Audi TDI AEL springt schlecht an | Posts 16+

Hi! I suspect that the distributor body of your fuel injection pump has already failed. Unfortunately, it's a wear item! The starting speed is significantly lower than the idle speed. This means that the leakage amount between the pump cylinder and the plunger is greater. This means that the starting amount may not be sufficient to start the engine. The AEL has definitely exceeded 200,000 km.

Best regards, Rudi.

That's right, the car has 250,000 kilometers on the odometer.

But after I checked everything, it needs 10 liters. No joke. According to the onboard computer, and it hasn't been refueled yet! Otherwise, it was somewhere between 7 and 7.5 liters. With a caravan on the highway, it sometimes reached 11. Could it really only be the pump? That's going to be an expensive repair.
Okay, yes, if it sits for more than 3 days, it starts 'normally' as well. Everything is very strange. Maybe I should have sold it earlier .
Greetings.

Please check the screw on the camshaft sprocket that's on the pump side of the camshaft. As far as I know (at least in the nearly identical R5 engine in the LT van), it's only held in place by a cone.
If the pump were to become misaligned later on, that would explain both effects (increased fuel consumption + starting problems). In particular, the inline five-cylinder engines seem to be very susceptible to this.
Similarly, the toothed belt tensioner or idler pulley on the pump side may be worn or loose, which can delay the pump's start-up.

Tip: Have an experienced mechanic adjust the timing of the pump slightly earlier, just to be sure, and then observe the behavior.

Hi,
If the starting problem is related to temperature (or "dwell time"), I don't believe it's the pump. It could be a misaligned injection timing, but that wouldn't correct itself after 3 days of sitting, would it?
Specifically, the high fuel consumption doesn't point to a worn distributor, because in that case, you would likely experience low pressure and a reduction in the amount of fuel injected. I've experienced very different starting behavior in my car when the timing belt is around 90,000 to 100,000 km old, especially when the outside temperature is too warm for the glow plugs to be effective. In those cases, it takes 4 to 5 attempts to start the engine. After replacing the timing belt and adjusting the injection timing, everything is fine again. (This was the same behavior with the last 3 timing belt replacements.) However, I've never seen fuel consumption increases of that magnitude. The fuel consumption is usually between 5.5 and 7.5 liters, calculated both by the onboard computer and by measuring the fuel used, depending on the driving conditions.
Checking (or having checked) the fuel injection timing is definitely a worthwhile thing to do. Advancing the timing can also help with starting. Otherwise, faulty sensors should also be considered (temperature sensors and their connectors!!).
Try disconnecting the temperature sensor for the engine control unit and see if the engine starts better with the glow plugs.

I find it hard to believe that an AEL or peripheral component would be completely worn out after 250,000 km with reasonably good maintenance. I'm currently at 370,000 km and so far, the only engine-related issue I've had is a burnt-out hose connected to the LD sensor (related to the AGR system).

Greetings from Berlin.
olli

Da der Verbrauch auch erst so hoch ist nachdem ich auf der Suche nach dem Anspringverhalten 'dranrumgewurschtelt' habe, könte ja evlt. wirklich irgenwo ein Kabel ab sein und der Motor ständig 'zu fett' sprich kalt läuft ? WäIs that possible?
How does a defective ESD manifest itself when using the 5th pin with a cable (I'm not quite sure what the name is, dementia b )?

Oh yeah, the toothed belt doesn't have 10,000 miles on it.

greetings

Hi,
A loose cable to the needle lifter or a partially defective needle lifter can manifest as a harsh knocking sound at higher engine speeds, especially when the knocking is coming from the area of the needle lifter.
In my AEL, it's located on the exhaust manifold of cylinder 4 or 2, depending on the viewing angle (i.e., the second one from the back).
If there's a cable break, it should be measurable as a high resistance to ground from the connector side; a broken cable will show many megaohms, while a good cable might show around 100 ohms, which is ultimately just an inductance.
I'm not sure whether a permanently missing NHG (presumably referring to a specific component or system) can lead to such excessively high consumption.
A faulty temperature sensor initially leads to an incorrect fuel injection quantity, resulting in unusual starting behavior. Therefore, disconnect it to simulate a minimal outside temperature. The engine should pre-glow, and the fuel injection quantity should be adjusted for a low temperature; the car should start without any problems.

The engine won't run if the fuel is too thick; at most, the idle speed will increase until a minimum temperature is reached.

Did these problems possibly only start occurring after the change in the ZR (presumably referring to a specific component or system)?
Then, I would definitely have someone else, other than the person who performed the fuel injector replacement, perform another ESP basic calibration, including both static and dynamic injection timing adjustments.

Best regards from Berlin.
olli

Quote:

Did these described problems possibly only start occurring after the ZR change? Then, I would definitely have someone else, other than the person who performed the fuel injector replacement, perform another ESP basic adjustment, including both static and dynamic injection timing points.

Right there, as I mentioned, is where I would also focus: an open screw connection carries the risk that it wasn't tightened correctly again.

Did these described problems possibly only start occurring after the ZR change?
Then, I would definitely have someone else, other than the person who performed the fuel injector replacement, perform another ESP basic adjustment, including both static and dynamic injection timing points.


Right there - as I mentioned - is where I would also start: a screw connection that was open carries the risk that it was not tightened correctly again;

It has already been done. The 'early' setting was used with the following values: 1st value: 48, 2nd value: 28. However, it didn't make any difference.

greetings