Cam chain tensioner: Screeching noise and Trouble code help needed

Hello,

First I would like to say thanks for any support you can give. Looks like I can start being a contributing member to the site .

Vehicle: 2006 GTI 6MT, 200K miles, APR stage 2.

Issue
Finally, I decided to tackle the cam chain tensioner as it was starting to rattle. Everything went seemingly well until startup. From that point, I'm dealing with a screeching noise and some fresh codes.


Next Actions
Re-ordered gaskets and cam adjuster bolt to re-assemble everything as it seems to check out. (cams are still in time)
Ordered a new PCV because I read it can cause a screeching / squealing noise (see below in explanation). Compression test to re-confirm no issues with bent valves.
When I have time, will check the MAF wiring (read it is an issue) as I think it relates to the code list below. If no wiring issue, will order new MAF.

See below for better detail and codes.



1) Rough Idle, Check engine, Screeching Noise

First Start up: In general the car did not idle very well at first (but I chalked that up to not priming the fuel pump) and no engine lights we on kind of eventually idled ok and then shut off to re-hook up the vcds to do TBA.

Second Start up: Check engine light came on very rough idle --> stalling. Pulled / cleared codes (same codes as below after 3rd start.)

Third Start up: Check engine light rough idle and then some screeching coming from the Vacuum pump area. Pulled Codesn(See below)

I immediately tore down the vehicle again, rotated to TDC (using the T-Belt cam gear mark) and checked against the sharpie marks I made on the intake and exhaust cams before performing the job. Cam's did not loose timing and both hit the marks....

Next Actions
Re-ordered gaskets and cam adjuster bolt to re-assemble everything since it seems to check out.
Ordered a new PCV because I read it can cause a screeching / squealing noise.
When I have time, will check the MAF wiring (read it is an issue). If no wiring issue, will order new MAF.

2) Pulled codes:

The way i read the timing, it looks like P0299 and P0456 are old codes (reading mileage / speed, etc). If I cleared them earlier, why do they still show? Should I be diagnosing around these codes also, or just jump straight to the MAF and missfires?

7 Faults Found:

000665 - Boost Pressure Regulation
P0299 - 002 - Control Range Not Reached - Intermittent
Freeze Frame:
Fault Status: 00110010
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 335631 km
Time Indication: 0
Date: 2000.00.00
Time: 16:16:35

Freeze Frame:
RPM: 3827 /min
Load: 81.1 %
Speed: 77.0 km/h
Temperature: 96.0°C
Temperature: 36.0°C
Absolute Pres.: 970.0 mbar
Voltage: 13.589 V

001110 - EVAP System
P0456 - 001 - Very Small Leak Detected - Intermittent
Freeze Frame:
Fault Status: 00110001
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 335729 km
Time Indication: 0
Date: 2000.00.00
Time: 07:32:11


Freeze Frame:
RPM: 2731 /min
Load: 16.9 %
Speed: 112.0 km/h
Temperature: 93.0°C
Temperature: 9.0°C
Absolute Pres.: 980.0 mbar
Voltage: 14.478 V

000256 - Mass Air Flow Sensor (G70)
P0100 - 004 - Supply Voltage - Intermittent
Freeze Frame:
Fault Status: 00100100
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 0 km
Time Indication: 0

Freeze Frame:
RPM: 0 /min
Load: 0.0 %
Speed: 0.0 km/h
Temperature: 6.0°C
Temperature: 11.0°C
Absolute Pres.: 970.0 mbar
Voltage: 11.430 V

000768 - Random/Multiple Cylinder Misfire Detected
P0300 - 008 - - MIL ON
Freeze Frame:
Fault Status: 11101000
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 335911 km
Time Indication: 0
Date: 2000.00.00
Time: 00:06:21

Freeze Frame:
RPM: 1190 /min
Load: 43.1 %
Speed: 0.0 km/h
Temperature: 13.0°C
Temperature: 3.0°C
Absolute Pres.: 980.0 mbar
Voltage: 14.605 V

000769 - Cylinder 1
P0301 - 008 - Misfire Detected - MIL ON
Freeze Frame:
Fault Status: 11101000
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 335911 km
Time Indication: 0
Date: 2000.00.00
Time: 00:06:33

Freeze Frame:
RPM: 1185 /min
Load: 42.3 %
Speed: 0.0 km/h
Temperature: 18.0°C
Temperature: 3.0°C
Absolute Pres.: 980.0 mbar
Voltage: 14.478 V

000772 - Cylinder 4
P0304 - 008 - Misfire Detected - MIL ON
Freeze Frame:
Fault Status: 11101000
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 335911 km
Time Indication: 0
Date: 2000.00.00
Time: 00:06:33

Freeze Frame:
RPM: 1185 /min
Load: 42.3 %
Speed: 0.0 km/h
Temperature: 18.0°C
Temperature: 3.0°C
Absolute Pres.: 980.0 mbar
Voltage: 14.478 V

000770 - Cylinder 2
P0302 - 008 - Misfire Detected - MIL ON
Freeze Frame:
Fault Status: 11101000
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 335911 km
Time Indication: 0
Date: 2000.00.00
Time: 00:06:33

Freeze Frame:
RPM: 1185 /min
Load: 42.3 %
Speed: 0.0 km/h
Temperature: 18.0°C
Temperature: 3.0°C
Absolute Pres.: 980.0 mbar
Voltage: 14.478 V

I see no mention of the fuel pump cam follower.....look there and you might find something.

dmfracer said:

I see no mention of the fuel pump cam follower.....look there and you might find something.

Click to expand...

Probably not as there is not fuel pressure DTC and a worn cam follower usually does not affect idle but only causes fuel cuts during hard accelerations.

P0299 and P0456 are fairly new too. I noticed that engine DTC are not cleared by vcds on autoscan but that they should be cleared going in engine module and the faults codes.

Regarding P0456 another culprit might be the N80 or its hoses. I would cure this vacuum leak before investigating further (might be that boost pressure is lost in the vacuum leak too). So the check valves like N80/PCV would be my first suspects

When my fuel pump cam follower wore through I did not have any DTCs. It also made a screeching noise. He needs to check it.

Thanks to both for he feedback. For the follower, I replaced it with a new one (lubed with oil) so I would think it should be ok. However I didn’t inspect it on teardown so I’ll look for some scoring marks or something.

Also related to the Evap issue. Looks like the n80 valves are cheap, so I’m going to order one of those up so I can continue working on the car next weekend. Thanks again and let me know if you have any more advise.

Speedr said:

Thanks to both for he feedback. For the follower, I replaced it with a new one (lubed with oil) so I would think it should be ok. However I didn’t inspect it on teardown so I’ll look for some scoring marks or something.

Also related tot eh Evan issue. Looks like the n80 valves are cheap, so I’m going to order one of those up so I can continue working on the car next weekend. Thanks again and let me know if you have any more advise.

Click to expand...

There is a non scientific way to check the valve: by removing it and trying to blow through. You should not be able at all to blow through. Then with VCDS you can test it (engine stopped, it should click very fast).

The correct way to test it would be to do an evap system check with VCDS (engine running at working temperature), but you will likely fail it anyway since you have a vacuum leak.

Keep in mind that it's just a lead. Mine was defective (partially I suppose) and the symptom was that the car did not start at every attempt, but it would idle well when started.

However I know that a bad PCV can affect idle. Check the hoses also.

VWengineer, thanks for the feedback. I just went ahead and ordered the new valve and vacuum hose as the cost was relatively low and these components are very old. I figure, if nothing else it is proactive maintenance . When possible (i.e. the car running ), I will perform the evap system check with the new parts installed.

FYI, here are some pics of cam alignment install for before and after. It looks like there is slight movement in the chain, but the cam's line up at TDC...


Original Condition, before any tear down.


Fresh install and everything lined up


After incident (looks like the chain moved 1/2 a link, but both intake and exhaust cams align at TDC)