Recent Posts

31

Fuel Injection / Re: Strange stuttering while driving with constant speed with a Porsche 944 Turbo

« Last post by GintsK on September 14, 2023, 09:34:45 pm »

Seems you drive on too retarded ignition for that load point. No? When engine gets degree more, it gain power and go in cycle back - forth.

Try add ignition there. Probably at that point you want 20...30deg. You can avoid steep Ignition table by retarding ignition with MAT/TPS table at low throttle openings but keep high values in RPM/MAp ign table. It helps for driveability. 

Second thing to try is to change Injection angle. In 720 cycle there is one point where something like this happens.

32

Calibration & Mapping / Re: Individual Cylinder Power - usefull tool

« Last post by Machismo on September 14, 2023, 07:09:34 pm »

Yes what I was reading that people had success with 4 and 6 cyl. So those are confirmed, I think.

Sure, I disconnected now cylinder 1 which should be channel 0. Started log, started car, let it run on idle for a moment then I revved to couple of thousand rpm:

http://vems.hu/download/VemsTune/bugreports/Report-2023.09.14-21.03.19.zip

I am wondering, if you disconnect one of your four cylinders, do you see it's then completely "out" in the power display, or is there a little bit power still shown? If you have interest and have not tested without one cyl before, try it with both idle and lets say 2500 rpm.

33

Calibration & Mapping / Re: Individual Cylinder Power - usefull tool

« Last post by z0tya on September 13, 2023, 02:16:11 pm »

I have only experience with 4 cyl.
Could you upload some log?

34

Calibration & Mapping / Re: Individual Cylinder Power - usefull tool

« Last post by Machismo on September 12, 2023, 05:44:35 pm »

Thanks for the swift answer.

I checked that but I had already the right selection there: "Realtime Data Option: ADC/Individ.power"

I now, just for testing put it to "Individ. knock data" which caused the individual power to stop showing anything. (like you said)

So, my problem is not that it wont show anything, the problem is, it shows mostly garbage. For example that if one cylinder does not ignite, I do not see it from the individual power display, they seem all pretty even at 2000 rpm. Only if I disconnect two cylinders, I start to see some less power in two "bars", but even then, they are the wrong cylinders.

Could it be that knock sensor would create some disturbance, should I disconnect it? I mean, if they are handled by the same circuit.

Edit: I disconnected the knock sensor, did not help, individual cylinder power readings still remain erratic.

I start to think that 8 cylinders has too many events per 60-2 trigger tooth for Vems to really see the differences between cylinders, unless of course someone can confirm that they have successfully used this feature with eight cylinders.

My 3.6 board is one of the very early ones. Could it be my hardware is not exactly the same as it should to be able to handle this?

35

Calibration & Mapping / Re: Individual Cylinder Power - usefull tool

« Last post by z0tya on September 12, 2023, 10:36:20 am »

Individual power works only when knock real time data disabled:
Vemstune Inputs/Knock Samplings/Knock real time

36

Calibration & Mapping / Re: Individual Cylinder Power - usefull tool

« Last post by Machismo on September 11, 2023, 06:47:30 pm »

I got excited about this individual power stuff, I have a V8 and when I turned the individual power gauge on it showed all 8 cylinders bouncing around at idle. Then I increased rpm to 2000 and 3000 and the display stabilized showing some cylinders a bit stronger than others. At that point I assumed it works since it looked convincing... Then I disconnected one cylinders coil which made one cylinder went dark. But it didnt change anything! All cylinders still according to the gauge were active. Why it does not work?

I then red this

https://www.vems.hu/vt/help/v3/datalog/individual_power.html

There is info about the association of the numbers, but no mention of 8 cylinders. Why the info is missing, is it supposed to work? I have a 60-2 trigger wheel, 3.6 board and latest firmware etc. So little information available about this subject, please enlighten me. I really would need this to work to be able to tune my engine better.

Oh one more thing, if I just power on Vems, some of the individual power gauges start to bounce erraticly, where does that come from? They should be at zero when the engine is not rotating.

37

Ignition / Re: Using the Stepper Motor Driver to control Ignition

« Last post by Kamuto on September 03, 2023, 11:38:21 pm »

Hi All, its been a long time since i needed to enquire on here, so excuse my ignorance, but i'm resurrecting an old VEMS SR20DET project... My standard nissan COPs are currently driven via the Stepper motor driver (and via the Stock ignitor) but they are now showing signs of failure, so my question is...
Can someone confirm if the VAG COPs (i have some NGK R8 U5014 available) can be driven by the same stepper outputs with no modifications? (with the stock ignitor removed of course).

yes

38

Ignition / Re: enabling camsync makes ignition pause in cycles

« Last post by Kamuto on September 03, 2023, 11:37:44 pm »

that's because it's not getting cam signal

39

Fuel Injection / Strange stuttering while driving with constant speed with a Porsche 944 Turbo

« Last post by pikard on August 14, 2023, 05:05:09 pm »

Hello guys,

I have a strange problem with my car. It happens almost at about 1600 rpm. While I am just trying to hold the speed the car starts to stutter.
You can download the log file here:
https://drive.google.com/file/d/1mHYLDcOw64xJjy0TpWk3nRLlYwGn2b58/view?usp=drive_link

And here a screenshot:
https://drive.google.com/file/d/1gw9qg_QE2SZAefa6RoIqwCa2v-ELJoLI/view?usp=drive_link

The vems data:
Creator=VemsTune 1.5.57 (2018-01-04)
Version=1.2.38
SerialNumber=v3.3_u022515

First I disabled the EGO correction but it does not solve it.
Next try was to disable the fuel cut and resume but nothing.
After that I played with the MAP filter in the ECU calibration but I had no improvement.

It happens in the 1600 rpm area only. Everything above is fine.
Sometimes it helps to turn the ignition off and on and the car runs fine.

Any ideas?

Thanks in advance
Marcus

40

Modifications and Repairs / Flex Fuel

« Last post by Pork Chops on August 03, 2023, 08:49:44 am »

Hi Guys, I've got an VEMS ECU running a home turbo charged Porsche 3.2 Carrera.  It's been built and tuned and runs well.  I'm preparing the car for a flex fuel (E85) set up and have modified the fuel system exhaust and intercooler and can't wait to get back to the dyno.

I'm hoping someone can assist with the physical side of getting the flex fuel set up.  The ethanol sensor is plumbed into the fuel system, the plug is pinned at the sensor and I've got signal, power and gound wires to the EC18 plug and have the correct female pins and seals.  I've been told the sensor ground goes to pin 17, but I need to establish where power is coming from, and lastly I need to get a wire from Wheel speed sensor 2 (which is on the board) to a free pin.  Can anyone assist in identifying where this is on the board?

I realise some of these questions may relate to the pinout used in this application but perhaps there is another Porsche PNP user out there that's done this before?

Many thanks.