techboy Posted July 12, 2011 Report Share Posted July 12, 2011 (edited) So, for no other reason than just trying to learn I decided today I wanted to test the 2 spare ISC's I have in the basement. So, I went out and bought a 6V battery from Home Depot and rigged up some alligator clips and spade connectors to leads 1 and 4 on the ISC as per the FSM. When I connect the alligator clips to the battery nothing happens ... on BOTH ISC's. So, what am I looking for ... or listening for .... or are they both dead? I had the impression a plunger under the black rubber boot should move in and out or something. I connected my contraption to a small LED bulb just to make sure there wasn't a bad connection somewhere and it lights up, so I definitely have juice. Thanks Edited July 12, 2011 by techboy Link to comment Share on other sites More sharing options...
techboy Posted July 12, 2011 Author Report Share Posted July 12, 2011 Ok, nevermind ... figured it out. It matters whether you connect the leads +/- or -/+. One way it'll make the plunger extend, the other it will retract. Mine weren't doing anything b/c they were fully retracted. Once I flipped the leads it extended. Kinda cool. Link to comment Share on other sites More sharing options...
Coke Posted July 12, 2011 Report Share Posted July 12, 2011 Ok, nevermind ... Once I flipped the leads it extended. Kinda cool. You have figured out how to arouse your ISC. Link to comment Share on other sites More sharing options...
StarquestRescue Posted July 12, 2011 Report Share Posted July 12, 2011 (edited) Ok, nevermind ... figured it out. It matters whether you connect the leads +/- or -/+. One way it'll make the plunger extend, the other it will retract. Mine weren't doing anything b/c they were fully retracted. Once I flipped the leads it extended. Kinda cool.Ok, that is one third of the test. Now you want to hook a volt ohm meter up to the motor position sensor wire and check that the output changes smoothly. That and check that the nose switch opens and closes reliably. Edited July 12, 2011 by StarquestRescue Link to comment Share on other sites More sharing options...
techboy Posted July 12, 2011 Author Report Share Posted July 12, 2011 Ok, that is one third of the test. Now you want to hook a volt ohm meter up to the motor position sensor wire and check that the output changes smoothly. That and check that the nose switch opens and closes reliably. Ok, I know about MPS output check, and I've done that previously. What is this "nose switch" that you speak of? Link to comment Share on other sites More sharing options...
StarquestRescue Posted July 12, 2011 Report Share Posted July 12, 2011 The manual calls it the idle position switch. A-72 plug yellow red wire that switches to ground on the 87-89. Page 14-65 in the 88 manual. Link to comment Share on other sites More sharing options...
techboy Posted July 13, 2011 Author Report Share Posted July 13, 2011 Thanks for the pg #. I'll either look it up through the online 88 manual here or find it in my 89 manual. Link to comment Share on other sites More sharing options...
Indiana Posted July 13, 2011 Report Share Posted July 13, 2011 Its the metal tip that gets mashed when the linkage closes it when you have your foot off the gas pedal. -and your cable has plently of slack in it Link to comment Share on other sites More sharing options...
MikeMeyerhoff Posted July 13, 2011 Report Share Posted July 13, 2011 Just because it runs back and forth doesn't guarantee its ok, especially on the 86- cars. The true way to bench test the ISC is to remove the DC motor from the ISC housing. Then connect a ohm meter and rotate the output shaft of the DC motor by hand. There is a OHM spec in the FSM and it should stay within that spec and be uniform as you rotate the shaft. As the brushes inside the DC motor wear there can be dead spots and/or the OHM value may get too high which will result in the ISC not working as quickly as it should or maybe even not at all. On 86- cars the working quickly part is VERY important because there is no MPS (motor position sensor). The computer basically assumes that running the ISC for some set amount of time will extend it X amount. If the ISC is worn, it might still move but not as fast as the computer assumes and the car might not run right as a result. This is likely the reason Mitsu added the MPS after 86, to give the computer some feedback on whether or not the ISC was actually doing its job, not just assumption. mm Link to comment Share on other sites More sharing options...
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