Starter Wiring Advice

Topic: Starter Wiring Advice (Read 1429 times) previous topic - next topic

Starter Wiring Advice

March 18, 2018, 06:25:39 pm

Hello all, I was hoping someone has been there done that. Recently I replaced my single 4d starting battery with 3 optima redtops in a configuration more appropriate and factory original. The coach cranked very quickly and all was well. But it is back to the same business despite the chassis battery setup being very ample. Boost helps but not tremendously.

When I couldn't get it started I noticed that both the ground wire from the starter as well as the crimp connection on the starter solenoid were hot. So hot actually that the heat shrink tubing was melting. I also have now a failed alternator but I think it is unrelated.

I was wondering what people would advise to replace. On the surface I almost think I should just buy a hydraulic crimper, ends, and cut off the last 1" on either wire and crimp a new end on it. But could the rest of the wire be bad. Would it be better to upgrade to a much thicker cable from starter to batteries? Is it more of a ground problem? I see the big ground wire that goes from the starter to the frame behind the radiator and I don't see any other ground connections from the engine.

I'm willing to spend money and buy the proper equipment. Just looking for advice as to what the best target to hit is. This is a 99 U320. I strongly suspect the problem is in the wiring and terminals instead of the starter.

Re: Starter Wiring Advice

Reply #1 – March 18, 2018, 06:36:49 pm

I ran a cable directly from the batter to he starter on my coach and put it on in front of the one coming from the isolator. It was a long run but no boost was needed to start the coach

Re: Starter Wiring Advice

Reply #2 – March 18, 2018, 06:41:18 pm

Block up the coach with safety stands. With a heavy duty screwdriver jump between the 2 big terminals on the starter, putting the battery direct to the motor and bypassing the starter drive. It should spin up fast and quick if it doesn't it is the motor.

Re: Starter Wiring Advice

Reply #3 – March 18, 2018, 06:50:16 pm

Quote from: craneman – March 18, 2018, 06:41:18 pm

Block up the coach with safety stands. With a heavy duty screwdriver jump between the 2 big terminals on the starter, putting the battery direct to the motor and bypassing the starter drive. It should spin up fast and quick if it doesn't it is the motor.

So you're saying to engage the starter motor without the bendix and see how fast it spins up? I'm not sure I'd be able to tell the difference between good and bad.

Re: Starter Wiring Advice

Reply #4 – March 18, 2018, 06:55:16 pm

Cut the end of the cable off, buy copper lugs (NAPA/welding shop), slide some shrink tubing on to the cable, solder with a propane/mapp gas torch, slide the shrink tubing down over the cable and park of the lug and then heat it a bit. Nice and water proof. No need to crimp, I solder all my joints.

Clean off all cable ends and terminals. No cable should get hot. Clean off the starter terminal until it's spotless. This is an important mating surface and there should be no resistance. Any heat you encountered is from resistance. A ground cable should also go from engine or transmission to the frame.

An extra ground cable is always good. I installed one from the engine batteries to the frame right next to the batteries. See my triple 31 series installation post a month or two ago.

Stop using the boost switch. You just mask any battery or cable problems you have plus wear out the switch. If the engine cranks any faster using the boost switch, something is wrong with cables. Worn starter bushings can also cause drag and can cause heat at the starter terminals. Check starter solenoid for connections.

Pierce

Re: Starter Wiring Advice

Reply #5 – March 18, 2018, 07:05:53 pm

Quote from: Mark D – March 18, 2018, 06:50:16 pm

So you're saying to engage the starter motor without the bendix and see how fast it spins up? I'm not sure I'd be able to tell the difference between good and bad.

When they are bad they drag. If you have never listened to a good starter spin I see your point, but not much time involved to listen and if it is really bad you would probably notice the lack of rpm's. I bench test old car starters and a bad one is pretty obvious. One other thing I have noticed on my '99 is where the cables go to the terminal on the battery box, there is another nut on the backside of the cables. I found mine loose as the main nut had bottomed out on the stud. A very thin 9/16th's wrench fit behind the cable ends and I got about 360 deg. tightening against the back of the cable ends.

Re: Starter Wiring Advice

Reply #6 – March 18, 2018, 07:11:26 pm

3/0 cable is likely what was OEM. 4/0 cable is quite a bit larger cross section and can be used. If you cable ends are hot then there is too much resistance. It could be the starter motor, the cable end or the post where the cable connects to the starter.

If it spun up and started at first but not later be sure the start batteries ar fully charged. Without a secondary charger the alternator is the only way the start batteri s get charged. If voltage is low then amps go way up which creates heat. If boost didn't help much the voltage could be quite low.

Start here.

Make sure the three batteries are connected properly. One way is right. Almost every other way is not so good.

On my 2001 the plus and minus cables from the starter batteries go to common posts, one plus and one minus. And then they go to the starter motor and several other points. If yours is like that there ae several wires connected to each post. These need to be clean and tight. My negative post is locked up, it it tight but i can neither tighten or loosen it. It needs to be replaced.

Many have run a cable, plus and minus directly from the battery +/- posts directly to the starter. These can be 4/0 cables. The original +/- cables still go to the common posts but the second set go directly to the starter. I have not done this so I am not sure where they go.

If your alternator is toast then it may be able to be rebuilt or you can replace the original LN with a more efficient brushless alternator. Least cost is to do a rebuild.

Re: Starter Wiring Advice

Reply #7 – March 18, 2018, 07:33:56 pm

There could also be corrosion inside the battery cable under the insulation. If you grab the cable with both hands and flex it along the length you might feel some areas that are not as flexible. Kind of a crunchy feeling. If you do that is corrosion under the insulation. If you have a heavy duty jumper cable you can jump from the battery to the starter terminal. If it starts easier then it is probably the cable that is bad.
Good luck.

Re: Starter Wiring Advice

Reply #8 – March 18, 2018, 07:40:31 pm

check your voltage at the start batteries. if the alternators out, they are not being recharged and as the voltage drops, the symptoms you describe will occur.

Re: Starter Wiring Advice

Reply #9 – March 18, 2018, 11:13:24 pm

Two days ago, I installed a rebuilt starter on my 96 270. (Starter solenoid would occasionally "hang on" and require a tap from a hammer to disengage.) Not that it matters for your problems, but I found 4 negative cables connected to the bottom mounting bolt of the old starter. Cleaned them all; coated them with Ox-Gard, and re-assembled them as found to get them to "lay" properly when the bolt was tightened. Finding these four cables nested together made me study the wiring diagram for my coach.... Next, I will ID each cable ( if the 21-year old labels are readable) and trace them to see how they follow the diagram. (I have a concrete floor and a creeper.)

More associated with your problem, is my interest in the Battery Voltage Sense wire modification. I am studying 3-wire and 4-wire alternators; downloaded a wiring diagram schematic from the Barry Beam material that had this mod drawn on it, and wondering if I need this for my Leece-Neville 2800J alternator that has been working for 15 years.

andy1

Re: Starter Wiring Advice

Reply #10 – March 19, 2018, 12:10:46 am

Our 03 U320 was slow cranking from the time we bought it 6 years ago until last year when the starter failed, luckyly in our driveway I bought a new starter from a truck shop and it spins the engine over much faster starting as it should. Surprisingly inexpensive for a new starter that large. It was a bit of a bear replacing since it too the longest cheater I could find to get enough leverage to break the bolts loose. Wish I had replaced the started sooner instead of waiting for failure. Would have been no fun on the side of the road.

Re: Starter Wiring Advice

Reply #11 – March 19, 2018, 12:19:45 am

1/2" drive impact and extension gets the bolts.

Re: Starter Wiring Advice

Reply #12 – March 19, 2018, 12:27:43 am

With both cable ends hot at the starter sounds to me like a starter dragging. I pull mine every five years and have it gone through, along with alternator. Given that the cables have been so hot new terminals would be in order.

Re: Starter Wiring Advice

Reply #13 – March 19, 2018, 05:07:09 pm

Mark,

For over one year, we dealt with a starter hesitation problem. Our engine is different.

Changed batteries, cleaned cables, added additional ground cable, added a bus bar for the three redtops. It just seem to not fix the start issues.

We found a new DelcoRemy starter, and with its heavy weight fought the installation difficulty. But only after starter installation, did our problem go away.

There are many 'cheap' new starters, I decided to buy DelcoRemy to see if it would fix the problem. Also exchanging our original starter for an unknown quality/brand rebuilt seems like a bad choice. We did rebuild our starter, but it did not fix the hesitation

It has been quite a few years since the new starter, but for sure it completely solved our problem. We never start with boost solenoid, and every crank now yields instant starting.

We did learn all about how the start circuit from battery to dash, to Allison computer, with ignition back to dash, to aux start relay, to starter solenoid, to starter. Several of the items in this long path were also changed.

Re: Starter Wiring Advice

Reply #14 – March 19, 2018, 05:30:11 pm

Andy, we ran a new small diameter wire from alternator voltage battery sense terminal directly to start battery, bypassing the OEM isolator panel connection.

Re: Starter Wiring Advice

Reply #15 – March 19, 2018, 07:54:44 pm

The alternator has been working every time up until the recent start. I am a gauge hawk and I would have noticed. Plus the moment I get home it gets plugged in. The most recent time after it took 2 hours to get it started before I left for 12 hours of sebring, I simply took off the alternator belt (just in case) and ran the generator. I was a bit surprised to see the engine only needs 25 amps and possibly even less to run. I checked the sense and ign wires and they are good. I will most likely start with a regulator and brushes and go from there. I was pretty happy with what the stock alternator could accomplish.

The situation overall is a little interesting. I noticed that the wiring on my xantrex temperature sensor is broken. Even at full charge rate I was only seeing 13.8v. I disconnected it and can now set the battery temperature manually so I set it to cold (as it was relatively cold that morning and got down to 37F that night) and the voltage bumped up to 14.5v. After an hour at this the crank pace was stronger. The chassis batteries shouldn't be dead as I leave the boost switch on all the time. But this is definitely a voltage drop issue that half a volt makes all the difference in the world on. Even so I'd believe that a battery bank floating at 13.5+ volts for months would be at and remain at full charge eventually. And I have checked the chassis batteries to make sure they are floating at a reasonable voltage with boost on and they are.

It really seems that every single time I start it it cranks differently with no rhyme or reason. Sometimes it barely starts, sometimes it cranks extremely fast. The cold definitely makes it very angry, and by cold I mean like 40F. I've jiggled and loosened and tightened lots of things. The cables and connections on the 3 batteries are all new and I wired it so that there are cables connecting each terminal in parallel. The negative connects on the rear battery and the positive connects on the front. It seemed like a good way to get current from all batteries equally but maybe it's not.

Based on responses I've decided to replace terminal ends and get a new starter. While it is bear heavy it shouldn't be too big of an issue as I have a monster cordless impact gun and every extension impact socket under the sun. I'm especially interested to swap the starter while making no other changes to see what happens just to report back to others as it seems this is a universal issue with many "solutions". Replacing the starter, the newly cleaned terminals may have been what actually solved it for some. I'm not too interested in it though. I want it to start and start fast every time and I'll replace it all if I need to. I save a lot of money not driving around in a new coach so why not.

I'll do the jump test though and see how it sounds. I have an idea what I might be listening for so we'll see.

Re: Starter Wiring Advice

Reply #16 – March 19, 2018, 08:16:16 pm

Those frame mounted junctions just above the chassis batteries are interesting too. Time to get a meter and starter diagnostic trigger (aka wife) out.

Re: Starter Wiring Advice

Reply #17 – March 19, 2018, 09:35:29 pm

Quote from: Mark D – March 19, 2018, 08:16:16 pm

Those frame mounted junctions just above the chassis batteries are interesting too. Time to get a meter and starter diagnostic trigger (aka wife) out.

There is a backing nut on the inside of the terminals. It takes a very thin 9/16" open end wrench. I had one or I would have ground one down, The backing nuts were loose on mine.

Re: Starter Wiring Advice

Reply #18 – March 20, 2018, 01:59:24 am

We found that a long strap looped around the starter and then up over exhaust manifold with someone pulling from the side of the coach helped a lot to support the weight of the starter while I worked to align the new starter in place.

Re: Starter Wiring Advice

Reply #19 – March 20, 2018, 09:17:07 am

Take a set of jumper cables and make additional grounds with them . Check crank speed and cable temps. Really good chance of crusty ground.

Re: Starter Wiring Advice

Reply #20 – March 20, 2018, 10:56:59 am

I do not have a problem with my starter, or alternator, but if I did I would not hesitate to take it to a good shop, like Texas Alternator and Starter here in Austin. They rebuilt my alternator to a like new condition. Hunt around for a shop near where you are if your problem is the starter.

Re: Starter Wiring Advice

Reply #21 – March 20, 2018, 09:51:36 pm

Thanks for all the help and advice everyone. Can't wait to get started on it.

Re: Starter Wiring Advice

Reply #22 – November 03, 2018, 06:54:20 pm

I know this is bringing back a dead thread but this is the conclusion. Today I installed a Delco 39MT starter and it definitively solved the problem. Cranked very fast without boost. I've never been able to start it without boost. The hesitation is because my rear start switch is flaky. The starter I pulled out was much bigger, heavier and said it was cummins reman.

https://www.youtube.com/watch?v=JmNmTbttMrs

Anyone know what torque to set those 5/8 12 point bolts to? I took a guess at 80Nm but it'd be nice to know the real value. Some comprehensive searching hasn't turned anything up yet.

Please don't judge the hitch wiring mess

Re: Starter Wiring Advice

Reply #23 – November 03, 2018, 08:38:45 pm

Mark I had my starter rebuilt and was not able to get a torque wrench on the bolts but I did put loc-tight on the threads. The bolts had loc-tight on them when I took them out so I figured I would be safe and put it on when I replaced them. Just a FYI my starter rebuild guy told me that a lot of shops were replacing the original starters with the new gear reduction model because it was a lot lighter and easier to put in. But , he also said the new starters were made from aluminum and the shaft would egg shape the hole on the end after a while. My m-11 would not start unless warm and using boost, after starter rebuild I waited for weather to drop to about 40 and when I turned switch engine turned over rapidly and started. I normally like to start after aqua hot has heated engine up but I wanted to test it at least once to make sure that had been problem.
Chris

Re: Starter Wiring Advice

Reply #24 – November 03, 2018, 09:18:13 pm

Those bolts are a grade 8, 1/2x13 according, to the chart they torque at 106 ft. lbs.

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