Cold Start Problems: Troubleshooting & Solutions

Hello Dieselschrauber.de enthusiasts!

I have a Volkswagen Golf III, TDI with 90 horsepower, manufactured in November 1994, engine code: 1Z, with a mileage of 122,000 km.

After my trusted workshop and I have slowly reached our limits in terms of patience and expertise, I am now asking for advice and assistance from you all. Here's what has happened so far:

- It started with some minor cold start issues, meaning that if the car had been standing for a while, my TDI wouldn't start properly. However, after 3-4 attempts, it would eventually start and run normally. Warm starts were no problem.

- This problem has now worsened to the point where the engine is very reluctant to start (requiring approximately 7-10 attempts), then runs very unevenly below 1000 RPM, before eventually stabilizing after about a minute and then running normally. Once it's warm, it starts without any problems. However, until it reaches that point, you can spend a very long time trying to start the engine. Furthermore, this cold start problem has now also evolved into a warm start problem, meaning that the car also starts poorly after a longer drive.

- Furthermore, there was a loss of power during the drive. This manifested as a failure to accelerate, with the engine speed dropping to 1000 RPM, followed by a resumption of acceleration. When I looked in the rearview mirror, I saw a very large, white/gray cloud coming out of the exhaust.

- Regardless of what else happened, the car simply stopped working while I was driving, and afterwards, it also started exhibiting the same starting problems mentioned earlier.

- Another curious phenomenon is a kind of "ringing" sound that occurs above 2500 RPM, which was noticed during a longer highway drive and has only appeared in the last two days.

So much for the symptoms. So far, the following attempts have been made to fix the problem:

- Checked fuses for heating system, OK.
- Spark plugs removed and checked, OK.
- Power supply to the glow plugs checked, OK.
- All cables checked, all are OK.
- Fuel lines checked for leaks, all OK, no air bubbles or similar issues detected in the fuel lines.
- Coolant temperature sensor replaced, no change in symptoms.
- Air mass sensor replaced, no change in symptoms.
- Replaced the electromagnetic shielding, but no change in symptoms.
- Replaced the X-Contact relay in the fuse box, position 3, but the symptoms remain unchanged.
- Crankshaft timing gear (including screw) replaced, no change in symptoms.

After each of the points mentioned above, the error memory was read, each time without revealing any significant findings. All the values displayed, including those related to injection timing and air mass, were also checked and showed normal readings.

Now, the replacement or repair of the fuel injection pump (VW part number 028 130 115 MX) would be necessary, which would cost a maximum of 1500 EUR. I find this very expensive, and I would like to get your expert and experienced opinion before committing to such a large expense to see if it could really be the cause and whether it would resolve the problems/symptoms.

In recent years, I've experienced many expensive defects with this car (e.g., a new fuel injector with a needle lift device, a new engine control unit, etc.), and I really don't want to deal with high repair costs again. Therefore, I'm asking for your opinions, tips, and advice on what other possibilities there might be to avoid having to install a new fuel pump.

Thank you very much for your advice and experiences!

Best regards,

Bux.

Was ist die Bedeutung von 'Relais 109' in diesem Zusammenhang?

You've already replaced everything else, or at least thoroughly checked it, right?

Quote:

A very large, white/gray cloud came out from the exhaust pipe.

White clouds always sound like a blown head gasket.

What do water and oil look like? Are there any mixtures of them?

What does the compression indicate?

m;

Hello everyone,

@hb2000
I'm not entirely sure if relay 109 was present in the 1Z model, but I didn't include it in my troubleshooting. I'll look into it and check right away.

@dieselmartin
I haven't considered the issue with the white smoke and head gasket yet, as it simply doesn't fit the observed symptoms, and I haven't been able to detect any coolant loss. There's also no oil in the coolant, and no signs of coolant in the oil. Furthermore, all the hoses appear to be in good condition.

The compression values are all within the normal range – assuming the engine starts and runs smoothly. I can't say what the values are like when the engine is running and the RPM drops, because I don't have a laptop with VAG-COM, only a stationary computer in the workshop.

So far, thank you very much for these tips. I will now have relay 109 checked, but I'm not very hopeful about it.

Best regards,
Bux.

How are the Duesens doing?

Are they hanging?
Are they dripping?

The 122,000 km for an 11-year-old diesel car seems strange – I would have expected more, around 222,000 km.

And then the nozzles will definitely no longer look "like new".

Sure, here's the translation:

"Just a heads-up."

m;

@dieselmartin
Thank you for the next suggestion regarding the fuel injectors... I would have checked those next anyway. It's a bit more work than what I've been doing so far, but I need to check them as well.

"And yes, my car only has 122,000 km on the odometer. The previous owner was a retiree, and I've driven about 15,000 km per year so far. Are you referring to the age or the mileage when you say "...not like new"? Should the injectors be replaced after 11 years? I can't imagine that being necessary right now. At 222,000 km, a replacement would certainly be recommended, but I don't believe the injectors are faulty at 122,000 km. However, with this car, nothing seems impossible or normal anymore."

I will keep you updated!

Best regards,
Bux.

Once it starts up and runs smoothly, the compression values are all within the normal range.


I'm sorry, I don't understand. Can you please rephrase your request?

'May I ask what and how the measurements were taken? The pattern of the results suggests to me a significant lack of compression. And, more importantly, who performs compression tests on a running engine?'

My first G2 diesel had the following pressure readings at the end (if I remember correctly): 9/24/31/24 bar.

Okay, so there's almost no cylinder present, and two are below the threshold (2.

He also tried to fix it that way. And when it finally worked, everything was normal.

I had also invested in all sorts of things, which felt even worse after the compression check.

The 50 euros should be worth it.

(The LMM was more expensive - how did you actually justify the exchange ???)

m;

Hello,
I also think that the engine's compression should be checked; it's the 'lifeline' of a diesel engine, and problems with it usually manifest first during cold starts.
Best regards,
Günther.

Fuel filter (hmm 3 f??) also replaced or definitely checked for blockage?

@dieselmartin
I justified the LMM replacement by citing a drop in performance, but I only had the replacement part installed for testing. Since there was no improvement, I reinstalled the original part.

Otherwise, the problem seems to have suddenly disappeared – my mechanic just called and told me. He re-checked all the previous tests, also re-installed the crankshaft pulley (with a new one, of course), and strangely enough, the car is now running. I can't explain it at the moment, but hopefully I'll learn more later when I talk to the mechanic. It's hard to get a clear picture over the phone.

@everyone

Thank you very much for your quick and helpful advice. I'm glad I discovered this forum!

Hello,
Bux.

109 is also available at 1Z!
Is the car always in the same workshop? I would definitely change that workshop. This constant swapping of workshops is a bad sign of incompetence.
Was the car always operated using diesel fuel?
The next step would be to check all the temperature sensors while the car is stationary and completely cold (ideally overnight). Any irregularities should then be detectable. If you can't do this yourself, leave the car at a qualified Bosch service center overnight. While there, have them check the injectors as well. It's also highly recommended to replace all the filters, and while you're at it, check the power cables leading to the starter for any resistance. A compression test is a must, and when the tank is about half-empty to empty, try leaving the fuel cap open.
To pinpoint the source of the noise, it could be a heat shield, but it could also be a developing exhaust leak or even the catalytic converter. It's worth tapping the catalytic converter to see if anything is loose. Alternatively, on a closed track, you could try driving with the exhaust open.
Considering the mileage, wear and tear seems unlikely, especially given the precautionary replacement of the parts.

Best regards, Robert.