Engine Management Light Flashes after Cambelt Change

[mik15]

by the error code it could be the MAF seals, maybe they didn't set right the airbox and under heavy acceleration when extra air flow is required it sucks too much air...check that the airbox sits tight, actually Audi recommends to change the MAf seals every time the airbox it's removed...or one of the vacuum hoses, both of these trigger the misfire error code...

[Lionheart]

Hmmm... Seems to be leading back to a timing belt issue.

Why would someone put a paint mark on there in the first place? Logic would say just lock everything in place and then change it so nothing moves.

Weird that it would not work when 'done correctly' but had to be reverted to the paint mark (one tooth out apparently).

Lets say, for arguments sake, that the timing is out of whack. How do you manually work out where each part should be?

[mik15]

they should've used the cam lock tools, it is recommended if you want to be 100% you don't screw it up, however, i guess that someone really experienced could improvise, you know better what kind of guys are the ones that worked on the car, this is why i go only to my mechanic for tasks such as this one and don't just try any Shop, i would go to MRC and have the other Shop to pay for the labor if it turns out that it was their fault from the beginning...

you could also check what i said earlier...just to eliminate other possible causes!

[nukinukinuki]

Sorry if i do, But i don’t want to sound like a DI£K, Yes i agree i cant either imagine it been 4 dodgy spark plugs just by coincidence to cause a misfire only at specific amounts of load on the engine.. It could be running lean under boost and causing the knock sensor to flash the engine management light.. (I’m totally not familiar with how the Ecu operates I’m just saying) It could be old fuel. It could be the Maf sensor. There are millions of “It could” ideas but the diagnostic has simply not given yourself enough of an indication. It has just confirmed what is happening on what cylinder. I just feel you are beating around the bush when you have paid for this to be done correctly.

I could totally understand if you had taken on the Timing belt job yourself we would be throwing ideas at you but these guys know the Tracks they have made and what they have removed prior to rebuilding the motor from its service position, The only thing you are doing from my experience is giving them more time to blame the issue on your own actions after the car left the workshop when/IF something Major goes wrong, I know you say they are good friends but money talks! If this Issues results in a HUGE cost to pay if the inevitable happens (These engines aren’t cheap) I can guarantee they won’t be paying. You will be going through a solicitor fighting against the fact that the car has been out of their hands for X amount of time doing your own diagnostics..You would soon find out how nice your garage pals are then they are refusing to pay for there actions.

The mechanic who did the job could easily look backwards over his work checking every individual wire/coil etc that was required to be removed or touched during the Belt change or when the Service on the motor was carried out, it’s quite possible they will find a little something that’s been missed or nipped during the process. The Spark plugs on the offending cylinders could be checked to indicate what type of misfire it is weather its fuelling issue related to timing or injection etc. It wouldn’t surprise me if the Timing was still out.

IF you did want to do something I feel the only possible thing you could do would be to check the Obvious... Remove the engine covers and check Wires/Plugs for damage and the basic things that possibly have not been seated properly during reassemble/Servicing.
I don’t want to you to think I’m a N0bh3”d.. I just want to try and save you money and give you my personal advice from previous experiences with “garages” to get your car rectified as soon as possible or it could all end in tears. Wishing you had of just taken it back to the garage if something catastrophic happens.. And since they have been playing around with the Timing belt I don’t think its you’re place really to be diagnosing a potentially catastrophic issue.

If you really want to diagnose this yourself id start logging the ignition timing to see if it's being pulled back by the ECU. Also check the engine vacuum + MAF leaks
Ignition system and components, coils/leads etc.

[Nobby]

Its all about the timing kit Lionheart for proper OE settings. If you know the settings (in terms of degrees opening before TDC then you can do it yourself with the right tools.

Cam locks physically won't fit on without the cams being in the correct place. The crank pin moves the crank so it also can't move when its located.
Like this


If people don't have the right kit then they often put a new mark somewhere - which is ok if its done perfecly with a dti gauge on a certain cylinder (normally no. 1)/protractor.

Have a look at this link - Guy Croft is a legend amongst Fiat/Lancia race engines and he explains things very well.

http://guy-croft.com/viewtopic.php?t=104

[Lionheart]

nukinukinuki - no problems at all! I probably should have mentioned that it was going to go back to the garage etc. No offense taken at all!!! And thanks for the info! I like to know what's happening, so when they fix it I want a good understanding of what the issue would have been, and therefore how is was resolved.

Nobby - you're a star. The guys at the garage are knowedgeable guys and so hopefully they'll know a lot of this stuff already - but for me it's quite interesting stuff!!!

[nukinukinuki]

awesome well i hope it all gets resolved hastle free! keep us updated would be good to know what the dianosis is

[Shoppinit]

You simply can't do this cambelt with paint and get it right. You need the proper crank lock and cam lock. I can't believe this place even attempted it. Why did you take it there?

[bakustax]

awesome well i hope it all gets resolved hastle free! keep us updated would be good to know what the dianosis is

Haven't got a clue would be my guess...RS6.com have a fairly good step by step guide to changing the cam belt...site seems to be down just now...grab their guide and give to the garage...they may be yanks but they know how a V8 works...and how to work on one.

[Shoppinit]

Log measuring block 90 values at idle and tell us what you've got.

[bakustax]

See attached procedure...I'd give the garage this...

TOOTHED TIMING BELT REMOVING AND INSTALLING.pdf

(562.4 KiB) Downloaded 178 times

[Mr Footlong]

Baku, before I stick this on the archive, that covers the C5 RS6 4.2 and S6 unless I am missing something? Thanks.

[bakustax]

Baku, before I stick this on the archive, that covers the C5 RS6 4.2 and S6 unless I am missing something? Thanks.

Correct Footers

[Lionheart]

Ok, car is back in at the garage.

I noted upon start up the last couple of times that there is a slight rattle noise.

Additionally, when nudging the accelerator back and forth lightly when stationary there is a very light rattle. You can also notice it when pulling away from stationary. Just half a second or so.

I assume this is one of the cam chains? Could this be down to the tension not being correct/tight enough on the cam??

To clarify guys, lets assume that the timing is out for whatever reason. Can it be manually set to the correct settings (ignoring locking tools)? And if so, how - and where do you get the correct settings from - or is it calculations???

[mik15]

the rattle you've noticed is made by the cam chain tensioners, and most of the RS6 C5 have it, i have it too and it comes briefly at a certain rpm, 1200rmp if i remember well...most likely it was there before but you didn't notice it, i noticed mine a few months after i bought the car, i heard the same noise to another 3 RS's...