hopefully someone here can help, I have a 59 reg Octavia 1.9 TDI estate with a misfire. the car was running fine without a fault then I stop in a layby for 10/15 minutes and when I started the car the tick over was lumpy, when I went to drive away I thought the engine was going to jump out the engine bay. no engine light came on at all . ive had the injectors checked and the garage also replaced them with another set and its still the same , compression is good in all cylinders, injector loom changed , engine coolant temp sensor changed, gearbox speed sensor changed , mass air flow sensor changed and crank sensor changed and no difference at all. 3 garages including skoda have tried but cannot find a fault they are all stumped so I was wondering if anyone here has had the same problem of a constant misfire and how you fixed it ?

fuel filter been checked ? when was it last changed

 

Any chance of fuel contamination or wrong fueling ?

_{everything has been checked on the fuel side , fuel pressure, cams , injectors all 3 garages have been stumped}

Not sure you'll get much of a response with responses like that IMO. Your original post doesn't mention the fuel filter so Alfatoad's question was reasonable. It does sounds like a fuel issue, but that is as much help as I can give.

 

Was the MAF sensor/other parts replaced with an OEM one? Does the fuel lift pump in the tank work? Are all the fuses sound?

sorry didn't realise I said something wrong

Is the engine noisy?

 

Phil

My car was a bit lumpy occasionally, turned out to be wires shorting out on the turbo actuator, but mines a PD170. It felt like it was trying to throw me out the windscreen occasionally.

hi phil and whitep the clutch knocks a bit when cold and the engine has a constant misfire effect, if you drive it under 1000 rpm its not too bad but if you accelerate harder its as if the engine wants to jump out the bonnet. ive had the whole fuel system checked and been told by the garage they are 100% sure its not a fuel problem. I have been told it could be the rear crank seal moved and its put the injectors out of sync but before I have the gearbox removed id like to try and find out more about it but not having much luck even skoda couldn't help when asked. but thanks for your help its just so annoying because the car was running fine I just stopped for 10/15 minutes and when I restarted the car  I acquired a misfire    

Is the engine noisy?

 

Phil

 

Hi Phil, why do you ask this? Mine is...

Hi Phil, why do you ask this? Mine is...

 

Haha. Maybe I should have asked in a different way. Is it noisier than usual.

 

It could be the injector wiring loom inside the head. They are prone to the wiring becoming brittle and cracking due to the heat etc.

Haha. Maybe I should have asked in a different way. Is it noisier than usual.

 

It could be the injector wiring loom inside the head. They are prone to the wiring becoming brittle and cracking due to the heat etc.

Aah, now mine is noisy as hell, sometimes, usually just before a hiccup. I have had my injector loom replaced but the garage said they did notice the wires at the end of the engine were brittle. Any idea if the injector loom would include the timing sensor wires? And do you think the next bit of loom, with the big plug on the outside of the engine could be brittle? I must admit I have been suspecting this for a while now....

Edited 9 September, 201510 yr by whitep

I don't think it includes the sensor wires (assume you mean the crank sensor?) but could be wrong.

 

It is possible that the big round plug wiring is at fault too. It is exposed somewhat to heat, cold, dirt etc and also movement with the engine.

Have you checked the engine timing. The belt could have jumped a tooth although it is unlikely its is worth checking.

I checked the timing, front cam (MB 004 - torsion value) is 0.35 (should be -3 to +3?)when warm and rear cam (MB 015 - consumption) is 2.5+ dropping slowly (Should be 0.6/0.7l/h?) at tickover. If it was sitting at a constant figure I would adjust the rear cam, but because it moves a bit then im reluctant. I need someone to explain how to check timing to me. Every time I take it to a garage they seem to do whatever they want and never actually fix it.

 

Oh Hi Radders, I was the chap who picked those tyres up from you last year, you were scratch removing from a car on your drive...

Edited 9 September, 201510 yr by whitep

Oh hi, yes i remember. I would whip the covers off and actually check the belt and the markings / put the pins in before I started with VCDS.  It seems you've / the OP have had quite a lot of work done to resolve the problem but no one has been able to identify the exact cause.

Yes thats right, im going round in circles. Someone must know how these PD170 engines work and the tricks you can use to check/fix/cure issues.

Have you had the cambelt replaced or checked ?

_{everything has been checked on the fuel side , fuel pressure, cams , injectors all 3 garages have been stumped}

think your large print was mistaken for shouting but it's not in capitals        I really wouldn't accept fuel filter "CHECKED"   only changed

Cambelt was replaced in feb when I had the engine reconditioned. Thinking about it thats when the problem started, because it started kangarooing the next day on the way in to work! Ahh... penny dropping

Edited 9 September, 201510 yr by whitep

Can anyone tell me how to disconnect the big round plug to the right of the engine that the injector wiring connect into. I think this might be at fault but cant get it apart to investigate.

It unscrews.

 

I would get the cambelt checked to ensure all the marks are in the right place.

Oh yes it unscrews. I have undone and redone it all up, lets see.

 

Its booked in for Tuesday for the garage to check it all.

OP, you say when driving it under 1000rpm it is OK. Does the engine misfire happen when stationery and out of gear? If not then get the DMF checked out

hi all, I bought myself a diagnostics and found out that one injector is working flat out all the time and the maf sensor is faulty so I bought a new maf sensor but its still coming up as faulty . im thinking it cant be an injector problem as I took it to an injector specialist and they cannot find a problem with anything on the fueling side of things ive also had the ecu checked and all the wiring checked and even had a new injector loom fitted. no one has tried the variable vane yet I will try and get under the car this week ive tried to move them by putting my arm down the back of the engine and they feel seized but im not 100% sure ill try and get under the car this week and try. im not sure if they will cause one injector to overfuel but worth a try I suppose

think your large print was mistaken for shouting but it's not in capitals        I really wouldn't accept fuel filter "CHECKED"   only changed

hi sorry I changed the font because the print was really small   I had the car serviced about 4000 miles before it all went wrong so I checked to see if it collapsed but all was fine. I have spent over 800 pound with garages trying to fix it so been fiddling myself when I get a chance