ferox Posted March 30, 2008 Share Posted March 30, 2008 First off I am asking about the Duty Solenoid Valves (DSV's) on ea81's that modify the A/F ratio in the carb...not automatic transmission duty solenoids. I have had my DSV's disconnected (along with the other emissions stuff) for a couple years and have been running rich. The car drives great, but I would like to have the correct Air/Fuel mixture. I am rebuilding another Hitachi, and when I install I would like to re-install the DSV's and vacuum switches. Can I test the DSV's for actuation with a small 9V battery and miti-vac? I know I can test resistance and voltage in the car with the DMM, but I'm thinking actuation is the real functional test and I can carry a small battery and miti-vac in a junkyard. Does anyone know a good parts source for new DSV's? Aside from having more things that can fail, are there downsides to having the DSV's installed? Link to comment Share on other sites More sharing options...
GeneralDisorder Posted March 30, 2008 Share Posted March 30, 2008 The DSV's are run from a square wave produced by the ECU. I beleive it's controlling the ground for them. The ECU will report a code if there is a problem with them - 31 and 32 indicate circuit faults. Testing them for proper opening and closing should be simple with a peice of hose to blow through when they are energized. This is a huge can of worms though. You could just rejet the carb to a non-feedback and rip all that crap out. You are better off that way in the long run. The whole feedback system is messy, and expensive for almost no benefit. You *might* see 1 MPG, but probably not. It was there to comply with emissions regs not to provide better fuel economy. If it did they they would have made them all that way. I battled with the feedback for a long time before I decided it was a lost cause. It's too old, too primitive, and too much work to use it. GD Link to comment Share on other sites More sharing options...
ferox Posted March 30, 2008 Author Share Posted March 30, 2008 Good to know. I ripped, well, removed all that stuff as soon as I got the car. Now that I have an '81 FSM it's obvious that the '81 feedback system is a lot simpler that later versions. I was mostly concerned about MPG, so if the gains are minor I will just leave it the way it is. Thanks GD Link to comment Share on other sites More sharing options...
Rmorball Posted February 5, 2022 Share Posted February 5, 2022 I realize this is a 14 year old thread but I am having a problem with the duty solenoids on my 81. It won’t idle above 400rpm with them hooked up unless the idle screw is turned way in then it will idle poorly. I unhooked the solenoids and it then idles perfectly until I drive it til warm and then it wants to idle between 1700-2200 rpm’s. I can sometimes rev it up real quick and about 50% of the time it will drop off to 800. Drives and accelerates fine just that little annoying thing. Any cure? I’d love to get the Weber but not possible at this time unless someone has a cheap one laying around. Any suggestions are appreciated. Thanks Link to comment Share on other sites More sharing options...
GeneralDisorder Posted February 5, 2022 Share Posted February 5, 2022 Carb throttle shaft bushings are shot. There's no fix but to replace the carb with one that has no or less play or upgrade it. GD 1 Link to comment Share on other sites More sharing options...
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