ALH: Pump, Injector & Water Pump Problems?

Hello everyone.

Since my wife drives an Ibiza with an ALH engine, I've also been considering installing ASV injectors.
It led me to some rather strange thoughts: namely, that the modified engine might potentially be more durable than it was in its original state.

"The Schalt-ALH and ASV engines share the same pump, but have different injectors."

Taking into account previous experiences with injector swaps, it is likely that the ALH engine is largely limited to 90 horsepower through the injectors, even though the fuel injection pump's characteristics, even with ASV injectors, still atomize the diesel sufficiently to meet Euro3 emissions standards.

According to this, the ALH nozzles would have to generate "unnecessarily" high injection pressures, which, in addition to increasing the load on the pump drive (including the timing belt), would also result in unnecessarily high pressure and material stress throughout the entire high-pressure system: This would mean increased stress on the injector plate, rollers, etc., more leakage losses, and faster wear, at least of the nozzle holes (erosion?), due to the higher flow velocity in the narrower bore.

If this assumption is correct, then equipping the ALH with ASV nozzles could even be more material-efficient. And (at least theoretically), it could also be more cost-effective, as no unnecessarily high amount of power would need to be supplied to the pump.

Since the engines are largely similar in design, it is likely (as an exception) that the exhaust emissions will still correspond to the original classification – unless the ALH and ASV have such different operating characteristics for injection timing and possibly turbocharger pressure that a modified ALH would still fail to meet Euro 3 standards...??

However, the likely loss of the operating permit due to an increase of approximately 20 horsepower is undoubtedly a significant issue.

My actual question is as follows:
Is it true that, due to the described higher material stresses in the area of the pump compared to the ASV, accelerated wear or earlier failures are to be expected with the ALH, so that the installation of ASV injectors (without frequently exploiting the increased power) could result in a longer, trouble-free operation of the engine?

Or, is anyone aware of any relevant experiences?

Hm, in short, the injection system in my ALHs (engine replacement) ran smoothly for almost 160,000 km until I sold it, even with quite good tuning (125 hp / 325 Nm). The car is still running now, owned by an Allianz representative.

So, if you only want to make the engine more durable (I hope I understood correctly) and don't want any extra power, then replacing the ASV injectors is not worth it (it's too expensive).
The ALH engine easily meets the D3 standard, even with tuning and with AGR (Active Grille) enabled. The only parameter that increased was the turbidity, going from 0 to 1, but values up to 2 are acceptable. Without AGR, the turbidity remained at 0, even with tuning.

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Do you know the saying: 'Never touch a running system?' If that applies to your ALH, I would strongly advise against modifying anything!

Julian wrote:

In short, the fuel injection system on my ALHs (engine replacement) ran smoothly for almost 160,000 km until I sold them,

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Hi Julian,

"Rumpfmotor" probably indicates a previous engine failure... what happened?

Quote:

So, if you only want to make the engine more durable (I hope I understood correctly) without increasing its power, then replacing the ASV injectors is not worth it (it's expensive!).

Installing ASV nozzles and preventing increased performance probably isn't possible .
But my wife wouldn't care about the extra power; she's happy with 90 horsepower.

Quote:

Do you know the saying: Never touch a running system? If that applies to your ALH, I would strongly advise against modifying anything!

Well, based on experiences shared in relevant forums, nothing particularly bad should happen, especially with the ALH engine using ASV injectors, since that combination of pump and injectors is used in every standard ASV system.

'Rumpfmotor' probably indicates a previous engine failure... what happened?

2 factors:

1) 0W-40 oil was added (which was not the recommended type, but the workshop makes good money from it).
'Due to a leaking coolant hose (seal in the engine block), the entire ESP system was inexplicably removed. During reinstallation, the timing belt was installed one tooth too early, and no error codes were read. 11,000 km later, I was surprised to find that the glow plugs were worn out, and then I noticed an oil consumption of up to 2.5 liters per 1000 km.'
After a rough start followed by a leisurely drive (~4km) to the supermarket, the fourth pot detached while the vehicle was idling as it was being maneuvered into a parking space.
Conclusion: Piston failure in cylinder 4 (located diagonally from 9 to 3 o'clock), and cylinder 2 has a compression difference of 6 bar compared to the other cylinders.
Possible cause: The early injection timing was only corrected after 11,000 km, which likely resulted in increased piston crown stress. At some point, the engine probably tried to compensate by increasing oil pressure, which then caused a problem.


Well, based on experiences in relevant forums, it's likely that nothing particularly bad can go wrong in this process - especially not with an ALH engine using ASV injectors, since this combination of pump and injectors is also used in every normal ASV system.

Sure, but if the performance is sufficient and the car is running well, I would stick with it. If the ALH injectors fail, you can always switch to something else later.
My injection system was taken over and was working perfectly until the sale.

You are assuming a very high degree of similarity between the two engines.
I think that's also justified, because in addition to the slightly better torque for the 90 hp engine compared to the older 1Z, the cost advantage certainly played a role in the introduction of the ALH engine.

I've heard that other pistons and (at least in the initial production) a different timing belt with a different tensioner were used in the ALH engine (compared to the 110hp version). Also, the exhaust system is different (possibly with a smaller cross-section). We should compare the main parts in the AKTE catalog.

I don't know if the "pressure throttling" is causing an overload. Could it not also be due to a different fuel injection map? In that case, the injectors wouldn't need to be designed for such large volumes. The overall engine load is definitely higher with the 110 hp version (crankshaft, pistons). The question is, which has a greater impact on lifespan: power output versus "fuel injection pump stress"?
The 110 HP timing belt kit, including the tensioner, is supposed to be more durable, and I believe it's now being installed in the ALH engine during the timing belt change anyway, due to the 90,000 km service interval.

Holger247 wrote:

However, I've heard that other pistons and (at least in the initial production) a different timing belt along with a different tensioner were used in the ALH engine (compared to the 110 HP version). Also, the exhaust system is different (possibly with a smaller cross-section).

Hi Holger,

The pistons and parts of the exhaust system are different, but the timing belt and tensioner are the same for the ALH and ASV Ibiza models.

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I don't know if the "pressure throttling" is causing an overload. Couldn't it also be due to a different fuel injection map? In that case, the injectors wouldn't need to be designed for such large volumes.

That's the point. Recently, someone here reported successfully tuning an ALH engine by only replacing the injectors with ASV injectors.
Therefore, ALH injectors must have smaller boreholes that allow less diesel to pass through at the same pump flow rate, and consequently, they inevitably generate a higher "back pressure" or injection pressure compared to ASV injectors. This results in increased stress on the high-pressure components when using ALH injectors (see also the technical article on injector replacement).
Of course, the software in the ALH and ASV engines is also different, at least in terms of the pump and torque curves.
However, at full throttle, the throttle valve should ultimately reach approximately the same position in each case – at least "closer" than the initial 20 horsepower difference might suggest.

Quote:

The overall stress on the engine is definitely higher with the 110 HP version (crankshaft, pistons). The question is, what has a greater impact on the lifespan, power output versus "fuel injection pump stress"

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If an ALH engine that has been modified with a performance chip is primarily used in situations requiring power output above 90 horsepower, the increased stress on the engine block may cause it to wear out faster than an ASV engine.
But as rarely as my better half drives a "low-riding car" (approximately 5 times a year for a few seconds to overtake ), I believe it is more likely that the relief effect of the injection system would influence the overall balance.