Air in the fuel system; Diesel filter priming pump

I have a Toyota Corolla 2.0D diesel, manufactured in 1997, with 160,000 km on the odometer. For the past month, it has been difficult to start. This problem appeared suddenly, from one day to the next.

The battery is new (2 months old).
2. The diesel filter has been drained (done 2 weeks ago); I admit that the filter is old and has never been replaced.
3. There is no white smoke coming from the exhaust.
4. If you turn the engine off and immediately restart it, it starts right up.
5. If you wait for 15 minutes or longer, you may already need to crank the engine for 3-10 seconds before it starts.


I suspect that the fuel injection system is drawing in air somewhere.

Bitte gib mir den Text, den du übersetzt haben möchtest.
Can you operate the bleed pump on the diesel filter even if you don't open any lines or other components in the fuel system?
Where should the air escape to?
Is there a specific opening that is intended for venting purposes, which should be opened before activating the ventilation pump?

I've been thinking about priming the fuel injection system briefly with a few strokes of the priming pump before starting the engine. However, I'm hesitant to do it because I'm not sure if I might damage the pump's diaphragm if I don't have anywhere else to release any trapped air.

I plan to change the diesel filter over Easter (when it's warmer and I have more time), and I'm also going to replace the fuel line directly in front of the pump with a transparent one, so I can see if any air is getting in.

Recently, while the engine was running, I briefly (for about 5 seconds) disconnected the fuel line to the injection pump, and the engine didn't stall; it continued to run normally. This surprised me a lot.
Then I briefly (for about 2 seconds) disconnected the return line from the injection pump. However, I quickly reconnected it because diesel fuel was already starting to leak out.

Here are two more visual representations.

the diesel filter with the pump on top.
To the left, the fuel line leading to the injection pump.
I don't know what that thing is located right below the pump button, where the electrical cables go in.

http://www.geocities.com/s.holl/diesel_20040221.html
http://www.geocities.com/s.holl/dieselfilter01.jpg
http://www.geocities.com/s.holl/dieselfilter01.jpg

the fuel injection pump.
That round, black thing with the orange button in the middle, located just below the oil dipstick, is the drain valve.
Between those two components is the fuel line clamp, which then acts as a metal conduit leading to the left side of the Vespa.
I want to replace the short, opaque section of the fuel line with a transparent hose during Easter. (Does anyone know where I can find a suitable transparent hose with an inner diameter of 7mm? The connector fittings have a diameter of 8mm, and I wanted to use a 7mm hose so that it fits snugly; I haven't found anything suitable at Globus or Toom hardware stores.)
The return line is connected directly to the left of the shut-off valve.
Coming from the connecting screw, there is also a small metal tube that extends upwards and is simply open.

'Is this the line where air is supposed to escape from the fuel system? Is there a valve in the screw that only allows air to escape?'
To the right of the control valve, and somewhat obscured, you can see the four lines that lead to the fuel injectors.

http://www.geocities.com/s.holl/diesel_20040221.html
http://www.geocities.com/s.holl/vesp01.jpg
http://www.geocities.com/s.holl/vesp01.jpg

Thank you in advance for any advice or information you may provide.
I've read a lot in this forum, and I think it's great. It's only thanks to the many contributions that I've been able to get as far as I described above in my troubleshooting.

Hi, Stefan.

The diesel filter has never been changed, even though the car has driven 160,000 km?

Okay, then you know what you have to do first!

TRY switching it and then try again.

VW has service intervals of 30,000 km for that!

m;

Yes, you're right, and I will change the diesel filter around Easter (in about 40 days).

Can anyone tell me if I can activate the bleed pump on the diesel filter without opening any lines?

and if so, where does the air escape from the system?

And, most importantly, would this help reduce the time it takes for the ignition organ to activate from 10 to 3 seconds?

Would it also help if I give it full throttle while starting?

In my opinion, Volkswagen recommends changing the diesel filter every 60,000 km.

nope Chris

During my last 30,000-mile service, the maintenance checklist included:

AIR filter replacement after 60,000 km.
Replacing diesel filters.

For the G2 Diesel, it was also 30,000 km.

m;

@ holl

VW diesel engines have been self-ventilating since the Golf 1 (referring to the 4-cylinder distributor injection diesel engines).

The air is simply pumped away through the return duct.

I have diligently completed all filter changes and "dry runs."

Therefore, I don't know what the Toyota buttons do.

I'm certain that the filter would have needed to be replaced a long time ago.

m;

Hello, at VW/Audi, diesel filters are typically replaced every 30,000 km or 60,000 km.
It depends on the model.
Regarding the question of whether you should operate the pump: Of course, that's what it's there for.
After a drive, check if you hear any hissing when you open the fuel cap. It's possible that your fuel tank is no longer properly ventilated, which could create a vacuum that slowly drains your ESP (Emergency Stop System).
If it's hissing, just drill a hole in the gas tank cap.

Please fill the new diesel filter with diesel before installation, otherwise the starter motor may overheat at some point, and it's also not good for the fuel injection pump, depending on the model installed.

Best regards, Rainer.

hello,

After the tip about the problem with the fuel tank ventilation:

Indeed, I hear a hissing sound when I open the fuel tank cap at the gas station.
Therefore, I've only loosely screwed the fuel cap on for now. However, unfortunately, I still have an unpleasantly long starting process. The last two times, it was so bad that it didn't start after 10 seconds of cranking (no signs of starting), even though the starter motor is turning the engine nicely. So, I opened the hood and manually pumped the fuel (about 20 times at the fuel filter). It's very easy to operate, which probably indicates that there's a lot of air in the system. Even after that, the engine doesn't start immediately, but only after about 5 seconds. Even if I give it full throttle right from the beginning of turning the key, it takes about 3 seconds for it to start, but then, despite the full throttle, it runs at a normal idle speed. The engine speed remains constant (for about 2 seconds). Only then does the engine rev up, at which point I naturally release the accelerator.

I'll keep you updated.

Another idea:

Obvious leaks at the fuel injection pump:

On the Volkswagen Golf 2, it's a common problem for the adjustment shaft to leak.

Try the following:

- Started the car with the usual difficulties.
- Let it run for a while until you're absolutely sure all the air is "out."
- turn off
- Now, listen to the fuel injection pump.
- My G2 used to make a very faint hissing sound because air was being sucked into the ESP through a leaky shaft.

You might also hear a hissing sound.

You could also try parking it on a steep hill with the engine facing downwards.
Then, a subsequent startup process should work better because the ESP won't be as likely to run empty.

m;

P.S.: Perhaps other parts of the lines are also leaking. It doesn't always have to be diesel that leaks; air can also enter - so don't just look for damp spots!!

hello,

I tried it. I started it, waited, turned it off, and it obeyed. However, I couldn't detect any hissing sound.

I've noticed that the hand pump is extremely easy to operate when I use it after a longer period of inactivity (e.g., one day).

'If I pump with the hand pump for a short time (about 5 minutes) after stopping the engine, it's easy to pump at first for the first few strokes, but then it becomes increasingly difficult to operate. This is how it should be, because the air is being displaced from the injection system, and air cannot be compressed.'

However, I'm still shocked that after just 5 minutes, there's already so much air in the system that the first 5 repetitions are so easy.

Okay, here's a practical question: To find the leak in the system, I've considered removing the diesel filter (which I'm going to replace anyway) along with its bracket. This would expose the line that leads to the injection pump. Would it be okay to introduce compressed air (1 bar) into this line to see where the air is escaping, thereby locating the leak? Of course, I would need to clamp and seal the return hose that connects to a T-piece between the tank and the filter and returns to the diesel supply line. Alternatively, is there an 'air vent' on the pump that would allow the air to escape? If so, I would also need to seal that.

Okay, by the way, I'm now parking on a downhill slope, and I'm hoping that the higher liquid level in the tank will help keep the fuel system full of diesel, which should significantly shorten the venting process when starting the engine.

Okay, here's the translation:

'Also, when I was still parked horizontally, and the tank was almost empty, I pumped about 60 times with the hand pump, and I never felt any noticeable resistance. I even thought the pump itself might have a leak, but I was able to rule that out (as mentioned above). How long would I have to pump if the entire system, from the diesel filter to the ESP and back, is completely empty?'

Is there a critical point beyond which even manual priming won't work, for example, if the diesel filter is filled with air, causing the pump to pump air instead of diesel?

Thank you for your suggestions.

If you have a vacuum in the tank, why don't you try removing the tank cap completely, just for a test?

hello,

The idea of using negative pressure in the tank is actually quite good. I've been practically driving with a loose gas cap for several days now. And today, when I was filling up at the gas station, there wasn't any hissing sound at all, because the gas cap is just loosely screwed on.

Conclusion: The vacuum in the tank (which I actually experienced when I tightened the fuel cap) is not the cause of the air in the fuel injection system, as the starting problem persists.

'Nevertheless, thank you for the tip.'

Best regards, your 'loose-gas-cap-driver'.

hello everyone,

Finally, I did the following.

1. full tank
2. Gas cap only loosely screwed on.
3. Parked downhill with the engine facing downwards on a steep slope.
4. Left standing overnight.
5. Tomorrow morning, open the hood.
6. Operate the hand pump on the diesel filter.
7. She was lighthearted - that is to say, things were back to normal.
8. After a few strokes of the pump (approximately 15), it became difficult to operate.
9. Look under the vehicle.
10. a diesel leak was detected.
11. A closer look inside the engine compartment.
12. The hose (black rubber hose) connecting the fuel line (the metal line that runs from the tank towards the engine compartment) to the diesel filter housing was completely saturated with diesel in one spot (dripping).
13. Yay - leak found. This cable had a worn spot (barely visible).
14. I went to the workshop and explained everything to them, and they even believed me.
15. They replaced the hose (and, by the way, they kindly also replaced the diesel filter, which I had already bought and was sitting on the passenger seat).
'Paid a little over 40 euros, and the car is running great again, totally super and reliable, just like a Toyota should.'

By the way, I can highly recommend that workshop. I was there once with a suspected engine problem, which turned out not to be the case. Fortunately, they identified the real issue, which saved me about 2900 euros, because an engine problem would have cost around 3000 euros. They drained the oil and noticed there were no metal shavings in it (which is something you have to pay attention to!). So, they refilled the oil, started the engine (which was making a lot of noise), but the noise gradually disappeared over time. It was probably a stuck (open) valve, caused by some dirt in the air intake system.
aja: Richter workshop, Dresden, Klotzsche, Boltenhagener Straße.


Well, I was lucky that the hose had such a large hole that the diesel also came out. But if anyone ever encounters the same problem, it's definitely worth trying.

And now - thank you all very much for all the tips. They helped me enormously in narrowing down the problem so quickly.

yours - Stefan, formerly a 'loose-tank-cap' driver.

Congratulations, and thank you for the feedback!

That brings joy.

Did you install a proper hose now?

I once had a similar problem with my 13S Kadett. The suction hose also crumbled.
simply stopped, of course, early in the morning...


but somehow, it makes me happy that the good old standard errors still exist .

CU Gremlin.