Low compression on No. 5 cylinder and rough idle

[Vipir]

46 minutes ago, Turbofix said:

Again sorry if I gave wrong impression!!

As xr6t is injected I felt all would recognise pouring water into carby was not possible and therefore I was not suggesting  Viper should do so.

Also from posts compression  problem  seems limited to cyl 5..

Therefore is it possible  the compression  problem is a valve stem guide problem as I experienced?

That is what I was endeavouring to contribute.

And  yes I do see the funny side of you  having a bit of fun with my posts

 

2 hours ago, Turbofix said:

Sorry if I gave wrong impression. 

As there is no carby on Viper I was pointing to my compression problem on no. 5 being a valve stem guide problem.

Therefore my post was intended as a positive contribution and I did hope it was received that way

 

Yes, No. 5 cylinder was pulling 85psi as opposed to the other 5 cylinders doing 125psi. A coil pack was replaced, a new injector was put in and then compression tests revealed the low psi. A wet test revealed pressure increased so...rings. Of course it's rings because I wanted it to be valves. But anyhoo, there we go.

A camera down the cylinder indicated no initial damage to the bore, but a more detailed inspection will now be performed and photos taken for Ford Australia to consider helping with some of the costs.

When I know, y'all will know. There will either be tears or champagne...

[Puffwagon]

Some clarity on the water issue. 

It is actually a thing. 

When water is introduced to the intake in minimal quantities, not poured, it will soften carbon that has attached to the valves and the pistons. The said carbon will then break up and disperse through the exhaust. 

This is not usually an issue with efi cars as the afr is usually a lot closer to stoich more often and does not build up as much carbon as cars from the 70s and 80s.

We also have much better ignition systems which burn a lot more intake charge and accumulates less carbon inside the engine. 

The benefits of removing carbon from the cylinder are; reducing compression in extreme cases, removing sharp outcrops of carbon that can glow and cause pre ignition or detonation, removing particles that can build up and hold the valves open and more indirectly improve fuel economy through tune related retardation. 

It is acceptable to spray water into your throttle body with a hair dressing atomizer. This will cause no damage. 

IMO this is unnecessary for our cars as the carbon build up should be minimal given normal operating conditions. 

I don't think this has anything to do with the problem outlined in this thread but it seemed worthwhile to mention given the last several comments. 

 

Edited 01/03/16 10:05 AM by Puffwagon
Extra words, grammar and a comma.

[Turbofix]

Thanks  Vipir. I really do hope it works out best possible for you.

Had I taken more time reading your posts wet testing increase explains  rings.

Edited 01/03/16 11:27 AM by Turbofix
oops

[Vipir]

Latest update 03/03/16

The problem started in No. 1 & 3 cylinders. Scoring is really bad. No. 5 just was the end result. The mechanic says that possibly a bad batch of fuel has caused the engine to lean out, but I must have got that bad batch in the first year because I have been having this problem since I got the car. The bitch of it is that it is a problem the mechanic could never replicate, despite my permission for him to put Vipir through his paces.

Perhaps if he had been able to replicate the problem, and do so earlier in the piece, I would not have ended up causing such dreadful damage to my beloved car.

Engine's going to be taken out and have to be rebuilt.

I feel like my ignorance of all things mechanical is my saving grace at the moment. Perhaps if I knew just how catastrophic this is I might be howling in tears.

So, I don't know if that's the end of it. We know the problem. Now it's just a matter of waiting for a quote and seeing if Ford Australia will help out in anyway. I am not sanguine.

[k31th]

If there's scoring and bore damage, buying a new short motor from Ford will be your cheapest and best option in terms of both parts expenditure and most definitely labour costs. 

To repair a damaged engine internally is an expensive (parts) and time consuming (read labour costs) process.

Labour costs should just be remove (+$), replace ($0), refit (+$). 

[Ralph Wiggum]

You're missing some significant steps there keify...like assembling the short motor.

[k31th]

you mean assembling the long motor (reverse of the removal of the "damaged short" motor)? the short motor comes pre-assembled from Ford, as far as I know.

[Ralph Wiggum]

A short motor is the block and rotating assembly. No cylinder head, No sump, No ancillaries. 

Essentially this-

[k31th]

Yes and if it comes in that from from Ford (which I'm pretty sure it does) then you just put the head/sump on (of course I'm over-simplifying the process) and of course the ancillaries (ancillaries would be necessary to remove/refit for even a long motor remove/replace)

[Vipir]

I could weep right now, but I have to strap on a pair and go have my once-a-month meeting with my boss and try to succumb to tears.

A librarian with a passion for hot cars and whose hot car is currently getting lemon aid.

Is it a lemon?

Stay tuned. Next week we'll be getting the quote and options.

PS: he was very impressed, I think, with my questions, and my little bit of understanding thanks to all of your inputs.

"Leaning out" was a new one which I will have to look up.