Hi guys...
Firstly, sincere apologies if I'm posting this in the wrong place and thank you for taking the time to read! Sorry for the ramble; I’ve tried to be a concise as possible to keep the thread short and minimal time spent and I didn’t want to omit details that might be clues to the expert eye.
I’m having real difficulty getting my Mk5 Golf 2.0L TDI started. I’m led to believe that diesels are ridiculously easy to start – you “just” need fuel, air and compression (not even working glow plugs unless it’s super cold? Note that I live in sunny Australia).
BACKGROUND:
The car had been driven solidly for years until a couple of months ago (when a replacement car was bought), since which time it was left on the driveway for a month, then driven without any issues perhaps 30 mins per week for a few weeks.
One day, I tried to start it, it made the usual cranking sounds (seemed like the starter was going at the usual frequency, though I haven’t measured this) but it just wouldn’t start. I tried several times without success, until the inevitable engine light and “STOP!”. It seemed as I imagine it would if there were no fuel present – all action but no actual start. It does sound as if the cranking frequency rises a little over the 10 second period.
DIAGNOSTICS:
My mechanic discovered engine fault codes. I bought an OBD tool, which identified an EGR Valve Insufficient Flow. I dismantled and carb-cleaned a very grotty EGR and ASV and cleared the codes, which are now permanently gone. I do get a brake pedal fault (unsure how that’s engine-related), but I can see that’s because the brake pedal is depressed so far that it does not engage with the switch actuator (normal/reasonable/relevant? "P0571 - Cruise/Brake Switch (A) Circ. Malfunction static").
The car has had dodgy electrics over the years (central locking, electric windows) so I’m concerned a loom is damaged somewhere which might cause the ECU controls to the engine electrics to fail – e.g. the injectors (do these need to be fully operational to start the car, or are they only necessary subsequently?)
Since the electric windows and central locking are dodgy, I’m surprised fault codes don’t currently show for those. When I last left the car the other day, the brake/rear lights remained on permanently after I’d locked up, with the headlights completely off – that’s a combination I’ve never seen before!
Finally, we did have routine issues when parked on a hill facing upwards, years ago – alternately toggling the key on/off I believe overcame the lame/depressurised fuel lift pump issue, and the car would then start just fine.
I visited this wonderful forum, which is totally stacked with info, and tried the "how-to" here but believe I exhausted all suggestions:
http://forums.tdiclub.com/showthread.php?t=199398
AIR:
I have removed the inlet hose, placed a mirror beneath the now-exposed ASV and observe that before, during and after trying to start the vehicle, this valve (“butterfly”?) remains open throughout. Additionally, I’ve sprayed “Start Ya Bastard” (SYB) into the ASV (
https://www.nulon.com.au/products/aerosols/start-ya-bastard-instant-engine-starter) Yes, I’m sure I’ll get decried as a heathen for doing such a thing, but I’m really not happy with a one-ton doorstop on my driveway and I'm clutching at straws here for clues. This stuff is supposed to be able to start pretty much any engine. Alas, while the cranking definitely sped up, almost to the point of starting, it still refused to actually start. That the ASV valve is open and SYB was clearly being drawn into the engine (because cranking frequency increased) suggests to me that air is not the issue (?).
FUEL:
I removed the fuel hose into the tandem pump from the fuel filter, stuck it in a cup and switched the ignition on – I got about 30ml of fuel in there, but this amount dropped off to *nothing* after repeating the key on/off a few times, which surprised me.
I know nothing of whether the fuel is correctly pressurised at/by the injectors, that the tandem pump is even working (or how to diagnose/what to inspect for). The diesel has been in the tank for at most 3 months. Removing the fuel filter lid (because I can’t get the hose off from the lift pump into the fuel filter) shows a steady 2-3 second flow from the lift pump every single time, so I assume that is working just fine, although I don’t know if the other 3 ports are causing an issue.
If fuel were the problem, SYB would surely have got the engine going, then the engine would have stalled after moving onto fuel. I have not yet drained and refilled the fuel filter with fresh diesel because of the above argument – I don’t see how SYB failed if bad fuel were the issue. I *have* tried to start with no filter medium at all, having filled the canister with diesel to minimise air. No improvement. If the injectors were the issue, I wouldn’t expect them all to fail simultaneously (instead expect lumpy/irregular or sub-optimal performance), nor for the OBD diagnostics to report no issue with them (please correct any weak assumptions/misunderstandings). I'm concerned that a dodgy ECU is not reporting its own failure in e.g. not driving the injectors or whatever else is electrically controlled during a start. I’ve tested the glow plugs – all 0.5 Ohm-ish.
COMPRESSION:
Removing the upper timing cover revealed that the crankshaft and belt are turning as I would expect, so I believe compression is good.
ADDITIONAL:
I’ve tested all fuses and relays in the engine fuse box. I’ve only become aware of the fuses/relays beneath the steering column since returning my friend’s multi-meter – need I check these also?
My mechanic did remark several years ago that the reason our car has *always* had to turn over at least 4 or 5 times to get started is because the very early Mk 5 2.0L TDI (late 2004 manufacture) has an underrated starter motor – I don’t know if this is making a contribution or totally irrelevant.
I’ve used this site lots over the years – thank you all so much for your contributions – you’ve saved me perhaps $thousands all up.
Sean.
), as the lift pump will displace it for me. So, if air in the system were an issue, several on/off ignition cycles should get fuel to the injectors (if the tandem pump is working - or does it not even play a role in getting the car started?)? If this understanding is incorrect and I *do* need to bleed the system, I guess I need the closest point to the injectors (though I have the PD engine, so there's nothing to "crack", unfortunately) Where is this location on my vehicle?
