Ignition interference with radio

Status
Not open for further replies.
R

Robenstein

Joined
Dec 23, 2009
Messages
5,653
Location
Central IA
So I just replaced the old points distributor on my 70 Nova with an ACCEL HEI complete with a hot coil. All of a sudden I am getting what almost sounds like a brief cut out on my JVC stereo with the car running. I get it about every 3-5 seconds. Run the stereo with the car off and its fine. Now I have the player hooked up to a constant hot wire so I can run it without the accessory mode on the ignition switch. But I have never had a problem before this. Any ideas on how to fix the issue?
 
Last edited:
Better wires (resistor wires) and resistor spark plugs help. They dampen the sudden shock load from the ignition system which reduces EMF. Another thing is a lot of car stereos come with an RF choke installed on the yellow wire (its a black box thing, not a fuse), though I have no idea where to actually purchase one or if it would make a big difference.

EMF is a real nuisance to deal with.
 
I have a set or resistor plugs in it, they are NGK V Power and the wires are brand new Autolites.

Would a more low voltage coil help? Could just go get a Borg Warner replacement.
 
Wires and plugs were bought last week along with distributor. So they are not old at all. Replaced the whole thing in one day as a tune up. Also replaced the quadrajet with a AFB.
 
I will say that it does it with the radio, the CD, and even the USB functions as well. So its not just the radio signal its the playability of the whole deck being effected.
 
Sorry you said they were new; my bad. I was browsing the Accel site and it looks like you've done what they say. Maybe try submitting a support ticket? Long shot I know.
 
Im thinking I will rewire the power wires and then if that doesnt work I will pull the deck and throw a couple snap together RF chokes from Radio Shack on and see what happens. At a few bucks a piece its worth a shot. Otherwise I guess I will pull the accel, sell it, and put a petronix kit in the old points distributor down the road a bit.
 
There should be a capacitor in the new distributor at the module.
Even new, it may be faulty.
Where did you wire it to? You should NOT use the stock hot wire, as it is a resistance wire for the points set up.
You need full voltage.
 
You don't need resistor wire, high putput systems burn that type of plug wire up. The spiral wrap stainless wire wrapped on a insulating core is the best for surpression and life. "Magnacore" if I remember correctly. You have an RFI problem. It may take bonding the hood, trunk, and exhaust system to the body with thick copper braid to cut it down. Various engine components are acting as antennas for the rf energy created by the ignition system. The exhaust system, mounted on rubber hangers, is like a big antenna. Quite often as one source of noise is reduced, another one is heard under it. You can Google "two way radio noise reduction" for all kinds of tricks.
Though the military doesn't use much gas powered equipment any more, a look at a military gas engine shielding system in quite interesting. Everything is inside braided shielding.
 
This is just an HEI with a slightly more robust 48k volt coil. It is not some ultra high performance unit with a box. Just a new HEI with a bump in coil. And no I did not run the original resistor wire, ran new wires for this. I have never actually had an issue with this in my other older cars before. This is a first.
 
Originally Posted By: mechtech2
There is always the possibility of an coincidental problem that occurred by pure luck.
Maybe a wire or connector was bumped ?


Ever look under the hood of a no A/C 70 Nova? The only wires in the vicinity are the ones I ran to the distributor. Im going to try the RF chokes when they arrive in the mail. If that doesn't work, I see crutch-field sells a RF filter I can try to install. If none of those work....its getting a petronix kit in the stock distributor. I can sell the accel to my old man for his street rod. He never listens to the radio. LOL
 
An RF choke on the ground side may not be a bad idea either. Sometimes it could be solved by a simple wire or two like, HerrStig, and other have mentioned.

If it's an aftermarket system, like this case, i usually go through all the wiring and make sure my grounds are good. You've already ran a new power wire, you could wrap it with a shielding wire, or run a pair of twisted wires (one power and one ground-ground) to see if that helps.
 
Installed the chokes on the distributor ground and hot wires. Helped a lot, but only fixed about 70 percent of it. Really happens now only between 1,500 and 1,700 rpm oddly. Talked to a stereo installer and he thinks its a ground issue. Not sure I believe that as the grounds all look good and the only thing that changed in the one day the car was down, was the distributor swap.
 
Originally Posted By: mechtech2
I have never seen a hot ignition 'burn up' any type of wires.
Ever.

One thing taught in logic classes is is to "Never deny, seldom affirm, and ALWAYS distinguish." I have seen "multiple restrike capacitive discharge" systems burn out carbon conductor wire more than once. The conductor is just a carbon string. It's cheap, and rf surpressive, but not needed with resistor plugs. That's why the stainless steel spiral wrap wire is so popular. But, I guess YOU know more than I do.
 
Status
Not open for further replies.

Similar threads

F
Stock Junkyard Radio - "Locked"
Replies
11
Views
680
Snagglefoot
Nick1994
Old School Ignition Coil Problems
2
Replies
24
Views
3K
Nick1994
D
96' Accord random stall fixed with two side effects
Replies
4
Views
299
JeffKeryk
Kantaro
Volvo multi-ground spark plugs - why?
Replies
19
Views
1K
Carmudgeon
Number_35
1949 Ford 8N Tractor Won't Start
2
Replies
28
Views
2K
Number_35
Back
Top