Glow Plug Problems: Troubleshooting & Repair

Hello everyone!
'This is a really nice forum! I hope you can help me with a problem I'm having with my Golf3 90PS TDI...'
So, I had my car at a body shop three weeks ago, and they did some welding work on it.
When I picked up the car, I noticed a lot of white smoke coming out when I started it! But it started up normally.
I didn't think anything of it because the car had been sitting for two weeks.
The following week, the problem worsened with every cold start! I was disturbing the entire neighborhood with the noise in the mornings!
Then I went on vacation for a week! However, I didn't have a car.
When I returned, I could barely start the car. It would eventually start on 2-3 cylinders and then run.
I removed the spark plugs and measured their resistance! All 4 are between 1 and 11 kilo-ohms!
After that, I got four new spark plugs and installed them.
However, the success I was expecting did not materialize!
It still starts poorly!
I measured the voltage at the glow plugs when I turned on the ignition, and it was 0 volts!
Okay, I think the glow plug relay might be broken! But I have no idea where it is! The two cables that run from each of the two pairs of glow plugs disappear somewhere in the engine compartment.

Can someone please tell me where the relay is located?

Or perhaps the error is already known, and something else is to blame.

Thank you!

Hi Supermac,

Supermac wrote:

I measured the voltage at the glow plugs when I turned on the ignition, and it was 0 volts!

Given the current outdoor temperatures, it might be difficult to get a TDI engine to glow. The standard glow plug system doesn't activate until around 5°C. Before that, the TDI engine doesn't require preheating.

Since you haven't mentioned the engine code or the year of manufacture for your Golfs, I'm assuming the worst-case scenario and believe it's a 1Z model. Early 1Z models had the unfortunate tendency to shed the crankshaft pulley. This ultimately leads to engine damage. In the early stages, a loose crankshaft pulley can cause the starting problems you described.
So, before you wait any longer, check (or have checked) the ESP timing and see if the KW wheel is rotating smoothly or wobbling. You can find more information (how, what, where) about this using the search function.

However, it is possible that the error is much less dramatic. To determine this, we need more information from you.

My Golf was first registered in September 1994.
KM: 215,000

Unfortunately, I left my vehicle registration document in the car, and now it's at the body shop!

Does this mean that my glow plugs were already broken, and that it doesn't even pre-glow in the summer?

The performance - when it's running - is normal... Also, the Russian development is also normal!

An engine failure is exactly what I need right now...

If it is indeed the crankshaft pulley, you should act quickly, as the timing belt is loosening, skipping teeth, and the valves are colliding with the pistons due to the misalignment of the camshaft. A TDI does not glow when the temperature is below 5° Celsius, and it shouldn't. The fact that the performance is normal when it's running is clear, even if there is already a misalignment of the camshaft. The TDI dynamically adjusts the injection timing. Since your Golf was manufactured in 7.94, it likely has one of the first 1Z engines with the crankshaft pulley, which has a low strength (8.). If that is the case, it must be replaced with one that has a strength of 12.8.

Best regards, WarLord.

Thank you for your efforts.

When it's warm, it starts up normally.

The timing belt was replaced 25,000 km ago! That was in July, exactly one year ago!
at a VW specialist workshop! They should be familiar with this problem and have used the 'stronger' screw!

If the timing belt has skipped a tooth, it should also cause difficulty starting the engine when it's warm.

Hi,

Supermac wrote:

My Golf was first registered in September 1994. KM: 215,000 Unfortunately, I left my vehicle registration document in the car, and now it's at the body shop!

That's all the information I need. It's a 1Z from the first series. These engines are extremely prone to losing the crankshaft pulley.
Please search for "crankshaft pulley" or "crankshaft bolt."

Quote:

Does this mean that my glow plugs were already broken, and that it doesn't even pre-glow in the summer?

"So, if the cold resistance is greater than 1 kOhm, I would consider the glow plugs to be defective."
As mentioned earlier, it should not require a pre-glow if the temperature is above approximately 5°C.

Quote:

The performance - when it's running - is normal... Also, the Russian development is also normal!

That's yet to come ...

Quote:

The timing belt was replaced 25,000 KM ago! That was in July, exactly one year ago! at a VW specialist workshop! they should be familiar with this problem and have used the "stronger" screw!

They should know this, but it's often "forgotten."

@Supermac

'Should' is truly the magic word. Regarding the topic of changing the crankshaft bolt: Click.

Best regards, WarLord.

Disconnect the coolant level sensor and check if there is at least battery voltage present at the glow plug connectors when the ignition is turned on.

@Julian: Where is that plug...?

@everyone, thank you for the tips... but could it not be something else?
because, as I said... it starts when it's warm!

Supermac wrote:

@everyone else, thank you for the tips... but could it not be something else?? because, as I said... it starts up when it's warm!!!!

Darn it and darn it all.

Finally, use the search function!

If the KW wheel is loose, then the engine starts poorly when cold, but starts perfectly fine when warm. Does this apply to you, or not?
A misadjusted ESP (Electronic Stability Program) or a skipped timing chain will cause the exact same problem (because if the wheel bearing is loose, it shifts the timing of the pump).

Without further information (e.g., error code entries, reading various data blocks...), we can only guess here.

@Julian: where is this plug.....


It's located where the main temperature sensor for the water is, usually near the engine, where the coolant flows from the engine block to the radiator.

And otherwise, you should really follow Bertil's advice!!!