First post! (and a long one)
Recently (mid-december) driving from Cardiff down to Cornwall I ran head first into some issues I've not been able to solve. At around the half-way point of the journey I pulled off the dual carriageway where I was happily cruising along at 70 (or more) and stopped to say a socially-distanced hello to some relatives who were about 20 mins off my route down some slow country lanes. On starting the car up again I was taken by surprise that it did not start when cranked and had to try a second time, usually it fires up after one or two seconds. Suspicious - but I made my way back to the dual carriageway.
The car seemed a bit sluggish and I didn't think much of it, but when I got on the the dual carriageway I found I had barely any power, possibly as if there was no boost from the turbo. I couldn't get above 60 on the flat although I managed to hit 70+ on a steep decline which made me think this is not limp mode. Going uphill was awful as the car slowed to a crawl and I could only go at a max of 25-35mph on steeper inclines. After leaving the car overnight it would not start unless you crank the car for a good 10 seconds until the oil pressure light appears, turn off, and repeat another 2 or 3 times until the car eventually starts. Starting the car not too long after it's been turned off leads to better results when starting but does nothing for the lack of power.
After some googling I opened up the bonnet and cleaned the intake manifold flap (because I thought it was the EGR valve!). No difference.
I took it to my local garage who had it for a month and did the following:
- Fitted new camshaft sensor
- Replaced glow plugs (apparently none of them worked anyway)
- Replaced glow plug relay
- Fitted new boost pressure sensor
- Fitted new fuel filter (the previous one was installed in nov. 2019)
- Also carried out various plug-in diagnostics (I imagine vag-com)
I got it back off them last week and have done the following myself:
- Fitted a newer starter motor (second hand from a breakers yard out of a 2009 model). It works a bit better than the old one which the garage said wasn't helping with starting, although it probably wasn't the cause of the issues
- Fitted a new coolant temperature sensor. The fan on the intercooler turns on sporadically and for seemingly no reason, now it doesn't and the temperature gauge shows just under 90C after a while of idling, where it did not before.
- Visually checked visible vacuum hose lines for holes - I didn't find any.
- Discovered the intake manifold flap does not shut at any point - it should at least close for 3 seconds when the engine is shut off but it doesn't - would explain why my engine always shakes a lot when turned off! Tested the electrical connector, seems to be fine, maybe the motor has gone.
- Trickle charged the battery to full every night - the battery is new last winter and is rated above what is needed for the engine - I was tired of killing my cheap euro car parts battery on short winter commutes.
- Checked all fuses on the battery cover as well as fuse F14 inside the dash - all are fine.
I've gotten a cheap wireless OBD2 reader from amazon and I get the following fault codes:
P0489: EGR System - circuit low
P0243: Turbocharger wastegate regulating valve A - circuit malfunction (Volkswagen: Turbocharger wastegate solenoid 1)
I also have two more codes to do with the throttle actuator control motor, P2100 and P2102, but these faults have been there since before I bought the car in 2016. Sneaky seller blanked out the check engine light!
The only thing I have found that helps is if I cycle the ignition many times before starting the car - It then only takes one or two attempts to start. This makes me think there is a potential fuel issue and fuel pressure is not maintained after the engine is shut off. Other than that, I've not made any progress. My question to you all is, have you ever experienced anything like this before or have any suggestions?
(edit) Other useful information:
Engine code: BNM
The car doesn't suffer from a rough idle or misfiring, the only symptoms are a hard start and lack of power (not neccessarily boost).