Engine rattle & misfire

dannyboy75

dannyboy75

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As of yesterday my B7 A4's engine has developed a rattle and misfire. The misfire isn't severe but is definitely noticeable under load, particularly at lower rpm. The speed of the rattle does change with engine rpm and sounds metallic/tappety to my layman's ear.

It's a 2.0 TFSI Quattro, with 120,000 miles but has had all its services. It's going into the garage tomorrow but just wondered if anyone had any thoughts?

P.S. Engine management light has NOT come on, nor have any other warning lights.

thanks :)
 
Well the garage didn't have time to have a proper look yesterday, but they're pretty sure the rattle is coming from the chain at the back of the engine. It gets a little quiter once the engine has warmed up, but not much.

Can't get it into the garage again until next Wednesday so just driving sensibly until then.....

Also done some googling and came across this thread which sounds very similar to my issue, and mentions chain and tensioner.

http://www.vwaudiforum.co.uk/forum/showthread.php?99308-A4-2-0T-FSI-sounds-like-a-DIESEL!/page2

I'll post back with any updates for the benefit of anyone else who has a similar issue in the future.

Edit: also meant to say, I think the misfire was unrelated as it's gone now. I think that was due to a dodgy batch of fuel from a Texaco near my office as it started right after that. Filled up with some Esso stuff yesterday and no more misfire....
 
I thought the cam chain was at the front of the engine ?

If its rattling at the rear of the engine, and the chain is at the front there are not many other things it could be.
Does it still make the noise when you press the clutch?
 
The garage showed me a diagram of the engine on their database software - I'm pretty sure the belt was at the front of the engine but there's also a chain and tensioner at the back of the engine, near the bulkhead. I could be wrong on this though as my memory isn't the best, and neither's my knowledge of engines.

TBH it's hard to tell exactly where the rattle is originating but it's definitely internal, as they checked all the auxiliary stuff. Pressing the clutch down doesn't stop it though.
 
belt at front
chain at the back iv had mine changed b4
dont let audi do it they will rob you blind
i think all the parts are around £250
 
bez101 said:
i think all the parts are around £250
Click to expand...

Ouch. Cheers for the info though.

Once this problem occurs is the chain in imminent danger of breaking, i.e. is it best not to use the car unless really necessary? Or would it be ok for a week or so until I can get the parts replaced, bearing in mind it's the chain rather than the belt?
 
if its from the back its the chain
i wouldnt drive it they have been known to snap
and its as bad as the belt snapping
it comes in 2 parts the chain and the full houseing sensor etc
make sure it all gets changed
 
Dumbass question of the day then, why a belt one end and a chain the other?
 
the belt drives the exhaust cam and the chain drives the inlet cam off the exhaust cam.

i too have seen two of these chains break, both times putting a hole thru the alloy housing at the back of the head bending inlet valves etc. these were both on b6 a4s, fsi engines "awa" engine code. they had like 150/180k miles on them tho.

proper big bills too. cheaper to fit replacement engines really!
 
Well it looks like its my oil pump has gone, as I lost oil pressure the day after my previous post. Took it to the garage and they confirmed the oil pressure is very low. They said it can also be the oil pickup/strainer, but I rather doubt it as that was replaced 6 months ago.

Anyway I didn't think an oil pump sounded like a huge deal until they told me the price of a new oil pump. Nearly four figures. Holy feck. :crying:
 
dannyboy75 said:
Well it looks like its my oil pump has gone, as I lost oil pressure the day after my previous post. Took it to the garage and they confirmed the oil pressure is very low. They said it can also be the oil pickup/strainer, but I rather doubt it as that was replaced 6 months ago.

Anyway I didn't think an oil pump sounded like a huge deal until they told me the price of a new oil pump. Nearly four figures. Holy feck. :crying:
Click to expand...

whos doing you the work for nealy 4 figures
cos there robbing you
 
if i read right you have a 2.0T fsi ?
the oil pump is not 800 = VAT
 
bez101 said:
if i read right you have a 2.0T fsi ?
the oil pump is not 800 = VAT
Click to expand...

Yep that's the one (engine code BGB). I'd assume the garages are putting their markup on it too before quoting me, but is that miles more than you would say for a pump & balance shaft then?
 
have you had the low preasure light up yet ?
it expect it to come on if its very low as they told you
also without checking the pump and strainer is around £250 ish
call audi get a price on the part
 
bez101 said:
have you had the low preasure light up yet ?
it expect it to come on if its very low as they told you
also without checking the pump and strainer is around £250 ish
call audi get a price on the part
Click to expand...

Yep low pressure light comes on soon after starting now, so car is off the road till sorted.

I rang Poole Audi and they confirmed the pump & balance shaft is £840 + Vat.

I have seen a used pump with balance shaft for less than £300 online, seller has good feedback and it's sold as being in full working order, so very tempted by that as I could save about £750. Just need to find a garage who'd fit it though, as the one it's at currently didn't want to know.
 
you need to find a good garage and have the problem looked at
id say you do defo need an oil pump cant see the pick up going again
but why how can they say it needs a balance shaft ?
 
bez101 said:
you need to find a good garage and have the problem looked at
id say you do defo need an oil pump cant see the pick up going again
but why how can they say it needs a balance shaft ?
Click to expand...

I spoke to a couple of local VAG specialists, they said the likely problem is that the hex drive on the balance shaft has become rounded (probably started when the pickup failed a few months ago). The trouble is, you can't buy the pump and balance shaft separately as Audi only supply them together as one package, at least for my engine anyway. I did check this with Audi when when I phoned to check the pricing.

I'm tempted by the cheap second-hand pump & b/s, but it's a calculated risk as I don't know the history of it. My head says I should just bite the bullet and get new parts though, particularly as the new pump has been redesigned to replace the chain and sprocket with gears. It's just heartbreaking to think what else I could've spent the £1,000 on, but I guess there's no point crying over spilt milk......
 
audi upgrades
You're best off getting the new parts seeing as getting them second hand will potentially end up with the same result.
 
iv not come across one yet that needed the B/S had a few done of mine and the lads i use have done there fair share
the TDI usaly needs the B/S
have it stripped 1st before you get the parts
 
dannyboy75 said:
Yep low pressure light comes on soon after starting now, so car is off the road till sorted.

I rang Poole Audi and they confirmed the pump & balance shaft is £840 + Vat.

I have seen a used pump with balance shaft for less than £300 online, seller has good feedback and it's sold as being in full working order, so very tempted by that as I could save about £750. Just need to find a garage who'd fit it though, as the one it's at currently didn't want to know.
Click to expand...

There is an Audi / VW specialist on the Nuffield iindustrial estate bud.

Its in the little area opposite Toys R Us.
 
Thanks, I think I've tried them as I tried a few specialists in the area (also tried Kartechnic, Auto-Care and Autotechnics in Gillingham). They all said much the same thing though, that they wouldn't want to fit a used part which could leave me back at square one in a week's time.

So in the end I told the garage where the car's at now to go ahead and strip it, then order the new pump if that's what's died as I've been without a car for 8 days now and really missing it. The wife's 1.25 Fiesta just isn't quite the same when I try and boot it!
 
The car was fixed a week or so ago and is running fine now. It turned into a rather expensive little outing in the end though.

Hard to tell what failed first, but I think it was probably the sprocket that has split in half. As a result there was some bad wear on the side of the pump unit, and it also sheared a section off the chain tensioner. End result was assorted bits of metal floating around in the sump. Not good.

I kept the bits as I'm tempted to write a letter of complaint to Audi UK and see if I can get some of my money back. Do you guys think I'd be wasting my time though? Car has FSH (not all from Audi), but is 7 years old and has done 120k miles.

DSCF5534s.jpg


DSCF5536s.jpg


DSCF5538s.jpg
 
Well that looks a mess.
Was the balance shaft worn then, or haven't you seen the part.
And , if you don't mind, what was the total damage to your wallet.
Brad.
 
I didn't see the balance shaft actually, the garage didn't mention it so I'd assume it wasn't one of the worn/broken bits. I know the hex end of it can get rounded off but I believe that's more common on the TDI, from googling Audi oil pump issues.

Cost wise it was a bit over £1,600. The pump/balance shaft alone is £840+vat, plus a chain, chain cover, tensioner, couple of other broken bits, cambelt, complete oil change and several hours labour. Oh and £55 to get it towed to the garage.

I remember having a £1,500 bill from my old Alfa 156 a few years back, but I never expected to have an even bigger bill for a german car. I guess that was naive of me!
 
Just for someone who gets into this problem in future. I had the same symptom for a week i.e. vibrations as if the balance shafts were out of alignment. Then one night on freeway, the oil pressure light came on. Engine started making rattling sounds (low oil pressure to lifters). I turned it off in seconds, towed to my mechanic, discovered the sprocket for balancer shaft was split in half. I got away without buying a new pump or engine. Just replaced the sprocket with a used one from eBay and that was it.
 

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