Poorly RS2 :(

[Ducky]

Unfortunately after changing numerous things to try and cure my poorly running RS2, it's coming down to possibly the compression being an issue.....

What originally started as just a rough idle is progressively getting worse as the car warms up, cylinders 3+4 seem to be the main ones affected.

Thinking it was a spark/fuel issue so far I've replaced:
New plugs
New coilpacks
Error404's wiring loom replacement
Injectors cleaned

So having discounted those, the next item is compression test, so I'm just waiting for my compression tester kit to turn up!

If it turns out the head has to come off, is it worth getting it refreshed while it's off (car has done 80K/miles), or anything else worth doing (porting etc)...if so any recommendations where to send it?

I only changed the water pump/crank pulley etc. not long ago when I did the cambelt, so they should be fine.

thanks
Chris

[Rusty]

Did you set the timing correctly after doing the cambelt? Notorious problem on RS2s as the marks dont line up.

If it's compression then it may be bottom end, like mine. Wait and see I guess... Do a dry and wet comp test to determine top or bottom of the engine.

Best of luck

[Rikki Kitto]

Sad times if you do take the head off get JP on here to do work on it,

[SteveH]

80K is very low mileage for a worn engine. If it is the bottom end you will need to find out why you have issues or your freshly rebuild unit may suffer the same fate!

[Ducky]

Cheers for the info peeps, Rusty the car ran fine since doing the cambelt etc, but I'll do the dry/wet test you mention soon as I get my comp kit. :thumb:

The car does sit unused a lot in my garage though, and I wonder if the lack of use has something to do with it.... I've owned it since 1998, so has been with me a long time, but only covered circa 11k miles!

[Rusty]

Short trips from cold a lot? Stock map? Boost leak? All make it run rich and wear the bores/rings

Do the test and you'll know what's what then.

As a rule, if it's low dry and high wet then it's rings, if it's low whatever, it's top end...

Mine was low dry, normal wet, so I have one cylinder that's heading south.

Have you checked the spark plugs? May be coming loose...

[Ducky]

Yup, I've had lots of bits on/off recently while changing parts/testing and plugs are tight. It has done longer journeys recently, but the majority were always short. (Homefried ECU)

Hopefully have my kit by the weekend, so I will find out then........

[simon20vq]

Surprised its rings or valves if you have always let it warm up and cool down properly. Did it run OK with the old plugs?
I would look for a split boost pipe or poor electrical connection. ISV, temp sender in the head, maff connect etc.
Hope you sort soon, hope to hear the final outcome.

[prj]

You've done lots of things, but did not sort the two most important issues:

1. Fault code check with VCDS
2. Boost leak test.

99% of 2.2T problems are solvable using these two methods.

[Rikki Kitto]

Talking of boost leak tests who does them and how much are they Mines never been 100% since I bought her and sure it's this

[Ducky]

Unfortunately I no longer have my Vag-com setup, and my friends Snap-On Modis refuses to connect. However, if I pull the injector plugs, cylinders 3+4 hardly make any noticeable difference, unlike 1,2+5 which when disconnected cause a big stumble in the idle.

Hence my thinking that there is an issue (compression or otherwise) on 3+4, as I've changed/replaced most of the obvious things now.

I actually have a boost test kit, however 'sods law' I'm in the middle of moving house and all my garage stuff is 100 miles away in storage...so not the best time for the car to play silly.

[Harvester]

Hello ,
I had some very simillar issue on my S6Plus few weeks ago . When cold , car was runnig..lets say properly . When get warmer , car ran very rough and definitely no smooth . Car has an autogas system in it and fuel injectors wasnt in use for a long time . Two of them was cracked . First i gave them to the injectors workshop to clean , but it didnt help . Then I have to buy new ones a problem is solved . Try to change injectors between each other , if the missfire move to other cylinders. If yes , you have found your problems.(Unpluging coil , like you did before) Good luck.

Do you have some O2 sensor fault codes from diag ? (vag)

[Ross]

Good advice above - it's worrying hearing that you're noticing an issue on particular cylinders and sounds like you've covered the key areas, spark/fuel/ingition.

I hope it's not the motor - 80k really is low; mine is recently rebuild at 160k and whilst the tappets did need replacement along with worn/leaky stem seals the bottom end wasn't too bad, I expect it would have gone to 200k but I went for a JP rebuild...

Definitely check and codes as well, grab a cheap cable and vagcom lite on ebay or do the old LED blink check. I've had my fair share of running issues due to small boost leaks, looks jubilee clips, knackered vac hoses etc... i have a kit that can be loaned out if needed. Just so long as I get it back.

[Ducky]

Got a cable and the freebie VCDS off Ross-Tech, I cleared the obvious codes created while I was unplugging stuff (maf etc), running the engine no codes appear. Be gutted if I have to pull it apart, as it's all original (apart from my coil changes) and untouched.

[Ducky]

Got my comp checker today....the compressions are roughly 100psi on 1,2+5 and 50psi on 3+4. However with the tester in 3, it blows out of 4!! and vice versa. Tis enough to shoot a tissue stuck in the plughole out the engine bay!

If I pour some oil down 4 it only goes up about 5/10psi....!

So at least head gasket has gone, albeit 100psi seems v.low anyway...so could also be leaky valves etc. Will have to whip the head off an get it refreshed.