Electromagnetic/RF interference and Sniper - Chevelle Tech
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post #1 of 12 (permalink) Old Apr 18th, 19, 10:48 PM Thread Starter
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Jim
 
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Electromagnetic/RF interference and Sniper

Iíve had my Sniper in for a couple weeks and The car has been running very poorly...backfiring, stumbling. the data on the handheld during these 1-2 second episodes reads ďno dataĒ or goes black. My (Holley certified) installer, after a long convo with Holley engineering have decided itís electromagnetic interference. Plan is to change my Taylor spark plug wires to a Holley Street Fire set for now. Per Holley, Taylorís are notorious for causing interference. Next up would be moving the ignition coil. Anybody else have issues like this too? I havenít read a lot about RF/EMI as the source of poor performance on this forum, so I figured Iíd throw it out there.
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post #2 of 12 (permalink) Old Apr 19th, 19, 12:03 AM
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I don’t have an RF issue with my sniper but I’d suggest using the super conductor wires rather than the street fire wires. And I’d move the coil away. Are you running timing control? Take a datalog and have the tech review it, that’ll show if it is a RF problem or not.

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post #3 of 12 (permalink) Old Apr 19th, 19, 5:40 PM
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Re: Electromagnetic/RF interference and Sniper

I just went through Holley Tier 1-3 training. I would also consider adding a ground strap to the air filter base. Also make sure you have good (use star washers and bare metal) grounds from the block to the body.

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post #4 of 12 (permalink) Old Apr 19th, 19, 8:12 PM
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Re: Electromagnetic/RF interference and Sniper

Run good grounds to each head, manifold, block and frame
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post #5 of 12 (permalink) Old Apr 19th, 19, 11:20 PM
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Re: Electromagnetic/RF interference and Sniper

You can also run twisted wire shielded cable for power and signal wiring and ground the shield only on the power source end.

Your just jealous because you can't hear the voices!

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post #6 of 12 (permalink) Old Apr 20th, 19, 12:32 AM
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Re: Electromagnetic/RF interference and Sniper

Is this a real big problem with Snipers or is it just something about this one setup? Doesn't seem like I have read about this being an issue before. Noise in the tach signal sure but everywhere else kinda seems like there has to be an issue in this car other than the sniper.

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post #7 of 12 (permalink) Old Apr 20th, 19, 6:46 AM
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post #8 of 12 (permalink) Old Apr 20th, 19, 8:03 AM
Joel
 
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Re: Electromagnetic/RF interference and Sniper

I had some EMI with my Super sniper as well. Its very susceptible to picking up EMI/RFI. I ended up moving all the sniper connectors and wires as far away from I could from the plug wires. I also got under the header plug wires and routed them out behind the engine and down to keep everything as far away as possible. It looks like you have some sniper wires actually touching the plug wires on the passenger side there. That maybe your issue (along with the coil location).

On my setup, the WBO2 wire was too close to the plug wire causing stalling issues. Once I move the plug wires as far away from it as I could the issue went away. Also, I think you said you were going to do this, but definitely get that coil out of there as that is not helping. As the others have mentioned make sure you have good grounds as well. Good luck!
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post #9 of 12 (permalink) Old Apr 20th, 19, 8:42 PM Thread Starter
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Jim
 
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Re: Electromagnetic/RF interference and Sniper

Quote:
Originally Posted by JF74chevelle View Post
I donít have an RF issue with my sniper but Iíd suggest using the super conductor wires rather than the street fire wires. And Iíd move the coil away. Are you running timing control? Take a datalog and have the tech review it, thatíll show if it is a RF problem or not.
The coilís getting moved away next week, when I take the car back to the shop. Timing is controlled via the Holley and a dual sync distributor. Datalogs are suggestive of RFI. Iíll try to include a short video of what the handheld looks like during these episodes. Basically, itís glitching...reads ďno dataĒ during the roughness.

https://youtu.be/3kt9h_4wzYQ


Quote:
Originally Posted by andrewb70 View Post
I just went through Holley Tier 1-3 training. I would also consider adding a ground strap to the air filter base. Also make sure you have good (use star washers and bare metal) grounds from the block to the body.

Andrew
I ran the car without the snorkel air cleaner and the car ran great! Itís getting grounded too, next week.

Quote:
Originally Posted by 73Eldo View Post
Is this a real big problem with Snipers or is it just something about this one setup? Doesn't seem like I have read about this being an issue before. Noise in the tach signal sure but everywhere else kinda seems like there has to be an issue in this car other than the sniper.
My installer was talking to Holley engineers and they admitted itís a problem in about 5% of their installs.

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post #10 of 12 (permalink) Old Apr 22nd, 19, 6:17 AM
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Rick
 
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Re: Electromagnetic/RF interference and Sniper

All those wire running back by the distributor and plug wires are an issue.

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post #11 of 12 (permalink) Old Apr 22nd, 19, 8:11 AM
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Re: Electromagnetic/RF interference and Sniper

Granatelli Motorsports makes a zero Ohm wire core spark plug wire. They slip an inductive ring on one end that quashes EMI. I've used them on many cars without issue, including the Monte with eight coils and Fitech fuel injection. I didn't do anything to separate wiring or do any special shielding. No EMI issues. They're great wires.
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post #12 of 12 (permalink) Old Apr 22nd, 19, 8:25 AM
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Chris
 
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Re: Electromagnetic/RF interference and Sniper

Im running Taylor 8.2 Thundervolts on my 454/sniper setup.No rfi.
Im not using sniper to control timing,just using it as a "carb" and everything's been good from the getgo.
Also using a pertronix flamethrower distributor.I did try to run the wires away from as much as possible on install(nearly impossible),lol.
Are your power and ground lines their own line,directly to the battery?
Also,holley recommends if you have to run past other wires,to cross them at a 90* to minimize RFI.

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