Testing with VRSSIM - problems

EDIS and Megajolt installation related topics. Be sure to review the <a href="http://www.autosportlabs.net/MJLJ_V4_vehicle_installation_guide">Vehicle installation guide</a>

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steve_c
Posts: 36
Joined: Wed Dec 13, 2006 2:59 pm

Testing with VRSSIM - problems

Post by steve_c »

I've just got a system together and have tested it with VRSSIM. I am seeing intermittant missing of sparks and a total failure at 3100 rpm. The signal from the VRSSIM PC is not hesitating, so am wondering if this is an EDIS module fault or a Megajolt board fault. The 'missing sparks' occur frequently once or twice a second) when changing the revs up and down and infrequently (once every 5 to 10 seconds) when at constant revs. As I say the system fails at 3100 revs. I'm not sure what bit to look at as being suspect. Has anyone experienced anything like this. I am running this on the bench with plugs attached. The Megajolt monitor software responds to these missing signals by dropping the rev counter momentarily.
Hope someone can point me in the right direction.

Steve

MartinM
Posts: 433
Joined: Sat Aug 27, 2005 12:08 pm

Re: Testing with VRSSIM - problems

Post by MartinM »

steve_c wrote:so am wondering if this is an EDIS module fault or a Megajolt board fault.
So with the MJLJ totally disconnected, does it still misbehave - that should be a good guide as to where the problem is :)

steve_c
Posts: 36
Joined: Wed Dec 13, 2006 2:59 pm

Post by steve_c »

I've just tried that. Sparks are regular with no Megajolt connected. The unit sparks unit around 6000rpm (varies a bit) then sparks stop. Revs have to go to 3000rpm for sparks to come back (is this a design function of the EDIS?). But no sporadic 'missing'

MartinM
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Post by MartinM »

EDIS should work perfectly from cranking rpm (200?) right through to at least 8000rpm and you should be able to go up and down the rev range at will.

Sounds like one or more of:
- a faulty EDIS
- faulty connections into the EDIS - check the pins in the plug
- some incompatibility with VRSSIM - try emailing the designer
- faulty coil pack

Good luck....

brentp
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Post by brentp »

The MJLJ calculates RPM by measuring the interval between PIP signals. Glitches on the RPM gauge in the configuration software will occur when PIP signals are missed or irregular.

The EDIS module you have may not like something about VRSSIM. Have you tried this on an actual running engine, or at least on a spinning trigger wheel with sensor?

If you have an oscilloscope it would be helpful to monitor the PIP, SAW and VRS signal lines to see what the signal looks like when the problems occur.
Brent Picasso
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steve_c
Posts: 36
Joined: Wed Dec 13, 2006 2:59 pm

Post by steve_c »

I am concentrating on the EDIS module at present. I can get it to spark up to over 8000rpm if I jump the VRSSIM revs in increments of 500. Using increments of 50 it gets nowhere near this. Oddly enough it always comes back to life when the rpm gets back down to 3000. I have disconnected the MJLJ. I have a single channel scope. The VRSSIM signal remains unchanged except for it's frequency. The SAW output of the EDIS goes high when it stops producing 'sparks'. I'm assuming this is a faulty module. I haven't had this on a car yet. I have yet to fabricate a bracket for my A series. I may be tempted to make up a dummy trigger wheel and mount it on my portable drill. Will an aluminium trigger wheel work or does it have to be ferrous?

steve_c
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Joined: Wed Dec 13, 2006 2:59 pm

Post by steve_c »

I should have said PIP signal not SAW.

alexander
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Location: sydney, australia.

Post by alexander »

the trigger wheel must be ferrous

steve_c
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Joined: Wed Dec 13, 2006 2:59 pm

Post by steve_c »

I'll think I'll try making a wooden disc and insert nails around the periphery. Hopefully the nail heads will register on the VR sensor.

MartinM
Posts: 433
Joined: Sat Aug 27, 2005 12:08 pm

Post by MartinM »

Even at 3000rpm, I wouldn't go anywhere near a spinning wooden disk with nails in it. And even getting 3000rpm would be a challenge - 50 revs/sec is actually quite fast! What's the plan to get those sort of rpms?...and greater?

Send Ben an email (email address on his web site) and see what he thinks about VRSSIM - he may have some thoughts. Bear in mind that VRSSIM models the VR sensor reasonably, but not exactly....

Up to you of course, but maybe it's not worth pursuing too far anyway - if the EDIS is faulty you'll have to get another one (where did it come from?) and if it's OK, then it's OK (obviously!). As you're obviously going to install it all on the engine anyway, I'd just press on and do so.

If you get similar problems in the car then you've a very good pointer that the EDIS is faulty.

steve_c
Posts: 36
Joined: Wed Dec 13, 2006 2:59 pm

Post by steve_c »

Hmm, you may be the voice of reason here Martin. You are correct of course. The module works fine up to half revs so I will install it all anyway. Better use of my time in making a sensor mounting bracket than testing the EDIS. Will make that decision when it's in the car. The EDIS stuff came from a guy on eBay a good 18 months ago.

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