1.4 TDI: Air in Fuel System?

Hello,

I'm having a small problem again with my 2001 AMF.

'When I stop the TDI after longer highway drives and don't start it again until the next morning, 1-2 cylinders briefly fire, and then only the starter motor turns.'
After 30 seconds of idling, the engine restarts with a jerk but then runs perfectly fine.
After short trips, when the fuel hasn't gotten hot, it starts normally. It seems like there's air in the system. This has been happening for about a week and has been getting worse each day. At first, when starting, the engine would only drop to 400 RPM and then recover. Now, it just stalls.

I have some oil or diesel lubricant underneath the tandem pump. Therefore, I'm going to replace the seals on the tandem pump.
Spark plugs, glow plugs, and fuel filters are only 10,000 km old.

Do you also think that's nonsense? Or does anyone have any other ideas?

Best regards and thanks.
Thomas.

The "Air Theory" is best demonstrated using transparent sleeping bags.

To the best of my knowledge, the PD doesn't have them anymore (meaning they aren't as good as the VP's transparent options, all the way up to ESP).

Maybe you could install one sometime.

If you're experiencing the same issue with the fuel filter as others have, it's likely leaking at the bimetal valve because it's not being pressed firmly enough against the seal. Simply replace the seal in this case.

m;

Unfortunately, I don't have any transparent hoses. I checked the catalog to see if VW sells the hoses as individual meters. At least for the A3 with VEP-TDI, there's a hose set included. I don't think I can just use any hose from the hardware store, because it needs to be able to withstand diesel and biodiesel.
Does anyone have any idea what kind of hose is needed, and where I can find it?

My fuel filter is dry. That wouldn't make sense anyway, because on my A2, the fuel filter is located at the back of the tank, which would mean the fuel line would have to be completely empty. In my opinion, it would take much longer than 30 seconds for the line to refill.

I've now removed the tandem pump, cleaned it, and partially disassembled it. I replaced the seals between the head and the pump (which are available individually). Then, I unscrewed the pump cover and glued it back on with 2K adhesive. I believe that the seal at the 'Y' junction wasn't completely tight.

I'll find out tomorrow morning if that was the problem.

Regards,
Thomas.

A2TDI wrote:

Unfortunately, I don't have any transparent hoses. I checked the catalog to see if VW sells the hoses as individual meters. At least for the A3 with VEP-TDI, there's a hose set. I don't think I can just use any hose from the hardware store, because it needs to be able to withstand diesel and biodiesel. Does anyone have any idea which hose to use and where to get one?

Hi,

"In my Polo, I proactively replaced the two thick black hoses (inlet and outlet) between the fuel filter and the fuel tank with clear fuel hose from the hardware store. This allows me to easily see any potential air bubbles, similar to what you see in VP engines."

I only use Dino diesel, but even with that, the special fuel hose becomes noticeably harder over the months .

But for a few weeks, that should be more than enough to easily observe air bubbles.

Yay, it worked. I drove the car like an idiot across the highway yesterday, and yet, this morning, it started right up.

Regards,
Thomas.

Good news.

Then that was probably the poetry you were referring to.
It's a shame about the Friendly company; their revenue has decreased again by a few hundred euros...

Thank you for your feedback.

A2TDI wrote:

Yay, it worked. I drove the car like an idiot across the highway yesterday, and this morning it still started right up.

Great

Then, you would likely have seen bubbles in the clear hoses, at least in the return line, if/when the pre-pump starts when the ignition is turned on.

That would have been a less complex initial assessment - perhaps someone else will try it later, if they find this thread .