Diesel Hard Start: Troubleshooting & Fixes

Hello.

The following problem:
'At approximately 120,000 km, the head gasket and timing belt were replaced on my Alfa Diesel. Since then, it has had starting problems. It starts immediately after pre-glowing, but I don't think it's firing on all cylinders. Without giving it any gas, it will stall, and there's quite a bit of blue smoke coming from the exhaust. This lasts only 3-5 seconds, depending on the outside temperature. After that, it runs smoothly. Before the repair, the engine would start immediately and continue running on its own when the key was turned.'
What did I check?
All glow plugs have 11 volts applied to them. All glow plugs glow within an acceptable time when removed. It seems to be running on all cylinders, at least it shows a drop in RPM when I open each fuel line one by one. All the glow plugs also appear to be in good condition visually.
Question: How can I further investigate the glow plugs, or what else could be the problem?



I'm finally looking forward to being able to start normally again!

Hi,

Please look at the bolded words at the top... and please rephrase your question more specifically:

It would be important, for example:

What kind of engine is it? "Alfa Diesel" could be anything from the very first diesel engine to the most modern common-rail diesel. At the very least, it would be important to know the injection technology.

What does your engine do when it actually runs smoothly? Does it then have the usual power and characteristics, or is something not quite right?

For the glow plugs, please perform the test described in the technical articles, or measure the current draw of each individual glow plug. This is a more reliable indicator than simply observing whether they glow.

Best regards,

Jan.

Sorry,

Okay, so it's an old diesel car, a 2.0 TD (manufactured in 1997), not a direct injection model.
When it runs, it performs normally in terms of power, fuel consumption, and overall characteristics. However, my 'butt meter' (i.e., my subjective feeling) tells me that it runs slightly more unevenly at idle when it's warm compared to before the repair. But so far, this has only been something I've noticed.
I am currently unable to measure the current draw of the glow plugs because I don't have an ammeter. Where can I find test results from technical articles?
Are there any other ways to find the problem, or should I just replace the spark plugs? But I really don't want to replace them without being able to identify the cause of the problem.

Best regards, Alfa.

Hi,

That was almost a rookie mistake... the search function, or simply browsing the topics in the relevant forum, will lead you here:

I'm sorry, but I cannot access external websites or specific files online. Therefore, I am unable to translate the text from the provided URL.

Take a look at this.

It would also be interesting to know how it behaves when starting a warm engine. What happens when you start the engine that's already warm? Does it start immediately? If not, you can rule out the glow plugs, because your old TD engine probably didn't need to glow when it was warm either.

Best regards,

Jan.

Okay, so the engine starts immediately in all cases, but it doesn't always run smoothly right away. Therefore, I never have to crank it.
In its warm state, it is either undetectable or does not occur at all.
He has always had a pre-glow. Even when it's already warm, it only lasts for a very, very short time.
Most of the information from the second troubleshooting guide is very specific to TDI engines. The test using a 60-watt light bulb is more informative than using a test lamp. All glow plugs pass the test when checked with a test lamp.
Should I try to find an ammeter?


Best regards, Alfa.

Hello,
The headlight bulb allows an electric current to flow through the filament, which is on the order of the operating current.
A test lamp only indicates the test lamp current, which is usually very low, and therefore cannot determine whether the glow plug is drawing enough current.
Best regards,
Günther.

Hi,

The thing about the glow plugs, however, is a general rule. The test with the test lamp doesn't really tell you anything, because you need a proper flow of electricity, as gwg already mentioned. Try it out.

Best regards,

Jan.