Dwell setup questions.

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T3Bunny
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Joined: Sun Nov 28, 2004 8:44 pm
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Dwell setup questions.

Post by T3Bunny »

Well this is my first time with a V3.0 running direct coil control that I setup. And this thing is giving me a bit of greif.

First off there is a bit of confusion. We are using a MS-1 with MsnSe 027d code. For our spark output, we are using the LED D14 modded with the 1k resistor as our signal out to the IGBTIN. The MS-2 info was what we found easily, after more digging we finally found the MS-1 information.

First question, does R57 need to be lifted up or removed for the MS-1 setup? It appares that it doesn't.

THe next issue is a little more complicated. We can NOT get this thing running smoothly. The information seems to be a little lean on the troubleshooting of it and what to expect. I would LOVE to see some scope patterns too.

In the meantime, the scope is broken and our only weapon is a timing light. Thr enging is a 4cyl VW 8v and a Jacobs coil (but not the control box, just running the coil, and it worked fine on the stock ignition setup).

At about 3.0ms running dwell, we seem to not be getting the coil charged after about 2800rpm. It runs smooth as glass up to that point then its almost like a rev limiter coming on. At 6.0ms, the light is dead steady but we are getting misfires. We did not realy find a value in between that would work either. We didn't try every one, but we went up and down a few times about 1/2ms at a time. We tried every setting around the 3.0ms mark as it seemed to sound a little better there.

Any setup tricks and recomendations? We have minimum discharge at 0.1ms.
Forget the porn, my bathroom is full of car manuals...
1977 Rabbit (retired)
1991 Cabriolet (retired)
jsmcortina
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Post by jsmcortina »

R57 is indeed removed. This is in this picture
Image
on
http://megasquirt.sourceforge.net/extra/setup-msns.html

If it is still on the board, you _may_ be getting some problems from it.

The only rough advice I can offer on dwell, is that the VB921 must not get hot. If either the VB921 or the coil start heating up you have excessive dwell.

James
I can repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk

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T3Bunny
Super MS/Extra'er
Posts: 1391
Joined: Sun Nov 28, 2004 8:44 pm
Location: Miami, Florida

Possible change of events....

Post by T3Bunny »

Okay, half the problem is I am not there at the car and working on this remotly. We may end up having to run the stock ignition module to get this thing up and running. At this point I am not sure if we are dealing with a dwell issue, or if there is another issue that is hidden.

Can we setup a stock module without changing the V3.0 internal setup from the high power Ignition driver over to the regular one? Here is the thought. A small test harness plugging into the coil power up wire and signal wire that now goes to the coil. Swap this to go to the module. Easy enough.

Only ONE real concern. I need to change the setting over from inverted singal to normal. Since this would no longer be powering the coil, is it an issue to do this? I do not want to burn the driver out.
Forget the porn, my bathroom is full of car manuals...
1977 Rabbit (retired)
1991 Cabriolet (retired)
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