viper 5704 comm issue

howie ll wrote: That points to inductance rather than radiation. Lotus Europa, the Europa bit being the engine out of a Renault 16, mid 70s. Fiberglass body. Aluminium foil glued to underside of hood. Grounding bonds to hood to engine block to bodywork. 3mfd. cap on alternator. 1mfd. cap on coil. Exhaust pipe bonded back to engine.

Well my body will be fiberglass. The foil is a no-go on the underside of the hood. It will be body color. Is this the only solution? My question is, how can you have a remote start function on a foxbody mustang (the type of engine and computer I am running) and not work on this?

If we are going in the right direction and remember this is only an experienced based hunch, the average steel bodied car is basically a series of Faraday cages. Some how you need to isolate the ignition electronics. I'm not sure how you would go about this because neither you nor I have the R&D resources of the motor manufacturers. In the late 70s I owned a Ford Capri and a Fiesta. I fitted a Bosch capacitive discharge ignition system to the Capri, it was a radio interference nightmare. I installed an infra-red point system unit on the Fiesta and it was wonderful!

You can try this to see if using capicators across the positive and negitive wires for the viper has any positive effect. The viper would be substituted for the motor in the diagrams. noise isolation

Thanks Lurch, I think figure 5 might be relevant. Those cap. values are far lower than we used back in the day. 1 mfd. on the coil and 3 mfd. on the alternator.

lurch228 wrote: You can try this to see if using capicators across the positive and negitive wires for the viper has any positive effect. The viper would be substituted for the motor in the diagrams. noise isolation

Are we talking just little radioshack capacitors? Run one in parallel between ground and power to viper? Run one in parallel of coil leads? For the alternator, its not a one wire style, It is a 3G ford style.

tylerwayne wrote: Are we talking just little radioshack capacitors?

YES

tylerwayne wrote: Run one in parallel between ground and power to viper?

YES first

tylerwayne wrote: Run one in parallel of coil leads?

YES second Start with the simplest solution and work your way out and up to the others.

lurch228 wrote: tylerwayne wrote: Are we talking just little radioshack capacitors? YES tylerwayne wrote: Run one in parallel between ground and power to viper? YES first tylerwayne wrote: Run one in parallel of coil leads? YES second Start with the simplest solution and work your way out and up to the others.

OK I will try this. Excuse my ignorance but can you specify what kind of cap I should use? Disc / electrolytic? 3mF? I have seen 16V, will this work? Will they require a charge similar to car audio larger caps? A part number would be excellent, or specs. Thanks for yalls help. Tyler

Follow the motor 1 diagram and start with the 0.1uf capacitor, as it applies to the viper. Since the problem is with the viper, and we need to try and isolate it from the noise. Single Capacitor Filtering Figure 1. A simple one-capacitor noise filter The simplest filter involves adding a capacitor across the motor terminals as shown in figure 1. Since a capacitor will conduct only currents that are changing at a high frequency, a single capacitor (typically 0.1µF) wired across the motor terminals (as shown in Figure 1) will act as a short circuit for high-frequency electrical noise, while not affecting the DC current to the motor at all. This reduces conduction of noise along the motor wiring.

Substitute the viper for the motor in the diagram to filter the power supply to the viper, as if the capacitor can block noise comming from a motor the the reverse is also true.