Why is only 1Z stuttering?

Hi.

One often reads about the jerky behavior of single-phase motors.
Almost never from others.

Aber die Pumpen (VP37) ist doch bei allen gleich, oder ?? (PD und 6-Zyl. (Excluding VP44)

Is it because the 1Z engines are old enough to be prone to issues, or has something been changed so that newer engines are better protected against this?

Could it perhaps be due to the old 8-bit engine control unit (ECU)?

m;

The subtle tremor slowly creeps in...

Could it perhaps also be due to the old 8-bit engine control unit (ECU)?


It definitely has to be a software problem. While the pump or the flow meter (due to debris, contamination, etc.) is the cause of the jerking, the software tries to compensate for the 'bad' flow meter readings, which then leads to the jerking.

Well,

I also experience some jerking with my ALH. This jerking is a phenomenon that hasn't been explained yet. I don't know if it's related to pump surging.

"When I'm in 4th gear on a nearly flat road, at 1800 RPM, and barely giving it any gas (right at the boundary between thrust/torque), there's a slight jerking (period ~0.5s). As soon as I give it a little more gas, or if I completely release the gas pedal, or if I'm going uphill, the jerking doesn't occur."

The jerking has been happening since I've owned the car (since 43,000 km). It hasn't changed. I think it only occurs when the engine is warm.
Once, the workshop tried to find the problem with a diagnostic test drive, but they didn't find anything (they probably weren't very skilled). Nowadays, I'm almost indifferent to it.

Because it occurred with such low mileage, I don't believe it's the classic "pump run" issue.

I had hoped that it might disappear after the change in the interest rate, but that hasn't proven to be the case.

Maybe someone has an idea?

Do only 1Z engines experience this kind of rough running? I have a 1Z engine that also runs rough, but I've also heard about it from others. Has anyone experienced a rough-running 1Z engine without having it chipped? I'm starting to think that it might be related to the tuned chip. I'm planning to reinstall my original chips soon and see how it is then. I think it's really related to the software, right?

My 1Z is shaking (but only slightly).

Tuning can exacerbate the shaking because the attempts by the EDC (Electronic Stability Control) to correct the vehicle's trajectory are amplified by the modifications made through the tuning process.

It's kind of like having to hold a coffee cup on a 2-meter stick when you're already trembling.

m;

Perhaps it would be a good idea to record the types of pumps being used.

The older VP37 EDC models had a mechanical feedback mechanism via a potentiometer, which would eventually wear out.
That's why the newer ones all use contactless communication via HDK.

CU Gremlin.

You can tell the difference by looking at the plug.

I have an HDK pump - that is, one with the oval 8-pin connector.

Why is it then shaking? Or have I misunderstood that potentiometer pumps are prime candidates for causing shaking, while contactless HDKs are less likely?

m;

that Poti-pumps are top candidates for causing jolts, and contactless HDKs are less likely?


I suspect it.

Pickled herring is certainly not the best food to eat while driving.

CU Gremlin.

I'm likely to be able to enjoy a new VP37 (still the old version with the potentiometer) in my B4 starting Friday evening. Then I can at least confirm the suspicion about the potentiometer being the issue. However, it's exactly the kind of stuttering that Holger247 describes.

I'm curious. The only question that remains is, what is it if not the pump .

Regards,
Hermann.