EMI / RFI and setting timing = problems

Bob Mulry · 09-08-2014, 04:16 PM

I know that you are not going to believe this.......But I made a mistake ONCE

I had the pickup polarity reversed and the timing mark bounced around like crazy. This was on an MSD-7A and crank trigger....

With the shielded leads they did a color swap and that caused my problem....

I reversed the leads and the problem went away....

It seems like a pretty easy test to do and it might solve your problem..

Bob

Sean Marconette · 09-08-2014, 04:42 PM

Quote:

Originally Posted by Bob Mulry

I know that you are not going to believe this.......But I made a mistake ONCE

I had the pickup polarity reversed and the timing mark bounced around like crazy. This was on an MSD-7A and crank trigger....

With the shielded leads they did a color swap and that caused my problem....

I reversed the leads and the problem went away....

It seems like a pretty easy test to do and it might solve your problem..

Bob

That's what I experienced too Bob! The timing was jacked as well! All because I replaced the Ford distributor adapter to MSD plug with Weather pack connectors. We are our own worst enemies at times!

joespanova · 09-08-2014, 08:35 PM

OK , Lets end this .......thanks for all your input BTW.
I had a friend of mine stop by with his plastic ( newer than my metal body ) Actron light......and it read the timing!
Actually surprised the crap outta me........anyway , my lights that normally work are suddenly quirky..........all those lights ( 3 ) are years old with the exception of my Flaming River light.......but his worked.
Anyway , I'm buying another light ( same as his ) now I'll have 5 lights LOL

buzzinhalfdozen · 09-09-2014, 09:47 AM

Glad you found your issue, my first thing when someone local has this issue is to use my timing lite to see if that's the problem, then go from there. Guess one can never be sure. BTW you actually will only have 1 lite that works on your race car!

art leong · 09-09-2014, 10:09 AM

You remarked about everything being grounded etc. If you ground the shielded cable pickup wires, you just created a magnetic for EMI problems.
I did this, so I learned from experience.

buzzinhalfdozen · 09-09-2014, 10:37 AM

Art, you are correct any shield should only be grounded on one end, by grounding both ends you're making an antenna.

joespanova · 09-09-2014, 11:15 AM

OK
So what the heck is the ground for?

joespanova · 09-09-2014, 11:17 AM

Quote:

Originally Posted by buzzinhalfdozen

btw you actually will only have 1 lite that works on your race car!

True LOL

buzzinhalfdozen · 09-10-2014, 08:05 AM

Joe the ground is for the shield, it should only be connected at 1 end to ground.

joespanova · 09-10-2014, 08:32 AM

Quote:

Originally Posted by buzzinhalfdozen

Joe the ground is for the shield, it should only be connected at 1 end to ground.

I dont follow..there's one pigtail.........how could you connect it at both ends?

09-08-2014, 04:16 PM	#1
Bob Mulry VIP Member Join Date: Apr 2002 Location: Coarsegold, CA Posts: 1,016 Likes: 57 Liked 320 Times in 102 Posts	Re: EMI / RFI and setting timing = problems I know that you are not going to believe this.......But I made a mistake ONCE I had the pickup polarity reversed and the timing mark bounced around like crazy. This was on an MSD-7A and crank trigger.... With the shielded leads they did a color swap and that caused my problem.... I reversed the leads and the problem went away.... It seems like a pretty easy test to do and it might solve your problem.. Bob __________________ Bob Mulry 7516 STK A & M Motorsports

09-08-2014, 08:35 PM	#3
joespanova Senior Member Join Date: Jun 2011 Location: Ga. Posts: 521 Likes: 7 Liked 13 Times in 11 Posts	Re: EMI / RFI and setting timing = problems OK , Lets end this .......thanks for all your input BTW. I had a friend of mine stop by with his plastic ( newer than my metal body ) Actron light......and it read the timing! Actually surprised the crap outta me........anyway , my lights that normally work are suddenly quirky..........all those lights ( 3 ) are years old with the exception of my Flaming River light.......but his worked. Anyway , I'm buying another light ( same as his ) now I'll have 5 lights LOL

09-09-2014, 09:47 AM	#4
buzzinhalfdozen Senior Member Join Date: Sep 2006 Location: Bellevue Ohio Posts: 984 Likes: 0 Liked 11 Times in 8 Posts	Re: EMI / RFI and setting timing = problems Glad you found your issue, my first thing when someone local has this issue is to use my timing lite to see if that's the problem, then go from there. Guess one can never be sure. BTW you actually will only have 1 lite that works on your race car! __________________ Joe Buchanan SS/BX 3117

09-09-2014, 10:09 AM	#5
art leong VIP Member Join Date: Dec 2001 Location: Richmond Hill, Georgia Posts: 2,003 Likes: 0 Liked 1 Time in 1 Post	Re: EMI / RFI and setting timing = problems You remarked about everything being grounded etc. If you ground the shielded cable pickup wires, you just created a magnetic for EMI problems. I did this, so I learned from experience. __________________ Art Leong 2095 SS

09-09-2014, 10:37 AM	#6
buzzinhalfdozen Senior Member Join Date: Sep 2006 Location: Bellevue Ohio Posts: 984 Likes: 0 Liked 11 Times in 8 Posts	Re: EMI / RFI and setting timing = problems Art, you are correct any shield should only be grounded on one end, by grounding both ends you're making an antenna. __________________ Joe Buchanan SS/BX 3117

09-09-2014, 11:15 AM	#7
joespanova Senior Member Join Date: Jun 2011 Location: Ga. Posts: 521 Likes: 7 Liked 13 Times in 11 Posts	Re: EMI / RFI and setting timing = problems OK So what the heck is the ground for?

09-10-2014, 08:05 AM	#9
buzzinhalfdozen Senior Member Join Date: Sep 2006 Location: Bellevue Ohio Posts: 984 Likes: 0 Liked 11 Times in 8 Posts	Re: EMI / RFI and setting timing = problems Joe the ground is for the shield, it should only be connected at 1 end to ground. __________________ Joe Buchanan SS/BX 3117

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