Starting Problems 1Z: Troubleshooting Guide

Hello,

I've had a Golf 3, model year 1995, with a 1Z engine and 176,000 km on the odometer for about a year.
Das Auto hat alle Kundendienste von VW erhalten und ist optisch in einem Top Zustand (1. Hand).

Unfortunately, I've been searching for a solution to a problem for almost a year now, and I'm slowly going crazy. I was even considering selling it because of it. Three VW workshops have just shrugged their shoulders and haven't been able to help!

It starts very poorly, especially, like now, when it's cold.
Then, sometimes, it takes a very long time for the engine to start, and it runs erratically before it finally catches and runs smoothly again.
When it's warm, it still starts okay (it takes about 4-5 seconds of cranking).
When it actually runs, the performance is okay. It pulls nicely and has normal fuel consumption.
'It only occasionally jerks when accelerating fully from 1,500 RPM in fourth gear. Around 3,500 RPM, it briefly hesitates before continuing to accelerate.'

Done.

Crankshaft pulley replaced, screw renewed, injection timing readjusted (using a TDI graph).
Spark plugs replaced, all fuses and relays checked.
The temperature sensor is functioning correctly, and the measured value in the data block corresponds to the outside temperature.
The diesel filter has been replaced.
There is no air in the diesel line.
The engine has full compression.
The starter motor is already new.
LMM delivers 850 mg/h in terms of dry matter basis (DMB).

Just now, we replaced the crankshaft bolt with the gear and re-calibrated the pump using VAG-Com. The injection timing is now set a bit too early.
It used to work before, but it wasn't free after all . Previously, the injection start point was more or less below the line in VAG-Com. Now it's above the line.

Today I also tried starting the engine with the temperature sensor disconnected, but there was no improvement. The preheating light stays on for a noticeably longer time, but the engine still cranks.

Tomorrow, I want to test the NHG (presumably a component). I'll spin it up to 3000 RPM and then tap on it to see if anything changes. I don't think it has anything to do with starting, but maybe it will eliminate the shaking/jerking.

Could those be the spray nozzles? It's quite a lot of money...
I really don't know what to do anymore.

It seems like it's related to the preheating system.
The lamp is on, but nothing is happening at the front. So, there's no power reaching the heating element!

The fuses are okay. The relay clicks during the diagnostic test performed with VAG-Com.
What else could it be? If I directly supply power to the candles themselves (using a battery), then they work, which means they are drawing power correctly and are therefore okay, right?

Okay, then start measuring. Do the spark plugs receive power when you activate them via the diagnostic system?
Otherwise, you'll have to check the cables one by one.

Dirk.

The cables appear to be in good condition, at least based on a visual inspection.
Kannst Du mir verraten wie ich die Kerzen ansteuern kann (Kanal? Login etc.

But I don't think that's the problem. I drove about 150km today. Starting around 3,500 RPM at full throttle, it starts to stutter. I stopped accelerating then. It could be something else, like the NHG (negative heat generator), but that's another defect (again).

Then I turned it off and immediately started it again. I did that again. 4-5 seconds of cranking...
He must be ready right away if he's that hot, right?

VW simply said: This is an old diesel engine, not a gasoline engine, and that would be perfectly normal .
They are crazy...

Quote:

The cables appear to be in good condition, at least based on a visual inspection. Can you tell me how I can access the candles (channel? login, etc.)

Hmm, I wouldn't always rely on visual inspection. Measuring is more reliable! As for how to navigate to the candles, you've already answered that yourself:

[/quote]The relay clicks during the diagnostic check using VAG-Com.

Quote:

Are you sure the engine was cold enough when you noticed that it wasn't being preheated? Otherwise, take another look at the technical articles; there's a lot of information in them! Regarding the issues you're experiencing, I don't have much more information to offer. But if I understand correctly from what I've learned about the VEP species here, the NHG shouldn't have any influence at the moment of starting. Therefore, your starting problems should have a different cause. However, the FAs might be able to help you with that as well. Best regards, Dirk

Last question from this topic: https://community.dieselschrauber.org/en/viewtopic.php?t=8592

Quote:

Have I never heard of that?! How can I test that? Where is the stop cock?

The valve for the fuel shut-off is located in the fuel injection pump, to the right of the quantity control unit (when facing the car). To access it, you need to unscrew the cable from the shut-off valve (using an 8mm wrench), then remove the shut-off valve and take out the valve's piston. Now, reinstall the shut-off valve and start the engine.

But, as mentioned in the previous post, since you've already checked everything, the symptoms suggest a worn distributor head.

Even if the glow plug wasn't working, it shouldn't take 4-5 seconds of cranking for a 1Z engine to start. While it might shake and smoke a lot in 0°C temperatures, it would still start.

Quote:

VW simply said: This is an old diesel engine, not a gasoline engine, and that would be perfectly normal

.
Normal?! No, no, neither playing the organ is normal, nor are...

Check the glow plugs using a test lamp or a voltmeter. Disconnect the wires to the glow plugs and measure the voltage between ground and the glow plug terminal. To do this, disconnect the connector at the water temperature sensor and turn on the ignition. You should then have the battery voltage for at least 20 seconds; otherwise, check all the wiring according to the wiring diagram.

If the car is otherwise in good condition, it will start at -15 degrees Celsius without needing to be pre-heated.

My ex-girlfriend started her Polo SDI in -15 degrees Celsius, and it started right up immediately, without any problems.

"You said I don't have to preheat it anymore..."

The AKU had somewhere between 70,000 and 90,000 kilometers on the odometer at the time.

m;

Yes, that's correct. Heating is useful, but not strictly necessary.

As far as I know, a single glow plug already draws 20 amps.

That is, simply turn on the headlights at night.
Let it glow; If the preheating works, you will see...
as the indicator light for the heating function almost simultaneously turns off.
that the headlights are getting a little brighter again.

You could easily rule out the possibility that it has something to do with that.

I can even tell when the afterglow ends by the change in speed.
I always stop at the traffic light (just after leaving the company parking lot), and then the engine speed momentarily increases slightly.

The TDI engine has easily accessible glow plugs; you can simply use a multimeter to check them. A resistance of around 0.8 ohms (when cold) is considered good. An infinite resistance indicates a burned-out glow plug.

m;

So, it's definitely glowing nicely, just like it's supposed to.
The tension is building, and the light is getting dimmer.

Is there anything that can be done with the pump? I already got the upper seal because a friend told me back then that there's something in there that can cause problems.
You need to carefully remove the top lid, verschandeln any 'adjuster' or 'knife' that might be present, replace the seal, and close it again. Alternatively, you can run a cleaning solution through it.

One problem is that I need the car every day, and the other problem is that I currently don't have the money for a new pump, which is supposed to cost over 1000 euros.
'But I don't want to sell the car, because it's in good condition overall and has low fuel consumption, etc.'

Hello.
I don't want to jump to conclusions, but if the engine doesn't start properly even when it's warm, it's probably not the glow plug system. Therefore, here's another possibility:

It's not uncommon, but it can happen that the two valves in the high-pressure section break. This has the effect that the injector lifter is no longer pushed back to its starting position. As a result, no or very little diesel fuel is injected. However, if the engine is already running, it seems to be enough to push the lifter back. Eventually, it may not start at all, or only starts with a push. The damage can be repaired for approximately 300 euros, including adjustment and sealing. However, this is only possible with a skilled Bosch service center; other workshops will try to sell you a replacement pump.
Symptoms: Difficulty starting, requiring several seconds of cranking. The same issue occurs whether the engine is cold or warm. Smoke is emitted during and especially after starting. Slightly increased fuel consumption or a slight decrease in performance. There may or may not be any error codes, but if there are, it could be related to things like fuel injectors, etc.
Oh yes, if you've been using the same starter coals for a year, you should probably start thinking about getting new ones, but those are also relatively easy to replace.

Best regards, Heri.

I know the issue with the glow plug system has already been discussed, but last winter I had two glow plugs fail, and the 1Z engine still started with the first few revolutions even at temperatures below -15°C. Then, when it was around -18°C, I had to crank it for a few seconds before it sputtered to life with a noticeable puff of smoke; before that, I didn't notice anything unusual.