Only 3 cylinders fire. HELP!

[Steffen]

Today i got some problems with my S4s.

I was entering the highway and i had almost 100% throttle in 3nd gear.

At around 4-5000 rpm i suddenly lost power. No high noice or anything.

The oil temp was at 70c and the water was 80c. Oil pressure at 5.

Now it runs on 3 cylinders. I have spark on all plugs.

I dont have smoke from the exhaust.

I have connected freescan and i dont get any errors.

I have a feeling that maby the injector is broken?

What do you guys think?.

Any sugestions?

I go and take a compression test tomorrow.

Hope its not serious

[rogerch]

Awaiting compression report.

[Steffen]

I have lost compression on cylinder 2

Looks like i have some water in the oil,

so maby its the head gasket?

What is a typical problem on the esprit when you loose compression?

[rogerch]

When you say "lost" does it show anything on the gauge, in fact what are the 4 readings ?

[Steffen]

I have 3bar in nr 2 and 8bar in rest of the cylinders

[Steffen]

Status report

Injectors are ok.

Sparkplugs and coils are ok.

Compression in cylinder 2 are 3bar and the rest is 8.

The hose on the fuel regulator was not connected.

Does it get to much or to less fuel without the fuel regulator working?

The sparkplug on cylinder 2 was really messy so i think maby a valve is not closing properly,

becouse of too much fuel from a non working fuel regulator?

Is that possible?

[Rich H]

If a valve was stuck then you'd get no compression. I'd suggest maybe a burned valve perhaps?

[rogerch]

Once you've established low compression the cause is academic, because it's cylinder head off. You could stick a camera down the plug hole and see if it's, head gasket, valve or piston, if it's piston it's 100% engine out, the other 2 could be done with only the head off, but even that's marginal in situ or engine out.

[Vulcan Grey]

The fuel pressure is increased with boost by that hose on the regulator. SO you might have gone lean with that hose disconnected.

[rogerch]

As a matter of interest, would lean toward a burnt piston, or damaged valves, my guess would be piston ?

[Steffen]

Thanks for reply.

Looks like the valve in not closing.

What can the reason be?

Is it garanteed that the valve is proken? or is it other posibillities?

Is it possible to take out the engine head without taking out the engine?

Edited May 6, 2011 by Steffen

[jonwat]

Looks like the valve in not closing.

Strange, what makes you think that it's broken??

What can the reason be?

It could be bent or the spring could have broken

Is it garanteed that the valve is proken?

No, see above.

or is it other posibillities?

Yes, see above.

Is it possible to take out the engine head without taking out the engine?

Yes, it's not easy but perfectly possible & I would suggest that as your first step to fixing the problem.

[Steffen]

Thanks for the reply

To be honest im not sure.

I have a mechanic friend that looked at it.

He sayd it sounds like a exhaust valve that is not working.

I have tested the ignition and fuel. Both are working.

How can I test if the cylinder rings are working?

I dont have fuel in the oil and the exhaust is good (no smoke)

Is there a guide somewhere to remove the head without taking out the engine?

It looks really hard. Should i lift the engine a bit?

[CHANGES]

First thing i would do is to remove, the cam covers and check the gaps. on the followers.....if one is extras big on no. 2 then its bent.!!!! while you are at it check all the followers ... if you have a cracked follower then it can jam the valve open....if you are lucky not enough to hit the piston....but don't hold your breath....if all the gaps are good then get an endoscope in the spark plug whole and study the valves / piston for burning....This i think is unlikely as your symptoms are to aggressive..... These procedures can help diagnose the problem without to much invasion and cost.....then you can proceed to the next level...

Dave L

[Mike6]

Oh god why does everything now come down to cam followers. I have been having nightmares since Dave correctly diagnosed a shattered follower. If you remove the top of the cam housing - only held down by two fixings you can see straight away if anything is wrong. If nothing is immediately visible like no cam follower other than millions of little bits you could be in luck. You then remove the spark plugs put the car in low gear and slowly push the car foward. You can then observe the rotation of the cam and spot any absence of movement in a cam follower which could indicate a stuck valve. Also as Dave suggests check the clearances- mine were virtually non existant. You can check all this for the price of a gasget. I would go for the exhaust cam in the first instance

[Sparky]

Slightly OT, I know, but Mike - the valve clearances are supposed to be virtually non-existent. Don't assume they're too tight. The inlets especially are a very small gap, and incorrect use of a feeler gauge will give you bad readings. The likelihood that they're all too small is remote.

[Steffen]

Thanks for the help guys!

I just checked the clearence on the followers.

The exhaust valve followers are all 0.30 mm

The intake valve followers was 0.15 mm. (some was actually 0.10mm, but it was not special on the nr 2 cylinder)

I did not see any typical errors. Should I remove the oil to see better? I only see the upper half of the follower.

Doesn't look like anything is wrong here.

Maby a piece of the valve is broken off?

I used a camera and didn't see any damage on the piston.

I was not able to see the valves with the camera.

[rogerch]

It is always possible that it's "only" the head gasket, but really all this is academic because the cylinder head is going to have to come off anyway. The only decision you have to make is do you take the head off with the engine still in the car, or take the whole engine out. Personally I'd save myself a lot heart ache and busted knuckles and take the engine out. But the again I have a hoist.

[trackmagic]

Steffen,

If you have a way to charge the cylinder with air you can tell for sure where the leak is going. I have done this with the hose that you use for the compression test but hooked to compressed air. You will need to put that cylinder on the firing stroke (valves closed) at TDC (top dead center). You can put the car in gear and hopefully have friend hold the brake (hand brake as well) and then put air to the cylinder. Escaping air can heard at the exhaust outlet (valve), intake (valve), oil filler (piston), or radiator expansion tank (head gasket).

Best,

Jeff

[Rich H]

Remember it's not a full on leak - you are still getting 2 bar of compression - if a valve was bent or chipped you would get no compression at all.

I suspect it's HG only (or a cracked liner/head but we'll hope it's just a HG) or a burned valve seat.

[richardvg]

try dropping oil down the cylinder and swing it - then re check the compression,,

[Steffen]

Thanks again!

I will try compress air to the cylinder to where the problem is.

The test with the oil is also easy to do.

I can't decide if to take out the engine or just the head.

I dont have a workshop. Only my garage.

I need to buy a hoist if im going to take it out.

How much time do i save? I guess the timing is hard without taking out the engine.

Anyone know a guide to take of the head?

I guess i get a problem with the exhaust manifold.

[Mike6]

Have a word with Wookie or Sparky for the photograhic guide they produced. I have a similar problem with space in my garage which doesnt allow use of a hoist. and havent had much time recently to make progress. From the looks of what I have done so far it is perfectly possible. Remove the cams first (be careful with the TORX heads) you can then gain access to the top exhuast manifold nuts (there are locking tabs) remove the heat shields (a bit trickier) and then you really have to become a contorsionist to undo the lower exhaust nuts (luckily the locking tabs were not in use) and you gain access by jacking the left side of the car and crawling underneath. Using a light you can then see the nuts but getting them undone depends on their state. Thats as far as I have got - just follow Wookies guide and I believe the rest is much simpler.

Let me know how you get on and we can share experiences.

[Steffen]

Hi.

I made the decision to take out the whole engine.

I want to take a overhauling on the engine so im sure everything is working perfect.

Thanks for the help guys.

I will inform you with updates on my rebuild.

Wish me luck

[rogerch]

Good decision.