Trouble Starting - Ignition solenoid? 95 U300 CAT 3176

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Re: Trouble Starting - Ignition solenoid? 95 U300 CAT 3176

Reply #25 – November 09, 2021, 11:43:03 am

I'm stumped...but I graduated with an English degree (5 decades ago) so I have a excuse. Hopefully some smarter member will come up with a bright idea to help you further test (isolate) the problem.

Re: Trouble Starting - Ignition solenoid? 95 U300 CAT 3176

Reply #26 – November 09, 2021, 11:43:24 am

Quote from: wolfe10 – November 09, 2021, 11:39:08 am

Then you DO have a bad connection or bad cable. Check cables at the battery end carefully. Green (oxidized copper) does not conduct electricity.

I am going to get the safety blocks out and crawl under there to check things out. Could this possibly be an issue with the ignition switch/tumbler itself? I know my father installed a new ignition as the one that was on it was the wrong one or something. He replaced it with the correct Chevy one that is shown in the wiring diagrams that came with the coach.

I am still a bit confused as to why the boost switch makes it so there is a full voltage at the solenoid? Would that indicate something like a particular wire to check? Are there different wires that run from the chassis batteries to the ignition then solenoid than the ones that run from the house batteries? Just trying to figure out why I don't see a voltage drop with the boost switch on, if they shared a wire to the ignition then the solenoid wouldn't it act the same in both situations?

Re: Trouble Starting - Ignition solenoid? 95 U300 CAT 3176

Reply #27 – November 09, 2021, 11:46:55 am

Chuck showed how to bypass everything to start the engine in reply 12. Have you
tried that. Those two pictures will tell you a lot.

Re: Trouble Starting - Ignition solenoid? 95 U300 CAT 3176

Reply #28 – November 09, 2021, 11:48:17 am

Quote from: GeoKM – November 09, 2021, 11:43:24 am

Could this possibly be an issue with the ignition switch/tumbler itself?

All the ignition switch does is supply the activating voltage (when you turn the key "ON") to the small positive terminal on the ignition solenoid. One small terminal is positive (activation) and one is negative (ground). The small posts are interchangeable - doesn't matter which is which.

Re: Trouble Starting - Ignition solenoid? 95 U300 CAT 3176

Reply #29 – November 09, 2021, 11:51:03 am

If the ignition switch is suspect, EASY to check.

Just use a small gauge jumper (not carrying much amps) between the battery lug side of the ignition solenoid and the positive small terminal on the solenoid that comes from the ignition switch. I would remove the wire from that small terminal so you aren't backfeeding anything.

Re: Trouble Starting - Ignition solenoid? 95 U300 CAT 3176

Reply #30 – November 09, 2021, 11:57:08 am

I don't believe it is the ignition switch as you said it tried to start on boost. It won't
start on boost batteries alone.

Re: Trouble Starting - Ignition solenoid? 95 U300 CAT 3176

Reply #31 – November 09, 2021, 12:02:25 pm

While you are under there checking, be sure to check the engine end of not only the positive, but also the negative/ground.

Re: Trouble Starting - Ignition solenoid? 95 U300 CAT 3176

Reply #32 – November 09, 2021, 12:07:34 pm

Quote from: GeoKM – November 09, 2021, 11:43:24 am

1. I am still a bit confused as to why the boost switch makes it so there is a full voltage at the solenoid?

2. Just trying to figure out why I don't see a voltage drop with the boost switch on, if they shared a wire to the ignition then the solenoid wouldn't it act the same in both situations?

All the boost switch does is physically connect the two battery banks together. It merely increases the number of batteries in the "Start" battery bank. All of the current required for starting the coach still flows through the exact same circuits, regardless of how many batteries there are in the "Start" battery bank.

So yes, IMO your ignition solenoid test should yield the same result with boost switch on and off. The results you report don't make logical sense (to me).

Re: Trouble Starting - Ignition solenoid? 95 U300 CAT 3176

Reply #33 – November 09, 2021, 12:07:53 pm

Im checking things out now, testing the ignition as Wolfe suggested. One thing I just noticed was the Overload was flashing on the Heart Inverter Panel above the door? I disconnected the shore power for a minute and then plugged back in. No more blinking.... not sure if that has something to do with this but seems connected?

Re: Trouble Starting - Ignition solenoid? 95 U300 CAT 3176

Reply #34 – November 09, 2021, 12:17:26 pm

Wolfe i did your text by jumping the battery side to the smaller solenoid pole.

Voltage measured at 13v on battery side, I jump to the small pole and it drops to 7v, solenoid does not click, just kinda soft buzz from it

Re: Trouble Starting - Ignition solenoid? 95 U300 CAT 3176

Reply #35 – November 09, 2021, 12:43:33 pm

Ya, 7 VDC will likely not activate the solenoid.

And if that 7 VDC reading was on the chassis battery lug of the isolator, it still says that even a small draw is dropping the voltage significantly.

Because voltage at the chassis battery is not dropping, that suggests "pathways" between batteries and solenoid and back through the ground circuit.

Re: Trouble Starting - Ignition solenoid? 95 U300 CAT 3176

Reply #36 – November 09, 2021, 01:33:55 pm

Okay little update. I unbolted and cleaned the main engine to frame ground connections. This included the cable from the engine to the starter. Ran my test again now I am seeing the voltage drop to 10v instead of 7v. I think im on the right track here. Now all I have to do is find all the connections I need to clean..... I am going to do both positive and negative throughout. Any idea how many connections/cables I am looking at having to sand and reconnect?

EDIT: So now the solenoid clicks a couple times but then the voltage on battery terminal drops to 3.3v......

Re: Trouble Starting - Ignition solenoid? 95 U300 CAT 3176

Reply #37 – November 09, 2021, 02:05:09 pm

Quote from: GeoKM – November 09, 2021, 01:33:55 pm

Any idea how many connections/cables I am looking at having to sand and reconnect?

https://www.foreforums.com/index.php?action=media;sa=media;in=4746

Re: Trouble Starting - Ignition solenoid? 95 U300 CAT 3176

Reply #38 – November 09, 2021, 02:58:31 pm

Okay so I have been waiting for a friend to come over to help with the wire inspection, in the meantime, I did a little more testing and found something odd, maybe enlightening.

If I disconnect the batteries and then reconnect them, then go inside and turn the ignition to the on position everything powers up as it should. When i try to start solenoid clicks over and you get the typical dead battery situation.

Heres where its odd, if I turn the key off and then try to turn it back on, 1 small click from the solenoid and no lights on the dash.

If I then go and disconnect and reconnect the batteries again and then turn the ignition from off to on, lights on the dash and everything comes on and the process restarts. To me this is odd.

Re: Trouble Starting - Ignition solenoid? 95 U300 CAT 3176

Reply #39 – November 09, 2021, 02:59:39 pm

That is not odd at all it is an indication of a bad connection.

Re: Trouble Starting - Ignition solenoid? 95 U300 CAT 3176

Reply #40 – November 09, 2021, 03:04:24 pm

Quote from: craneman – November 09, 2021, 02:59:39 pm

That is not odd at all it is an indication of a bad connection.

Okay well then that is one more thing in the direction of bad connection then, thanks

One thing to note is I just went and tried to start the generator, started with no issues. Not sure if that eliminates a certain number of the possible bad connections but I am trying to narrow it down as I cannot get easy access under the coach and there are so many wires to chase down. I am now trying to find where the large red cable that comes from the battery bank to the ignition solenoid is located and where it has connection points.

Re: Trouble Starting - Ignition solenoid? 95 U300 CAT 3176

Reply #41 – November 09, 2021, 03:38:37 pm

Try pulling on your cables one at a time and see if they stretch. You may have a broken
cable.

Re: Trouble Starting - Ignition solenoid? 95 U300 CAT 3176

Reply #42 – November 09, 2021, 04:30:22 pm

Quote from: GeoKM – November 09, 2021, 03:04:24 pm

1. One thing to note is I just went and tried to start the generator, started with no issues.

2. I am now trying to find where the large red cable that comes from the battery bank to the ignition solenoid is located

3. and where it has connection points.

1. Your generator most likely starts off the "Coach" (house) battery bank. It does not use the same "starting" circuits as the big engine.

2. Anything (cable, hose, tubing, wire etc) that runs from the rear of the coach to the front of the coach will be located in the galvanized metal pan found in the center of each storage bay, attached to the ceiling of the bay with sheet metal screws.

3. Look at the electrical schematic I linked in Reply #37.

The most likely place for problems with any battery cable is at the two ends. Corrosion can work up under the open end of the insulation and weaken the individual strands of wire. In extreme cases the cable can pull completely loose from the crimped end connector. If it becomes necessary, you can buy the tool required to attach new end connectors to a cable.

At the urging of tech guru Roger I invested in the proper tools/materials to build my own battery cables. Have used on several projects. I highly recommend his recommendations. See posts linked below:

Battery Cable Lugs

Delco Remy 28SI Alternator Installation

Re: Trouble Starting - Ignition solenoid? 95 U300 CAT 3176

Reply #43 – November 09, 2021, 05:03:51 pm

Quote from: oldguy – November 09, 2021, 03:38:37 pm

Try pulling on your cables one at a time and see if they stretch. You may have a broken
cable.

Well well well, so I went back there and started pulling on the cables. I checked the grounds at the engine, frame, and starter first, tugged a little no noticeable stretch. Went to the front and gave it a try... the same thing. Then I went out to the batteries and gave those ones a couple of tugs, no noticeable stretch to them. Went back in to check..... fired right up!!!! Of course, I am relieved but now I am wondering what the heck is going on and what is the best approach to fix this before my maiden voyage?

Re: Trouble Starting - Ignition solenoid? 95 U300 CAT 3176

Reply #44 – November 09, 2021, 05:06:35 pm

Quote from: Chuck & Jeannie – November 09, 2021, 04:30:22 pm

The most likely place for problems with any battery cable is at the two ends. Corrosion can work up under the open end of the insulation and weaken the individual strands of wire. In extreme cases the cable can pull completely loose from the crimped end connector. If it becomes necessary, you can buy the tool required to attach new end connectors to a cable.

I think that is where I am going to start. I will look at those links you sent and see if it's something I want to invest in the tools for or if it's something I will have done by...... an electrician?

Re: Trouble Starting - Ignition solenoid? 95 U300 CAT 3176

Reply #45 – November 09, 2021, 05:26:33 pm

You need to cut back the jacket until you are able to expose the cable that is clean, shiny copper. If it will still reach the battery/end, swedge on a new terminal.

Plan "B" is to cut it back to good copper and use an isolator lug/terminal and use a new short cable to replace the bad section.

Plan "XXXXXXXXXXXXXX" would be to replace the whole bad cable. EXTREMELY unlikely that this will be needed.

Re: Trouble Starting - Ignition solenoid? 95 U300 CAT 3176

Reply #46 – November 09, 2021, 05:27:07 pm

So I imagine you have a bad connection at one of the terminals and pulling on
them tighten the connection. It's really hard to find a problem when it's working.
I would push and pull at the connections and maybe you will feel something loose.

Re: Trouble Starting - Ignition solenoid? 95 U300 CAT 3176

Reply #47 – November 09, 2021, 05:27:27 pm

If you find a bad cable, you have 2 choices:

1. If you can remove the cable from the coach, you can take it to electrical shop and have new end connectors swaged on, OR just have them build a new cable.

2. If you cannot remove the cable, then it must be repaired in place, either by you or by calling a electrician to come to your location. Service calls are expensive. You will have to weigh the expense of a service call against the expense of buying what is necessary to do the job yourself.

Except in a emergency situation, I would not recommend using any kind of bolt-on or clamp type cable repair connectors. There are connectors that use a compression nut to tighten the lug to the cable. I have no experience with that type connector. See the description in the catalog linked below:

https://www.powerandsignal.com/Images/PDFs/Catalog_Full_Line__English_Connectors.pdf

Re: Trouble Starting - Ignition solenoid? 95 U300 CAT 3176

Reply #48 – November 09, 2021, 06:19:34 pm

Quote from: GeoKM – November 09, 2021, 05:03:51 pm

Well well well, so I went back there and started pulling on the cables. I checked the grounds at the engine, frame, and starter first, tugged a little no noticeable stretch. Went to the front and gave it a try... the same thing. Then I went out to the batteries and gave those ones a couple of tugs, no noticeable stretch to them. Went back in to check..... fired right up!!!! Of course, I am relieved but now I am wondering what the heck is going on and what is the best approach to fix this before my maiden voyage?

Good job narrowing things down and finding the issue! I say you remove/clean/check each connection one at a time and see what you find.

Re: Trouble Starting - Ignition solenoid? 95 U300 CAT 3176

Reply #49 – November 09, 2021, 06:22:08 pm

So I narrowed it down to the cable that runs from the negative 3-way manifold on the batteries up to the engine grounding point. Thinking I will have an electrician friend either fix the ends or fabricate a whole new one. Luckily the ground side has the shorter and more easily removed cables, the positives run-up to the larger fuse box that is in the main storage bay through some bulkheads and all that.

Thank you all for the assistance with this issue!!

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