Ignition Solonoid Question

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Ignition Solonoid Question

October 02, 2017, 09:55:35 pm

Had a start problem again, and after hours of trouble-shooting with Aubrey at MOT, disconnected a small diode that goes between the two smaller middle posts on the ignition solenoid, and was able to get a start. My question is; anyone else have this diode running between the two middle posts? Does your ignition solenoid run hot? Mine was too hot to touch during engine operation.
Thanks,
Mike

Re: Ignition Solonoid Question

Reply #1 – October 02, 2017, 10:02:23 pm

Quote from: Yetch – October 02, 2017, 09:55:35 pm

1. My question is; anyone else have this diode running between the two middle posts?

2. Does your ignition solenoid run hot?

1. No diode on our '93 model.

2. I don't know. I've never tried to touch it when engine is running. Lots of voltage present...something I avoid messing with.

Check this entry at beamalarm. Might have info of interest?

Solenoid - Isolator Replacement

Re: Ignition Solonoid Question

Reply #2 – October 02, 2017, 11:58:54 pm

No Diode in mine. Just went through this on my coach. Went through a lot of grief finding the issue. Coach would start fine run fine. Once it was at operating temp. it would crank, but not start. After 15 min. it would start. Turned out being a bad ign. solenoid. But wait, there is more.
It only dropped out (unlatched) when going into start mode (when hot). The rest the time everything worked. This is what made it hard to diagnose. Found later I could start the coach at the back, but not the front.
Here is the other deal. They look just like a Ford starter relay. in fact, they look so much like it, that someone had put one in for replacement. A ford one may work, but they are for momentary service, not constant duty. The part number on mine was for a Ford starter. I replaced it with a constant duty. $30.00 on Ebay. Bought a spare too.

Re: Ignition Solonoid Question

Reply #3 – October 03, 2017, 12:05:22 am

Are you referring to the ignition solenoid behind the dash panel or the remote "start" solenoid in the engine compartment?
Not sure about the diode, a resistor maybe.....
And yes our ignition solenoid gets pretty warm. Could consider it hot depending on what is on at the time.

Re: Ignition Solonoid Question

Reply #4 – October 03, 2017, 07:51:17 pm

The diode was placed there to prevent voltage spikes to the electronics in the coach.

Re: Ignition Solonoid Question

Reply #5 – October 03, 2017, 07:55:03 pm

When the solenoid shut down!?

Jim

Re: Ignition Solonoid Question

Reply #6 – October 03, 2017, 07:58:28 pm

Yes, correct on the diode, absorbes the spike at shutdown. On my '91 U300 there was no diode, maybe Foretravel started adding these later. My solenoid would run hot, too hot to touch after several hours on the road.

Re: Ignition Solonoid Question

Reply #7 – October 03, 2017, 09:00:03 pm

For those of you with the Detroit Diesel 6V92TA engine you can take the DDEC computer off the ignition solenoid and hook it directly to the ignition switch so your engine will keep running even if your ignition solenoid quits. This is an important safety concern because the solenoid often quits while going down the road. My DDEC computer has been running directly off the ignition switch for many years now and the engine has never quit since I made this easy modification. I don't know about other engines.

Re: Ignition Solonoid Question

Reply #8 – October 03, 2017, 09:55:39 pm

Quote from: RRadio – October 03, 2017, 09:00:03 pm

For those of you with the Detroit Diesel 6V92TA engine you can take the DDEC computer off the ignition solenoid and hook it directly to the ignition switch so your engine will keep running even if your ignition solenoid quits.

What is the amp load of the DDEC computer? Most ignition switches are not designed for much more than switching loads.

There are other pretty easy "work arounds" for a failed ignition solenoid-- basically just label all wires on one large lug and JOIN THEM to the other large lug.

Re: Ignition Solonoid Question

Reply #9 – October 03, 2017, 10:23:34 pm

Perhaps we should build a "Emergency Solenoid Bypass" (ESB) to carry in our tool box. It would be like a really short jumper cable with a heavy duty alligator clamp on each end. No need to move any wires. In case of solenoid failure, just clip it on both big lugs, and off you go!

Edit: Above comment made with tongue in cheek.

Re: Ignition Solonoid Question

Reply #10 – October 03, 2017, 10:32:18 pm

Quote from: prfleming – October 03, 2017, 07:58:28 pm

Yes, correct on the diode, absorbes the spike at shutdown. On my '91 U300 there was no diode, maybe Foretravel started adding these later. My solenoid would run hot, too hot to touch after several hours on the road.

Before I ruffle any feathers I not an electrical engineer, just a HVAC and hydronics engineer hoping to learn some of the idiosyncrasies of my coach. How does a diode absorb energy? I know when you "collapse a coil" voltage wants to rise to infinity but somewhat limited I think by the number of turns of the coil if IRC causing spikes.

Re: Ignition Solonoid Question

Reply #11 – October 03, 2017, 10:33:09 pm

Quote from: Chuck & Jeannie – October 03, 2017, 10:23:34 pm

Perhaps we should build a "Emergency Solenoid Bypass" (ESB) to carry in our tool box. It would be like a really short jumper cable with a heavy duty alligator clamp on each end. No need to move any wires. In case of solenoid failure, just clip it on both big lugs, and off you go!

Re: Ignition Solonoid Question

Reply #12 – October 03, 2017, 10:38:48 pm

Big Channel locks for the brave maybe, but your big bulky jumper cables can do the same duty.

Re: Ignition Solonoid Question

Reply #13 – October 03, 2017, 10:45:26 pm

Small C clamp dipped in liquid rubber except for the contact area. Or as Brett said just move the cables to one terminal

Re: Ignition Solonoid Question

Reply #14 – October 03, 2017, 10:46:08 pm

Quote from: Chuck & Jeannie – October 03, 2017, 10:23:34 pm

Perhaps we should build a "Emergency Solenoid Bypass" (ESB) to carry in our tool box. It would be like a really short jumper cable with a heavy duty alligator clamp on each end. No need to move any wires. In case of solenoid failure, just clip it on both big lugs, and off you go!

After mine crapped out in the fast lane on a busy freeway and I had to glide with no engine and no power steering across 3 lanes to the shoulder, and then spent a hour wiring all the wires on both big terminals together, I tore an old jumper cable in half and put under dash by solenoid. Of course, never had a problem again. but I did stay only in the slow lane for a while after that.

Re: Ignition Solonoid Question

Reply #15 – October 03, 2017, 10:58:32 pm

I really don't like the idea of using jumper cables. If one end jumps off as you drive, not only will you stop right where you are, but a good chance of doing some arc welding.

Please, if you don't want to move wires, make up a 6-8 gauge "emergency jumper" 1' long and carry it along with two nuts that fit the large lugs of the ignition solenoid. Connect to the "dead side" first, then carefully to the hot/battery side.

Re: Ignition Solonoid Question

Reply #16 – October 03, 2017, 11:14:42 pm

Quote from: wolfe10 – October 03, 2017, 10:58:32 pm

I really don't like the idea of using jumper cables. If one end jumps off as you drive, not only will you stop right where you are, but a good chance of doing some arc welding.

Please, if you don't want to move wires, make up a 6-8 gauge "emergency jumper" 1' long and carry it along with two nuts that fit the large lugs of the ignition solenoid. Connect to the "dead side" first, then carefully to the hot/battery side.

You are right Brett, but when you are on the 6 ft wide shoulder of a busy California freeway, you just want to get to a safe place.
Your suggestions of buying better quality solenoid and carrying it with you, is spot on . You would only use the jumper cable to get off the freeway to a safe place to do a proper repair.

Re: Ignition Solonoid Question

Reply #17 – October 03, 2017, 11:19:08 pm

The ignition switch in my 1991 U300 is the typical GM ignition switch that was in most cars and trucks at the time. It easily handles the entire electrical load of everything that was connected to the ignition switches of vehicles of that era. I've had my DDEC computer connected directly to the ignition switch for many years now and over 50,000 miles of driving all over the country. I'm not gonna put it back on the ignition solenoid, ever. I've had the ignition solenoid die in traffic, killing the engine, and had to coast across lanes of traffic to safety. I'll never let that happen again... Yes, I do have all the wires connected to large conductors for easy ignition solenoid change out on the side of the road, and I do carry a spare solenoid, but I still don't want the engine to die ever again... This is a safety thing... My ignition switch is only running the ignition solenoid and the DDEC computer, which together have much lower amperage draw than what was on the ignition switch of a typical 1991 GM vehicle... For those of you reading this, I'm not speculating about this modification. I have actually done this and it works perfectly and it can save your life. There are no negative side effects, even over many years and many thousands of miles... Why don't we just split this off as a separate subject because it deserves full attention. It can save your life and it costs nothing.

Re: Ignition Solonoid Question

Reply #18 – October 03, 2017, 11:25:15 pm

I hope to God that the tiny underdash solenoid is only carrying enough juice to actuate the big honk'n solenoid on the starter motor itself. Pretty sure that is the case. Correct me if I'm wrong. Scrawny Wire sizes would seem to indicate the same.

Re: Ignition Solonoid Question

Reply #19 – October 03, 2017, 11:43:54 pm

Quote from: wolfe10 – October 03, 2017, 10:58:32 pm

I really don't like the idea of using jumper cables. Iif you don't want to move wires, make up a 6-8 gauge "emergency jumper" 1' long and carry it along with two nuts that fit the large lugs of the ignition solenoid. Connect to the "dead side" first, then carefully to the hot/battery side.

OK scratch the ESB idea, although it did have a nice ring to it. How about a permanent hard-wired jumper with a heavy duty toggle switch in the middle? Solenoid gives up the smoke, flip the switch, you're back in business! EASY!

Re: Ignition Solonoid Question

Reply #20 – October 04, 2017, 08:17:34 am

As has been posted many times before, here is the "bomb-proof" upgrade for the ignition solenoid: L Solenoid - 12/24V DC 250A - Blue Sea Systems

Read the specs, particularly the 450 amp continuous rating and 1 MILLION cycle life expectancy.

Re: Ignition Solonoid Question

Reply #21 – October 04, 2017, 08:28:35 am

Quote from: wolfe10 – October 04, 2017, 08:17:34 am

As has been posted many times before, here is the "bomb-proof" upgrade for the ignition solenoid: L Solenoid - 12/24V DC 250A - Blue Sea Systems

Here is what it looks like, mounted under the dash cover on a '93 GV U280 (ours). As you can see, not a lot of room for additional wires to attach.

Note: Ours is the earlier (2014) gray version. The new, improved black version is shown in Brett's link.

Re: Ignition Solonoid Question

Reply #22 – October 04, 2017, 08:45:34 am

Chuck,

With that e-switch, I personally would not be very concerned about a failure. Have never heard of a failure, and with a life expectancy of 1 million cycles and 450 amp rating, would probably be one of the least likely things to leave you on the side of the road.

Re: Ignition Solonoid Question

Reply #23 – October 04, 2017, 08:57:24 am

Quote from: wolfe10 – October 04, 2017, 08:45:34 am

With that e-switch, I personally would not be very concerned about a failure.

Thanks, Brett. I'm not the least bit worried about our 9012 solenoid failing. I've just been posting in this thread to stir the pot.

Re: Ignition Solonoid Question

Reply #24 – October 04, 2017, 09:46:16 am

Is the Blue Sea 9012 an option for a 2003 FT?

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