Engine does not start

G

Gabi

Member
Hi, everyone, very merry holidays to you all!


We have a recurring problem (with our 1.2 TDI, 2003), which started the first time temperature dropped below zero C. While trying to turn on the engine nothing happens - no starter sound, no nothing (battery is new and working, you can turn on the radio, lights are working, etc....).
When I came home in the evening, it was above zero and the car turned on - everything was good for a month or so, and again - with the sudden drop of temperature the same happened, I tried to turn on the ignition and tried to change gears manually, but it wasn't possible. After trying few times of opening the car with the alarm thingie (remote?), the engine started, however after few seconds it would stop and the light of oil pressure would turn on. Once I was even able to drive for fifty meters or so and the the engine stopped, the gear was thrown into neutral. I took it to the service, they found the following errors: 00263 and 01071 and the sensor behind the break was faulty, so they changed it - it seemed to fix everything, as there were no errors and the gear box seemed to start working even better, smoother than before (not sure how it's possible).
Now, about a month pasted, temperatures were around zero, but this night it fell to -13, and in the morning the same problem with the car again...

Would you perhaps have any ideas what and where to look for?
 
It could be a clutch/hydraulic fault. Not enough hydraulic oil? In this case the engine will not start until the fault is cured.

Changing into neutral is likely caused by the sensor which monitors the gearbox shaft speed to check that the clutch is not slipping. I believe this check is only made in fifth gear. More likely a poor connection at the sensor rather than a faulty sensor. This will not prevent the engine from starting though.

So you may have more than one problem. Scan with VCDS.

RAB
 
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It seems, that everything is ok with the hydraulic oil...

Do you think it could be somehow electronis or some conections having faults during to the sudden change in the weather (wet changing suddenly to freezing?), or is it more likely to be just a coincidence.

I guess, it's really high time to buy us a vagcom....

Thank you for ideas :)
 
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Possibly connection problems. Does the hydraulic pump run at all? Can you change gear in tiptronic mode with the ignition on and the engine NOT running? Is there any chance of water in the hydraulic system (the hydraulic unit is very close to the windscreen drain)?

RAB
 
The pump runs and you can not change gears in triptronic.
The strangest is that it looks like the problem comes and goes (as it's probably safe to assume the last repair at the service haven't done anything related to this particular problem).
 
Is the flexible drain in place on the underside of the plenum cover (next to the hydraulic unit)? You should also check that it is not blocked. That might indicate that there is water in the hydraulic system. If there is, it might be frozen and therefore the actuators would not work. However if there is pressure, the engine should start. How long does the pump run for?

RAB
 
Another factor that might be temperature dependent is water in the clutch housing. When I bought my A2, the rubber moulding (for clutch inspection?) in the top of the clutch housing was missiing. This was replaced but I subsequently had problems with the clutch, particularly in cold weather. In turned out that water had entered the housing at some time and the clutch had seized. Replacement was the only option.

Assuming that you have any hydraulic pressure, you can check this by pressing on the brake pedal with the ignition on (engine not running) - the clutch should open. If the clutch does not operate normally, this will inhibit starting.

RAB
 
Thank you once again or the ideas, hubby was working these days so didn't have when to check thoroughly, but you couldn't change the gear - there was no sounds of changing gears and in triptonic nothing. And when you tried - the display of that gear was flashing.

But - this night the tempreture risen to plus and in the morning - tadam, the car was running, you could change all the gears, etc...

So I guess we should really look into the clutch thingy you mentioned?

We bought this car from my aunt (she bought it new), but she was always keeping it in the garage, so such problems never occured (though last winter we hadn't had them too).
 
It is also worth checking the drain from the plenum cover at the base of the windscreen (driver's side). Check whether the plastic pipe is connected to the cover (by a clip) and whether the pipe is blocked or not. The drain is right over the hydraulic system reservoir. The green cap of the reservoir has a small hole in it. When the hydraulic pump switches on, it pumps oil from the reservoir to the accumulator and the small hole lets in air to replace the oil. Needless to say, if the cap is wet, water will be drawn into the reservoir when the pump runs. If this happens, oil/emulsion is likely to freeze during cold weather and generally increase wear during warmer weather.

RAB
 
We still haven't time to get the car to the mechanic, but it was going for awhile now, as the weather was better :D

But my husband asked me to ask:

Could you please explain more about the clutch. How can I check if it is opening or no when car does not start. Does it make any sound? I am asking this because I've noticed that when the weather conditions are normal and you turn the key (engine not running), push the break (gear is on parking) you can hear a faint sound *tinnnng* somewhere on the drivers side as if some spring being released or some contact being made, and when you turn the key more the car starts. You can hear that sound as well when you turn the key on N gear (without pushing the break). Whereas when the temperature falls bellow -10 C I have noticed that no sound appears and the car does not start. Do you have any ideas? Is it related to clutch?
And one more thing, when I was checking the screenwash drain as you suggested, I have noticed that one thick wire on the side of the driver bellow the (container where the liquid against overheating - I do not know how it is called in English...), going from the red bolt (please see the photo attached) is damaged - the outer shell is torn and you can see wires. Could it be related to the problems or cant i cause others? I suppose I have to fix that ASAP...

Thank you in advance.

IMG_0571.JPGIMG_0572.JPG
 
Hi Gabi,

Without VCDS software, the easiest way to see whether there is any movement of the clutch is to first remove the bonnet. You can then see whether the clutch arm, on the top of the clutch housing between the engine and gearbox, moves when you press the brake pedal with the ignition on. The sound you hear is the clutch cylinder.

I suspect that when the temperature falls there is insufficient (or no) pressure and that will prevent the engine from starting. Does the pump run when the temperature is below -10°C? Possible causes: water in the hydraulic oil or it could just be a weak battery. You could get the battery tested. Also test the drain above the green cap with some water; it might be blocked lower down but you cannot see the blockage. Blockage might indicate water in the oil.

The cable looks like an earth although I can't be certain. Does it connect to the chassis? If so don't worry about the insulation but check if it is a good connection.

RAB
 
The pump does run even at the lowest temperatures there was (below minus 10), however once it made high-pitched noise. But it was only once. Otherwise I've tried changing gears in tip tronic (ignition on, engine not running) and I've managed to change all gears through to 5th gear before hydraulic pump starts working again, so it seems it works properly.
As for the battery we changed it this summer to completely new VARTA Silver so it should be fine...
Water in the system sounds most plausible. I suppose changing hydraulic oil should fix the problem at least for some time... Is it possible to change it completely? And if water does enter the system, any suggestions where the problem might be?
Finally we got our VCDS cable and software so I will try to connect the computer and scan for problems during the weekend. If I find something I'll write it here.
Many many thanks once more!
 
Water and the oil form a green emulsion. The emulsion in the pipework is most likely to freeze. The only way to remove it would be to dismantle the hydraulic system which you might not want to do. There is a thread on here that describes it but I can't find it at the moment.

Water can enter the system via the green cap on the white translucent reservoir, as detailed in #10. It can be avoided by ensuring that the drain above it is not blocked and/or covering the reservoir with a small loose plastic bag - loose because air has to enter and leave through the hole in the green cap during operation.

Thread with emulsion removal is here: http://www.a2oc.net/forum/showthrea...h-pics-and-Fluid-question&highlight=hydraulic

RAB
 
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Just some information that might help. First thing to do is to take a sample from the base of the reservoir. Remove the green cap and take a sample from the base of the reservoir with a piece of clean tubing. The oil should be clear and green. Any sign of a translucent white greenish colour will indicate that water is present. The clutch atuator has a single hydaulic line; this is because it is actuated by a spool valve in the hydraulic unit and there is no need for a return line, so removal of the actuator and emptying it of any oil should be sufficient.

The gearbox actuator is driven by solenoids within the actuator so it needs a supply line and an unpressurised return line. Therefore it will need flushing sufficient times (by changing gear) to remove the emulsion. The trick will be to stop and change the oil before the emulsion returned to the reservoir is re-used. The oil required is VW/Audi steering hydraulic oil.

Before you disconnect anything, de-pressurise the system by unplugging the electrical plug for the hydraulic pump unit and unscrewing the accumulator half a turn.

RAB
 
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