Uh oh, knocking...

Sam_

Sam_

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It's not the rods heh. I've noticed of late that I sometimes I get the odd knocking on boost if I'm sudden or build up and then nail it (overtaking etc). It sounds very much like knocking/pinking so I let off straight away when it happens of course. It's random, and doesn't throw a fault code that I can see (liquid gauge says it's all clear). The car's on 120,000km (75,000 miles) so not that old. Plugs are probably around 15,000km old iridium NGKs but might be worth doing - was going to get BKUR7ETs and change more often? Fuel pump getting tired? MAF is genuine Bosch about the same age as the plugs, same for the coilpacks (bolt downs). Checked for misfires, nothing. The odd thing is that it drives ok whilst doing this (as in, smooth), but does feel a little underpowered. Which suggests to me running lean. I'll try to run the AFR gauge more and see whether it is running lean. The ambients will have picked up a little recently (getting towards summer, today was 30+) which probably doesn't help, if it's pinking.

I've been granny-ing it until I know what's wrong :(

Any ideas what it could be?
 
Yeah I think it needs a proper VCDS session. I had issues doing logging before (eBay cable with Lite software, on a MacBook with VM...) but I will try again.

What's block 20 for?
 
Haha sorry - I should have googled...

I did notice using the "Timing pull" function on the Liquid Gauge that I was getting 3.0 on #2 and 6.0 on #4 without even giving it death, and at less than 3.5k rpm. Can't be good?
 
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No... getting 6's is fairly iffy...

Pull the hose off the throttle body and see if its full of oil... (wet with...) clean it up and go for a drive... check to see if its back...

Also... pull the hose off the top charge pipe (the one that goes behind the headlight) and see if oil is there... agian clean, drive and check...

Oil here would suggest turbo seals... this oil will dilute the octane rating of the fuel and promote knock...

<tuffty/>
 
******. Cheers, full of good info as always. If it is the turbo, I might have to nurse it until I get the new engine built :(

I'll chuck some new plugs in and give it a once over. It's due a service anyhow but I've been putting it off as I need to swap the sump and do the pickup. I know it's going to be a messy/fiddly job. Might have to attempt it this weekend.
 
Thinking about it, it has been burning/loosing a bit recently. I've been gradually topping it up more often, and it was mildly smokey (oily) on the dyno when the haldex was freaking out.

******++
 
wow , damn i thought i had issues... i hope your sort it out.. seb will be doing all that from me hehe... i can be smug about it too.. he will be doing the oil pump tensioner pick up rear main seal new 580ft clutch and well LSD box :D finally..

why is it burning oil though i dont replace not a dropplet of oil on mine thank God.. its stays at the same level each time i check
 
Changed the plugs (BKR7Es) but it's still doing it. I went to give it some stick on a sliproad and had to let off straight away.

I decided to checkout what the timing pull was up to...

2012-10-25%20at%2001:46.png


Not good. Then I logged again on the way home from getting some iso alcohol to clean the MAF:

2012-10-25%20at%2001:46.png


Mental numbers.

At least the brakes are awesome :) I haven't done a logging session (need to setup a Windows XP vm again...) but that's next along with a MAF clean. I'm almost positive it's knock. Could it be a lambda?
 
Thats some reasonable timing pull for sure dude. What RON fuel are you using out of interest?

Avoid booting with figures like that.

Is it mapped?
 
I get high timing pull like that in.fact higher sometimes iv now put it Down to a crappy map on my car
 
Well it's never done it in the 18 months I've owned it, only in the last month or so.

I went out for a curry with a few mates tonight and on the drive back, this:

2012-10-25%20at%2010:18.png


It was cooler tonight but still...

I'll give the MAF (<12 months old) and AIT sensor a clean at the weekend, check for obvious vac/boost leaks and give it a proper scan/log.

Don't worry, I've not been booting it with it like this. The noise of knocking sends shivers down my spine. I build a 1.6 n/a engine once and the CR worked out to be like 12:1 and the ****** thing would never stop pinking.

Welly: I always use 98, either Shell or BP without fail. It's got a stage 1 map of some sort, unsure which but it runs 21psi and generally drives well, just recently is having issues. It's getting itself quite hot and bothered at times. Idle has been a bit off too.
 
I always do it for oil temp, quicker way to get to it as its the last item, wait for it to hit 75-80 then nail it :) (although not at the moment :'( )
 
Yeah I did sorry. It was dry as a bone. The catch can must be helping...

I also checked the oil when I changed the plugs and I'd not lost much, if anything.

This morning's drive (it's cool again):

2012-10-26%20at%2009:04.png
 
audi upgrades
It's odd though, it didn't do it last summer (which was hotter than now, still spring). Not sure about entering the WMI lottery. Is there a solid, easy to fit kit that doesn't **** out everywhere or ruin throttle bodies? I'll give the maf a clean and check a few things tomorrow like I say and go from there...
 
Didn't get a chance to do a scan or clean on the weekend but maybe tonight.

I seem to have another issue, not sure if it's related but I get a very intermittent cut of all power for milliseconds sometimes, it's like the car stalls and then comes back to life. Only this morning on the way to work, it cut out completely. It doesn't seem like a normal stall, more like a complete loss of power but the key brings it back to life. It's only ever happened at idle though, never cut out while driving (fingers crossed!!).
 
Still getting this occasionally. I think the other issue of stalling now and then is caused by the crank sensor which arrived at work today, so might attempt it at the weekend.

Here's a detailed pic of the plugs:

plugs.jpg


Larger pic here: plugs.jpg

Does it look like it's running lean?

Possible failures?
- Fuel pump slowly dying a death. It's not loud though?
- EGT threw a code, 17863, but it's not come back today - I do have an exhaust leak (where the Milltek joins the cat) which apparently effects EGT? If the EGT sensor was duff, wouldn't it be rich? I got 24mpg from it on the last tank.
- Could the crank sensor cause this as well? Cam sensor?

Not measured block 020 but I should be able to this weekend if I can nick the mrs' macbook.
 
I can't understand what it can be then. It's definitely pinking/knocking now and then and it seems to be when the fuel system is asked to respond very quickly, i.e. dropping it to 2nd to clear a gap etc.

It done it tonight on the way home, oil was hot, IATs were 25c odd and it wasn't a hot day really.

I guess no ones had anything similar? Fuel pump?
 
I've been doing more reading. Is it possible that a cam sensor could cause this? Is the crank sensor used for timing or just during start up or are both essential for running? I have a new crank sensor here, could order a cam sensor too, if that's a likely cause.

What would I log to indicate whether the fuel pump is shot? I'll check the hose to the FPR but I've got a feeling it's not that - it's silicone, not old, and that'd cause a constant issue I'd assume.
 
Checked all vacuum and n75 hoses. Nothing obvious :(

Checked for boost spikes and the same old 1.5 bar peak (but also had no pinking today).

I'll keep investigating.
 
Hi Sam, are you able to do some logs of the AFR?
I believe the blocks are 001 and 031 and post them up.
Or alternately fit a fuel pressure gauge in line just before the injector rail and go for a spirited drive, preferably with a passenger so he can watch fuel pressure behavior.
Fuel pressure should shift if on boost or overrun, in other words total fuel pressure is 3 bar + boost.
Ross
 
if its fuel related could your injectors need a clean? as that a quick and easy thing to do.
 
I did them about 6 months ago but won't harm to do them again but I just think its something else. If the injectors were dirty it would effect it at other times too I'd say.
 
yeah your probably right but its worth checking plus you can give the FPR a good clean too just for good measure.

Hope you solve it soon
 
Cheers dude, yeah I'll give them both a clean when I fit the fuel pressure gauge.
 
Sam_ said:
Didn't get a chance to do a scan or clean on the weekend but maybe tonight.

I seem to have another issue, not sure if it's related but I get a very intermittent cut of all power for milliseconds sometimes, it's like the car stalls and then comes back to life. Only this morning on the way to work, it cut out completely. It doesn't seem like a normal stall, more like a complete loss of power but the key brings it back to life. It's only ever happened at idle though, never cut out while driving (fingers crossed!!).
Click to expand...
I'd also like to know, because when you mentioned the intermittent loss of power, it immediately sounded like a problem my mate had on his TT, I suspected the n75 so we tried swappping it to my car and it knocked like you have never heard before on my car because it was running very high boost and the out of spec n75 showed up real bad.
my advice is to get it changed and your car will drive like it's got a new lease of life. Only £50! Well worth it, rather than a new turbo or worse engine.

Lol, thought this was December 2014, sure it's sorted now!
 
It's still doing it 2 years on but its very occasional which is the strange thing. I've tried all sorts but nothing obvious has worked. The N75 is reasonably new (3 years now) but I guess it can't harm to try a new one. I've waited really getting into since I'm building a new engine for it (longest build ever).
 
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