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Vems Car No Start, Maybe Vems Maybe Not? Help
Posted: Tue Dec 16, 2014 11:07 pm
by Jon411
I have a 94 S4, the car has had vems for about 50K miles and 4ish years, car was tuned and daily driver.
Im not the best with the vems part of the car, i appolagize ahead of time for my lack of knowledge. Im hoping I can get some help or guidance and what to do next.
The head gasket went back in may, i started to take apart but due to busy summer i never finished. I just got around to finishing and now the car wont start. Timings been double checked. Pulled a trigger log, im not positive on reading them, but there was the primary and secondary trigger and spark event shown, everything on the logs appears consistant to me.
As i was reading up i found some poeple saying that after the ecu has been dissable for a while they had to do an update it to get the car to start, so i went through and updated the firmware from version 1.1.81 to 1.1.94 and then put the tune back on. Still no go. Fuel pump is priming but im not positive the injectors are firing.
I have an older tune for the car from about 2-3 years ago and tried that next., the car still did not start.
I looked through the base setup settings between the older tune and the current tune and all seems to be the same.
And now im stumped!! Any thoughts??? All help is super appriciated!!

Oh yea im not completely sure on how to put the trigget log on here but if someone can chime in i will gladly. Or i can email to someone you wants to just look through vems.
Thanks again!
Re: Vems Car No Start, Maybe Vems Maybe Not? Help
Posted: Thu Dec 18, 2014 5:03 pm
by carl
Imo you probs need to check that the coils are getting power and properly grounded. The engine harness has a couple of grounds bolted to the engine. Maybe you forgot em? Is power getting to the coils and injectors while cranking (use testlight on connector) ? Read that some people have ignition switch issues. Without a log (you should post one) and confirmed test that the coils and injector fire (with vemstune you can test them by turning test mode on in visual outputs and pressing the test buttons for each), hard to know.
Re: Vems Car No Start, Maybe Vems Maybe Not? Help
Posted: Thu Dec 18, 2014 5:07 pm
by pilihp2
Check spark, Check fuel, if you want to upload your current tune you can, one of us can check it out and make sure everything looks correct.
Re: Vems Car No Start, Maybe Vems Maybe Not? Help
Posted: Mon Dec 22, 2014 9:45 pm
by Jon411
See attached for trigger log and tune. If someone could look those over that would be awesome!
I have 150 compression on all 5 cylinders. I verified fuel pump operation is good. Using a test light i verified injectors are NOT firing and NOT getting spark whith a shot of starting fluid. If i change the below setting to "auditrigger divby2" instead of the "auditrigger divby3" it is currently set at the car fires off a shot of starting fluid... this leads me to beleive there is something not quite set right. But then again the tune from a couple years ago didnt work either
Base setup- primary trigger settings- special trigger type - auditrigger divby3
I also verified all grounds, even had a second pair of eyes look at it.
I'm stumped

Re: Vems Car No Start, Maybe Vems Maybe Not? Help
Posted: Tue Dec 23, 2014 7:35 am
by chaloux
Did you connect the cam position sensor? Or smash it or break a wire? I'll look at the trigger log on a computer. Are there secondary triggers on the log? If not... No start/no cps. And otherwise the car setup is stock -flywheel and trigger setup? Ie pin on the flywheel and not a front or rear 60-2?
Re: Vems Car No Start, Maybe Vems Maybe Not? Help
Posted: Tue Dec 23, 2014 7:56 am
by chaloux
Trigger log looked superb to me. My trigger logs with the 60-2 up front looked like crap compared to that, lol. And my car ran/started perfect.
Something has to be up with your timing. Get a timing light! But also if injectors and spark are not firing, you have something going on there for sure. Clearly the car won't start without fuel and spark.
Re: Vems Car No Start, Maybe Vems Maybe Not? Help
Posted: Tue Dec 23, 2014 6:50 pm
by Jon411
Did you get a chance to look at the tune?
that trigger log was taken with car setup at auditrigger divby3.
timings been double verified. coils are getting the constant power just not that fire each cylinder power. and injectors don't seem to be doing anything.
flywheel and trigger setup is stock. it has the vems ecu for aan configuration. and the 3 pin adapter harness for reverse crank trigger
Re: Vems Car No Start, Maybe Vems Maybe Not? Help
Posted: Wed Dec 31, 2014 4:31 pm
by Jon411
Okay i think im making progress.
I did an output test on the coils and they are working.
I did an output test on the injectors and they are NOT working. I verified grounds and there is no voltage going to each injector when doing an injector test.
SOOO-
Could it be possible for that part of the ecu/output to go bad?
Re: Vems Car No Start, Maybe Vems Maybe Not? Help
Posted: Wed Dec 31, 2014 10:07 pm
by 88a5tq
I could be wrong but it's my understanding that each injector FET driver (all 5) would need to fail for none of them to work. None work?
Re: Vems Car No Start, Maybe Vems Maybe Not? Help
Posted: Thu Jan 01, 2015 3:56 pm
by chaloux
Yes, 5 FETs, I doubt they all asploded. There's gotta be something more basic going on.
Re: Vems Car No Start, Maybe Vems Maybe Not? Help
Posted: Thu Jan 01, 2015 3:56 pm
by chaloux
Check the fuses in the passenger side footwell. One of them is for injectors.
Re: Vems Car No Start, Maybe Vems Maybe Not? Help
Posted: Thu Jan 01, 2015 11:06 pm
by Jon411
I checked those a while ago, there is only two fuzes there and both were good. There's a bunch of the self resetting breakers also, i wiggled all those around and made sure they were seated all the way.
Re: Vems Car No Start, Maybe Vems Maybe Not? Help
Posted: Fri Jan 02, 2015 1:09 pm
by carl
Hmm so no voltage ever to them when using testlight and light grounded to body/engine? Like Matt said try to swap the resettable fuse for a real fuse (the brown connector), i know they fail/contact gets erosion inside them. I've had this issue. If it doesn't solve it check this:
http://forums.quattroworld.com/s4s6/msgs/22583.phtml check from relay 87a to injectors 12v for continuity or that 87a at the relay has power when cycling.