[djustice]

I have been driving with a holley sniper for a year, no problems works flawlessly. but efi without timingcontroll is half an efi system. so i invested in the complete hyperspark package, coil, cd box and halleffect distributor all holley sniper series, as it is plug and play. Got it installed and i have major rfi! same spark plug cables from D.U.I. livewires (i applied dieletric grease to the boots prior to installation). but i guess the added sparkstrengt is just blowing interference to a new level,
I have seperated signal cables as much as possible . Data log shows a ton of interference. only way to drive the car is take the aircleaner off and open the hood.
if i put the hood down or come within an a foot with trying to place the aircleaner the car sputters and dies.

CD box is in drivers side coresupport , coil on driversside firewall as far away as the harness wil go from eachoter, no cables in parallel with other cables.

What i am looking for is recomandations on a GOOD set of EMI/RFI supression spark plug leads .

[adynes]

Try a resistor spark plug if you aren't already running them

[djustice]

Thank you for replying, i am currently running ngk ur4 plugs with a rated resitance of 5K Ohm the dui livewires are rated at 300-350 Ohms Per Foot.
i am guessing i need something above 500 ohms pr.foot, or going full out and getting grafite/carbon core spark plug wires.
in desperation i have also prepared some ferrite snapon cores.

[grivera]

Lots of info on the Sniper Owners EFI Tech forum on FB. One thing mentioned is you may need to step up your grounds to 4 gauge cable. In one build the mechanic added grounds battery to engine, battery to body, engine to frame, engine to body. Apparently the factory type ground straps are not adequate in some situations. In that build, nothing else had worked. After adding those grounds, he was able to put the ECU wire close to all ignition sources and data logs showed no RFI.

[Scott65]

Are the trigger wires for the Holley shielded? I use shielded wires on mine for cam/crank sensors, and regular resistor plugs and wires. I'm not familiar with Holley though... Make absolutely certain your grounding is as recommended by Holley. Mine has the grounds for the cam/crank sensors to sensor ground. Does your alternator wiring pass anywhere close to the ignition stuff?

[djustice]

The triggerwires (green/purple twisted pair) does not seem to be insulated. alternator wiring run along driverside valvecover and intake, passing trough the same firewall grommet as the rest of the wires.
As for grounds i have the battery negative wired directly to a groundingstud on drivers side head, a groundwire from passenger head to frame, agroundwire from innerfender directly to battery and finally a thick braided groundstrap from passenger head to firewall with a starwasher for contact.

i had no interference with just the sniper, it seems the added ignitionpower from a cd box and possible the e-core coil has overpowerd the sparkplugwires ability to supress noise.

i will do an experiment and wrap the triggerwires in tinfoil just or testing , not a permanent solution, and possibly add tinfol to the ignition leads.

here is a picture of the interference while cranking and a no start situation :

[grivera]

What gauge are your ground wires?

Here is the FB post by Mick LePiane re: ground cables:
https://www.facebook.com/groups/Snip...6043479965816/

Ok so last Sunday i took on this job for a local guy - Sniper plagued with rfi and a hyper spark conversion ! The rfi problem was easy to solve "grounds" people - You must pay attention to grounds and they must be heavy enough to carry at least 30% more current than is being drawn. Once i rewired the ground circuit the rfi vanished. And from then on, it didn't matter how i routed the harnesses, there was no rfi to speak of. The grounds i used were 1 gauge from battery to cyl head and 4 gauge from batt to body then 4 gauge from back of cyl head to firewall. So next i fitted the hyperspark complete kit for timing control. Well, that didn't go so well as the engine started to misfire badly. Turned out cyl no 1 not firing and no matter what i tried i couldn't get spark to that cyl. Of course the first thing i suspected was the distributor but testing it on an oscilloscope showed the distributor was working correctly. Tried different plug wires, new plugs, another distributor cap and still no spark to no. 1 cyl. After 3 days of scratching my head and almost gave up i decided to update the firmware from 200 to 330 and bingo - away it went. Fired right up, no misfire, revs up clean ! I hope this helps some of you that are having unexplained problems. I have to give some credit to Craig Harding and his tech team from Race Car Engineering for working with me on this problem - Its the old saying - 2 or 3 heads are better than one lol

[djustice]

Originally Posted by grivera

What gauge are your ground wires?

Not a 100% sure but i think battery to engine and engine to frame is about 6awg
the body to battery is a lot thinner maybe 12/14 awg. the braid is about 2/3 of an inch wide going from firewall to engine

[adynes]

Originally Posted by djustice

i will do an experiment and wrap the triggerwires in tinfoil just or testing , not a permanent solution, and possibly add tinfol to the ignition leads.

Be sure to connect your foil shield wrap to ground with a length of wire (only at one end of each wrap)

[djustice]

Originally Posted by adynes

Be sure to connect your foil shield wrap to ground with a length of wire (only at one end of the wrap)

ill see if i can get some aligator clips to clip on to the foil and somwhere on the engine block

[76TA462]

I had lots of RFI gremlins with my Sniper. After doing the wire positioning thing, dielectric grease, removing of unused wires from auxiliary wiring harness, separating the CD box trigger wire and power lead, and etc. etc. Holley guidance, I did a huge ground wire upgrade which finally fixed things. I am using a 1-gauge ground from the battery to the front of the engine block. From the same bolt I added another 1 gauge from the block to the frame. Also based on the Holley tech advice I added a 11 gauge from the battery to the rad support. At the bell housing I upgraded to a heavier strap on the driver side to the frame. On the passenger side I upgraded to a heavy gauge from the bell housing to the chassis. The bell housing locations are original. And cleaned and scrapped all the frame and chassis surfaces. Even though they looked clean, after decades a rust scale had built up between frame and chassis contact points and the cable/straps. Hope this might help somewhat.

[djustice]

Originally Posted by grivera

What gauge are your ground wires?

Here is the FB post by Mick LePiane re: ground cables:
https://www.facebook.com/groups/Snip...6043479965816/

Ok so last Sunday i took on this job for a local guy - Sniper plagued with rfi and a hyper spark conversion ! The rfi problem was easy to solve "grounds" people - You must pay attention to grounds and they must be heavy enough to carry at least 30% more current than is being drawn. Once i rewired the ground circuit the rfi vanished. And from then on, it didn't matter how i routed the harnesses, there was no rfi to speak of. The grounds i used were 1 gauge from battery to cyl head and 4 gauge from batt to body then 4 gauge from back of cyl head to firewall. So next i fitted the hyperspark complete kit for timing control. Well, that didn't go so well as the engine started to misfire badly. Turned out cyl no 1 not firing and no matter what i tried i couldn't get spark to that cyl. Of course the first thing i suspected was the distributor but testing it on an oscilloscope showed the distributor was working correctly. Tried different plug wires, new plugs, another distributor cap and still no spark to no. 1 cyl. After 3 days of scratching my head and almost gave up i decided to update the firmware from 200 to 330 and bingo - away it went. Fired right up, no misfire, revs up clean ! I hope this helps some of you that are having unexplained problems. I have to give some credit to Craig Harding and his tech team from Race Car Engineering for working with me on this problem - Its the old saying - 2 or 3 heads are better than one lol

Hey! just talked to Mick LePiane on that facebook group yesterday, lots of good input , just need to get the fustration out of my head before i go at it again lol

[djustice]

Originally Posted by 76TA462

I had lots of RFI gremlins with my Sniper. After doing the wire positioning thing, dielectric grease, removing of unused wires from auxiliary wiring harness, separating the CD box trigger wire and power lead, and etc. etc. Holley guidance, I did a huge ground wire upgrade which finally fixed things. I am using a 1-gauge ground from the battery to the front of the engine block. From the same bolt I added another 1 gauge from the block to the frame. Also based on the Holley tech advice I added a 11 gauge from the battery to the rad support. At the bell housing I upgraded to a heavier strap on the driver side to the frame. On the passenger side I upgraded to a heavy gauge from the bell housing to the chassis. The bell housing locations are original. And cleaned and scrapped all the frame and chassis surfaces. Even though they looked clean, after decades a rust scale had built up between frame and chassis contact points and the cable/straps. Hope this might help somewhat.

Thank you for the tip, seems i am missing a groundstrap on the bellhousing never been one there.

[ponjohn]

You can troubleshoot possible grounds by running a temporary ground directly to the battery. While doing this isolate the case of the box from the body.

Don't arbitrarily just start adding ground wires all over the place. Run a good heavy ground wire back to the battery or very close to the main battery ground. Terminate all boxes to this one single ground.

[Scott65]

^This. Try to keep a single ground plane. But sensors don't necessarily go to main ground. Follow directions for your particular product.

[Schurkey]

Originally Posted by djustice

the dui livewires are rated at 300-350 Ohms Per Foot.
i am guessing i need something above 500 ohms pr.foot, or going full out and getting grafite/carbon core spark plug wires.

RFI is reduced by reducing the current (amperage) flow through the secondary ignition system.

This can be done with resistance, or it can be done with inductance. If your plug wires are using inductance (helical-wound) then ohms-per-foot is no measure of how effective the RFI suppression is.

[djustice]

Originally Posted by Schurkey

RFI is reduced by reducing the current (amperage) flow through the secondary ignition system.

This can be done with resistance, or it can be done with inductance. If your plug wires are using inductance (helical-wound) then ohms-per-foot is no measure of how effective the RFI suppression is.

After reading about RFI and doing some research i have found out that advertised ohms is indeed more of a sales trick. take msd 8.5 superconductor with advertised "less than 50 ohms per foot resistance" but shielding equal to 1500 ohms per foot and the subject gets cloudy.

[djustice]

Update:
i swapped out the sparkplug wires, to an old set that came with the car, measuerd all 8 wires and they all came within 5-7 K ohms short to long.
no other changes, fired the car let it settle into a steady idle, placed air cleaner, closed hood and drove it around the block, no sign of interference. no missfire, no cutouts.
On the dui livewires i removed i found one gash in the heat insulation sleeve did not seem to penetrate into the silicone layer, and one had seprated from the crimp at cylinder 4.
so far so good it is a 100% improved, but i will go trough and upgrade my ground cabels to 1 gauge, and finish cleaning up the wiring.

[grivera]

Good news. You should datalog to make sure.