Leviathan888
Leviathan888 New Reader
3/25/23 8:36 p.m.

If you've been following my other posts, you'll know I've been tinkering with a 2008 Audi A4 Quattro. After hooking up some electrical, adding MTL and engine oil, and redoing battery connections, today I was ready to start the 2.0L turbo engine. 

I was having trouble with the "press clutch to start engine" light, turns out the positive lead to the starter was rusted and worn through. After figuring this out, I basically hotwired the car to see if that fixed it, and the engine spun over. Going back into the car, pressing the clutch doesn't make the light go away but it happily started anyway. Theres some problem with the clutch switches for that, but it started anyway so I don't really care. 

 The Audi started up well, but quickly died. A second start and it kept going this time. Intitially it was running a bit rough and noisy (attributed to the 6ish month old but stabilized fuel, and the fact that there is no exhaust) but it quickly cleared up and started purring. The coolant temp hit about 65 celsius (160 fahrenheit) when it started running rough again, almost knocking. This continued the duration of 15 minutes, until we shut it off. Below is a link to a video of it running near the end of the 15 minutes.

Video

Looking for some advice on whether or that sounds like knock? Pretty cold out today though, so maybe just exhaust? As I say, it is straight piped right out of the turbo. A little suspicious that it doesn't clear up when you rev it though...                                                                                                                                                                                                                                               

 Comments, tips, advice, and criticism appreciated! 

1SlowVW
1SlowVW Dork
3/26/23 1:03 p.m.

Always hard to tell a knock from a video, drop the oil and see if it looks like glitter? 
 
 

Leviathan888
Leviathan888 New Reader
3/26/23 3:04 p.m.

In reply to 1SlowVW :

Right, I will check all the fluids for metallics and maybe remove the valve cover also. Really haven't done much to the internals other than check compression (which was good), do you think it's worth it to get a boroscope and check inside the cylinders? 

Slippery
Slippery PowerDork
3/26/23 3:08 p.m.

To me it sounds more like top end noise. But like 1SlowVW said, its difficult to tell from a video. 

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
3/26/23 3:17 p.m.

In reply to Leviathan888 :

No valve cover on this engine.  It's a cylinder head top.  It is also the camshaft caps and is sealed with a weird shellac, you don't remove it unless you really want to, and have the timing chains off. The early ones had access plugs and cutouts in the camshafts so one could access the head bolts without removing it, too!

if it has no converter, does that also mean it has no O2 sensors?  Really need to have everything assembled before bothering to run an engine nowadays.

GeddesB
GeddesB Reader
3/26/23 3:43 p.m.

Sounds like engine management.  Engine reaches operating temp and the 'at temp' parameters are off with no O2 sensors.  

1SlowVW
1SlowVW Dork
3/26/23 4:48 p.m.

Some things to note that I've run into on 2.0 fsi vw motors. A bad timing chain tensioner on the chain between the cams will cause quite a racket but not necessarily throw codes at idle. (Installed a no good one once). If you checking stuff out maybe pull the high pressure fuel pump too, I assume it's the same design and they like to eat the cam follower and could cause a pretty real top end noise. 
 

Leviathan888
Leviathan888 New Reader
3/26/23 8:56 p.m.

In reply to Pete. (l33t FS) :

Issue with reinstallation of the exhaust is that I don't have the exhaust. Since this car is from an auto wrecker, the downpipe housing catalytic converters and O2 sensors is missing. I can replace that piece of tube but would still need to source new sensors. Is it possible to run without them and patch engine management somehow?

Pete. (l33t FS)
Pete. (l33t FS) MegaDork
3/26/23 9:07 p.m.

In reply to Leviathan888 :

Technically yes, but it will be cheaper and easier to buy a new converter and sensors.

Leviathan888
Leviathan888 New Reader
3/26/23 11:00 p.m.

In reply to Pete. (l33t FS) :

I found a custom downpipe for sale locally, it has the holes for sensors and is just aftermarket and missing the converter. Might pick that up along with this, if necessary

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