Just to update my last thread .

My Octavia eligance starts fine hot or cold no smoke ticks over fine . First rev it cuts out ,wont restart .it turns over as if no compression then starts to fire on one cylinder then two three then runs smooth all the time smokeing like unburnt fuel,once its done this the smoke clears and it will rev fine . No fault codes no lights .ive changed immobiliser modified wireing

Vac pipes

Egr disconected and cleaned

Asv valve working fine

Coolent temp sensor

And today maf (topend reading over 370mg s ) haven't had it rechecked .both with gen Skoda items at great expense and its still doing the same .is there any one in the middlesborough area good with vcds that could look it over or any one got a next step for me.

Cheers for your time jim

More than likely the timing is out and you will need VCDs to check it.

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Sorry forgot to say I've checked with vcds and adjusted it in speck . It had a belt kit just before I got it .

Jim

Cam position sensor possibly.

Its seems to be only when cold .no codes comeing up . What figures should a good one give?

Have you checked the glow plug resistances? They usually start without plugs but this might be the exception.

 

Also, what about the Coolant Temperature Sensor?

New plugs before I got it and working ok . Got new cts on aswell gen from tps . What about fuel temp sensor in pump? Its the only other temp sensor I can think of .

109 relay, that can cause random cut outs.

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Not random .it only dose it first cold engine rev once its got temp its fine .?

Has anyone ever had trouble with the fuel temp sensor in the injection pump? Started the beast today and gave it a rev and it faultered but dident cut out .new maf new cts only other temp related thing is fuel temp in pump. (only thinking this as its warmer today and temp makes a difrence it seems ) or am I missing something .im wateing to get my own vcds so I can go further into the figures . I'm thinking of takei g the belt covers off and checking the timeing belt all lines up ,I dident change it(was done before I got it) so its unknown even tho I've set it inspeck with vcds I'm wondering if I could be slightly out? Phisacly .its strange how it starts fine and drives well loads of power just that first hard set off or rev from cold upsets the apple cart

Jim

There is a pressure relief valve in the fuel pump which can come apart, but I can't remember what problems it causes. But it is simple to check.

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Il be checking this ,not sure uts me problem but worth a try.

Injector harness is another possibility. Pretty common problem on VAG 1.9 tdi's.

Injector harness is another possibility. Pretty common problem on VAG 1.9 tdi's.

thought that was on the PD engines

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Wireing looks pretty good all conectors are clean . Took out the pressure valve in the ip and the retaining coller was halfway out so I've pressed it back in and refitted it .Il do the test in the morn see if its made any diffrance . Il try post up a pic .

Jim

Started like this clip so far out

Ended up like this .im slowly ticking things off the list .

i had the exact same symptoms but mine did it when i booted it hard, then it cut out.

 

for me, i had a replacement turbo, and it needed the vanes unsticking, as they were stuck in a position, and the turbo was overboosting!

Well it started worse than ever loads of air in the fuel lines and still cutting out . .to be fair I haven't bled the system after refitted the valve so its just reserculating the air I've let in i think . I've had a look at turbo and the vnt rods moveing on and off fine when vac is applyed also geting no boost faults coming up .

Well I've removed the flap valve in the tank sender feed .inspected the tank ,no gunk and very little metal speckles changed fuel filter and air filter re bleed the system and tested . Just the same . I did however not try to restart the car once it had cut out ,instead I left it and tryed a restart a couple of hours later and it started no problem im begining to think its in the pump, temp sender quanty adjuster whatever alters advance retard.wateing for my copy of vcds to get some figures before I pull the pump apart . I will beat this fault . Jim any one been into a tdi pump before?

Right I think I'm geting valve jack . To much oil pressure causing the tappits to expand enough to open valves to drop compression. I've now flushed the oil and replaced it with 5/30 fully synthetic vag spec .if it still persists Il have to find and remove the pressure relief valve ? Any ideas ?

Jim

I believe I've sorted it . Flushing the oil and new 5 30synthetic vag spec . Going to wash down and check for leeks and flush again after some miles on it . Apparently there's a pressure relief valve at the pump set at 170psi as a safety incase of major blockages and a second set to 60psi in the filter houseing ( the one I thinks sticking) also a by pass incase the filter gets blocked .

Il keep an update as I use the beast . Cheers for the help Jim

Edited 7 May, 201511 yr by jublybug

Right I think I'm geting valve jack . To much oil pressure causing the tappits to expand enough to open valves to drop compression. I've now flushed the oil and replaced it with 5/30 fully synthetic vag spec .if it still persists Il have to find and remove the pressure relief valve ? Any ideas ?

Jim

Just to check our mutual understanding; is this phenomenon also known as "tappet pump"?

Yes I believe so matey . Its definitely fixed my tdi a good flush and good oil

Jim

Yes I believe so matey . Its definitely fixed my tdi a good flush and good oil

Jim

Cheers, I'd just never come across the term "valve jack" before.

I have but never experienced it on an engine before . So it took some tracking down .i ended sorting other problems and fault codes aswell along the way. Just hoping the smoke clears up once its on the road (I'm thinking the amount of times its cut out its just un burnd diesel sat in the cat and exhaust system ) if it doesn't then could be bad injector dripping maby or turbo?

Jim