Cylinder 2 misfire any one have an idea of what to check next?

[Ben Cordy]

I got a quote from my local garage for ultrasonic injector cleaning. just £15 an injector so if it does like thats the issue and the redex or alternative doesn't work you can always go down the full cleaning route as suggested by avalon!

[Tech1e]

The issue with having them cleaned is the replacement injectors are modified I believe, though it's ok to mix and match if you have one with issue it might not be just because it's dirty.

[joe-on-the-rock]

Sorry Ben just re-read your post, my revs are also low, what bounces is the engine when idling, call the dealer and they say they are going to try Forte. However I dont know about the injector cause the only thing the did was a compression test and the replace the coil pack but still didnt make a difference. Would it help getting the untrasonic clean for the injectors?

Thanks

[Ben Cordy]

Ironically after saying the fuel additive helped my eml just came on although there was no fault code by the time I got home.

[Ben Cordy]

It just happened again but again no fault code recorded? Is that not a bit odd? It light up car started to rev oddly, I turned the ignition off (sat at lights idling) then turned back on, revs back to normal no warning light no fault code.

[Ben Cordy]

Re Joe I really can't say, try the suggestion Tech1e made of swapping the injector and see if the fault code follows. My plan was to do that if the fuel additive didn't work, which it did until 10 or 15 min ago! That way you can be sure the issue is the injector which can be replaced fairly easily with a scrap one or new If you have the money!

[Tech1e]

There are known issues with some engine codes and worn valve guides. This wears the valve seats oddly and causes a drop in compression and a misfire. This is best diagnosed with a cylinder leakage tester.

[Overhaul ed]

I personally would carry out a compression test both hot and cold, as said above certain 1.2's had problems with the top ends and Skoda used to do

kits for these which included new head/valves when the cars were in warranty.

[Tech1e]

A compression test is a good start however I've had the leaking valve ones appear ok on a compression check. I think it's because all a compression check does is measure the peak pressure of the cylinder during the test. If the valve manages to shut properly on one of the strokes it appears ok. But a leak down test is a lot better at finding the issue.

[Ben Cordy]

If it was worn valve guides or seals would I be right in saying I should have some oil loss and smokey exhaust? Could be wrong but I thought these were common signs of this. In my case I am yet to see any smoke or visible gas what so ever from the exhaust (I thought a sign of it running fairly well). I've also not seen any change in the oil level over the 3 or 4 weeks I've had the car.

[Tech1e]

No, not normally.

The valve stem seal is further up so doesn't normally suffer.

[Ben Cordy]

Would there be any other symtoms? Still feel like I haven't totally diagnosed it. Admittedly I haven't tried swapping the injectors like you suggested however the two occasions I had EML's today there wasn't any codes left on the ecu so I wouldn't have a means of checking where the issue was. I've never done a compression test or cylinder leak test, plus don't have the kit. Whats the chances of skoda considering this a warranty issue? Anyone have experience of trying to get a repair like this on warranty?

[Tech1e]

It's unlikely given the age of your vehicle.

[Ben Cordy]

If it was worn valve seats would I not have the issue more constantly? Currently I can go days without any issues, in fact as said above I thought everything was fine as it hasn't showed up in nearly a week. It pulls perfectly and doesn't even slightly stutter even when driven hard. It's just on idle occasionally.

[Tech1e]

Yes I agree, yours sounds very much like an injector fault to me. And I've done a fair few.

[Ben Cordy]

Cool, really appreciate your help on this! Still learning! Once this weekend is out of the way the injectors are coming off and will check as you have suggested!

[Tech1e]

It's real easy to do, just take your time and keep track of the seals.

[joe-on-the-rock]

Mine got the compression test but it was inconclusive, the middle cylinder was lower in compression than tghe other two (200 against 150) and the ecu just gave the misfire in cylinder 2, I havent tried with the injectors but I will try to get hold of a mechanic to try that and see. Apparently the dealer is going to put a solution called Forte cause he said its a sticky valve and this can help, I do not really think it will make a difference but since he is paying for it I will give it a go. The only other solution is to open the whole gasket up, change the head, skim the cylinder and either clean or replace the valves which I dont want to do for obvious reasons, it will also involve a new timing chain. The engine light EML has been up for three days now. I dont really know what to do with the whole problem and even if its worth tryong to get it sorted or rather go to small clamis and ask for my money back since it has been only two weeks since i got it.

[joe-on-the-rock]

Btw Ive read in some other forums about using Diesel Oil 10w40 too to help the sticky valve, at the moment the fuel consumption is very high for a 1.2, doing less than 30mpg..any idea if this would help. Thanks

[Ben Cordy]

So I've just pulled the fuel rail out! Had a bit of fuel squirt despite trying to tur it over 3 or 4 times without the fuse in! oh well cleanup the worst and the rest has evaporated. the seal of cylinder 2's injector has a small split in it. So looks like thats my problem. I've swapped it to cylinder 1 and im ordering a new seal so will have to see if the fault code follows!

[Ben Cordy]

Grrr so despite cylinder 2's injector having a split in the seal which would be an obvious answer for my problems it's still misfiring on cylinder 2 after swapping injectors with no1. Is there a way of testing the loom? Should I be getting a certain voltage on the connector?

[Tech1e]

I would have been suprised if it was a split seal, that would be ****ing fuel out not just missfiring. I'm also doubting wiring as that would register an injector fault.

[Ben Cordy]

Well the seal wasn't totally split, it had a small break horizontally but as you say there's no fuel coming out. Not sure what to try next,

Checked coils,

now checked injector,

checked spark plugs,

but all still leave the misfire on cylinder 2.

[Tech1e]

Need to check compression and cylinder leakage.

[Ben Cordy]

Okay so quick update on the misfire. Had the guys at Brookroyd in Harrogate check the car over. They were massively helpful but sadly they found compression was very low on cylinder 2 (half that of the other 2). So looks like the head is coming off for them to replace the valves (or seats). Hopefully will drop it in next week.

Quick question but is there any point in trying to argue with Skoda for the repair as it's only 30000 miles and full service history so I wouldn't expect this kind of issue, it's clearly a design flaw.