Hi

 

My car has recently developed a fault which I cant put my finger on.  Its a mk1 tdi with a hybrid turbo, & darkside intercooler kit with 51mm alu pipes, leading onto a 57mm egr delete into a pd150 inlet manifold.

 

Ive been slowly been mapping the car with john and the boost is up to about 1.4 bar at the moment I think.

 

The car had been running fine, and ive recently added the pd150 inlet and 57mm hose and all was fine for a week or 2.

 

Now, ive noticed the sound of the engine has changed - sounds a bit heavier.  If I drive the car 'normally', then it seems ok, apart from the change in engine note.

 

If I put my foot down, say in 2nd gear, I get a sudden hesitation, and engine cuts out.

 

Now when I try to start the engine, the starter just spins as if there is no compression (I experienced this on a previous engine where the oil feed pipe came loose and dumped all the oil seizing the engine)

 

However, if on the 3rd time I try, the engine slowly splutters into life - misfiring for about a minute and then starts running as normal.

 

Has anyone got any idea what can cause this?  ive parked up the car as something is obviously not right with it, and I actually miss the car (been driving a Passat I got for sale - and I much prefer the Octavia!!)

 

Kaz

Has a boost pipe came loose?

Do you get any warning lights on?

no warning lights - boost pipes all intact (silicon and aluminium with proper clamps!)

Try the air flow mass sensor

but that wouldnt explain why the starter just spins over as if there is no compression

Has the starting problem only happened since the mods?

 

Is the engine actually turning over or is it just the sound of the starter motor spinning that you're hearing?

 

It could be as simple as the starter motor isn't engaging into the flywheel.  A new starter or if you're lucky a few engineered taps with a rubber hammer on the starter to free it could fix that side of things.

 

Is this a 110 or 130 TDI engine?

Just seen your sig stating 110 - DoH!

 

1.4 Bar seems really low.  The 130's run 2.1 bar as standard and about 2.3 when mapped.  Not sure what the 110 does as standard.

the maxiumum boost that the hybrid can handle is 1.8 bar

 

I think the original is only 1 bar

 

when I put my foot down, I feel the boost kick in, but then the engine cuts out. This has happened since the inlet conversion.

 

once the engine cuts out, the starter just spins over - I experienced this after my last engine blew from the turbo oil pipe coming loose and dumping all the oil.  It feels like no compression, but after about 5 seconds of cranking, it finally catches what seems like 1 cylinder at a time.  Anouther 20 secs later, its idling as normal.

 

so.... any ideas?

This is strange. How about fitting the old setup and seeing what happens?

was there any difference in the logs I sent you?

No difference really. Will take a second look later in the week.

Might be worth checking the pump timing?

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Might be worth checking the pump timing?

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Pump timing is spot on - I'm changing the oil pickup tomorrow - another friend of mine suggested injectors might be maxing out - which log can I check this on?

Faulty 109 relay can cause random cut outs.

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it only happens when on full boost, (mainly from second gear WOT) - I don't want to be too far from home when testing!

 

on trying to start the engine, its as it there is no compression - starter just whizzes freely (that's what it sounds like!)

 

would relay 109 display these symptoms??

The 109 relay supplies power to the engine ECU, random problems such as stalling tend to happen rather than at particular events.

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well, its only a tenner so nothing to loose really!

 

that's the oil pick up and 109 relay - any thing else to look out for??

right - I put the oil pick up pipe on, and there is no difference.

 

what I have noticed is that if I use wot in 2nd gear after idle, I get a boost surge and that's when the issue happens. Then,  I accelerated and when I felt the surge, let off the accelerator and I heard the turbo flutter as if it was a petrol car.

 

ive never heard this happen before.

 

after this, happens, I can drive as harsh as I want and the car will behave - so, any ideas??

i have a feeling there is a boost leak somewhere - how can i check where?

 

i hear a low droan comming from the left side of the engine similar to when the egr bolts came loose previously and it was leaking boost / sucking in air

Has the starter spinning free thing gone away then? Only, it sounded like a description of the solenoid not engaging at all.

 

The cutting out sounded a bit like an extreme case of an overboost error (but that leaves codes) or a complete loss of fuelling.

ive not accelerated on WOT enough for the car to hesitate and stall.  I am hearing more turbo flutter which i didnt previously which leads me to think that air is comming in / comming out somewhere else and the turbo is not acting as it should

ive not accelerated on WOT enough for the car to hesitate and stall.  I am hearing more turbo flutter which i didnt previously which leads me to think that air is comming in / comming out somewhere else and the turbo is not acting as it should

I'd tend to agree, and that means listening to the pipes with a stethoscope whilst the engine is revving.

im not having any luck with this :(

 

ive checked all the connections and cant find the leak!

 

Could it be that the pipe im running from the intercooler is a 51mm, and then the egr pipe and inlet becomes a 57mm - therefore the air is under less pressure/ pressure decreases then before??

Ok, I've just been revising thermodynamics that I've not used since university first year. The intercooler itself works on the constant(ish) pressure law, but a change in pipe diameter like you describe usually works on constant temperature, so when the diameter increases you do indeed get a pressure drop.