@ Tim 27 regarding pump tuning

Hi Tim,

As far as I remember, you have a single VP 37 for testing.

In my attempts, I've now reached a dead end, with the only alternatives being "significant performance improvement" or "stuttering/lagging."

When the ignition is turned on, the engine control unit checks the relationship between the actuator current and the signal from the throttle position sensor. As soon as the sensor is adjusted to a significant increase in flow rates, the engine control unit detects the higher actuator current required for this (to overcome the force of the return spring) and, if the tolerance limit is exceeded, sets a flashing error message.

To prevent this, the spring force would need to be reduced slightly. If the reduction is too drastic, the opposite error would most likely be detected, and we would be just as clueless as before.

Have you ever disassembled the pump to the point where you can access the spring(s)? Is there a well-controlled way to adjust the spring force?

Best regards, Ulf.

Hi,
I had already seen the feathers, but there's no easy way to remove them - you basically have to pull them out with a pair of pliers!

What happens if you install a rectifier (+ signal amplifier = voltage drop of 0.8V) and slightly rotate the positive sensor of the signal amplifier backwards?

What's the idea?

Hello,
Okay, so there is one way, but it also involves some tinkering.

So, if you've ever had your hands on a control panel, you've probably seen the 'pin' that's adjusted within the control ring. You just need to slightly adjust this pin so that the path of the control ring becomes longer. And lo, the STG (Steuergerät/Engine Control Unit) doesn't register anything.

This will work perfectly, with absolutely no errors.

Technically speaking, I could probably manage it.

Hi Tim,

-- What if you install a rectifier (+ signal amplifier = voltage drop of 0.8V) and slightly rotate the positive sensor of the signal amplifier backwards? --

That probably won't achieve anything (using a series connection), because it won't change the slope of the sensor's characteristic curve (volts per degree of rotation).
Once you manage to smooth out the idle again, the result is like compensating for a misaligned switch with a twisted position sensor.

I believe it's a fatal mistake to pull feathers out with pliers based on suspicion alone.
1. too inaccurate.
2. Just a little too much, and the signaling system is down (only error messages appear) because the spring's extension cannot be reversed.



-- So, if you've ever worked with the signaling system, you've probably seen the "pin" that's adjusted into the signaling ring. --

No, I had only loosened the switch mechanism so far to move it, but I hadn't removed it yet.

-- You just need to slightly modify this thorn so that the path of the retaining ring becomes longer. And lo, the engine control unit (ECU) doesn't register anything.

This will work 1000% without any errors.

A longer lever arm results in a flatter flow rate curve, which is correct.
I could also sand it down / shorten it, but extending it...

-- I could technically make it happen. --

How so? Would you like to add something?

Hi,
It might be possible to mount a ring and this pin (securing it with set screws to prevent twisting and shifting) so that the ring is almost flush with the pin holder (I'm not sure what the exact name is), and then screw the new pin onto the ring.

That wouldn't be such a big problem.

For me personally, it might not be worth it to continue working on it, because I've already pushed my engine hard enough. More would only do more harm than good.