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I have narrowed it down to injectors 3 and 4 not firing. They click on and off in test mode but they do not fire when running. I can get a solid 2 cylinder idle now, just 1 and 2.
The injectors work in the test mode, but not in normal operation? And the engine runs normal when injectors fire in the test mode? Sounds like the wiring is okay, then. Assuming both banks are configured together, then that sounds like a software problem or maybe a hardware fault in the VEMS? Or are there different options for the two different banks of injectors?
I have narrowed it down to injectors 3 and 4 not firing. They click on and off in test mode but they do not fire when running. I can get a solid 2 cylinder idle now, just 1 and 2.
found your problem. Its injector settings. please see attached images. left is your setup and right is mine. Wrong settings which would explain injector tests work, but not run engine properly. change injector firing and injGroup. Dont change injector opening and pwm, as I have High Z injectors.
found your problem. Its injector settings. please see attached images. left is your setup and right is mine. Wrong settings which would explain injector tests work, but not run engine properly. change injector firing and injGroup. Dont change injector opening and pwm, as I have High Z injectors.
I think I've tried all the combinations on both those pages, haha. I've been talking with Peep a bit. He had me put both injectors groups on the same channel even, and it still only runs on two cylinders. I will take another look at this for sure though. Thanks!!
Edit: unfortunately that didn't do it. Still 2 cylinders.
OK, finally got my car running on all 4. Looking there's something wrong with my injector driver on pin 19. Per Peeps instructions, I moved the wire from pin 19 to pin 20 and that was it. Started right up. Thanks everybody for the help!
Hi,
does anybody know what happend to the vemssupport.com forum? It has been offline for weeks. Sorry for offtopic, but I try to prepare my 931 for a VEMS-installation and need some further information, which I usually got from the vemssupport board.
Thanks!
Hello, Happy New Year to everyone, I´m hoping someone can help me with some inside knowledge of vems. I have a V3.3 (bought from Peep as a pnp as i really didn´t want to be going into the nittygritty diy of ecu´s at the mo) installed on a Porsche 944 turbo. It starts, idles and runs great on a good start BUT on about 50% of starts it is BAD and has a light misfire (like a vac leak or weak spark), almost dies on accel (like a carb accel pump not working) and has `hard´ backfires on rapid decels (like a bad vac leak). Once started in this state it will not recover unless restarted (ecu reset ?) and is immediately obvious by the popping sounds at idle in the exhaust. At idle (800rpm) The 02 is approx .05 higher than a good start (i presume unburnt fuel?) and very unstable as are the rpms & 02 with tps held at 4%. Turn it off & on again and it will run perfect - 02 @ 99 or wherever it is set, no misfire, backfire etc. I´ve tried all external troubleshooting i can find & think of, and am now wondering if its possible for Vems to initialise and latch in a state that can cause these issues until the power is cycled. I was running WS with new leads (from Peep), but for t/s have put the orig stock coil n cap/leads back in, tried 3 new ws coils, deactivated and plugged the IAC, 2 new sets of plugs (resistor & non), checked for vac leaks, swapped inj, ign Channels & pins, jiggled harness´s conned out connectors, checked tps sweep, disabled inj cha´s during idle but cant find anything wrong. Trigger logs look good, timing strobe looks good steady n solid also. Cylinder head recon & turbo were replaced at the same time as installing vems. Next thing i´m going to try is reinstalling the Motronic ecu but i was hoping for some ideas before doing that.
Logs & Trigger files attached. (Maps are untested at this time & idle is setup for t/s this problem - Idle EGO/Timing control deactivated) Any advice appreciated, Thanks !
If you read this thread, shortyboy has the same issue. May want to pick his brain to combine your folks data and knowledge. I took his ecu and ran my pigtail and config, I could not replicate the issue on my car. I think we are the only two in Hawaii that have the PNP kit.
Hello MD & V2,
I´m using Deka 80 injectors with req fuel at 5.2.
Idle pw is 1.7.fuel pres is showing 45psi.
Also has a new fuel pump...044 copy.
I believe it´s getting enough fuel as it will drive and smells rich when it´s misfiring.
It has done a few miles & a couple of easy laps at the local gp circuit and goes really well on a good start...
Ive read the forum and thought shortboy´s issue was resolved with an uo driver repair, so i had look & smell at mine but all looks ok...
It seems like vems doesnt power up well and remains confused until power is cycled.
Thanks.
Hello, Happy New Year to everyone, I´m hoping someone can help me with some inside knowledge of vems. I have a V3.3 (bought from Peep as a pnp as i really didn´t want to be going into the nittygritty diy of ecu´s at the mo) installed on a Porsche 944 turbo. It starts, idles and runs great on a good start BUT on about 50% of starts it is BAD and has a light misfire (like a vac leak or weak spark), almost dies on accel (like a carb accel pump not working) and has `hard´ backfires on rapid decels (like a bad vac leak). Once started in this state it will not recover unless restarted (ecu reset ?) and is immediately obvious by the popping sounds at idle in the exhaust. At idle (800rpm) The 02 is approx .05 higher than a good start (i presume unburnt fuel?) and very unstable as are the rpms & 02 with tps held at 4%. Turn it off & on again and it will run perfect - 02 @ 99 or wherever it is set, no misfire, backfire etc. I´ve tried all external troubleshooting i can find & think of, and am now wondering if its possible for Vems to initialise and latch in a state that can cause these issues until the power is cycled. I was running WS with new leads (from Peep), but for t/s have put the orig stock coil n cap/leads back in, tried 3 new ws coils, deactivated and plugged the IAC, 2 new sets of plugs (resistor & non), checked for vac leaks, swapped inj, ign Channels & pins, jiggled harness´s conned out connectors, checked tps sweep, disabled inj cha´s during idle but cant find anything wrong. Trigger logs look good, timing strobe looks good steady n solid also. Cylinder head recon & turbo were replaced at the same time as installing vems. Next thing i´m going to try is reinstalling the Motronic ecu but i was hoping for some ideas before doing that.
Logs & Trigger files attached. (Maps are untested at this time & idle is setup for t/s this problem - Idle EGO/Timing control deactivated) Any advice appreciated, Thanks !
I'm running VEMS on my 944 NA without any problem. The PnP config for my car was more or less a startup config that made the car driveable.
In my case some tweaks were necessary to get it perfect. Just as an example, in my case I had to set the "IAC PWM Frequency" to 100 Hz.
I noticed in your attached config-file, that your "Iac Integral Minmap" value is 50, which appears to me as too high. Try some lower values. Also "Integral Deadband" = 0 rpm won't help smothing the idle. A larger dead band for IAC valve movement should help.
A great help to understand the idle settings is this posting --> https://forums.quattroworld.com/s4s6...ds/11637.phtml
I suggest, you tune your idle according to the steps as described here.
Is there anyone running the VEMS P&P successfully?
Mike G.
Plenty of folks.
I had it for 5 years, always started and ran well, I just had to chase some tuning issues to get it dialed in but never anything that prevented it from driving.
I sold it with my last 944 engine last year, when I decided to do a swap to something more modern.
Is there anyone running the VEMS P&P successfully?
Mike G.
Yep! Two years now. Initial tune out of the box was reasonable, and the self-tuning feature got it pretty close. Had a local shop do a driving tune for me, which wasn't a huge increase in performance.
Biggest issue I had was cold starts, but I finally got around to playing around with the fueling and it's reasonable now.
I developed a new problem this past summer where under full throttle it would cut out hard, but if I rolled on the throttle smoothly, it wouldn't happen. Haven't had time to investigate, but I wonder if my stock ignition parts are holding me back.
02-06-2021, 03:26 PM
