Fuel Cut Off Help w/ pictures (3 Viewers)

[slaterson]

But did ICS work or stop working?

btw, Emissions Computer controls the ICS by switching Ground, not + ... That's why if you ground the white wire it bypasses EC

what is ICS?

 

[Spike Strip]

Idle control solenoid

 

[Gretsch]

what is ICS?

Idle control solenoid

This is incorrect. The solenoid gets power from the ignition switch through the engine fuse.
But yeah, the computer might not be supplying a reliable ground.

FCS/ICS, same thing. Idle Control Solenoid I think is the proper term in Toyotaland.

Don't know if it would help in your case but I was able to fix my computer by simply re-flowing the solder on the solder joints on the EC connector to fix the switched ground setup on the EC/ICS system:

1984 FJ60 Engine Sputtering, Bucking - FIXED!!!

that is the vacuum switch and its in the stock location. the diagram makes it look like its someplace else(like carb or manifold) its been awhile, but I think the vac switch only comes into play during coasting or off the throttle or something like that.........but I will wait to be corrected...

forum.ih8mud.com

Sounds like you were able to determine good ground however so may be something more involved with your EC. Incidentally, when troubleshooting mine, I did the 'click' test everyone tells you to do to test ICS functionality. It always clicked when doing this test but would not work properly during normal engine operation.

Interesting video (at least to me)of a visual representation of the operation of the ICS setup:



HTH

 

[OSS]

This is incorrect

Well...
To split hairs---
In reality, an electric current is nothing but the flow of electrons. Electrons are negatively charged particles and are attracted towards the positive charge. Also, many experiments have revealed that it is free electrons in a conductor that flow. Negatively charged electrons move from the negative terminal to the positive terminal. This is the direction of the actual current flow.

So that being the case... the emissions computer is actually supplying power to the FCS.
But --
In terms of circuit analysis, it is normally considered that the direction of electric current is from positive to negative.

There isn't a right answer or wrong answer since circuit analysis interpretation of the direction of current flow is commonly used, but technically it is incorrect

 

[slaterson]

thanks again for the thoughts and advice. i wired up the fuel cut-off solenoid to the engine fuse. the idle problem improved, however it wasn't fully fixed. so i drove the truck a bit over the course of a few days, and gradually it got better and better each day. after a few days of driving only a few miles each day (less than 10), it idles pretty good again. i won't be surprised if the idle issue comes back again, as it has always been intermittent and just really bad for the past few months, enough so to motivate me to try to fix it.

i have an issue with my tach as well. the gauge is not broken, however it doesn't move now for several months as well. when i was messing with the fuel cut-off solenoid wiring and testing various things, the tach suddenly started working again. then it stopped. then i put the most recent solution in place and it's still not working of course. seems there are electrical demons in my truck. dome light works sometimes, not every time, though. nothing obvious, such as the door switch sticking.

 

[Spike Strip]

On the end of the Idle Solenoid is an O-ring. I can deteriorate and mess things up. Also, you could have schumtz in your carb idle circuit. Has the Carb ever been rebuilt ?

Tach wire is a single-wire to the Neg side of the coil. If that's coil terminal is corroded, you may have jiggled it while testing.

Pix are your friend. Don't be friendless.

 

[CruiserWil]

Well...
To split hairs---
In reality, an electric current is nothing but the flow of electrons. Electrons are negatively charged particles and are attracted towards the positive charge. Also, many experiments have revealed that it is free electrons in a conductor that flow. Negatively charged electrons move from the negative terminal to the positive terminal. This is the direction of the actual current flow.

So that being the case... the emissions computer is actually supplying power to the FCS.
But --
In terms of circuit analysis, it is normally considered that the direction of electric current is from positive to negative.

There isn't a right answer or wrong answer since circuit analysis interpretation of the direction of current flow is commonly used, but technically it is incorrect

Just a brief side comment: that's all true, and when my electronics instructor told me that forty years ago, I am to this day still ambivalent about circuit analysis. The classic example being the diode. Now I just plunge ahead and say current flows positive to negative when reading schematics. Jeeesh.