solenoid on top of Detroit 8.2

10-15-2010, 03:22 PM

Jim & Barb

This is directed to Bill NY or anyone else that may know the answer.

I am replacing a bad 12 volt plug that connects two wires to the solenoid that is on top of the 8.2 engine.
The plug has a ground wire and a hot wire.
When I removed the wires from the back side of the broken plug I found a bare single strand wire running from the neg. wire to the pos. wire. About half way along there this wire is a red plastic dot a little larger than this "O".
What is that and do I need it? If I do need it this will make it a little harder putting in the new connector plug.

Jim 1985 Barth Regency

10-15-2010, 06:17 PM

Bill N.Y.

Send me a picture please.

˙ʎ˙u ןןıq- „ǝןƃuɐ ʇuǝɹǝɟɟıp ɐ ɯoɹɟ pןɹoʍ ǝɥʇ ʇɐ ʞooן ɐ ƃuıʞɐʇ sı ǝɟıן oʇ ʇǝɹɔǝs ǝɥʇ„
	1990 Barth Regis Widebody 8908 0128 40RDS-C1 L-10 Cummins Allison MT647 Transmission Spartan Chassis	1991 Medical Lab Conversion 9102 3709 33S-12 Ford 460 MPFI C6 Transmission Oshkosh Chassis
Quick Link: Members Only Link To Send Me A Private Message

10-17-2010, 07:06 PM

Bill N.Y.

quote:

I realized the red plastic ( a possible resistor of some type? - but why) had something on it so I used a magnifier loop and found those numbers.

I have already completed putting in the new connector and it is ready to go with the exception of the mystery wire. I have not tried to start the Barth in case this wire is important. I can say it looks like it was added, just can't figure out why.
I know when I had the new engine put in the mechanic ran the electric fans from these wires (the electric fans were an idea that did not work for cooling the radiator- the fan blade was better). Is it possible this may have had something to do with the relays he used? I also did not know how much he butchered -errrr- altered this connector until the Barth quit on me. Just figured that out too.

Jim

Anyone?

˙ʎ˙u ןןıq- „ǝןƃuɐ ʇuǝɹǝɟɟıp ɐ ɯoɹɟ pןɹoʍ ǝɥʇ ʇɐ ʞooן ɐ ƃuıʞɐʇ sı ǝɟıן oʇ ʇǝɹɔǝs ǝɥʇ„
	1990 Barth Regis Widebody 8908 0128 40RDS-C1 L-10 Cummins Allison MT647 Transmission Spartan Chassis	1991 Medical Lab Conversion 9102 3709 33S-12 Ford 460 MPFI C6 Transmission Oshkosh Chassis
Quick Link: Members Only Link To Send Me A Private Message

10-17-2010, 08:26 PM

Patch1st

Most interesting.... First off wouldnt the pos to neg be a dead short? Could that red plastic thing be some kind of splice the mech used to feed the relay with positive? I took this drawing out of the service manual and it only shows ONE wire going to that soleniod...

What was the other end of the mystery wire connected to? Is it possible it was also a POS wire?

10-17-2010, 08:58 PM

Moonbeam-Express

My guess is that it is a capacitor put in place to smooth an erratic power surge which may have released the magnetic solenoid. Since a capacitor does not ground the circuit, it makes sense that it went from pos to ground.

Formerly: 1997 Barth Monarch
Now: 2000 BlueBird Wanderlodge 43' LXi Millennium Edition DD Series 60 500HP 3 stage Jake, Overbuilt bike lift with R1200GS BMW, followed by 2011 Jeep Wrangler Unlimited,
“I haven’t been everywhere, but it’s on my list.”

10-17-2010, 09:12 PM

Jim & Barb

Patch,

There are two wires in that solenoid harness.
A positive and a negative.
In the diagram you produced, you can almost see the two wires right next to the solenoid.
The mystery wire was between the two wires just behind the connector plug similar to the one shown in your diagram.
Like you said: That would be a dead short.
The plastic thing must be keeping it from being a dead short. So what's the purpose of it.
I think I'll just try starting it tomorrow and see what happens.
The connector on mine was a straight one and not angled like the one in the diagram, so it is possible the whole connector was altered.
Thanks for the diagram for it sure doesn't show something behind that connector.

Jim

10-17-2010, 09:16 PM

Jim & Barb

Corey,

If you are right, is there any danger to starting it and see what happens without it???

Jim

10-17-2010, 09:25 PM

Moonbeam-Express

No danger, but if there is an erratic power supply it may shut the solenoid off unexpectedly. Or that is my theory at least.

10-17-2010, 09:33 PM

Jim & Barb

Ok! That is good news. I'll be starting it up tomorrow and see what happens.

I think I'll keep that little mystery wire just in case it is needed. I should be able to figure a way to add it back, however I just hate to make splices when I don't have to.

10-17-2010, 11:23 PM

Doorman

Will agree with Corey that it look like a cap. mabey to prevent burning contacts on operating relay or switch when solinoid field drops. would probaly reconect if it does not present a problem.

Doorman

10-18-2010, 03:04 PM

Jim & Barb

Thanks for all the imput.

The Barth started up right away and ran with-out a problem.
So I guess the mystery wire is not needed.
My prayer now is the solenoid won't miss it.

10-18-2010, 05:27 PM

roman

The device you are looking at is an overvoltage transient suppressor or MOV (metal oxide varistor) . I'm currently looking in my reference books to see if I can give you the spec's on it. We use to use them years ago to protective voltage sensitive devices from overvoltage spikes. I have also seen them used across coils/solenoids to help collapse the electrical field when the device is de-energized. Basically when a voltage spike ocurrs the suppressor breaks down (or shorts itself out) to bleed the voltage down to a safe level for the device it is connected to. Normally you don't find them on low voltage applications but almost always on higher voltage applications.

I will post the spec's when I find them. Until then I wouldn't be too concerned.

Roman

10-18-2010, 06:02 PM

roman

Found it

It's a 17 VRMS, 22 VDC MOV. This mean it will protect the device from voltage spikes greater than 17 volts RMS and 22 VDC. It crosses to an ECG 1V017 or to an SK MV17B. These MOV'should be available at Radio Shack for about 70 cents each if you want to put one back. They are not polarity sensitive so it doesn't matter which lead goes to the negative or positive.

10-18-2010, 06:40 PM

Patch1st

Thank you Roman.... I was curious also.... It's that kind of knowledge that makes me love this place!!!

10-18-2010, 08:35 PM

Jim & Barb

Great research Roman - thanks!
I don't think I'll be too concerned, unless someone with a 24 volt battery tries to jump the Barth- of course that won't be good for a lot of things. While on that subject I was told once to never let anyone do a 50amp quick jump as it could cause damage to the system.

I have to agree with Patch- Barthmobile is the place to find out answers. We have a great mix of folks here and an excellent site. Someone here always seems to find the answer.