve!
With the engine switched OFF, what you do is give the Valve a series of short pulses, about 15 to 20 while the engine is still very warm. Hold one wire end to the Battery negative while dabbing the other wire on the Battery positive terminal. Then reverse the tool's connections to the Scirocco's Battery and do another 15 to 20 pulses. Each pulse is about 1/8th of a second ON with a 1/2 second OFF pause inbetween. Tick, tick, tick.......
Disconnect the homemade tool, reconnect the engine loom's connector to the Solenoid Valve and replace the Engine Cover. Job done!
This worked and since three weeks ago, no rattle. Here is how the engine now sounds today..........
When I do the Intermediate Service in three weeks time, I will give the engine a oil additive flush (Forte - Advanced Formula Motor Flush) clear out the Valve and Camshaft Adjuster just to polish it off.
Saved pulling apart the engine unnecessarily
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But this was not the only thing that changed. The engine runs better when warmed up because the Camshaft Adjuster works all the time as controlled by the Engine ECU. Not only that, fuel consumption has improved by about 8% and the DSG runs in D6 at 30 mph which it didn't do before (previously D5 with spark plug gaps revised, originally D4). I don't know if this would be for all 1.4TSi 160PS engines or just those engines being used on very short runs where the dirty oil is clogging up the Valve and Adjuster.
C.