Vems wideband lambda not working

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Vems wideband lambda not working

Postby diesel des » Sun Jul 03, 2016 6:14 pm

I have managed to get my motronic style vems running my URQ build. My issue is that i seem to have a non functioning wideband lambda setup and i dont know why. I have tried 2 sensors and i get the same issues. The issue seems to be related to this vems unit, as when i plug in my second vems unit(econo plug style) from my URS4 lambda works fine with both sensors. It could also be an issue with the config obviously, or the lambda loom in the motronic style ecu. I have attached the config which runs the car on the Motronic style ecu. What i get is lambda showing 1.83 for a short time then it goes full rich to 0.63. I know its not actually that rich as i removed the probe from the exhaust and left it in air and it does the same thing. Changing probe has NO effect. I cannot get vems to do a free air calibration. It just sticks at the heating stage.

I have followed these instructions http://www.vems.hu/wiki/index.php?page= ... rdwareTest

I seem to have the readings that pages wants. What i did was test at the connection for my LSU 4.2 sensor with the sensor connected as i have a motronic connector ecu so the connections are different than that pages asks for. I connected the 2 100 ohm resistors as described and Measured the voltages. I didnt have a normal LED so i used an old 12v LED from a car alarm and it lit up when i enabled the Lambda calibration in software. Also the sensor does heat up when left for some time.
I have 4.14 volts from Pump - to Gnd.
I have -1.4 mV from pump - to pump + with Pump-PW-Zero set at 103
When testing for Nerst DC Target i get 0 volts until after about 30 seconds approx it jumps to 454mV. Adjusting Nernst dc target does nothing to vary this value.

The software came with the WBO2 cal set at 206, and i tried changing it to 150, but that made no difference. When the engine running i get the following voltages on the sensor plug relative to ground.

1. Nernst 4.5v
2. NA
3. battery 13.5 V
4. Heat - 12 v
5. Pump - 4 v
6. Pump + 12v

On my other ecu which is an econo seal with and adapter loom with separate WBO2 loom i get the following with a working WBO2 setup.

1. Nernst 4.5v
2. NA
3. battery 13.5 V
4. Heat - 3-10 v varying
5. Pump - 4 v
6. Pump + 4.9v


So it is possible that the wiring on my motronic style Vems is wrong, but how do i determine which pin is which? This is turning into an electronics project not a car build.... Is my description of the pins correct above??


Thanks in advance, des.
Attachments
v3.3_u001441-A-2016.07.03-22.45.05.vemscfg
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Re: Vems wideband lambda not working

Postby Grillage » Mon Jul 04, 2016 7:08 am

I had a similar problem that was wiring related. See this thread:
viewtopic.php?f=14&t=445
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Re: Vems wideband lambda not working

Postby Mcstiff » Mon Jul 04, 2016 10:52 am

To be clear, Grillage fixed his issue but the one I started that thread about is ongoing. Need to send my VEMS to Marc I think.
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Re: Vems wideband lambda not working

Postby diesel des » Mon Jul 04, 2016 4:56 pm

Was off today and made good progress. Got the wideband lambda issue sorted. Just need a 12v supply to the probe which I had done but also a 12v supply to a pin on the ecu. Got it a run up the road there. It set fire to the turbo blanket Ffs. No damage done other than a panic. Was ment to be running on low boost with boost valve disconnected but for some reason it was making big boost. Starts to pick up at 3 k rpm and making plenty of boost at 4 k rpm. At 5 k rpm it spun up the wheels in third gear on a dry road over a bump. Then boost cut due to my boost limit set at 2.2 bar boost and a big back fire. Sounds class. Its mental over 5 k..
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Re: Vems wideband lambda not working

Postby vt10vt » Mon Jul 11, 2016 9:49 pm

If you leave the wastegate unplugged you will have infinite boost. Plum the bottom port of the gate straight into the intake manifold, and when you get your N75 or equivalent set up it will just get t'd into that line.
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1989 MC-1 200 Avant- MS1 MSnS -Gone but will never forget her lessons
1987 5ktq Sedan - Best $500 beater ever
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Re: Vems wideband lambda not working

Postby diesel des » Tue Jul 12, 2016 4:52 am

Thanks. I had the wastgate connected but it has 4 ports. 2 for each chamber and I had left a plug out by mistake so the lower chamber wouldn't pressurise. Its running wasgate pressure now but I have more vems issues.

As you know i had no wideband sensor working and I found that I had only have 12v to the sensor and not the ecu. After I connected the 12v to the lambda probe AND the ecu lambda probe pin wideband is working but I have other issues now.

What is happening is that the ecu is randomly crashing when I try and start the car. When it crashes vems tune cannot connect to the ecu and I have to jumper pins 2 and 3 on the the rs232 connector to force the ecu to go to boot loader mode. I then can upload firmware and config and restart the car ok.

The ecu crashes when I turn on the ignition. It sometimes runs the fuel pump constantly and other times not at all. Vems tune cannot connect and the car won't start. When the ecu is correct the fuel pumps should only run for about 2 seconds and stop and start again while cranking.

The ecu seems to get confused somehow. Why would this be? It happens at random and I can't force vems to do it. I could start the car 10 times no problem and then the next time the ecu won't do what it should somehow. This issue only started after I connected the 12v to the ecu wideband connection. Could this be related. I seem to have good ground and 12 v supplies but is there anything else I should check? This is a Motronic style vems ecu.

Also I have no internet connection in my garage so I'm uploading firmware 1.9x boot loader. Is there a way of downloading firmware 1.2.3x into my laptop do I can load the latest firmware when not online?

Thanks des
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Re: Vems wideband lambda not working

Postby carl » Mon Jul 25, 2016 11:03 am

Can't help you on the 12v sensor issue, the "also a 12v supply to a pin on the ecu" i'm guessing is the normal 12v ecu pin.

I'd check that you have good grounds and power first to actual ecu feeds, check that the voltage is steady when cranking. I had a funny issue where when i started the car it would almost stall right after. Chased that problem for a while thinking it was config related, cranking ve massively multiplying fuel when transitioning out, etc. Turns out the ecu would shut off for a microsec after letting go of the key, the starter switch had a contact gap in between.

Also never start car while connected to serial port, connect after (ok to do changes before just disconnect while cranking). There's also the prolific adapter issues that can end up in firmware corruption, ftdi is much better. Then there's connectors that are badly wired or grounding. Shorted my injector connector the other day to driver trying to find injector deadtimes, had to reflash firmware, config had stuff changed to funny values.

Also yes, you can download new firmware from internet locally using the vemtune tools, firmware web tool, you can select one then download and install later in garage.

There should be better checksum algos for vems imo.
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Re: Vems wideband lambda not working

Postby diesel des » Mon Jul 25, 2016 2:40 pm

Thanks for the advice. I checked power and grounds and found no problems so I have sent it back to vems and they are going to change the main board. I will let you know how I get on. But I have an oil issue with the engine and it has spun a rod bearing..
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Re: Vems wideband lambda not working

Postby carl » Fri Jul 29, 2016 12:11 pm

Sucks btdt, me this week i just suddenly got some nice thin blue smoke when engine temp approaches 90c, not sure if it's turbo, valve, or rings, i guess it's the way it goes with wanting more hp lol. You should get some nice calico coated bearing in there if doing a rebuild, really worth it imo if the tolerances and pump are good.
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Re: Vems wideband lambda not working

Postby diesel des » Fri Jul 29, 2016 12:55 pm

I like to stock to the stock oem brands for bearings like kolbenschmidt rs2 parts. The engine was a stroker just built with all forged parts and had covered only 28 miles when it spun this bearing. Really sucks. But crank is now back repaired and I'm just waiting on some other parts now. Hope your smoke is something minor.
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Re: Vems wideband lambda not working

Postby diesel des » Fri Jul 29, 2016 1:16 pm

Short video of its track run at 1 bar of boost and very safe map. Maybe 350 ish bhp?
https://youtu.be/mWTxrcZJyT0
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Re: Vems wideband lambda not working

Postby carl » Sun Jul 31, 2016 1:27 pm

Nice Vid! The calico mains are kolben but no separate thrust bearings, not sure on rods mind you, pretty sure not the sputter rs2 type.
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