Scirocco Central

Hi guys,
Sorry for my first post to be a request for help, but I'm having some trouble with my 1.4 TSI 'rocco. I bought it as a bit of a project with piston failure on cyl 1 - compression test showed around 80psi; I had it running briefly when I first bought it after I cleared all the hoses of oily muck but eventually while I was trying to make sure the turbo wasn't leaking oil etc after having a bit of a clean up, it was just firing then dying shortly after. I wasn't too worried and pressed on with repairing the engine, piston 1 had some impressive damage around the ring lands. A new set of pistons and a rehone, timing chain and a few other bits changed while there, and the result is a good even 170 psi across all cylinders. Unfortunately however she still doesn't start - sometimes starting then dying but mainly just cranking and showing little sign of starting. I've checked and double-checked:

-cam timing, repeatedly - seems perfect
-fuel - there's fuel at the HPFP, vcds shows 60psi on measured values (not sure if this is typical on ignition), there's plenty of fuel in the bores and the spark plugs are wet. If I crank the car over with no plugs in, fuel is ejected. I've put in some fresh fuel too to make sure it's all good.
-spark - spark tester lights up as expected on each coil
-throttle body - I've recalibrated it and removed the hose to it to see it moving to make sure it is functioning
-fault codes - all clear and none re-appearing, I've reset to ensure all trims are reset, and left the battery off overnight. The battery is new.

I'm not sure I can easily test the crank sensor given its location, but given it was previously running, that it tries to start occasionally, there's no fault code and that the rev counter works, I'm hoping it's ok.
Any other ideas of things to try or toubleshoot would be greatly appreciated, as I'm rapidly running out of ideas!
Many thanks
Tim

Hi,

How did you time the engine?, did you use the proper camshaft locking tool, the crankshaft locking bolt along with a TDC gauge - following the official procedure here:

http://www.sciroccocentral.co.uk/forum/ ... 02#p206702" onclick="window.open(this.href);return false;

If the engine is timed correctly, and you have fuel, spark and compression then i would check the camshaft position sensor along with the aforementioned crankshaft position sensor (sensor and wiring).
If either of those sensors has an issue the engine will not start / run.

Hi there, thanks for the reply, appreciate it! I timed it with a dial gauge and the cam locking tool, I rechecked it yesterday to make triple sure (I used cyl 4 to find tdc when verifying as easier access, but when I originally timed it I used cyl 1!)

Given the issue seemed to carry over from prior to after the engine work, my working assumption is that the engine itself is not preventing it starting...

Some of the other tests:








I have no reference for the fuel rail pressure.
I'll try to meter the resistance of the crank sensor later at the ecu pin, I've not yet found a pinout but something I googled suggested pin 56 on one of the connectors. The rev gauge works when cranking, on most cars ive worked on the rev gauge is based on a rpm output from the ecu so on that basis im thinking there's a fair chance that the crank sensor works and that the ecu is correctly interpreting it.
I think I'll buy a cheap cam sensor for testing, from a doc I read suggests it shouldn't cause a non start, presumably the ecu just goes wasted spark with no signal. I may test by unplugging it. Given I appear to have plenty of fuel, and moving the throttle about doesn't seem to help much, I do wonder about spark timing as I've not tested anything beyond checking that there is a spark. I'll have to see if I can view ign angle off the ecu.
I tried the car again briefly this morning and it wasn't even trying to start. Frustrating! I'm more than willing to try any test or take on board any suggestions

Detailed information on this engine can be found here : http://www.volkspage.net/technik/ssp/ssp/SSP_359.pdf" onclick="window.open(this.href);return false; (Hall sender G40, page 34)

It states if there is no camshaft sensor output - the engine will continue to run if already running, but will not start again.

From what i remember ~50 bar is correct for the HPFP pressure when idling/starting so fueling looks ok.
The fact you get fuel pumping out of the cylinders with the plugs removed also indicates injectors firing.

Ignition could be an issue - Hope that spark plug doesn't still look like it does in the photo, i.e. covered in oil.....which begs the question why is it covered in oil? Are they all like that, and still like it after the engine rebuild? - if so sounds like you have a leak in the rubber gaskets/seals between the cylinder head cover and the cylinder head.

Thanks, good info on the cam sensor. I'll get one on order... I could prob test the one in there I guess too, see if a voltage is generated. I should also see what ign angle the ecu is trying to run.
Do you have an ecu pinout by any chance?
The plug has fuel on it (not oil), was trying to demonstrate that the plugs are soaked in fuel. There's a lot of fuel, it's flooding - when cleaned out by removing plugs and turning it will generally make an attempt to start but fail.

Took a look at live data, can see rpm at 300rpm on cranking, timing 8 degrees, throttle position 7% or so. The ecu seems happy and cam/crank sensors appear to be functioning. Taking no fault codes logged on the ecu at face value and the live data/fuel and sparks tests, it seems there's nothing amiss with ecu/sensors. I tried removing the cat to see whether that made any difference as it must have been oil contaminated with the knackered piston - it didn't. Checked all breather hoses to make sure no glaring air leaks, tried plugging the air hose from the breather valve to make sure nothing had gone astray there, all without success. Put a new set of plugs in and let the fuel in the bores evaporate a bit, the engine is now starting then dying after a second or maybe less, just as it was before the engine work. Pretty much at a loss as to what to try next!

Just to close this off, not entirely sure why, but today it finally managed to fire and after running pretty badly for a minute or so and kicking out a lot of smoke, it has settled down and starts on the button now.