Opel Astra 1.7tds Diesel Pump, 1996

Hello,
My diesel car, which has 250,000 km on the odometer, has difficulty starting in cold weather. My initial suspicion that the glow plugs or the preheating system were faulty has not been confirmed.
I replaced the glow plugs, checked the voltage to the plugs, and verified the preheating duration: everything seems to be fine...

This phenomenon only occurs when the engine is cold, after it has started and run for 1-2 minutes - no problem. I suspect a slow pressure leak in the high-pressure section. Could that be the issue? Or should I replace the diesel filter (including the water separator)? It's still the original one!!! But why would it fail specifically during startup? Not much diesel flows then...

I had similar starting problems with my old Ford Escort: the pump is divided into two parts: a primer and a high-pressure (HD) section. In that case, the primer section was the cause of the poor starting performance due to wear and tear, which resulted in a loss of pressure.

Tips and documentation regarding the diesel pump are generally welcome.

Thank you.

Frank.

Diesel filters should be changed more often than during the "usual 250,000 km service," I once heard .

However, problems with mileage and difficulty starting in cold weather can also be caused by low compression.

It might even be worth measuring the values *before* installing the new filter, because then the new filter will be used with the new motor!

m;

I agree with what dieselmartin said.
Okay, before I start replacing something as basic as a diesel filter after 250,000 km (check the owner's manual; it should have been replaced about five times by now), I would first check all other factors. As I mentioned, I would look at things like compression, the fuel injection pump, injection timing, and the overall settings. And only then, if everything else is in order, would I replace the wear items.

Hello,

First of all, thank you for the tips. I also understand that the filter should be changed more often. However, I can't see how the filter is related to the problem.

Ich denke vielmehr, dass auch die Ventile eingestellt werden müssen. Isuzumotoren sollten da ja anfällig sein... WWhat do you mean?

I'll change the filter... and report back.

Best regards, Frank.

What? Adjusting the valves? Did I misunderstand something?

And why Isuzu?

because the small diesel engines used by Opel back then were supplied by Isuzu.
and the larger ones from BMW...

CU Gremlin.

Opel uses ISUZU diesel engines because they don't manufacture their own. And now, Fiat diesel engines are also being used . (They also sell Isuzu SUVs as their own...)
I also read somewhere that Isuzu diesel engines still have valves that need adjustment. If you only do that every 250,000 km, then cheers, I guess we can't really change anything now, because the correct valve clearance is quite important for achieving high mileage. Start by looking at the front, as described.
Misadjusted valves, especially those that weren't adjusted at the recommended 250,000 km interval, will become quite noticeable.

Year of manufacture: 1996, and still using valve lifters?
Not bad...

So that no one gets the wrong impression:

'The valves need adjustment every 30,000 km on my car, specifically the valve lifters. I've had them adjusted the last two times. I'm just surprised that this issue can manifest itself with starting problems. During the previous checks, nothing was ever found.'

Okay, I have a workshop appointment on Saturday and I'm taking it there to have the valves adjusted. I'll let you know how it goes.

ps: I ordered the diesel filter for the VW.

Okay, sleeves up and let's get to work...

frank

Das Ventilspiel muß bei allen Fiat JTD (meiner is Baujahr 2003) alle 40tkm kontrolliert werden. No hydraulic shocks.
With the new 16V or Multijet engines, it's no longer necessary.

Quote:

No hydraulic shocks.

Awesome!

At VW, the cup-shaped tappets 10/85 are obsolete - but in the almost 20 years, not much has really changed in the automotive industry, so it doesn't really make a difference .

m;

...ahhh, that's why Opel is now using Fiat diesel engines, so they can continue to hire people.

Now that long-life service intervals have been introduced, problems are likely to arise, and that's probably why it's the hydraulic lifters.

The new Fiat diesel engine is the 1.3 CDTI.

He is __completely__ new and should then fall under the category of those already containing water .

m;

Hello,

Your enthusiasm about the different types of plungers doesn't really help me. But here's something to think about:

Explain to me why the theory of a supposedly clogged filter behaves differently during a cold start versus a warm start. After all, the filter shouldn't care whether the engine is cold or warm, right?

I think the issue with the valves is the only reasonable approach, or maybe the high-pressure part of the pump is slowly losing pressure. What do you think about that, with your expertise? Please elaborate here (because that would help ).

Best regards, Frank.

Hello Frank!

Quote:

But here's a brain teaser

.

He who sits in a glass house should not throw stones .


Okay, but now let's get to the topic:

The viscosity of diesel fuel decreases as the temperature increases. Consequently, the fuel is thickest and most viscous during a cold start.
When the diesel fuel is cold, the highest pressure loss occurs across the filter. While the injection quantity is low during starting or idling, the pre-injection pump, which is normally integrated into the ESP (Electronic Stability Program), delivers a speed-dependent amount of fuel, regardless of the actual amount injected.
This means there's a high probability that, especially during a cold start, the vacuum in the system becomes too high, preventing fuel from reaching the engine. If there's even a slight leak between the differential pressure sensor (DiFi) and the electronic stability program (ESP), the pump will only draw in air and virtually no diesel fuel.
Normally, there is a thermostat valve in the return line that mixes the slightly pre-warmed fuel with the fuel going to the injectors. This also warms up the fuel injectors, and the problem is less pronounced when the engine is warm.

Okay .

Regards,
Alex.

"And something else I could imagine is that the water level present after 250,000 km might not be very good at temperatures below 0 degrees Celsius. However, this is really just speculation. Just drain it; it's quite simple. There's a screw at the bottom; let the liquid drain out and then refill it."
Or maybe it's time to buy something new.