I just bought an a4 1.9 tdi cheap with a misfire the car is on a p plate in descent standard engine looks good and serviceable however there is the end of a glow plug missing is there a slim chance it may have tried to be pushed through the exhaust valve and perhaps damaged it,or I'm in fairy land. If I need to rebuild I will but cn anyone help me with cheap parts? Many thanks a new Audi owner hoping to get it on the road very soon for very little money.
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A snapped glow plug can cause much damage, even a small piece. Not just to the valves, head and piston crown but also the bore and even the turbo. I'd stop running it and pull the head off ASAP.1990 B3 2.0 80 quattro.
1992 C4 2.8 Avant quattro
1994 MTM RS2.
1998 B5 TDI quattro Sport.
2000 B5 TQS. -
is it a constant misfire or just now and then?Comment
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Just run a compression check if the exhaust valve has been damaged by fragments of the glow plug it will show up pretty quick. To strip and rebuild the head and replace a couple of valves shouldn't cost if you are handy with a spanner. A VCDS check might shed some light on the matter too but that said at this age it should be a VE fuel pump engine and will have limited diagnostic capability.
You could try loosening the union to each injector in turn with the engine running (watch your eyes as diesel will pulse out) it should clearly be heard to run on 3 cylinders if 1 makes no difference there is you troubled cylinder.Comment
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It constant on no 1cyl I need to get hold of a compression tester, and I am hoping for the lesser of a burnt out valveComment
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@ monkeymagic I am a mechanic by trade, a little rusty on engine builds, but confident I can do this may need to find more info on torque setting etc. I bought the car knowing it had a misfire just wasn't sure of the cause now I know, but it is a simple engine so shouldn't be to hard to fix. The other problem is cost of parts and working on the drive.
Oh how I dish I was rich.Comment
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@ monkeymagic I am a mechanic by trade, a little rusty on engine builds, but confident I can do this may need to find more info on torque setting etc. I bought the car knowing it had a misfire just wasn't sure of the cause now I know, but it is a simple engine so shouldn't be to hard to fix. The other problem is cost of parts and working on the drive.
Oh how I wish I was rich.Comment
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for what it would cost on that engine price up what it would cost to sort and you'd probably get a complete engine cheap enough and swap that in.
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True but it's finding one could be funComment
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In all honestly with it running i would undo each injector in turn whichever one makes no difference to running is the likely culprit. If you have access to diesel compression tester you could use that. At the end of the day it could simply be a failed injector. Do you know if it is a VE style eg a cambelt driven pump and injectors externally on head.
It if were me I would then try a compression check and see if you have poor compression on one. If so its likely the piece of missing glow plug has dropped off and been bashed about by the piston. If you diagnose a weak cylinder pull the head off and see what you have. I you're lucky a headset and a couple of valves head bolts coolant etc and you will be sorted. If you're unlucky then the head/bore will be damaged beyond economic repair.
With the right tools and a little help you can strip rebuild and refit the head in a weekend.
Good luck.Comment
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Just read your previous thread about it being on cylinder number 1. Scrounge a compression tester and get the figures. If all level figures try swapping injectors round and see if mis fire changes cylinders. Don't forget if this is the case you will need to replace the injector heat washer thing when finally bolted down the torque setting is about 75nm from memory.
I'm not familiar with this engine in an A4 but suspect it is the same as in golfs and vans of the same era. If you need specific torque settings in the future give me the engine code i'll check elsawin and see what I can do. It sounds like you have nothing to lose and once it's rebuilt you know the top end is good and will have the chance to look at bottom end. As you have said they are pretty simple engines with good access.Comment
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Just read your previous thread about it being on cylinder number 1. Scrounge a compression tester and get the figures. If all level figures try swapping injectors round and see if mis fire changes cylinders. Don't forget if this is the case you will need to replace the injector heat washer thing when finally bolted down the torque setting is about 75nm from memory.
I'm not familiar with this engine in an A4 but suspect it is the same as in golfs and vans of the same era. If you need specific torque settings in the future give me the engine code i'll check elsawin and see what I can do. It sounds like you have nothing to lose and once it's rebuilt you know the top end is good and will have the chance to look at bottom end. As you have said they are pretty simple engines with good access.Comment
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well the front end is off now i can get to the head and see whats occouring.Comment
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Cool. Did you diagnose low compression on cylinder #1?Comment
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just cracked open the injector and found it didn't change the miss fire and when i pulled out the shortened heater plug i guessed what had gone wrong,
the guy at the engineering shop (replaceing the valve seat) was wanting me to replace all valve guides and valves etc. he was saying they have a tendancy to snap off at the collets is there any truth in this?
i have posted a pic of the piston top in the gallery.Comment
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