Another S4 Cam Chain Thread

TomCrox41

TomCrox41

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Hi Guys,

So i think i have the dreaded broken cam chain tensioner on my hands ::keule:

Only owned the car for 2 weeks!!!

This is the first time in my life ive had two cars on the road and so thought i would have a go at doing this myself. And enjoy working on my own car for a change,

But before i begin, is there anything else i should test before??? I have kind of jumped to the conclusion that it is the chain tensioner.

the chain rattle is only during cold startup and is less than a second, i believe this is 'normal'
i noticed a lack of power, and CEL warning light under load. at low load it drives sweet,
Haven't yet plugged in VAGCOM, only used generic bluetooth one on phone, it read. random cylinder misfire code. and misfire on cylinders 5, 6, 7 and 8.

when under the bonnet, i can hear a very slight chain rattle on overrun but nothing more than this.

So is there anything else i should check before this, cam position sensor? anything else? please????

if it runs ok at idle, will a compression test show anything???

Has anyone on here had a go at doing this work DIY???


Tom

PS. car is 2004 4.2 S4 avant. 94,000 miles
 
chain rattle for less than a second I wouldnt have thought its broken. Just sounds like common misfire symptoms.
Under load the ECL will flash at you if it is miss firing. Id change the coil packs before doing anything with chains and tensioners lol you might save yourself billions :p
 
The previous owner had a few coil packs fitted, dotted randomly around the engine.

If im getting misfire readings all down one bank this kind of rules out a coil packs no? they wouldn't all go at once would they? or can they give each other a domino effect?
 
I'd certainly be checking the coil packs and for the price of a set of plugs, those too.

I'm just starting an engine out to have mine done.

I'm taking the engine out myself and then taking the engine to a specialist to have all the timing components removed and replaced. It's a very expensive job (Bearing in mind the value of the cars), but if it's a good one, I believe it's worth doing.

Here's the link.... http://www.audi-sport.net/vb/a4-a4-...6-2005-nogaro-s4-4-2-newbi-owner-england.html

I haven't posted any pics of the engine out/engine bay yet, because I'm not as far ahead as I expected to be, but that's me being a bit anal and cleaning and labelling all the nuts, bolts, fittings as I'm doing it.

Pics will follow though.
 
Yeah as above, for the price of plugs and coils I would replace the entire lot and start fresh. That will likely cure your issue. If it doesn't, at least you know they are good to go and to look at other options. As the misfire error is coming up I would certainly start there.
 
needs diagnosing with proper vag com not generic stuff
have a look on the map to see who has a genuine lead and is closest
 
So ive changed out my plugs and coils tonight, that needed doing, the plugs were not in good shape!

but to no avail... still hesitating, still same error codes.

got my vagcom laptop plugged in, it read similar error codes, random misfire cylinders 5-8
and a bonus two of
Bank 1 system too lean upper limit exceeded and
bank 2 system to rich lower limit exceeded,

While doing the plugs i had the battery disconnected so fuel trims could reset.

Also got P3041 Implausible Engine Temp. Message from Isnt. Panel. No Signal/Communication- Intermittent. Could this have anything to do with it???


Can i read any information from the measuring blocks that could point me in the correct direction??? cam angle vs crank angle???


could this be injectors not working???
 
Its the tensioner and or tensioner solenoid, the symtoms as are you describe. Less likely is the pickup in the sump that is blocked slighty and restricting oil flow to the head until pressure builds. Less likely still is a worn chain or cam sprockets that you may initially hear with too much play until pressure builds but id put money on first two.
 
Ive rather ovelooked this as the s4 b6 has chain not belt so can have timing chain tensioner issues so cld be this as know a commonish complaint
 
implausible engine temp , could be the coolant temp sensor
the bank 1 and bank 2 lean and rich could well be oxygen sensors at both ends of the scale and the ecu trying to sort out how to compensate for both
this could well be causing the problem
 
Done some logging,

91, 92, 93,

the actual and demanded seem to follow each other pretty closely , does this mean that my adjusters are working ok???

no movement on the phasing info in block 93, this cant be normal can it?

have a look see if you noticed anything.

PS. misfire is getting worse, near enough unable to drive it now.

Got allot more data but all shows similar info,

3 July 2014 18:14:47
4.2L V8/5V 0040

Group A: '091 Group B: '092 Group C: '093
RPM Load Demanded Actual RPM Load Demanded Actual Idle Stabilization Idle Stabilization
TIME TIME TIME
STAMP /min % CF CF STAMP /min % CF CF STAMP CF CF
27.64 760 42 12 12.5 27.81 760 47.1 12 10.5 27.98 -5 -7
28.15 720 40.4 12 13.5 28.33 760 40.8 12 13.5 28.5 -5 -7
28.67 760 46.3 12 11 28.84 760 39.6 12 13.5 29.01 -5 -7
29.18 720 47.8 12 10.5 29.36 720 47.8 12 10.5 29.54 -5 -7
29.72 680 43.1 12 12.5 29.9 680 48.2 12 10.5 30.07 -5 -7
30.25 720 40.8 12 13.5 30.43 720 49 12 9.5 30.6 -5 -7
30.78 720 45.9 12 11 30.95 720 40.8 12 13 31.12 -5 -7
31.29 800 48.2 12 10.5 31.46 800 47.1 12 11 31.63 -5 -7
31.82 760 46.3 12 11 31.98 800 41.2 12 13 32.17 -5 -7
32.35 800 42.4 12 13 32.52 800 47.1 12 10.5 32.7 -5 -7
32.88 760 46.3 12 11 33.05 760 39.6 12 13.5 33.22 -5 -7
42.24 760 46.3 12 11.5 42.41 800 41.2 12 13 42.58 -5 -7
42.75 760 48.2 12 10.5 42.92 760 47.5 12 10.5 43.09 -5 -7
43.27 1280 58.8 36.5 28 43.44 1480 56.9 50 45 43.61 -5 -7
43.78 1160 46.7 37.5 37 43.95 1280 54.5 43.5 39.5 44.12 -5 -7
44.3 1160 38 41.5 44.5 44.48 1080 34.9 36 39.5 44.65 -5 -7
44.83 1240 47.1 38.5 37.5 45 1320 47.8 43 41.5 45.17 -5 -7
45.34 1560 48.2 52 51 45.51 1640 49.8 52 50 45.68 -5 -7
45.86 1880 47.8 52 51.5 46.03 2000 49.8 52 50.5 46.2 -5 -7
46.37 2240 46.3 52 52 46.54 2120 5.1 35 51.5 46.71 -5 -7
46.89 1720 40 10.5 12.5 47.06 1640 44.7 8.5 8.5 47.23 -5 -7
47.4 1920 48.6 52 51 47.57 1720 47.8 52 50.5 47.74 -5 -7
47.92 1360 28.6 43.5 50 48.09 1360 46.7 46 43 48.26 -5 -7
48.43 1400 37.6 24.5 27 48.6 1360 47.8 25.5 23.5 48.78 -5 -7
48.96 1360 5.1 0 8.5 49.13 1320 5.1 0 -0.5 49.3 -5 -7
49.48 1280 5.1 0 0.5 49.65 1320 43.1 0 0 49.82 -5 -7
49.99 1280 60.4 30 23 50.16 1280 42.7 29.5 30 50.34 -5 -7
50.52 1240 5.1 0 0.5 50.69 1240 85.1 25.5 5 50.87 -5 -7
51.04 1200 38.4 34 36.5 51.21 1280 45.5 39 38.5 51.38 -5 -7
51.55 1280 52.2 45.5 42.5 51.73 1360 38.8 40 42 51.91 -5 -7
52.08 1480 46.3 37.5 36.5 52.25 1600 47.8 39.5 38 52.43 -5 -7
52.6 1720 52.5 44.5 41.5 52.77 1800 50.2 47 44.5 52.94 -5 -7
53.11 2000 49.4 50.5 49 53.28 2040 45.9 52 51.5 53.46 -5 -7
53.63 2160 47.1 52 51.5 53.8 2240 48.6 52 50.5 53.97 -5 -7
54.14 2360 47.5 52 51.5 54.32 2400 50.2 52 50.5 54.5 -5 -7
54.67 2600 47.5 52 51.5 54.85 2680 49.8 52 50.5 55.02 -5 -7
55.19 2840 45.1 52 52 55.36 2920 50.2 52 50.5 55.53 -5 -7
55.7 2880 45.5 52 52 55.88 2880 46.3 51 51.5 56.06 -5 -7
 
ah that didnt work as i wanted it too

Capture
 
So is there anyway I can know for sure it is or isn't the cam chain tensioners?

If I take of the top covers can I see the middle chain?

Anyone on here done this work before. Did the car rattle allot be before you did the work?

Cheers guys.
 
Ok so time for a update,

Decided to pull the engine myself,

got it out, whipped of exhaust, g-box, manifold, valve covers and chain covers and the usual suspect guide had cracked in two places.

replaced all the guides. chain skipped a tooth while changing guides so i had to rent out the tools to reset all the timing,

pricey for a weeks rental of hand tools!

also put a new DMF and clutch in, got it all together and engine back in car yesterday, only to struggle with what i thought was bleeding the clutch, now thinking that the SAC wasn't set right, and i haven't got the correct travel on the release springs. i spotted the springs were close as i assembled, but thought that was just the way it was and the inner ring would be designed to move as well. after a bit of interweb investigation turns out that this is the stop ring.

anyway, seeing as engine is all disconnected when i get some time it will all come out together again.

pics to follow
 
  • Like
Reactions: RyanJonS4
Ready to Lift



Engine out



Gearbox off



All electrics and plumping cleared



Top Covers off



The Broken



Old and New


And Half rebuilt

 
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OK another update,

not good news.

So work has been slowed due to a holiday, however since the last update

got the engine out again,
reset the clutch.
refitted gbox, then engine, (was alot easier second time over)
refitted subframe, driveshafts, exhaust, all plumbing, all electrics, radiators,

Started it up, all sounds sweet! a few eml codes flash up, mainly due to things not fitted yet, lights etc. and a lambda sensor plug that was apart.
Got those bit sorted, refitted bumper, suspension and brakes
Go for first drive,

and

Exactly the same as before i started!!!! :keule:

its times like this when i think stamp collecting would be a easier hobby!

Anyway, trying to decide what is next,

getting out there today todo little bits that need doing and have a think, bleed brake+clutch, spanner check everything, check fluid levels.


as for what is causing this misfire on bank two, i am slightly lost, possibly cam adjuster??? i haven't got any cam over advanced warnings.

All advice is welcomed.
 
may have to take off and inspect the cam adjusters
look at the hole where the locating pin goes and see if it is elongated and worn
new ones are expensive im afraid , but jh motorsports has just released a new one which is made from a harder wearing metal and is a lot cheaper than buying from audi
 
What a pain!, does the car run normal from cold? I was thinking if with the broken tensioner if the valves have slightly touched the pistons on that side as you mention that the timing had skipped a tooth? Maybe worth doing some compression tests? All the breather system is clean no blockages and no leaks? I have seen people with problems with PCV valves that give issues.... Also how is your battery/ charging system is this tip top. Sometimes this can cause some electrical gremlins.

Cheers

Al
 
Last edited:
Back when I had my S4 I had the tensioner go and they changed that but didn't realise that the chain had stretched and all the exhaust valves on one side touched. So I second the compression test. I still have one of the old valves somewhere that was bent, looking at it it just looks normal
 
Cheers for the info guys,

i did a compression test and got good results,
Bank 1 (good side)
140
138
120
142
Bank 2 (misfirey)
152
147
139
137

I spent abit of time on VAGCOM with her yesterday, looking at blocks 91 92 93. the demanded and actual follow each other, so that should mean my adjusters are good then, Plus looking on JH Motorsport, they suggest that the car will have problems at idle which are better the faster the engine goes, effectively it like running a high speed cam at idle. All of this would give me low compression results right???

On top of all this as i was going to analyse the info i got last night but my workshop laptop has packed in!!!!
yay.......

running out of possibility's here!

So working on first principals, whats left

Ignition timing? surely it can't be that different left to right
Harness Problems, seems strange
Mix.
Fueling
fuel injectors?
Low Fuel Pressure? (i checked flow, that is good)
ECU commanding incorrect fuel? is it possible that the ECU commands majorly different left to right?


Anyone had a failed lambda sensor on one of these cars??? would it be able to detect that one is not reading right by the other sensor in that exhaust?
 
Thinking about it I had problems with random misfires after my tensioners were done. One of the injector seals were cracked and the connectors on the injector harness were broken so every now and then they would have a loose connection
 
TomCrox41 said:
Anyone had a failed lambda sensor on one of these cars??? would it be able to detect that one is not reading right by the other sensor in that exhaust?
Click to expand...

Lamda's do fail, had to replace one on my old RS Clio, EML light kept popping up, but was a specific fault code.

Got a derv myself, but does the S4 have one for each bank? Is it worth swapping across to other bank if possible? See if the fault moves?


Sorry to hear of your issues......one of the reasons I'm nervous of making the hop to an S4!
 
How's it going Tom.......... This is like dejavu for me seeing you do exactly the same as I've just had done.

Luckily I didn't have any issues to deal with and it was just a straight rebuild for me.

Keep us informed........

Great thread.
 
Thanks Guys,

No progress to report, being keeping away from it so i don't lose all enthusiasm

although intake manifold rattle seems to be getting worse quickly which is abit strange, there's nothing in there that could cause my problem right????

Jim your car looks great! Top work with it all! do wish my bank would let me do as much as you. Did you notice any performance problems before doing your timing chain? i see the guide was cracked.


I have a long term plan now, it is booked into the Audi specialist near me for diagnosis, unfortunately their top Audi man is on holiday for the next two weeks so its booked for when he returns, This give me two weeks to try and solve it by myself. maybe.....
 
No performance difference at all, apart from the cold/warm start rattle which only occurred occasionally she run as if nothing was wrong.
 
tom
you mention a rattle coming from the intake manifold , there is actually a reason this could be happening
right on the front of the block there is an actuator which can fail
its directly above the grey plug in the centre of the picture in post 19
if the actuator isnt working correctly it can in fact cause misfires but it is usually only above 5000 where there is trouble
the actuator controls the secondary air system inside the intake manifold
might be worth checking to see if its working correctly
 
Gents,

Some progress has been made,
i lifted off the intake manifold and found some light coking on the intake valves on bank 2, this suggests to me some bad timing on that bank, off comes the rocker covers


i put a spanner on the intake cam and was able to rotate it without the sprocket moving until i got a click and it locked up.

So this is the cam adjuster and if im not mistaken at idle it should be locked right??? then at speed oil pressure builds, lifts the pin and it becomes free to move to the end of its range, So mine was in its high speed setting even thou i have only been at idle, hmm, was it there when i set my timing last time???

Hmm food for thought,

anyway me thinks, get it out, get it open and see what we got
 
Awesome thread Tom, very interested to see what the Audi technician comes up with. A mate of mine is after an S4 and showed me an ad on eBay. Localknoxville is selling his, I remember the first picture he posted back in March, beautiful stunning motor. Anyone know why he is selling? I would drop him a PM but can't see how to with the new site.
Once again great thread with pictures of a V8. Get in!
 
So im in there, cover is now unbolted and free, but for the life of me i cant get it out.
it being held in by the coolant pipe which i cant get the way enough and the little bit of exhaust manifold heat shield that overlaps slightly,

They were each alot easier to move when the engine was out.

anyone got any tricks for this???
 
Ok so a fresh mind and hot of cup of tea solves all problems!

Cover cam of easily once i looked again and assess what needs to happen.

got the cams locked to TDC. (got a great deal on the tools on flee bay)

Whipped of the adjuster quick air test, all seems good,

opened it up and we find a only a small amount of wear on the pin hole


Now that doesn't seem to bad to me. Comparing to other web images anyway.

hmm.

so why was it not locked up when i took it apart???

much confuse. could i have timed it up wrong?

Right so thinking out loud what if....
1. guide breaks
2. for a unknown reason the adjuster is not back to its 'home' position i.e. the pin not sitting back in.
3. i get the chains off, lock the cams to TDC, lock the crank to TDC, the adjuster still not set to home,
4. i refit the chains a tooth out on that cam because the adjuster was set to home.
5. so what effect would that have???

the adjuster forces the intake cam out of timing?

hmm there is too many moving things here!!!! :think:
 
Right just thought about this.

when i checked the timing tonight i know i had the pin in the hole, so when i had the timing set last time the pin must have been in the hole, otherwise the chain wouldn't allow it.

so why did the pin not go back when the engine was running? the cam sensor wheel was correctly positioned

is my electronic actuator working???? hmm think i need to test this
 
Hi Tom

This is all very similar to the issues I was having once I'd replaced all of my components.

Your mechanical adjuster doesn't look too bad at all.

Did you fit new Electronic adjusters ?????
 
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