I finished an install of a VEMS V3.3 on a Corrado VR6 Turbo a few months back. I successfully tuned the engine on the rolling road up to 8psi. I did not notice any erratic changes while driving. But customer says that while he is driving at a constant speed/throttle the car will 'turn off' and then after a few seconds resume with a loud backfire the engine will resume again. I have since then driven the car for myself and felt this.
The ONLY was to correct this (or better to say to get the injectors to come back on) is to push in the clutch to return the engine speed back to idle. You can then immediately resume back to normal cruising engine speed until it randomly happens again the next time.
All this only every happens during small/constant throttle movements (ie constant city driving and/or highway cruise situations). If you're constantly varying the throttle the misfire never happens!
Now I have had this issue once before on my friends BMW. At first I thought it was the RPM sensor (VR) and or the wiring, so the sensor was replaced with a brand new unit, and the shielded wire from the VR sensor plug back to the ECU with new wire. The problem still persisted. What I did to get rid of the issue was to load an older MSQ file and that made the problem go away. At that point all I did was import the VE, IGN, and LAMBDA tables into the older MSQ and the car ran fine after ever since. Firmware of the BMW was always 1.0.73!
I also have this EXACT same issue on another VR6 Turbo car.... I don't get what is happening here. I will admit both VR6 turbo cars are running 1.0.78 firmware w/ 14x16 tables. But like I said above with the BMW that happened to develop this issue on it's own somehow it was only ever running FW 1.0.73.
Now last friday the Corrado wanted to be tuned for higher boost (approx 500whp), so we strapped it onto the dyno and I began to tune, but I was having massive driveablilty problems on the dyno, MegaTune was randomly freezing (I believe during the driveability problems) and also the LCD screen would go all funny and either show normal values with gibberish or normal values just moved all around the screen and the WBO2 would no longer work and just show ??.? until the next restart.
Here are specs for the Corrado:
9:1 CR
forged pistons/rods
GT4088R turbo
3" turbo back exhaust
86# LOW-Z Siemens injectors (using 2x Honda Resistor boxes)
VEMS V3.3 w/ 30V flyback running 1.0.78RC2 16x14 tables
Electromotive 3x2 DFU's
Stock 60-2 crank trigger, no cam sync.
Here are the specs for the 24V VR6 Turbo that is also having the same issues (but much worse IMO - as in more frequent):
9:1 CR
forged pistons/rods
GT4094R turbo
3" turbo back exhaust
89# LOW-Z injectors (using 2x Honda Resistor boxes)
VEMS V3.3 w/ 30V flyback running 1.0.78RC2 16x14 tables
Electromotive 3x2 DFU's
Stock 60-2 crank trigger, no cam sync.
So two very similar setups, injectors are slightly different though.
Also I have noticed that during logs I would sometimes get a zero (0) RPM blip as if it's loosing the trigger... but the car drive fine otherwise and never shows trigger errors otherwise. Polarity is correct on the VR sensor on both counts because reversing them will make the car not show RPM signal at all.
Here are a few files from the dyno run with the Corrado:
MT Log:
--RPM blip to zero happens @ 99.202 sec
http://www.vems.hu/files/MembersPage/Sascha/HIBOOST/hiboost-3.xlsMSQ:
http://www.vems.hu/files/MembersPage/Sascha/HIBOOST/dyno%20tune%208psi%20-%20306whp+%202step%20active.msqConfig & Tables:
http://www.vems.hu/files/MembersPage/Sascha/HIBOOST/config.txthttp://www.vems.hu/files/MembersPage/Sascha/HIBOOST/tables.txtAnd finally my (seemingly useless) Wiki page:
http://www.vems.hu/wiki/index.php?page=MembersPage/Sascha/HIBOOSTCorradoI really need some help on this, so any input would be great!
Thanks,
Sascha