Crank sensor voltage??
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Staging Lane
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From: Palm Beach Gardens, FL
Crank sensor voltage?? I have a '06 Corvette LS2 engine with a carb, 58 tooth reluctor wheel and MSD carb ignition box. My problem is that I am not getting any spark; the lap top said I was not getting any crank sensor signal. I have replaced the sensor twice with a new sensor from GM, I have checked and am sending 5 volts to the sensor. With the ignition just turned on I am getting ~ 1 volt back from the sensor to the box, and when I crank the engine (with battery and a charger hooked up to the battery) I only get ~1.4 volts back to the box. I talked with the MSD expert and he said I should be getting 3 to 4 volts from the sensor and that is not enough voltage for the box to send a trigger signal to the coils.
So my question is, anybody have any idea what I should change next?
Another crank sensor?
The box is not sending a trigger signal to the coils so I get no spark. The MSD get said that maybe the reluctor wheel was not mounted square to the crank, but I checked that and its fine.
How do I get more voltage back from the crank sensor?
I am getting 4.5 volts back from the cam sensor, but that doesn’t seem to let the box trigger the coils.
Help!
So my question is, anybody have any idea what I should change next?
Another crank sensor?
The box is not sending a trigger signal to the coils so I get no spark. The MSD get said that maybe the reluctor wheel was not mounted square to the crank, but I checked that and its fine.
How do I get more voltage back from the crank sensor?
I am getting 4.5 volts back from the cam sensor, but that doesn’t seem to let the box trigger the coils.
Help!
There were some posts a few years back about people that had problems getting crank sensor signals into their MSD box. A couple of the guys had Callias cranks. Others just couldn't get a signal unless they could get the engine cranking over a certain RPM. One guy had to crank the engine with no spark plugs before it turned fast enough to see a crank signal..
Try a search both here (conversions section) and on the MSD fourms. Might lend some insight.
I seem to remember someone saying they sent their box back to MSD and had them flash a new firmware load. The guy with the Callias crank ended up switching from the MSD to a FAST ignition controller. But I also seem to remember someone posting about a signal condition they made to clean up the crank signal before sending it into the MSD box. But do a search cause the more I think about it I might be mixing the MSD box up with what I read about the innovate wideband O2 box I have.
I think you will have a hard time measuring a "voltage" out of the sensor. The signal should be a square wave toggling between 5 and 0 volts. Higher RPM = faster on-off toggling. Best way to look at that would be with an O scope. A low buck volt meter set on the AC scale will return nebulous results at best.
Try a search both here (conversions section) and on the MSD fourms. Might lend some insight.
I seem to remember someone saying they sent their box back to MSD and had them flash a new firmware load. The guy with the Callias crank ended up switching from the MSD to a FAST ignition controller. But I also seem to remember someone posting about a signal condition they made to clean up the crank signal before sending it into the MSD box. But do a search cause the more I think about it I might be mixing the MSD box up with what I read about the innovate wideband O2 box I have.
I think you will have a hard time measuring a "voltage" out of the sensor. The signal should be a square wave toggling between 5 and 0 volts. Higher RPM = faster on-off toggling. Best way to look at that would be with an O scope. A low buck volt meter set on the AC scale will return nebulous results at best.
check to make sure you are not experiencing a voltage drop during cranking. check voltage at the msd 12v supply while cranking, you dont want it dropping much at all, definately not below 11v durring cranking.
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Staging Lane
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From: Palm Beach Gardens, FL
Thanks guys.
I am cranking the engine with the battery and a battery charger hooked up and the input cranking voltage is good.
I went on line to JustAsk.com and ask the question, one expert came back and said that you had to set the gap between the sensor and the reluctor wheel. Have you ever heard of this?
I am cranking the engine with the battery and a battery charger hooked up and the input cranking voltage is good.
I went on line to JustAsk.com and ask the question, one expert came back and said that you had to set the gap between the sensor and the reluctor wheel. Have you ever heard of this?
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Thanks guys.
I am cranking the engine with the battery and a battery charger hooked up and the input cranking voltage is good.
I went on line to JustAsk.com and ask the question, one expert came back and said that you had to set the gap between the sensor and the reluctor wheel. Have you ever heard of this?
I am cranking the engine with the battery and a battery charger hooked up and the input cranking voltage is good.
I went on line to JustAsk.com and ask the question, one expert came back and said that you had to set the gap between the sensor and the reluctor wheel. Have you ever heard of this?
I have a problem with my cam sensor doing the same thing, I'm on MSD #2, and cam sensor #3. At least I can start and run mine, it just has to guess at tdc compressin stroke.
I think theese MSD's are too finiky with the sensor inputs.
Last edited by 3pedals; Dec 18, 2010 at 06:54 PM.
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Staging Lane
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From: Palm Beach Gardens, FL
I'm getting power direct from the fuse box. A while cranking the lap top is telling me the voltage is onl dropping down to 11.o volts. One thng that did bother me is how small the power wires are in the MSD kit. Just seems too small which could cause resistance. Did you run a bigger power wire direct to the box and not use the stock wiring?
If you are getting full voltage, i dont see an issue, i am running straight into the stock ignition power wire from under the hood that ran into the stock distributor.
pull all the spark plugs, and try to turn it over... see if the MSD shows RPM during cranking.
This will take less voltage for the starter to turn the engine over, and will also spin the engine over faster.
2 Common problems with the 601X boxes... must have proper cranking voltage and RPM to excite enough signal from the sensors.
This will take less voltage for the starter to turn the engine over, and will also spin the engine over faster.
2 Common problems with the 601X boxes... must have proper cranking voltage and RPM to excite enough signal from the sensors.
keep cranking, pull the plugs, take the belt off the waterpump, you need to get it to "turn" over excessively fast. i had the same issue with my 6012 box, check and make sure all the connections to cam and crank sensors are good.
Thread Starter
Staging Lane
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From: Palm Beach Gardens, FL
I have been doing most of the trouble shooting with the plugs out so I could get the fastest crank speed, still on crank signal or RPM on the lap top. 
I'm getting a good 5 volts to the crank sensor, but only 1.4 back to the box when cranking. The MSD expert said I should see 3 to 4.5 volts back from the sensor when cranking. Off to get one more crank sensor, then call MSD again.
I'm getting a good 5 volts to the crank sensor, but only 1.4 back to the box when cranking. The MSD expert said I should see 3 to 4.5 volts back from the sensor when cranking. Off to get one more crank sensor, then call MSD again.
i've also heard that the "weathpack" style electrical connectors can be a slight issue, sometimes the rubber seals they have dont allow a full tight connection, might want to double check all the connections again. good luck, post back results after you try the new crank sensor
I have delt with this box for 4 years now. I run a 6010 on a carb 383.
The cranking speed was the first thing that got me. It has to spin about 200 rpm's to fire. I've seen as low as 175 and it fired. But at first we had to pull the plugs and that was enough to get the plugs to fire. Put a plug in one wire and ground it. Have someone watch that plug while you crank it.
The next thing that got me was it having voltage issues at 7K rpm's and it would back fire. I ran a 10 ga wire from the battery to the box and it went away.
Try running a power and a ground STRAIGHT from the batt to the box and see what happens.
One of these two will get you fired up. Unless it is a connection problem in something else.
I love the box now that I know it's quirks lol.
The cranking speed was the first thing that got me. It has to spin about 200 rpm's to fire. I've seen as low as 175 and it fired. But at first we had to pull the plugs and that was enough to get the plugs to fire. Put a plug in one wire and ground it. Have someone watch that plug while you crank it.
The next thing that got me was it having voltage issues at 7K rpm's and it would back fire. I ran a 10 ga wire from the battery to the box and it went away.
Try running a power and a ground STRAIGHT from the batt to the box and see what happens.
One of these two will get you fired up. Unless it is a connection problem in something else.
I love the box now that I know it's quirks lol.
Thread Starter
Staging Lane
iTrader: (7)
Joined: Sep 2009
Posts: 88
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From: Palm Beach Gardens, FL
I don’t want to celebrate victory before it happens, but…………………
After talking with the local nationally know LS2 engine builder (Mike), and talking to the GM Performance Hot Line and finally talking with the MSD expert while standing next to the Panoz we discovered that the return signal wire from the crank sensor had a break in the harness somewhere. The interesting thing is that the broken wire would carry 1.4 volts back from the sensor, but not the full 4.8 volts the sensor was trying to send, and as a result the box would not trigger the coils.
So, MSD is sending me a new wiring harness (at no charge) which should fix the problem. The MSD expert has been a great help with this and was very willing to stay on the line as we went through the wires looking for a break or short.
Good news is that I now have 2 new crank sensors. J
After talking with the local nationally know LS2 engine builder (Mike), and talking to the GM Performance Hot Line and finally talking with the MSD expert while standing next to the Panoz we discovered that the return signal wire from the crank sensor had a break in the harness somewhere. The interesting thing is that the broken wire would carry 1.4 volts back from the sensor, but not the full 4.8 volts the sensor was trying to send, and as a result the box would not trigger the coils.
So, MSD is sending me a new wiring harness (at no charge) which should fix the problem. The MSD expert has been a great help with this and was very willing to stay on the line as we went through the wires looking for a break or short.
Good news is that I now have 2 new crank sensors. J
