Carburetor Solenoid Valve - Hardwired (1 Viewer)

[smokedpig]

I noticed today that the line running to my Carburetor Solenoid Valve has no voltage. As a test, I hardwired it to my battery, it opens and closes and idling improved.

There are several posts (like the one below) that discuss work arounds for a failed Carburetor Solenoid Valve due to lack of voltage from the Emissions Computer.

Fuel cut off solenoid

The manual for my 67 fj40 calls this the "magnetic switch valve." Mine fell apart, literally, when I removed the 2 screws that hold it in place on the back side of the carb. The wires crumbled from the spool, plastic spool piece was cracked and the pin was bent. I suspected this was my idle...

forum.ih8mud.com

The solution being tapping into a keyed power source and keeping the solenoid actuated (open) continuously while the engine is running.

The only drawback to this work around that I have come across is a slight decrease in mileage when decelerating. Not an issue with this old pig!

Q: Assuming a single wire solenoid, no control line, is it advisable to keep continuous voltage flowing to it while running?

 

[65swb45]

Yes, it is advisable.

Positive terminal of the coil is the preferred mounting point.

I am doubtful of the negative effect of the solenoid on fuel economy. The opposite is logical: a carburetor with a non-functioning solenoid has to be substantially enrichened to compensate for the non-performing idle circuit.

www.marksoffroad.net

 

[smokedpig]

Yes, it is advisable.

Positive terminal of the coil is the preferred mounting point.

I am doubtful of the negative effect of the solenoid on fuel economy. The opposite is logical: a carburetor with a non-functioning solenoid has to be substantially enrichened to compensate for the non-performing idle circuit.

www.marksoffroad.net

Thanks for the confirmation @65swb45.

I have an HEI Distributor (internal coil). I assume using the positive lead coming off that would accomplish the same thing?

 

[John Smith]

Yes it would.

 

[Mark W]

Q: Assuming a single wire solenoid, no control line, is it advisable to keep continuous voltage flowing to it while running?

Toyota intended it to be energized constantly when the rig is running. If not, you definitely will not run right. The idle circuit contribution to the fuel balance is expected to be there under all conditions.

Mark...

 

[DeskJock]

I ran a line from the Positive side of the coil in the dash board and out the same port that the temp sensors uses to keep that wire as much out of harms way as possible.

I had thought about tapping into the ignition circuit- but - felt this was an easier way to understand my logic if someone else needed to get under the hood.

My rig has been de-smogged. I might at some point try to figure out an ignition hard wire from the smog harness - but - that’s at the bottom of my list of things to do at this point. .

 

[Pighead]

I disabled my solenoid years ago. I don't miss it.

 

[Mark W]

I disabled my solenoid years ago. I don't miss it.

If it is disabled, since the default non-powered position is closed, you have no fuel flowing through your idle circuit and the rest of your jetting has to have been... totally hacked... if the rig runs. Unless you are saying that your removed it and plugged the port, or in some other way are preventing it from closing?

Mark...

 

[Pighead]

Unless you are saying that your removed it and plugged the port, or in some other way are preventing it from closing

Yes, that is what I'm saying. First I tried just cutting the rod short, that worked fine. Then I got tired of looking at it so I took it apart, filled the hole in the base plate and put that back on.

 

[Mark W]

Yes, that is what I'm saying. First I tried just cutting the rod short, that worked fine. Then I got tired of looking at it so I took it apart, filled the hole in the base plate and put that back on.

I like that approach. Mo simple, Mo betta.

I my environment, I doubt that I would ever see any shut down dieseling issues. How does that work in warmer climes?

Mark...

 

[smokedpig]

Yes, that is what I'm saying. First I tried just cutting the rod short, that worked fine. Then I got tired of looking at it so I took it apart, filled the hole in the base plate and put that back on.

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I would think this would cause dieseling when you try to shut the rig off, or worse yet flooding. No issues with this setup?

 

[Pighead]

I like that approach. Mo simple, Mo betta.

I my environment, I doubt that I would ever see any shut down dieseling issues. How does that work in warmer climes?

Mark...

I have not had one dieseling or run-on. It's been several years now.

 

[65swb45]

I have not had one dieseling or run-on. It's been several years now.

The fact that you have your timing as far advanced as you do, and have no run on, is a testament to your ability to properly tune your truck.

 

[Mark W]

I would think this would cause dieseling when you try to shut the rig off, or worse yet flooding. No issues with this setup?

Could not cause flooding.

Mark...

 

[Engineer8000]

Could impact your ability to pass smog testing if you live in one of those states. It will run rich on decel.

 

[smokedpig]

Could impact your ability to pass smog testing if you live in one of those states. It will run rich on decel.

It has been desmogged. My state does not require emissions testing for vehicles over 20 years old so all set there.

 

[Engineer8000]

ok, that's great,. but emissions impacts the world so I would make it work like it should.

 

[charliemeyer007]

I ran the numbers once, one B-52 strike has a larger carbon footprint than my life. But I do agree getting the best gas mileage you can is a good plan. If you mind the nickels and dimes the dollars will take care of themselves.

 

[smokedpig]

ok, that's great,. but emissions impacts the world so I would make it work like it should.

My daily driver's are highly efficient as is my home. The heavy hitters. My 50 year old Classic that is parked in the garage and driven 100 miles a year, not so much.

Frankly I need to get it running before it will make any environmental impact, good or bad.

 

[Engineer8000]

I know, I sort of said that jokingly.