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Discussion Starter #1
I just got my car running for the first time in years and everything was fine ideling and all of a sudden the car shuts off. Go to crank it over and there is no spark. I have the BS3 and a 7531 on the car and there is no spark getting to the coil while cranking. When you look at the red light on the MSD box it does not blink either while cranking. I cut the white points wire going to the BS and did the ground touch test and I got spark at the coil. Hook it back up to the BS and nothing. So then I put a test light on the white wire while hooked up to the BS and turned the ignition on. The test light was dim but on the whole time. Went to crank the car with the test light went even dimmer and after about four seconds or cranking the fuel ignited and went boooom.

So then I tested the red wire going to the crank trigger sensor with a test light while cranking and got nothing. This is all brand new MSD stuff but I guess it's possible to have a sensor go out that quick.

Is there any other test methods I could use to determine if it's the crank trigger sensor or the BS3 box before I go replacing parts? I need to figure out why the white points wire is not getting a spark signal to the MSD box.

Thanks for any help!

Josh
 

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Go online with the BS3 and open up any table that will show rpm in the dash. Crank the engine over and see if it shows any rpm while cranking. this will tell you if it's a trigger issue or if it's the points driver circuit in the BS3 that's the issue.
 

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Discussion Starter #3
Go online with the BS3 and open up any table that will show rpm in the dash. Crank the engine over and see if it shows any rpm while cranking. this will tell you if it's a trigger issue or if it's the points driver circuit in the BS3 that's the issue.
Aww that's true. I'll try it and see what happens. I don't understand why the points wire always has a faint power source though indicated by the dim bulb of the test light. Then when you crank it it get's dimmer.
 

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MSD box on a points input should be looking for current high then low.

When the coil would be charging the Output from the points would be High B+ then when the points go open to discharge the Negative or low. the MSD box is looking for this behavior.

If the ouput does not go High then low the MSD will not trigger. Do you have an o-scope ??


Aww that's true. I'll try it and see what happens. I don't understand why the points wire always has a faint power source though indicated by the dim bulb of the test light. Then when you crank it it get's dimmer.
 

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Discussion Starter #5
MSD box on a points input should be looking for current high then low.

When the coil would be charging the Output from the points would be High B+ then when the points go open to discharge the Negative or low. the MSD box is looking for this behavior.

If the ouput does not go High then low the MSD will not trigger. Do you have an o-scope ??
Is an o-scope the device to check ohms? If so then yes but how many ohms should the crank sensor see?
 

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Discussion Starter #6
Well I changed out the crank sensor and still have the same no spark issue. I then hooked the computer up to the BS3 and opened a dashboard and when I crank the motor over it does show 150rpm's. I talked with John Meany and he asked a few questions about it being on 16 volts and stated if the box see's over 20 volts it will fry the points output board and possibly more. Something has to be wrong in the BS as he is mentioning since I have tested everything else but it makes no sense the BS box would see that much voltage. The battery is a brand new (just bought last month) powermaster and the car doesn't have an alternator to charge it. The BS dashboard showed 17.1 volts but the car just shut off like you killed the ignition. It had a total of maybe 5 minutes of idle and soft reving to 2500 or so on it before this problem occured.

Has anyone heard or experianced this issue with the BS3 before as far as the circuit driver going out? The only thing I could possibly do differant would be to put a voltage step down box on the BS but I never had these issues running 16 volts on the old FAST B2B box. This stupid problem has cost me so much time and money it rediculous.:smt093
 
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