Relay chatter

Terry Syd · 04-11-2008

Since I have the relay for my basic system mounted inside the cab I can hear the relay click on and off for the water injection. When I come up onto the boost pressure the relay can chatter a bit. Sometimes when I am slowly bringing it to boost the chatter can go on for a fair bit.

I could see this being a potential problem (also excessive relay wear) with a pre-turbo nozzle as the pump could be putting out low pressure while the relay is figuring out what it wants to do.

I thought about adding a 220 uf capacitor to the line voltage (hmm, maybe the ignition wire would be a better idea). Yeah, it would have to be the 12v ignition wire going into the relay. I can bring the system up to where the WI system is on steady and then switch it on and off from the switch on my dash and the relay doesn't chatter.

Hmm, nope, maybe it needs to be on the line from pin 85 to the pressure switch. That way the capacitor can pick up the intermitent moments. Yeah, that must be it. ??

Anybody with some suggestions?

Terry Syd · 04-12-2008

That fixed it, pin 85.

Rocket468 · 04-13-2008

Not sure why your having the issue with the relay. Should not need to use a cap. Might check the ground and see if its got some resistance to it.

Terry Syd · 04-14-2008

I have a switch on the dash that is in series with the pressure switch. When it is up on boost and the pressure switch is fully engaged I can flick the dash switch back and forth and there is no chatter.

It was only when the pressure switch was coming up to or down from full contact that I would get the chatter. It may be that as the pressure switch begins to close/open that there is intermittent contact. The chatter was especially prevalent when the boost slowly went through the switch point. Sometimes I could get the relay to chatter for about a full second.

The capacitor took care of it. I tried to slowly go through the switch point and I did hear a couple of clicks, but noting like the chatter before.

04-11-2008	#1 (permalink)
Terry Syd Alcohol Water Injection Year: 1990 Make: Toyota Model: Hilux Join Date: Nov 2007 Posts: 95	Relay chatter Since I have the relay for my basic system mounted inside the cab I can hear the relay click on and off for the water injection. When I come up onto the boost pressure the relay can chatter a bit. Sometimes when I am slowly bringing it to boost the chatter can go on for a fair bit. I could see this being a potential problem (also excessive relay wear) with a pre-turbo nozzle as the pump could be putting out low pressure while the relay is figuring out what it wants to do. I thought about adding a 220 uf capacitor to the line voltage (hmm, maybe the ignition wire would be a better idea). Yeah, it would have to be the 12v ignition wire going into the relay. I can bring the system up to where the WI system is on steady and then switch it on and off from the switch on my dash and the relay doesn't chatter. Hmm, nope, maybe it needs to be on the line from pin 85 to the pressure switch. That way the capacitor can pick up the intermitent moments. Yeah, that must be it. ?? Anybody with some suggestions? Last edited by Terry Syd; 04-11-2008 at 05:49 AM.

04-12-2008	#2 (permalink)
Terry Syd Alcohol Water Injection Year: 1990 Make: Toyota Model: Hilux Join Date: Nov 2007 Posts: 95	Re: Relay chatter That fixed it, pin 85.

04-13-2008	#3 (permalink)
Rocket468 DevilsOwn Staff Year: 2000 Make: Pontiac Model: Grand Prix Join Date: Apr 2005 Posts: 1,073	Re: Relay chatter Not sure why your having the issue with the relay. Should not need to use a cap. Might check the ground and see if its got some resistance to it.

04-14-2008	#4 (permalink)
Terry Syd Alcohol Water Injection Year: 1990 Make: Toyota Model: Hilux Join Date: Nov 2007 Posts: 95	Re: Relay chatter I have a switch on the dash that is in series with the pressure switch. When it is up on boost and the pressure switch is fully engaged I can flick the dash switch back and forth and there is no chatter. It was only when the pressure switch was coming up to or down from full contact that I would get the chatter. It may be that as the pressure switch begins to close/open that there is intermittent contact. The chatter was especially prevalent when the boost slowly went through the switch point. Sometimes I could get the relay to chatter for about a full second. The capacitor took care of it. I tried to slowly go through the switch point and I did hear a couple of clicks, but noting like the chatter before.