Fabia mk 11 misfire help

[Pappafox]

We have a 56 plate Fabia  mk 11 with 28,000 miles with the problem of misfire.

 

 

We have a friend who's a mechanic and he thought coil pack  or valve guide problem.

Changed all the coil packs ... no joy .  Put in some liquid cleaner in the petrol mechanic recommended this.

Had error code P16687  cyl 3 misfire before we did this.

Afterwards  P16687 and P1668 cyl 2 misfire. Mechanic used diagnostic machine and I was with him.

 

Mechanic did compression test today - i was with him.  

Looking towards the rear of the car on a UK right hand drive model  what is the cylindered sequence?

 

 

Is it:-      LHS = cyl 1 middle = cyl 2  RHS  = cyl 3           

 

The spark plug on the middle cylinder was very black and dirty compared to the other two.

Pressure down on 2 and 3.

 

Mechanic seems to think big job .replacing the valve guides £600 plus.

 

Could it be an electrical wiring issue.

 

Any help appreciated.

 

 

Yours ..tight wad from God's county..Yorkshire!!1

 

 

 

 

 

[Richf]

56 plate Mk2?

[Toxicvrs]

56 plate Mk2?

Yes I'm sure I've seen one about before with it on! 56 runs until feb or March of the next year too

[Pappafox]

The engine code is  BME  . I think it's a MK2 

[Pappafox]

My mistake it's MK1  

 

From Wikipedia!!

1.2 HTP 12V 2003–2007 I3 AZQ/BME 1198 cc 47 kW (64 PS; 63 hp) at 5400 rpm
 

 

Seems this has been a real problem engine. Our car does short runs circa 3,000 miles per annum

[Jabozuma]

Valve guides have nothing to do with compresion as such, if worn will make valve train noisy and let oil in.

If compression is out valves themselves, piston rings or head gasket are usually to blame. Hole in a piston is possible as well. 

Get your mechanic to use good bore scope to investigate the cylinders before he starts spending your money.

This way he will be able to see if there is a problem with valves or pistons and have a look at the condition of bores. 

 

How much was the compression off by percentage wise?

 

Have put in fresh plugs as a first port of call? this is a consumable and should be done before anything else is entertained.

[Pappafox]

Hi,

 

 

Thanks Jabozuma

 

Just put in a new set of plugs. The old plugs taken out of in cyl 1 and 2 were very dirty after last nights running for 5 minutes after compression test.  

 

We were just going to start up when we noticed the vacuum booster pipe from the brake cylinder was split!! Part number on it read 59.29.03.06.

So as a temporary measure we put insulating tape to cover the split. 

 

Fired up the engine and seemed ok for a minute then  engine moving a lot. Set off up a gradient and after approx 400m the power started to go and the engine light flashing then on permanently. Switched on and off and the light went out and started to run ok downhill. Did a second run ....same result!!!

 

Ran diagnostics and it shows problem on No 2 cylinder. Mechanic thinks perhaps a valve issue now!!

 

 

Suggestions now please 

[Pappafox]

Sorry folks meant to say vacuum booster pipe split 

[Pappafox]

No help anyone?

[xman]

Check both ends of the servo vacuum pipe. They split at both ends. You need something much more substantial than insulating tape to bodge the splits as the engine block rocks back and forth a lot under accell/decell, and the stiff pipe will just pull itself off/on the connection. Normally any vacuum leak manifests itself with fast and/or erratic idle speeds, as well as a hard brake pedal.

 

Fix the vacuum pipe properly, replace it. Remove the battery lead for 3 or 4 minutes, this will reset the ecu trim values. Then try again. 

 

If you have been running the car, with a gross vacuum leak (with very apparent poor braking and erratic/elevated idle speed) for a long time (weeks), there is a possibilty of burnt exhaust valves due to a weak mixture.

 

Cylinder misfire codes are because of faulty coil packs and/or spark plugs. Change the plugs with new ones first. A duff spark plug can kill a coil pack in next to no time. If that doesnt fix it then change the coil pak on the faulty cylinder for a NEW one. If you are really strapped for cash you can move the existing coil paks around and see  if the error follows the swap. Remember misfire errors and the EM light only reset after the engine has been running correctly over a given period and several starts, unless you reset it manually via diagnostics.

Edited 1 October, 2014 by xman

[Pappafox]

Xman,

 

Thank you so much for this. That may be a possibility. We only looked at the top end of the pipe.

 

The tape was only just to see if this had any effect on the problem .

I will replace this as part of the repair and can see how the engine rocks when running. 

The brake peddle doesn't seem to have been having poor braking...so my wife says who drives it 90% of the time.

Actually I had noticed a couple of time that the idle speed was high a few times a few months ago but not now

 

 

Prior to seeing the split in the vac pipe  this we have

 

1. Replaced all the ALL of the coil packs

3 Replaced ALL of the spark plugs.

 

We also reset the the EM light with the diagnostics kit more than a couple of times trying out all of the remedies.

 

 

Any more thoughts?

[Jabozuma]

You done the plugs and coils, good.

Check and repair all vacuum leaks first. If you have diagnostic tool showing fuel trims it is instantly obvious you have a problem.

Otherwise just spray flammable spray around air hoses in the engine and look for increase in revs. If they go up you found another leak. 

[Pappafox]

Will ask the  mechanic whose worked on it to try this. 

 

However, retired mechanic who used to look after this little treasure believes that it is symptomatic of valve guide problems on the exhaust side!! common problem apparently!!

This means BIG money for repair!

 

If it has to be done it has to be done!! Anybody know a specialist in the Huddersfield area who can sort it?

[Pappafox]

Jazumba,

 

Forgot to say,  No oil -  blue smoke evident when revving up.    

[xman]

Jazumba,

 

Forgot to say,  No oil -  blue smoke evident when revving up.    

 

Thats a classic symptom of worn valve guides....

 

I remember reading somewhere that this was a manufacturing problem for vw/skoda on these engines and they supplied replacement fully built cylinder heads as a kit. You might want to inquire with Skoda. As ever, always press for a 30% discount....good luck...

[Jabozuma]

Jazumba,

 

Forgot to say,  No oil -  blue smoke evident when revving up.    

 

Well, yes, that is different then

[Pappafox]

XMAN Will ring the dealers now

 

Jabozuma

 

What I meant to say was that surely that if the oil was getting in you would see blue smoke when revving up?

There is no blue smoke on this car

 

Sorry if i confused anyone

[xman]

You certainly confused me! If there is no oil useage and no blue smoke, the valve guides are ok!

 

It is more than likely its an induction fault, e.g. vacuum system leak or an electrical fault.

 

If the misfire codes reappear, check the wiring and connectors up to the coil paks and change your (faulted) coil pak again, did you get the replacements off fleabay? Remember the old paks you took out, at least one will be ok..

Edited 3 October, 2014 by xman

[Pappafox]

Hi there XMAN.

 

Im really confused too!

 

All mechanics so far say valve guide problem without mentioning you would see blue smoke.

One said guides get elongated and the valve seats get affected.!!!!??

 

 

So a question I have is If the guides get elongated then does that mean the oil doesn't get through and burnt?

 

I bought the replacement coil packs at GSF retailer of all kinds of foreign car parts.

 

They sell cheepy and not so cheap. Went for the more expensive ones. Still have the original coils which I could put back in.

 

I asked the local mechanic if it could be electrical and he says no. As compression is down - in 2 and 3 cylinder he doesn't think electrical is the cause.

Im gonna ask him to check.

 

Also gonna buy the vac booster pipe first thing in the morning and get that fitted. Let's see where this takes us!!!

[Pappafox]

3 coil packs cost £75 in total

[xman]

Elongated valve guides? That's a new one on me. Are you sure thats what he said? If they could some how become longer, that wouldnt effect the valves or seats, as far as I can visualise.....

 

The usual problem with valve guides is wear, the clearance between stem and the inside of the guide, due to lack of lubrication or poor material. The wear allows oil to be drawn into the inlet or exhaust port where it gets partly burnt and usually produces smoke.

 

What are the pressure readings?

 

I would seek a second opinion before spending lots of cash.... Is the car worth spending that amount of cash on it, would a replacement engine be cheaper or is it more cost effective to break it for sale of parts on ebay?

Edited 4 October, 2014 by xman

[Richf]

I don't see how that worn valve guides would a) manifest as a running fault and be identified without stripping the engine , that's just not possible

Need to see the compression results although a leakdown test would be more useful

[Pappafox]

Hi there Gents

 

Thanks for the comments.

 

Pressure was down...cant remember readings exactly on no 1 and 2 pot. no 3 seemed OK  i was with the mechanic when he did he it. He tested first then second time I held the compression test gauge onto the cyinder.

 

We've had the car from new and it's in great shape with only 28,750 miles on the clock!!!! Only does short journey - which I know is probably worse for the car - about 3,000 per annum.

 

The only problem we've had is leaky rear doors which has meant two or three trips to a dealer to get them fixed and stop it filling up in the rear footwells like a canoe!! Usually discover this in Autumn when the inside windows steam up and thee's an inch of water squelching underfoot!

 

Any idea on the cost of a new engine. I had thought about it. I suppose a main dealer item only?

 

 

Thanks for any advice !

[Richf]

Pressure was down to what?

I very much doubt you need a new engine at 28,000 miles

[Richf]

You need to get the codes read properly with vag com and if that doesn't give a clear indication get the compression tested again .

My money is on a crank position sensor