Help, need advice!

[Billman]

Hi,

i have a problem in my Rs2 and cylinder 3 is not working. I have spark and i see that the lambda value changes when i connect or disconnect the injector plug.

What could it be? Clogged up injectors (they are ca. 20000km on the car)

Are there any fuses or relais for the injectors on the car that i should check?
What else could it be?

thanks in advance

[Ducky]

Is the plug wet when you take it out; if totally dry then I would look at an injector failed perhaps and stuck shut?

[Billman]

So today i did some test to narrow the problem down!

Exchanged the Injector between cylinders---->no change
Exchanged Injector plugs between cylinders -----> no problem there (ECU and cables OK)

If i look in the cylinder with through the spark hole i see that in piston 3 there is black gag and is wet. In cylinder 2. i.e. the surface is somehow dark but dry.

So where is the problem? Can it be that the intake valves not opening enough so this cylinder doesnt burn the fuel?

How can i check it?

dont hear a sound of bent rod and dont see any smoke in the exhaust.

also remember the car did approx. 1000km like this (injector plug and coil plug removed) so i think if something else was wrong like bent rod or piston rings after 1000km it would have worsened. What do you think?

thanks

[Knight Rider S4]

Had same problem on my Coupe when i first got it and hydraulic tappet was screwed causing the cylinder not to run properly

[rs200]

do you look compresion ratio betwen cilinders? mesure them and you will know.... maybe is valve or piston ring.

[Billman]

didnt checked yet! Will do it on Monday......

[Billman]

Had same problem on my Coupe when i first got it and hydraulic tappet was screwed causing the cylinder not to run properly

did you hear any noises from the engine back then? the only noise on mine is the different exhaust note and the vibrations on low revs!

[Billman]

If the tappet is stucked then it doesn't push the valve to open? This could be an explanation to me.....if not enough air is coming in then it cant burn the fuel so it doesn't work and thats why it seems wet when i look inside.

I am going to start stripping it down tomorow! Any tip on cam removal since i don't have any special tool??

[220bhp]

Is it wet with petrol or could it be water from a failing head gasket.
If a tappet has failed you should be able to see which one has collapsed with the rocker cover of.

[Billman]

will do that....it seems like petrol with something black!
I guess and hope that it is like this because the fuel burnt partially and it buildet carbon deposits on the piston.

[Billman]

Today i took appart a 7A head and noticed that the center piston of the tappet has a spring and if you push it it comes right up. On the tappets i removed from my car nothing happened! they where simply inside (they came out only if pulled). I suppose they must come up with the spring and not only with the hand, dont they?

[denniselbows]

are you sure you have a spark on number 3 .if you have a week coil pac you may get a spark with the plug out of the head but not with it back in the head due to the compression .i take it you have tried swapping the coil pac and pos

[Billman]

yes, i did it! Spark is the same on every cylinder, tryied also other coils (LS2 high output coils), nothing changes!

[GazzaG60]

do a compression test. it may save lots of time.

my snapped cam gave similar symptoms. i had compression on no 4 as it snapped between the lobes so half always shut and half moving. i had nothing on 5 as all exhaust was stuck open.

no engine damage either.

[denniselbows]

yes, i did it! Spark is the same on every cylinder, tryied also other coils (LS2 high output coils), nothing changes!

ok just checking it is so easy to over look things some times.
as said all ready comression test is the next in line to test it out. if it is a valve or ring problem then that identifie that. one last thing this is a bit of a long short and lightning only strikes once sort of thing you haven't got a fabricated intercooler by any chance the reson i ask is a friend of my and his boss have a A2 replice they biult in whick they had a intercooler made which had the inlet and outlet on the same side .and when making it the guy cut the plate to seperate the 2 parts too small and rather make a plate the correct size tacked a bit on to fill up the gap . anyway this little peice broke away and managed to make its way up the pipe past the throttle body into the manifold down one of the ports and pritty much blocked off one of the cylinders. this was only found out as a result of taking the head off as it wouldn't run right and running rich all the time. jeff only found it as there was a rattling noise in the inlet manifold when he put it down.