After years of putting up with spastic gauges in my 1987 E-350 it's time to try the home built ICVR cure:

1) I got the DE-SWADJ
2) Soldered it up with male terminal on voltage in, female terminal on voltage out and ring terminal on the ground.

Ford Truck Enthusiasts Forums - Gary Lewis's Album: How To Build an ICVR Replacement

And I even read through this entire tread:

https://www.ford-trucks.com/forums/1...ervations.html

So I'm about ready to pull the instrument cluster and slap it in but I've got a couple questions:

1) I'm confused about the input voltage it'll be receiving. Driving down the road system voltage would be about 13+ volts or so HOWEVER I saw some comments indicating that there's a resistor wire and that the input voltage to the ICVR will be closer to 8 volts. Is this true?

2) How do I calibrate the new unit. Do I just hook it up to a car battery (12.5V) and dial in 5.4 volts on the output side or should I use a little square 9 volt battery for the input voltage? But the really big question is, since the ICVR is supposed to maintain a constant output voltage (regardless of input voltage?) does it even make a difference?

3) In the original thread I saw comments suggesting a failure of the home built unit could cause a 12 volt surge through the gauge system and possibly fry my senders. Is this possible or does the resistor wire that steps the voltage down to 8 volts eliminate this possibility?

and finally, can you think of any other questions I should ask?

Many thanks.

 

Just connect it to your standard battery in your truck, and use a digital volt meter to adjust it to 5.4 volts. The regulator will maintain that voltage as long as the input side has 8V or more. There is technically an upper limit these regulators will work at as well, but we'll never hit it with our truck's charging system...I think it's around 24V or more. I installed one of these last fall and it works very well.

 

Thank you for your reply Tempest. Electrical stuff is amazing to me. How humankind ever figured out how to control electrons flowing through a wire I'll never know. Thank you all you smart people (like Gary Lewis)!

FWIW, I hooked it up to a 12V car battery and set the output voltage to 5.4V. Then I tried it on a little square 9V battery and the output voltage remained 5.4V.

Conclusion: it doesn't matter what the input voltage is*. I guess that's the whole point of a "voltage regulator"; to regulate voltage. Duh!

*Except for exceeding it's upper 30V limit which, as you say, is far higher than our automotive systems will produce, and also being mindful of the 1.3V input / output voltage drop inherent in the unit which would put the minimum input voltage, to maintain 5.4V, at 6.7V....I think...

Anyway, can't wait to install it and see how it works.

 

But wait, it gets more entertaining than that! read a little bit about things like transistors, op-amps, 555 timer chips, etc...You'll begin to think of several uses for even rudimentary circuits. In some cases however, electronics are relied upon too much. The best example I can think of is traction control. Over the life of a vehicle, electronic items become the most problematic. Electronics can perform some tricks that mechanical means could never do as well reliably, like fuel injection, while at the same time cluttering up cars and trucks with useless gadgets...

 

You guys have it nailed. Set it at 5.4 and go. There is a resistor that will drop the input voltage to the regulator depending on the current the gauges pull, which is determined by how much fuel you have, the water temp, and the oil pressure. (More of each of those things reduces the resistance of the sender, therefore increasing the current.). But, it won't go below 8 volts at the input to the regulator, and it can still do its job at that voltage.

 

Wow! I have been gone too long.

When was it I built that 5.0v regulator? Too long. And yes it is still in my truck.

But I just ordered the one above.

Thanks Brnfree for bringing this up or I may have missed it.

 

Update to report that the home-built ICVR works beautifully but, of course, once one thing is fixed another issue is revealed.

Now that the gauges aren't swinging all over the place I could tell the oil pressure gauge wasn't right. On a cold start it would initially read about 2/3rds of the scale but once it warmed up, and I'd sat at idle, the needle would drop down to the "N" in NORMAL and stay there no matter what.

So, after 25 years the oil sending unit wasn't up to the job anymore. In fiddling with it, it was interesting to note that I could rev the engine to 1,500 - 2,000, tap on it with a screwdriver handle, and the needle would read higher. In the end I went ahead and replaced the oil pressure sending unit and now the oil pressure gauge reads right in the middle of the scale cruising down the freeway. Nice!

As for the temperature gauge, in normal operation it reads about "M", and maybe a needle width higher with the AC running. According to my cheap infrared thermometer this is about 195 - 200 degrees at the t-stat housing and I reckon this is about right for a 195 thermostat.

I did however touch the "L" in NORMAL pulling the boat over Willamette Pass. From Oakridge, to the top of the pass, it's about a 4,000 foot rise in altitude, over a 30 mile stretch, and it was an 85 degree day. At that point I pulled over and got a reading of 210 - 215 at the t-stat housing.

(Thus, based on the above readings, and the distance from the end of the "L" to the top of the scale, I'd say the top of the scale would be about 240 - 250 degrees)

My buddy says I worry too much and, "Your readings are all within the "normal" range, and what do you expect with a 10,000 pound RV pulling a 3,000 pound boat? You're working it hard so naturally it's gonna get a little hot."

Of course he's right, I obsess at times, but I'm curious to know what you may think. What do you consider NORMAL, and too hot, when it comes to temperature?

 

Glad the ICVR replacement worked for you.

As for what is "hot', I'd say that 210 - 215 degrees isn't hot. In fact, that's exactly the boiling point of water at atmospheric pressure. However, you should be running a 50/50 mix of antifreeze and water, so the boiling point is raised to 225 degrees - at atmospheric pressure. But you have a pressure cap that should pop off at 13 psi. Water doesn't boil until something like 250 degrees at 13 psi, so the 50/50 mix probably won't boil until at least 265 degrees. So running 212 isn't hot if the system could go to 265 before boiling over.

IOW, your friend is right. But, I wouldn't want to run at the L all of the time.

 

I just got the new regulator in the mail and will hopefully put it in tomorrow. Thanks again for reminding me.

And your temps are fine.

 

Again, thanks for the reminder!

Finally got mine installed today. Used Gary's instructions. Seems to work well. Going to fill up tomorrow and see where the gas gage settles at. Was only going to 7/8 tank with the 5.0v regulator.

 

Let us know how it works for you. And, if you found a better installation method I'm interested. Going to build a new one when the truck goes back together, so can do it differently if need be.

 

Gary, I did almost exactly what you did. Same 9v battery clips. Solder, shrinkwrap, etc. The only thing different is my leads were shorter and I stuck it to the back of the instrument cluster with double sided tape. I put it in the small indent where the original ICVR sits. The tape is actually stuck the the top of the two caps on the regulator so the heatsink is floating.

I am interested to see where the gas gage sits when full. If it still is low, I will adjust it so it sits on F when full. Also, when I fill it up tomorrow, it will tell me that when I have just over 1/4 tank, how much is left.

 

Ok, tnx. I'd already planned to go with shorter leads and put it elsewhere since it ran so cool. The long leads were just a test, and I put it where it was easy to get to in case I needed to adjust it. After 5000 miles I didn't need to change it a bit.