No RPM with VR sensor

[cw25]

I will start with my problem. I have no tach signal to the MS, I crank it over and it shows zero RPM.

MSII V3.57 2.88.

I wired the VR sensor in the dist directly to the INJ wire with the polarity going negative to the sheilding wire and positive to the white wire. I found a post that said to set the pins on J1 to 1 and 2 and JP1 to 3 and 4 I think, I did this but I can't find any other info in this. I have the ignition input capture set on rising edge althought I have tried both. It is probably a stupid setting that I am overlooking but I can not get this thing to register the VR signal. I have had this thing running off fuel only for over a year now using the coil negative for a tach input. So I know the MS works I just want control over the ignition timing as well as fuel. Let me throw away my MSD BTM retard. LOL

[Matt Cramer]

Can you get RPM on a Stimulator?

Also, is this a normal distributor trigger, or some sort of missing tooth wheel setup?

[cw25]

I was under the assumtion that the stim didn't send out a RPM signal when setup for VR. I have this stim not the Jim stim with the extra wheel. It was working just fine with a basic tach signal... I will have to try the stim tonight. Is there any other settings I have missed? What is the proper setup for the VR conversion? Thanks for your time.

[cw25]

Sorry this is a just a regular dist with a magnetic pickup. I removed the dist module as I want to have as few parts to fail as possible.

[Matt Cramer]

You should be able to get an RPM reading with the V3.57 VR conditioner on a Stim.

Also, I could check your settings if you post a copy of your MSQ (tune) file.

[cw25]

I will post a copy of the MSQ tonight it is on my truck laptop at home. Maybe I have to install the pull up resistor and run the module in the dist but I really don't want to as I like how simple the magnteic pickup is.

[cw25]

Here is a copy of my tune.

[cw25]

I pulled the distributer and found that it would not read anything below 180 RPM. I thought that it was reading nothing at all because I was trying while cranking. My battery is a little low and the garage is cold but that number seems high for minimum cranking RPM. Any way to make it more sensitive?

[Matt Cramer]

I pulled the distributer and found that it would not read anything below 180 RPM. I thought that it was reading nothing at all because I was trying while cranking. My battery is a little low and the garage is cold but that number seems high for minimum cranking RPM. Any way to make it more sensitive?

Yes, you need to adjust the trim pots:

http://www.megamanual.com/ms2/vradjust.htm

On a V3.57, they're more like 5 or 6 turns and don't click, but are otherwise the same as on a V3.0. You may also need to adjust the sensor gap.

[cw25]

Thanks Matt. Looks like that will solve my issues.

Maybe I can get my 11 second slip with the MS in charge of everything.

[cw25]

I celebrated a little early. As soon as the engine hits 3100 RPM it goes nuts and even when the timing is all set to 30* it still walks to 40* or so as I rev it up. I would really like to drive this thing faster than 3100 LOL. The distributer is locked out and this is a new engine wih only 700 miles so I doubt anything mechanical is worn like timing chain.

[Matt Cramer]

From the log, it looks as if you may have made it too sensitive - see the RPM spike? You may be able to get away with shielding the wiring, or it may take more fine tuning of the VR sensor pots. Make sure the senor wiring is routed away from all noise sources - in particular, don't let it touch the spark plug wires.

[cw25]

I adjusted the VR sensors from scratch and it works perfect right now. At least in the garage. The only think keeping the motor from reving now is the 6200 limiter. I will cold start it again and see if it likes the setting I have. If you were here I would probably be humping your leg. LOL Getting the grasp on this definitly took some time for me but it seems to be paying off. I have full spark and fuel control of this motor now and it cost me $12 for the BIP373 with sipping