Starter motor problems: Cold start issues and solutions

hi,

My Golf IV ATD starts immediately in cold weather (around or below 5 degrees Celsius), but it runs roughly with some smoke initially, then settles down after about 5-10 seconds. When warm, it starts immediately and smoothly. It might run a bit rough and loud (at least compared to my other Golf IV with 90 horsepower).
"I once measured the glow plug with an ohmmeter, and it read 0.8 ohms. It also seems to be preheating. When it's cold (as mentioned above), the lamp stays on for about 2-3 seconds, which is significantly longer than the function test of the light."
"Where is the temperature sensor that's relevant here? I want to disconnect it to simulate cold conditions, which should result in a longer pre-glow time and an increased fuel injection amount..."
The fuses for the glow plugs are okay, and the fuses on the battery are also fine. The battery terminals themselves have already been thoroughly sprayed with a copper-containing contact cleaner by the previous owner!
I will still measure the voltage when the candles are lit.

What else can I check without any additional equipment (like a VAG-COM)?

Peter K.

PeterK wrote:

I once measured the glow plug with an ohmmeter, and it reads 0.8 ohms; it seems to be preheating. When it's cold (as mentioned above), the lamp stays on for about 2-3 seconds, which is significantly longer than the function test of the light. Where is the temperature sensor that plays a role here? I want to disconnect it to simulate cold temperatures -> achieve a longer preheating time / increase the fuel injection amount...?

You probably don't need it, as 2-3 seconds at around 5°C is acceptable.
The sensor for the ASZ Polo is located at the bottom of the engine block, near the exhaust manifold/tandem pump, making it very difficult to access.

Quote:

I will still measure the voltage when the candles are lit.

I think you'll find what you're looking for here, because the symptoms fit together very well.
The question then becomes, where is the break in the circuit? In the simplest case, it's the preheating relay.

hello ulf,

The relay is probably located behind the fuses on the left side under the dashboard, right?
Does it have a part number at VW (like 109?)!

Peter K.

PeterK wrote:

Isn't the relay definitely located behind the fuses on the left side under the dashboard? Does it have a part number at VW (like 109?)

For the Polo 9N, the fit is correct, although it's listed as 100.
109 is usually the main relay for the fuel injection system.

Hello,

The glow plug relay in my Golf has the part number 103.

Hi everyone,

I haven't been able to measure the voltage yet, but the realization that multiple pre-glows allow it to start up smoothly gives me some reassurance .
My car is parked outside, and since I'm coming home in the dark and cold now, I won't be able to deal with it until the weekend.
I had the idea that if less voltage arrives, a relay could be used to directly connect the glow plugs to the fuse? Surely, there can't be much less voltage than that?

Peter K.

I'm a little surprised by that.

My ex-girlfriend's VP SDI started immediately after a night with temperatures dropping to -15 degrees Celsius, without any preheating (2000s Polo 1.7 SDI - AKU), and it also ignited on all cylinders.

Then I also knew that the battery was okay, and I could see if the very expensive oil that went in the day before was any good .

If I think about it carefully, I've never actually experienced an xDI that didn't eventually terminate.
(Oh, by the way, that Polo I mentioned recently had a complete misfire (25 degrees early - fixed), which was quite amusing!)


My two Volkswagen Golf 2 diesel cars have achieved some quite different and impressive feats.

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

Hi Peter, You wrote that after several attempts at pre-heating, the engine started better... I just remember that in the Golf 2, there was a resistor specifically for the glow plug relay. This resistor would be bypassed when the battery voltage was low, to ensure enough power reached the glow plugs for pre-heating. Is your battery voltage okay? Otherwise, it might be an issue somewhere along those lines.

PeterK wrote:

I haven't been able to measure the voltage yet, but the realization that multiple pre-glows allow it to start smoothly gives me some reassurance .

You don't necessarily need to relight the lamp immediately when it goes out: the wicks will still receive fuel for a few seconds after that (initial reaction time for quick learners ), before they are turned off.
The latter can be heard as a quiet click from the relay. Only then should you turn the ignition off and on again.
That's definitely the case with my car.

Quote:

I had the idea that if less voltage arrives, a relay could be used to directly connect the glow plugs to the fuse?! Surely, there can't be less voltage than that?

Okay, if you can't find the other weakness... with your solution, the glow plugs will also be subjected to a higher load during the afterglow phase (something?), which in turn could shorten their lifespan.

@ AnKoe

However, this only applied to the Golf 2 TD with the LLK (liquid-cooled turbocharger), which had 80 horsepower and engine codes RA or SB.

All other Golf 2 diesel models only had an on/off relay for the glow plugs and did NOT have afterglow.

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

Hello,

I've always struggled with a rough start in the winter, having trouble getting the engine to run smoothly for the first few seconds.
Isn't that normal ?

ObenbeiMutti wrote:

I've always struggled with a rough start in the winter, having trouble getting going for the first few seconds. Is that not normal

?
Okay, I'm ready. Please provide the German text you want me to translate into English.

oopsie

I probably should have read that more carefully earlier.
Then it's probably not normal, and I have something to figure out for my Word of the Day.

It starts after a crankshaft rotation, but it still sputters and rumbles for a few seconds (probably due to the glow plug system, or possibly defective contacts/glow plugs).

So, I'm joining the thread started by 'Stranger' with my problem and I am very confident that I can solve it with the help of forum users .

Good evening.

I now have a VAG-COM diagnostic tool with the adapter to check things out. The temperature readings for the automatic transmission and engine seem a bit strange. I've looked at them at different times and in different conditions, and I've repeatedly seen a reading of 36 degrees...
I'll check again when the car is definitely cold, and if I find anything, I'll contact the seller again, pointing out the temperature sensor for a "warranty repair."

Peter K.

Hi there,

I once used VCDS (VAG-COM) to measure temperatures and saw the following:
MFA indicates -0.5 degrees. The engine group 07 (!) shows air at 0.5, diesel at 2.7, and water at 4.5. Shouldn't these all be roughly the same?

Peter K.

Yes, already.

However, the values often vary greatly even in new cars.

I would say your temperature readings are still within the acceptable range.

Best regards, Georg.