Author Topic: interference, sudden rpm loss, solved (Read 14758 times)

dundersmurfen · « **on:** July 23, 2009, 05:05:45 am »

solved partly: (thanks jörgen!!)
rpm loss comes from this setting fuelpump on after inactivity = 0 change that to 1 and it works. apperantly this setting affects almost everything so everything basically shuts down.

Problem is that coils signal pin is to noisy, dont think stepper chip has enough protection. Some sort of high voltage finds its way back through signal cables. this makes vems do things like freeze, miss trigger events and other nasty stuff.

most likely this interference comes from secondary side coils ground to head, going to make som changes and well see.

Yep this is solved also, running ground wires far away from other sensitive stuff makes wonders.

rob@vems.co.uk · « **Reply #1 on:** July 23, 2009, 02:58:53 pm »

How good is the grounding from the block to the chassis?
Those earthing kits really work well, and they're so easy to make your own.

dundersmurfen · « **Reply #2 on:** July 23, 2009, 05:20:40 pm »

im pretty sure this problem isnt related to poor grounding, i have that splitfire grounding kit on, there are leads everywhere that grounds on everything... some crazy jap guy installed it...

going to try lower the coils chargetime to minimum. that should reduce interference. then i suppose just wrap some metal around the ignition bits...

dundersmurfen · « **Reply #3 on:** July 24, 2009, 03:45:14 am »

lambda is not a symptom of my problem, its just that it "restarts" warmup, after rpm was 0 noticed that when i saw afterstart being activated all the time (after rpm drops)

going to minimum dwell did nothing, still same

changed some grounding, wrapped sparkplug wires in thin aluminum (for food) grounded that, same with signal cables from vems (stepper) to coils. but still same.

what have i missed, where is the interference coming from, and how can it find its way to vems unit inside passenger compartment.

Vems does not reset, no trigger errors, rpm just drops for a split second, or just totally hangs and needs manual reset. same without laptop plugged in.

changed cas to another, changed vems to a brand new one, guess what, still same.

What bothers me most is that my brothers s13 runs with a similar setup, stepper driven coils, no problems. a friend also uses this setup on his ca18, and i told them how to plug it in and that works...going to grab a log and put up my msq next.

gunni · « **Reply #4 on:** July 24, 2009, 04:35:46 am »

If it´s not the CAS and not the VEMS, it´s going to be software/config or wiring.
Those are the only options.

So post up your msq and the log.

dundersmurfen · « **Reply #5 on:** July 24, 2009, 04:54:55 am »

http://www.box.net/shared/mqg10tj2iy

http://www.box.net/shared/a68etues9u

msq and log. fw 1.1.18

dundersmurfen · « **Reply #6 on:** July 24, 2009, 08:19:53 pm »

ok did some more testing, got my hands on a inductive amplifier, a listening device that makes sounds so i can listen to electric stuff. the trigger sounds nice, sparkplug wires are almost totally silent, coils make a distinct noise but easily sheilded with tin foil, that makes them totally quiet.

most noise comes from the vems unit itself, plenty of different noises whining and crackling of all sorts...

put diodes on signal cables between vems and coils, and like flyback, but still same problem.

im starting to think theres something else that causes my problem. maybe the cas gets insuffient voltage? but since its fed through nissans standard relay box it seems far fetched.

going to install some bosch motorsport wastespark coils and see what happens...

gunni · « **Reply #7 on:** July 24, 2009, 09:53:30 pm »

I can see that your lambda didn´t start working cause your coolant temp didn´t go up to the required temp.

And your rpm problem will cause the ecu to restart the warmup and such cause it will see it as a normal start from 0.

If your getting 0 rpm readings it´s going to be the signal from the CAS to the chip in the ecu. And if you have swapped the ecu´s then it´s going to be the CAS or wiring. If you have swapped CAS´s and the problem is exactly the same it´s going to be 12v or ground to the CAS or the signal from the CAS to the unit. Can you get an oscilloscope on the CAS signal to the ecu?

Have you tuned the fuel at all yet? The fuel table doesn´t seem to be tuned.

dundersmurfen · « **Reply #8 on:** July 25, 2009, 04:12:50 am »

Thats right fuel is not tuned. why bother when i have this other problem.. and i've come to same conclusion on lambda not working.

so today i swapped coils, msd's are not causing the problem.

redid wiring to cas tried different power supplys and grounding, ran external signalcables to avoid noise. still same. got much worse when i used separate battery for the cas...

oscilloscope... not my cup of thea but i must try this also, just have to find one...

my last thought tonigt was a problem this illusive must be related to poor grounding. going to recheck all grounding tomorrow.

are there any known causes that makes vems hang? or is it a security feature? shut down on serious trigger or other error??

dundersmurfen · « **Reply #9 on:** July 26, 2009, 06:46:28 am »

Ok update. Have tried just about everything. took out my other car the s13rb25, had problems,misfires with this last year so put that away for winter. now its back, standard coils on, works really nice runs smooth and responsive and no problems at all. put my bosch coilpack on it, ran like crap misfireres all over idle, on revs everywhere. then just like that vems hangs, freezes or dies, well it just gives up. this happens all the time with bosch coils (6cyl wastespark) difference is on this car im not loosing rpm signal, never have, just freezing and misfires like last year. now i even put in brand new quality sparkplug wires.
Put nissans coils back in, cars works nicely, no problems. (I know that i have to change some in ignition outputs for wastespark, no problem there)

Why cant i get a car (with 6 cyl rb engine) working with anything other than nissan standard coils?? I'm really getting tired of this since i want to put on some more booost yey. Everyone knows that nissans rb coils are weak, pretty much useless.

Oh checked grounds on the rb26 also, they are just fine, darn it, was really hoping that was it...

I have a strong feeling that if i put the standard coils back in the rb26 all problems will go away. but i dont want to, i want my msds.....

rob@vems.co.uk · « **Reply #10 on:** July 26, 2009, 07:01:57 pm »

where are you powering the coils from? And how are you grounding them?
Nissan coils have three connectors - +Vbat, Signal, Earth.
When we did the first S13 the coil earth was bad, so Gary@APT was testing possible grounding points for the coils and found that the grounding connector (when held with a pair of pliars) was arcing with enough energy to jump 2cm.

dundersmurfen · « **Reply #11 on:** July 27, 2009, 03:37:57 am »

I think we are on to something here... did some new wiring today (surprise??) finally got my rb25 working with the bosch wastespark coilpack, really nice too. What the problem was... well maybe some bad connectors on coilpack, redid this but soldered (spelling?) wires in and secured them with this wonderful thing i dont know the name of "melting glue gun???" grounded coilpack cores to cars chassi instead of engine. Nice to finally have my s13 sorted, now i may continue my evil plans

Going to try some new wiring on gtr tomorrow, im going to nail this one! Murhpy better back of or get hurt

Yes coil grounds are charged pretty high, that is the backside of spark plug so to say.

On side of config, could using trigger tooth 0 in reference tooth table be bad? there is no such tooth right? must be more accurate using 1 as first tooth

Power supply to coils are straight from nissans relay box.

Last thing i did tonight was this ignition amplifier. Hoping this will get rid of any noise going backway in my signal cables from vems... wait for it... new idea what about redoing wiring in the vems unit so that it provides the logic 12+ signal needed for my msd coils via standard ignition drivers. can they take supplying (logic level) 12+ instead of ground, that would make it possible to get fully seq with this... since stepper are only 4

rob@vems.co.uk · « **Reply #12 on:** July 27, 2009, 04:18:05 am »

Trigger tooth 0 is the first trigger tooth after the sync/missing tooth.
In the world of computing we count from 0 up.

As you know the IGBTs switch to ground, so you need a 12v drive, Hilly used these to drive his Audi coils:
http://www.datasheetcatalog.org/datasheet/TelComSemiconductor/mXttvzy.pdf

And I've used them successfully with Honda F20 coils

dundersmurfen · « **Reply #13 on:** July 28, 2009, 04:37:16 am »

No luck today, but another idea... Why not use some sort of pullup and invert ignition outputs?? what resistors to use and where to get 12v+ without risking to fry coils, fuelpump maybe...

Never tested my amplifier, now i want it fully sequential.

dundersmurfen · « **Reply #14 on:** July 29, 2009, 03:51:50 am »

These must be driven by logic (+) signal i suppose...
Wich one, inverting, no inverting, differential? no inverting sounds best...
What are the pins, nc? Vdd?

esd protected, that sounds useful...

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