Recent posts

#1

Triggering / Poor VR triggering - Wiring pu...

Last post by RogueEngineer - March 17, 2025, 05:30:39 PM

I'm using a Clewett VR sensor on a 60-2 wheel on a Porsche 3.2 Engine with VEMS board v3.8.

I have to have the sensor physically touching the wheel to get any useful signal. This seems to work, and when it starts it runs well all the way up to redline.

However, cold starting is very hard. I have to crank and crank, several times, before the engine shoots to life. It seems like I'm not getting any spark signal to the coils during most of the cranking, but then as soon as it gets a useful VR reading(s) it immediately fires.

This is occasional though, sometimes when cold it fires immediately, sometimes it takes 5 cranks. It seems possible that this is a trigger issue.

Seems plausible that I may need a pull-up resistor installed. My understanding is that I would install a resistor from one of the 5V output pins to the VR+ pin, correct? Would a 1/2W or 1/4W resistor work?

#2

Modifications and Repairs / Re: Flex Fuel

Last post by jrussell - March 17, 2025, 04:36:34 PM

It will depend on which version of the main board you have. There were protection and filter components added on the later boards, but would need to be added off-board if you have an earlier version.

#3

Software / Re: vems software from 2011

Last post by jrussell - July 09, 2024, 01:51:26 PM

All the released firmware versions are available. The latest VemsTune is backward compatible and is what should be used.

As far as upgrading firmware from 1.0.7x to 1.2.42... there are SO MANY feature additions and code changes in that span, it would need a re-tune at the very least. With that big of a jump you can think of it as a whole new ECU upgrade.

You can go through the FirmwareChanges: https://www.vems.hu/wiki/index.php?page=GenBoard%2FUnderDevelopment%2FFirmwareChanges which is standard best practice when upgrading firmware and read from installed firmware version to what you want to upgrade to, and those features will need to be tuned or at least looked at. The list is massive between 1.0.7x and 1.2.42 or even 1.2.31.

You can easily keep 1.0.7x and tune it for the changes. Just download the newest VemsTune and connect to the ECU, adjust.

#4

General Discussion / Re: Old Vems Update

Last post by k33emo - July 09, 2024, 11:40:37 AM

Morning did you have any success updating to he newer firmware ?

#5

Software / vems software from 2011

Last post by k33emo - July 09, 2024, 10:25:13 AM

Morning im looking to get my race car back up and running again last ran in 2009 i believe from reading old messages with rob that i was on v 1.073 or1.078 firmware is it possible to still download this version and will it be possible to update to the latest software without losing the info and map allready on my ecu
reason for question is i changes tps sensor and throttle bodies so need to re calibrate to the new sensors etc to get it to run,
also what serial connections are being used successfully links would be appriciated

#6

Ignition / Re: strange issues

Last post by yhzman - June 18, 2024, 04:57:11 PM

Sorry  i should have mentioned we tried driving the coils directly with all 7 amp outputs. no luck. or in test mode.
Would taking a picture of the inside of module help determine if the 7 amp outlets are operational?

#7

Configuration / Re: LOADING config files

Last post by jrussell - June 18, 2024, 04:40:20 PM

Depends where you're starting from and ending at as far as firmware versions. I'm going to guess you were going from a very old firmware to one of the more current ones. 1.2.31 and 1.2.38 are the most common these days, unless you need one of the features from the newer firmwares. You should always check the firmware changes page in the wiki and read the changes from old version to new version so you can check settings after the firmware update. https://www.vems.hu/wiki/index.php?page=GenBoard%2FUnderDevelopment%2FFirmwareChanges

#8

Ignition / Re: strange issues

Last post by jrussell - June 18, 2024, 04:36:19 PM

Ignition outputs are configured at order time. So not knowing how the ECU was built, it's hard to help too much here in a direct manner. If the ec36-35 output (and other 7 you tried) are configured with IGBTs, they won't work with the ignition amplifier/ignitor. They drive a coil directly by grounding it. Could explain your issues there. When you took apart the ECU, if there's 3 rows of transistors and the row nearest the case side is populated, that would be 6 of the 8 ignition channels. If there's transistors in that row, they are configured with IGBTs and meant to drive a coil directly.

#9

Configuration / LOADING config files

Last post by yhzman - June 18, 2024, 02:57:37 PM

Hello. Quite new to vems, but been working in auto field for 30+ years. Have what i consider an odd problem with this unit.
I had been using an older version of firmware and had problems with spark-see in ignition section- so I loaded the latest version of the firmware and also updated the vemstune.
Before this I had saved 3 config files from the older firmware and the car ran and had no issues when running config verification.
Now with the new firmware when I load the config it fails to load. Loads for 70 seconds and says unable to verify config.
Do I  need to start over?

#10

Ignition / strange issues

Last post by yhzman - June 18, 2024, 02:42:43 PM

Hello everyone. i'm working on my brothers 85 peugeot that the previous owner installed vems in, along with other goodies.
The problem has always been starting the car. he wired the spark out to the stepper motor outputs in the ec18 plug with a ignition amplifier.
the spark was always weak cranking so the car would start when turning key from start to run. tried changing to pin 35 and all of the other 7 amp outputs and have no spark. Even when going into test mode.
loaded new firmware and updated vemstune. same result.
took apart vems ecu, no visually burned circuits.
Need help, suggestions.
Thanks
Have another issue I will post in fuel injection.