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My MS doesn't see RPM's on step 56

Posted: Tue May 09, 2006 12:34 am
by Jose_76
Yesterday I made the test on step 56 and saw on the Realtime Display that it all went right but the RPM's. It read zero RPMs all the time, although I twisted both RPM knobs for a while.

The only modifications I'd already done at this point are:

STEP 47: Installed a 1K5 resistor
STEP 48: Installed a 1N4007 instead of the 1N4001.
STEP 51: Installed a 0.01uF capacitor.
STEP 53: Installed 2K2 resistors
STEP 54: Soldered a wire on XG-1 (to ground)

Where's the problem?? :shock:

Posted: Tue May 09, 2006 2:03 am
by Steve R
Could be any of a few things:

Check the stim instructions to make sure that grounding XG1 is compatible with the stim (this is nagging at my memory from somewhere but could be a red herring).

The increased resistance 1k5 instead of 390 and the bigger diode MIGHT be reducing the weak stim signal enough that nothing happens. Remember the stim is very low voltage / low power compared to the "in car" set up. You could try bridging them with the 390 ohm & 1N4001 to restore the stock MS set up and then try it on the stim again.

It could just be a stim fault, check this first, especially the meg ohm pot.

S

Posted: Tue May 09, 2006 2:15 am
by Jose_76
Thanks, Steve! I'll try that a.s.a.p.

Could you send me some pics of your EDIS installation? :lol:

Thanks!

Posted: Tue May 09, 2006 6:07 am
by Steve R
I'd love to, but I didn't do an EDIS instal ! Mine uses a welded up GTV6 distributor and Bosch (VW sourced) ignition unit & coil fired by MS. :wink:

Posted: Tue May 09, 2006 6:37 am
by Jose_76
:shock: How did you do that?? Pics? :wink:

Posted: Tue May 09, 2006 11:00 am
by Jose_76
I've just put the 390Ohm resistor and the 1N4001 in place and still donesn't see the revs on the stim!!! :?

Posted: Tue May 09, 2006 3:18 pm
by Murray
Jose I don't have my MS reference material close by but if I remember correctly at one point if you wire up the board for coil negative input you lose the RPM simulation on the stim.Hope this helps.It states this somewhere in the assembly instructions.

Posted: Thu May 11, 2006 11:00 am
by Jose_76
I just find U4 on a wrong position. When fitted correctly it all went OK.

Thanks!

Posted: Thu May 11, 2006 11:45 am
by P.Webb
Jumper XG1 and XG2. Common problem on the stim.

-Peter

Posted: Fri May 12, 2006 3:54 am
by Steve R
Hey, Welcome back Peter. Long time no posts!

Posted: Fri May 12, 2006 7:19 am
by P.Webb
Howdy all.

I've been watching the progress here for some time. I've sent a few of you PMs about issues you've been having.

I'm really glad to see how you've all been supporting each other with the MS installs and many of you have taken on the MSII and V3 boards. Good stuff. That's what it's all about IMO. Each new install adds to the support base.

I've been following the ignition installs closely. I haven't touched my car in many months due to a 105 based race car project. However, last fall I ran a 2:54 at Road America and a 1:39 at Gingerman Raceway. For comparison, no street Alfa has broken 3:00 at RA for as long as the club remembers and the vintage racing Alfa's were clicking off 1:36's at Gingerman. Not bad to be 3 seconds behind an 1800lb race car. There was an Elise at Gingerman doing 1:40's so an even bigger thrill to be a second faster than a lotus in a 20 year old sedan.

-Peter