msd 7531 with nitrous

MSD Digital Ignition Programming & Troubleshooting, Playing with Dots, Slew and other fun toys for traction challanged racers

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John_Heard
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Re: msd 7531 with nitrous

#16 Post by John_Heard » Tue Nov 10, 2015 10:29 am

Two blinks is the error code for no cam sync. Which if you don't have the cam sync sensor is normal.

Hard to say what might be wrong, could be your crank trigger, or a coil, maybe the box is bad ? You have any spares to swap out?

raffaplymouth
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Re: msd 7531 with nitrous

#17 Post by raffaplymouth » Tue Nov 10, 2015 11:01 am

John. . when the car was OK. .. The led flash with trigger when pulsating when you crank. ... now make two flash. .. And no flash when cranking , coil is OK
1970 Super Cuda 496 Indyheads
ET 9.32@148 1.42 60ft (250 shot ) :shock:

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Re: msd 7531 with nitrous

#18 Post by John_Heard » Tue Nov 10, 2015 11:25 am

What do you use to trigger the MSD? A crank trigger? Distributor pickup? This article might help trouble shoot it -

http://www.dragstuff.com/techarticles/m ... oting.html

raffaplymouth
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Re: msd 7531 with nitrous

#19 Post by raffaplymouth » Tue Nov 10, 2015 11:32 am

crank trigger
1970 Super Cuda 496 Indyheads
ET 9.32@148 1.42 60ft (250 shot ) :shock:

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Re: msd 7531 with nitrous

#20 Post by John_Heard » Tue Nov 10, 2015 11:40 am

Those do act up from time to time. That article will show you how to test it. You can ohm it out, etc. to see what is wrong.

raffaplymouth
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Re: msd 7531 with nitrous

#21 Post by raffaplymouth » Tue Nov 10, 2015 1:41 pm

make test :
wrong flash ... I have not two flash but 3 flash ! 3 flash = low battery tension

trigger resistance is 80 ohm OK and trigger gap is correct .070

tension on msd connection when cranking is 10,6 volts ... is low ?? I have two battery on trunk and 100 ah alternator
1970 Super Cuda 496 Indyheads
ET 9.32@148 1.42 60ft (250 shot ) :shock:

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John_Heard
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Re: msd 7531 with nitrous

#22 Post by John_Heard » Tue Nov 10, 2015 2:40 pm

I've seen them start with lower voltage, but all your signs are pointing at a low voltage situation. It sounds like testing your battery/s, battery connections, etc. would be worthwhile at this point.

raffaplymouth
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Re: msd 7531 with nitrous

#23 Post by raffaplymouth » Thu Nov 12, 2015 5:45 am

Checked everything is ok , now im speaking with MSD technical service ... i dont know what to do ... i have also checked the check spark with white wire at ground and green violet with jump .... no change ... no spark
1970 Super Cuda 496 Indyheads
ET 9.32@148 1.42 60ft (250 shot ) :shock:

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Re: msd 7531 with nitrous

#24 Post by John_Heard » Thu Nov 12, 2015 7:26 am

Starting to sound like you have a bad 7531 box.

raffaplymouth
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Joined: Tue Jul 24, 2012 2:07 pm

Re: msd 7531 with nitrous

#25 Post by raffaplymouth » Thu Nov 12, 2015 7:40 am

Yes John ...
1970 Super Cuda 496 Indyheads
ET 9.32@148 1.42 60ft (250 shot ) :shock:

raffaplymouth
Posts: 162
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Re: msd 7531 with nitrous

#26 Post by raffaplymouth » Wed Mar 30, 2016 1:47 pm

hello .. Finally my box was damaged from tension jump ... now is repaired OK. . now this is the installation specs :

Idle 28 degree
total timing 36 degree
start retard 9 degree
nitrous activation retard 10 degree ( 250 HP) on pink wire

I don't understand very well the slew rate gear ... I don't want use this .. I fear that can active in automatic and make some problems.
1970 Super Cuda 496 Indyheads
ET 9.32@148 1.42 60ft (250 shot ) :shock:

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