Misfire - not plugs or coil packs?!

Lee M

Guest
It was definitely worth checking mate. Glad to hear that's ok.

Out of interest and for future reference, what were the figures?

Well..... Looking on elsawin it said I should have done it with the oil 30 degrees >. However I don't want to run it now on idle as its got worse and has shown a fault code on VCDS. Don't know if the temp thing will effect results but they were all ~ 150 psi. About 11 bar.



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Lee M

Guest
Anyone know if the cylinders are 1 - 4 left to right. I.e. from Cambelt side to fuel pump. Or are they the other way round?

I'd like to make sure I change the correct injector!


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Cupra R

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Dec 5, 2001
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Anyone know if the cylinders are 1 - 4 left to right. I.e. from Cambelt side to fuel pump. Or are they the other way round?

I'd like to make sure I change the correct injector!


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Cylinder 1 is Cambelt side Lee.
 

Lee M

Guest
Cylinder 1 is Cambelt side Lee.

Excellent. Thanks mate. I know it sounds a stupid question but I don't want to get it wrong.

I need a couple of parts to be able to do the work so i'll strip it down tomorrow, give the valves a clean if needed.

I've ordered injector service kits and I think i may need to buy/borrow an injector removal tool. I'll see how i get on tomorrow.

Thanks for all you help :thumbup:
 
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mini_racer

Active Member
Dec 16, 2011
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Hi mate I don't know if this helps you at all but I had the same mis fire as you and got someone to test my injectors and they were all fine too. It turned out to be a bent exhaust valve and needed the whole head rebuilding! Maybe before you pay out for a new injector get yours checked first and go from there.
 

Cupra R

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Hi mate I don't know if this helps you at all but I had the same mis fire as you and got someone to test my injectors and they were all fine too. It turned out to be a bent exhaust valve and needed the whole head rebuilding! Maybe before you pay out for a new injector get yours checked first and go from there.

Did you do a compression test?
 

Lee M

Guest
Hi mate I don't know if this helps you at all but I had the same mis fire as you and got someone to test my injectors and they were all fine too. It turned out to be a bent exhaust valve and needed the whole head rebuilding! Maybe before you pay out for a new injector get yours checked first and go from there.

Hi mate thanks for the heads up.

How did a valve bend?

I'm quite far down injector route now so I'm just going to have to bite the bullet and go for it. If its not that I'm going to cry anyway.....
 

Lee M

Guest
It doesn't hurt to ask to be on the safe side mate.

*cough* documented tutorial lol????

Ha ha lol.

I've got some info I have researched etc so I very we'll may post something up after I've finished.
If it doesn't work all that will be left is a pile of bits...
 

Cupra R

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It's just that if a compression test is done and an abnormal cylinder pressure is found then the misfire cause is likely to be the problem you had ie bent valve.

If a compression test shows all cylinders to be fine (and within tolerance) as Lees does, then it points more to something else ie it does "appear" to be an injector fault in this case.

It's all a process of elimination. It's good that he got the compression test done as for the cost involved, it's way cheaper than changing parts only to find its something else.

Out of interest Mate, how much does it cost for injectors testing? Does or did it take them long to do it.

Sorry for all the questions but I like to learn about stuff :)
 

Jarre

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Dec 9, 2011
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Yeah my compression tests were all good. Sparks done, coils done. In the end it was leaking injector on cylinder 4 as I previously said. That would be my guess :)
 

mini_racer

Active Member
Dec 16, 2011
57
0
It's just that if a compression test is done and an abnormal cylinder pressure is found then the misfire cause is likely to be the problem you had ie bent valve.

If a compression test shows all cylinders to be fine (and within tolerance) as Lees does, then it points more to something else ie it does "appear" to be an injector fault in this case.

It's all a process of elimination. It's good that he got the compression test done as for the cost involved, it's way cheaper than changing parts only to find its something else.

Out of interest Mate, how much does it cost for injectors testing? Does or did it take them long to do it.

Sorry for all the questions but I like to learn about stuff :)

I must have missed where he said he had a compression test and it come back fine my bad. Mine was low on cylinder 3 which turned out to be where the bent valve was.

It was done whilst it was at a local garage, they got some bloke in to do it. Only charged me for the diagnostics because they couldn't find the reason why it was mis firing, that's why I took it SEAT where they had my pants down with the head rebuild :cry:

Anyways hope you find out the cause of your problems and doesn't cost you a small fortune like it did me!

Grant
 

Lee M

Guest
Yeah my compression tests were all good. Sparks done, coils done. In the end it was leaking injector on cylinder 4 as I previously said. That would be my guess :)

That's what I'm hoping jarre.
 

Lee M

Guest
I must have missed where he said he had a compression test and it come back fine my bad. Mine was low on cylinder 3 which turned out to be where the bent valve was.

It was done whilst it was at a local garage, they got some bloke in to do it. Only charged me for the diagnostics because they couldn't find the reason why it was mis firing, that's why I took it SEAT where they had my pants down with the head rebuild :cry:

Anyways hope you find out the cause of your problems and doesn't cost you a small fortune like it did me!

Grant

Thanks mate :)
 

Lee M

Guest
It's just that if a compression test is done and an abnormal cylinder pressure is found then the misfire cause is likely to be the problem you had ie bent valve.

If a compression test shows all cylinders to be fine (and within tolerance) as Lees does, then it points more to something else ie it does "appear" to be an injector fault in this case.

It's all a process of elimination. It's good that he got the compression test done as for the cost involved, it's way cheaper than changing parts only to find its something else.

Out of interest Mate, how much does it cost for injectors testing? Does or did it take them long to do it.

Sorry for all the questions but I like to learn about stuff :)

I did the test myself using a DIY kit I borrowed from a friend. It only took me 15 mins to whip the plugs out and do it.
 

Cupra R

Active Member
Dec 5, 2001
2,215
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UK.
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I must have missed where he said he had a compression test and it come back fine my bad. Mine was low on cylinder 3 which turned out to be where the bent valve was.

It was done whilst it was at a local garage, they got some bloke in to do it. Only charged me for the diagnostics because they couldn't find the reason why it was mis firing, that's why I took it SEAT where they had my pants down with the head rebuild :cry:

Anyways hope you find out the cause of your problems and doesn't cost you a small fortune like it did me!

Grant


Yeah. Garage bills can be a bit big at times hey. At least you got it sorted.

I did the test myself using a DIY kit I borrowed from a friend. It only took me 15 mins to whip the plugs out and do it.

Yes, I once bought myself a compression tester too.. Long time ago though lol, I doubt it would fit the TFSI.
 
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robdf2

Yellow is the best
Feb 21, 2006
3,605
3
location , location
Just incase I did a compression test today and all of the cylinders are the same value.

I'm short a few parts coming next week so ill be stripping down tomorrow in readiness...


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Did you do a cold and warm compression test?
My cold compression test showed everything normal , my warm test showed 3 cylinders with 1 bar of difference , so just doing the one test is not conclusive enough.

Rob
 

robdf2

Yellow is the best
Feb 21, 2006
3,605
3
location , location
I'm surprised you still have yours rob

Mine will be going this month hopefully Steve,
still not sure what to replace it with yet , was looking at a few new cars but do i want a car costing me £500 a month to run when i can do the same journey in a 2 year old car and cost me about £150 a month to run?
diesel or petrol , i have used your spreadsheet , cheers mate
with all the hastle i have had from SEAT , i just want to buy once this time and not get shafted again.
SEAT still not off the hook yet.
 
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