Jenvey ETA2 Servo (DBW) issues

[parsonsj]

I've been battling a very annoying DBW issue. When I power up the ECU (M150), sometimes it generates an Aim Tracking error. This happens after a previous session where the car does a significant number of laps, returns to the paddock, and sits for a half hour or so. I think it’s heat-soak-related, but I don’t have any way to provide data about what the ECU actually sees.

If I wait a bit (15 minutes or so), then recycle the ECU, sometimes the condition clears, then I'm good to go until the next time.

Is there any way to dig into this a bit more? I'm looking for something I can show Jenvey.

[Stephen Dean]

Hi,

I would be logging the Main and Tracking voltages for both banks, and comparing them when the engine is cold and hot (when you are getting the Aim Tracking Fault).

If the M1 is aiming for 2% at startup, and the servos cannot drive to that position, then you will get the Aim Tracking Fault reported. If you start with a slightly higher throttle position, does it do the same thing? Namely, is the throttle stop, or something else, physically stopping the plates from closing further?

[parsonsj]

Thanks Stephen. I'll check the logging of those voltages and look carefully at them during failure vs success. The throttle stop notion occurred to me as well, but I don't think that's it. But I'll look at that again.

[Salasko Racing]

I've fought these Jenvey DBW servos quite a bit. They seem to be pretty crappy motors compared to literally everything else I've used.

My feed forward is

0 - 0
1 - 10
100 - 21

P 45
I 15 -25 clamp
D 70
Freq 8000

It's not perfect but no errors anymore.

[parsonsj]

Salasko: that's great information. I'll compare to my tune, and give that a try. Is there another servo that's similar in size that you'd recommend over the Jenvey?

[greenamex2]

How many throttle bodies are you opening?

If it is 6 Jenvey bodies, happy to share my current settings.

[parsonsj]

I've got dual throttle servos, each driving 4 throttles, thanks!

[greenamex2]

I've got dual throttle servos, each driving 4 throttles, thanks!

You tried the 4 cylinder settings from Jenvey on each bank?

[parsonsj]

You tried the 4 cylinder settings from Jenvey on each bank?

Yes -- if you mean the datasheet Jenvey have on their website. In fact, I've never tried any other setting other than that.

[parsonsj]

Checking my calibration: It's the same as Salasko's above except for the feed forward table. Mine is at
0 0
1 8, rather than 10
100 21