GolfGTIforum.co.uk
Model specific boards => Golf mk4 => Golf mk4 TDI => Topic started by: Bloke on 17 April 2013, 23:04
-
TLDR: Car cut out while driving on motorway for about 1 second, maybe 2. Pulled over in services, car refused to start, car refuses to jump start, car refuses to bump start at low speeds (pushing). Car finally started after tow starting it.
I've tried all I can think of, any ideas?
Important info:
- OBD2 measured voltage while car was running post tow start = 13.4v
- Multimeter measured open circuit voltage measured once engine refused to start = 12.28-12.41 V
- Multimeter measured voltage once engine refused to start and while attempting to "start" the engine = 11.98v
- OBD2 voltage once engine refused to start = 11.98v but multimeter was showing 12.28v at the same moment.
- Checked fuses that had "unknown" functions or related to engine stuff for continuity - all were fine.
- Checked cables from battery to car for continuity - all was fine.
- Tried cranking engine using only the jumpstarter unit I have, same outcome as with the battery.
- No OBD2 Error Codes.
Symptoms:
- Cut out while driving, but self resumed within moments of it happening.
- Insert Key, turn to acc - preheat thing lights up along with diag lights. Radio comes on, air con comes on, I hear a burbly noise of the fuel pump priming.
- Turn all the way to turn on the car, diag lights go out except for the alternator light but no error message on MFD.
Now for an anecdotal retelling of wtf happened in full:
Picture this, you're driving back from Nottingham to Bristol at about 1am. Cruise control is on doing 70mph, favourite tune is blasting away on the stereo and your satnav is happily saying you're about an hour from home.
You're happy, everything is all good with the world.
Then everything turns off and moments later the engine cuts out. It plunges you into complete darkness, steering turns into treacle, brakes (which you hit because you can't see anything) are like pushing solid bricks.
The car about a mile behind you starts flashing his lights at you thinking you're a mad man who just turned off all his lights.
Then... as quick as it happened the lights all come on, aircon radio, engine restarts of its own accord and you're still doing over 50mph.
Man who flashes you now sounds his horn as he overtakes you as you're straddling two lanes and he decides to overtake you anyway.
Understandably this s**t you up quite a bit and you now want a coffee and to check wtf happened to your car. So you pull into strensham services when you get there and grab a brew.
Head back out to the car and open the bonnet, assuming its battery related as you'd been eyeing up the corrosion that's going on with a "when I get a round tuit" look and decide right well lets give the terminals a good jostle and try and get some fresh metal surface.
Jostle complete you get in the car and try to start it... nothing.
On your own in the car park, you decide "f**k it, i'll try ghost bumping the whip". Push the bloody car to the top of the car park and running over your own foot twice in the process, attempt to push and hop into the vehicle once its at speed, but the camber isn't steep enough and the moment you drop it in second it stops dead.
You wander into the service station hoping to find a living soul and you find 3. None of them have jump leads. The service station... while you can buy carabina's take a breaks and bloody tents... Don't sell jump leads.
You trapse over to the garage section of the services and YES! they sell jump leads, only 1 kidney and your lifesavings!
You buy, you trapse back and everyone has buggered off. You wait until a white van man comes up and ask him if he wouldn't mind giving you a jump, he obliges and comes out of his van with his own jump leads. (FFS...I just sold a kidney!)
Try jumping as per the manual... nothing. nada... not even a feeble "whir" from the starter, nothing is happening. Dash lights come on, radio comes on, aircon is on but not sausage from the engine.
So we resort to a bump only this time with him pushing means a bit more speed. 2nd... let out the clutch... JIGGA JIGGA JIGGA JIGGA JIGGA JIGGA... nothing, just a vicious case of the "FF" sakes and motion sickness.
Try a few more times, and WVM is panting a goodun from all the pushing I call it quits.
WVM though is a gem and refuses to leave me there, we find the tow loop in the boot, discover that the VW manual tells you where to find the tow loop and how to use the bloody thing in two different books, separated by a few books of "this has no relevance whatsoever to you".
Hook it up, use a tiedown strap from his van and he tows me. Nothing...
Nothing.... still towing and then about 30 seconds into towing, we're about to turn around and go back up the car park it comes to life.
You head home, before you turn off the engine though you had the presence of mind to plug in your OBD2 dongle thing and fire up torque to look at the voltages and write down 13.4v. You head off and get some kip... its 4:50am.
Next morning, the car doesn't start. Same symptoms as last night. Dash lights light up, battery/alternator light stays lit. No "alternator workshop" message though.
Not a sound from the engine bay.
You clean the corrosion, but realise having removed the terminals that actually the posts and terminals on the inside are pristine metal it was only the outside that appeared to be a bit crusty.
It doesn't work.
You try a jump from your neighbours car... no change.
It's electrics, you're a geek, you can solve this.
I break out the multimeter. Open Circuit Voltage of the battery = 12.28-12.41 V
I crank the engine while watching the multimeter. Voltage drops to 11.98 V.
Okay so the voltage isn't fantastic but its not exactly a disaster either.
Fuses! Has to be fuses.
You pull every fuse from the battery cover and check for continuity.
You also check the battery cables for continuity just in case the corrosion has eaten one of those.
You open the fuse box panel on the drivers side door panel bit, Find every fuse that's says "refer to owners manual" (Why I've no idea, they don't explain wtf it is anywhere in that) or has anything to do with engine electrics.
All fuses and cables checked are fine they have continuity.
A scour through the owners manual reveals no more fuse boxes so now you're onto repeating yourself with more expensive things.
You buy a battery tender/jump starter for £100. Hoping that well maybe the battery just needs more oomph, you also don't approve of wandering around a dead service station hoping for a jump too so next time you'll be prepared.
Having googled earlier and seen stuff saying about a battery short can make jump leads ineffective and a car not start or turn over, you consider a crazy idea.
It is crazy, but well you're not going to start the car are you. So maybe it'll work. you just want to hear a whir, tiz all. Just to confirm if its the battery or something else.
You disconnect the battery completely and basically perform a heart bypass, wiring in the jump starter instead.
Get in the car, lights are working so its promising, blip the key to try starting... nothing, hold the key for a few seconds... nothing.
Same issue as before, battery/alternator light remains lit after all diagnostic lights go out, but no alternator errors.
You reattach the battery and look at the OBD2 stuff once again. Voltage reported by that is now showing 11.99v Multimeter is showing 12.28V
You're out of ideas and are now posting on a forum at 22:50 hoping to god this isn't going to be a costly fix and that someone knows wtf is happening.
-
Faulty ecu relay number 109 possibly!
-
id be leaning toward the relay 109 too! especailly if its an earlier model. sounds like a right pain in the butt though! hope u get it sorted quick
-
Don't think it's relay 109 because I get the glow plug lights, etc...
Did some more investigating today.
Battery was discharged (reading 12.23v) so charged it up with a decent trickle charger.
Removed lower fascia panels (what a pain!) and got to the relay panel. Checked the few fuses it has... All good.
Checked relay 109 using a multimeter shows a decent resistant load across the trigger terminals and an open circuit across the other side. So looks good at least.
Tested relay 100 (starter relay) (continued... As this site is crap on phones. Please for the love of all that is golf based, get tapatalk on this forum)
... And again saw a nice resistive load on the trigger and open circuit on the rest. However knowing this one should be clicking when I turn the key I confirmed it by taking two leads and shorting the trigger across the battery terminals. It clicked. Re fitted it... Turned key, still clicked.
Couldn't find any other things to test in the cabin fuse or relay wise, confirmed the fuel pump was the noise I was hearing when turning the key too.
So yeah. I'm down to calling out the RAC dude tomorrow morning, think I've pretty much tried everything I can think of.
Not tried the starter cabling or checking if its getting a trigger but no neighbours and I don't have a really long third arm that can turn over the car while I hold the probes and look at the reading.
-
Mine kept cutting out as well when driving. The soldered contacts in the relay overheat causing the engine to cut out. Have you had it scanned for faults?
-
Scanned myself for faults. None found (as said in first post).
RAC side turned up "you've done more than I can do mate, I'll just recover it somewhere then".
£235 later and one starter motor fitted the car is running again. Asked the garage what the odd cutting out was and they couldn't find anything else wrong with it, just a knackered starter.