AJM Idle Speed Instability: Causes & Fixes

Hello,

My acquaintance also has a 115 hp AJM engine with a Tiptronic transmission.
However, there are fluctuations in the idle speed.
particularly noticeable/perceptible when a gear is engaged.
and you're stuck on the brakes.

I have little experience with PD technology.
In a typical Direct Injection (DI) scenario, I would say:
ESD sprays tend to atomize poorly or drip.
But does that also apply to PD elements?

Best regards, Rodion.

ESD sprays either atomize poorly or drip. But does this also apply to PD elements?

Deactivating the solenoid valves should make dripping almost impossible. However, with defective pressure reducing valves (PDE), this may not be 100% excluded.


What does the injection quantity (MWB 001, position 2 in the MSG, warm engine) indicate? Injection quantity: 3.0 ... 11.0 mg, or desired start of injection: 4° BTDC ... 2° ATDC (MWB 004, position 2 & 3), and also MWB 13, which is the idle stabilization (a likely culprit), and finally, MWB 18, which shows the status of the valves for the pump-injector. Fluctuations can also be caused by many connected consumers; check the values with no, a few, and many connected consumers. Perhaps the symptom can be reproduced, or it will provide information about the condition of the components. Manufacturing tolerances are also a factor; the attachment of the PDE (pump-injector) to the cylinder head leaves something to be desired (it's only attached on one side), which can lead to minimal movements in the cylinder head. This can result in leaky seals and noticeable traces on the PDE and in the cylinder head. Otherwise, the PDUs are quickly replaced. The price is relatively low. Maybe upgrade the components at the same time. I'm keeping my fingers crossed that it's not as bad as it seems.

Hello,

That's the problem. I'm the kind of person who doesn't deal with electronics.
because, until now, I've only driven cars with Mercedes-Benz pre-chamber diesel engines.
There was only electricity available for the glow plugs.
Even the shut-off valve wasn't even electric .
Timing belt replacement, new piston rings, or something like that - sure, I'm interested.
'However, I haven't yet looked into the measurement values, target data, etc.'
It's probably about time.

I had turned off the consumer device, but it's not normal behavior.
According to the tachometer, it fluctuates by about 50 RPM.

Do the 130 horsepower elements actually make a difference?
Probably only with the larger loader and software calibration.
Is that then just a matter of two violet bills ?

Best regards, Rodion.

I had turned off the consumer, but it's not normal.
It fluctuates by approximately 50 RPM according to the tachometer.

So, 50 is quite a lot of wood . But if in doubt, a colleague at VW can check it. It should remain within the scope of a coffee fund contribution.

Do the 130 horsepower elements actually make a difference?
Probably only with the larger loader and software calibration.
Is that then equivalent to two violet bills ?

The PDE alone (at least subjectively ) can bring about quite a bit, especially when combined with a charger update and software. However, whether that's healthy for the AJM is another question.

Purple? Nice color . I think the prices for a set are around €750-€1000, depending on the purchase and condition. You can probably install it yourself, if I understand correctly .

Hello,

When it comes to a 'major' upgrade, it's important to ensure you have a solid software foundation.
The installation is a piece of cake, but ultimately, the software is what really matters.

Here's another 'by the way' question, since I see that you're quite knowledgeable about the subject.
Regarding PD (Pumpe-Düse) engine oil: It's quite difficult to find information when searching because 'PD' and 'OIL' generate too many results. Is the requirement for PD oil really that strict? Or is it just a lot of hype? I and my father use 10W60 in all our vehicles. However, I'm a bit apprehensive about using it in the PD engine. Is that concern justified? The 60-grade oil should theoretically be able to withstand the stresses of the PD injectors. I always change the oil every 7-8,000 km (approximately 4,350-5,000 miles).

Best regards, Rodion.

There are so many great discussions about the pros and cons of oils. I'll put it cautiously, and as I tell my customers, you're not doing anything wrong if you use oil that meets the specifications or standards. In the case of AJM engines, in my opinion, extra caution is definitely needed. There's that specific pump-nozzle oil. It can't hurt to use that as well. Shorter intervals are certainly not a bad thing, thanks to the fresh oil and the new filter. }

Hello,

In AJM engines, it's actually quite common for the connecting rod bearing to fail.
That would ease my conscience more than if I were to pour in some thin, watery soup .

Best regards, Rodion.