Engine won't start

Topic: Engine won't start (Read 1801 times) previous topic - next topic

Engine won't start

December 13, 2022, 10:14:54 pm

I haven't started my coach for about 4 months. I was going to take it somewhere today and it wouldn't start.
It was at first very slow in turning the engine then the starter just clicked. The battery reads 13.5 on my meter. But could it
still be bad.
I checked the voltage on the starter (the large starter wire) and it was 13.5. I tried to get a reading on the smaller wire as someone was trying to start it, but it read 3. 2.. That doesn't sound right. Shouldn't either be zero or the same as the larger wire.
I know there is a relay on the firewall but I'm not sure which one.
I started the generator with no problem as I was trying to get a little more juice for the battery.
I think there is a relay in the front also in front of the passenger seat but I'm not sure which one.
Is a relay either good or bad (It seems as though there is a current or no current). Not a partial current.
Attached is a picture of the relays on the firewall. Does anyone know which one goes to the starter.

Thanks

Re: Engine won't start

Reply #1 – December 13, 2022, 10:19:15 pm

Quote from: 18360 – December 13, 2022, 10:14:54 pm

It was at first very slow in turning the engine then the starter just clicked.

Classic symptoms of low cranking voltage (weak batteries) or inadequate starting current (loose or corroded battery cable connections).

Did you try turning on the BOOST switch with your generator running and your inverter/battery charger turned ON?

Re: Engine won't start

Reply #2 – December 13, 2022, 10:24:58 pm

On my coach the starter relay is a solenoid that looks the same as the boost solenoid.

Re: Engine won't start

Reply #3 – December 13, 2022, 10:39:17 pm

What Chuck said.
Clean the start battery cables at the battery and starter.

Re: Engine won't start

Reply #4 – December 13, 2022, 10:58:02 pm

I took the little cable off of the starter and cleaned it (it had a blue corrosive color to it). But that didn't help (although it seemed like it tried to turn over better. The larger cables seemed good.
I think I will take one battery off and take it to an auto parts store. I think they can do a load test. The battery terminals
look good with no acid residue.
I will let you know.

Thanks,

Rick

Re: Engine won't start

Reply #5 – December 13, 2022, 11:05:25 pm

How cold is it where you are?

Re: Engine won't start

Reply #6 – December 13, 2022, 11:37:41 pm

We are in Florida. It has been a little chilly at night. Maybe high 60's at night.
I had the aqua hot on in the AM to get the engine warm.

Re: Engine won't start

Reply #7 – December 14, 2022, 12:11:15 am

I recommend load testing individually each of the start batteries. It is a pain in the neck but you can get fooled by multiple start batteries. Mine showed good voltage but one of two utterly failed the load test.

Re: Engine won't start

Reply #8 – December 14, 2022, 12:35:29 am

When starting the engine bad batteries, a bad starter or poor cables or connections can cause
a huge voltage drop. Also did you try the boost like Chuck suggested.

Re: Engine won't start

Reply #9 – December 14, 2022, 12:41:43 am

18360, try cranking then immediately go put your hand on your battery cable connections, both h +and -. Including the starter connections. If you find one warm that's a sign of poor connections or cable. Quick field check.

Re: Engine won't start

Reply #10 – December 14, 2022, 11:06:16 am

I bought a battery load tester from Harbor Freight. Was not that expensive and way easier then taking batteries out and having to reinstall if they check out good.

This is the one I got. It works good on 12V batteries but found out it does not work on 6v batteries.
http://www.harborfreight.com/digital-automotive-battery-analyzer-66892.html

They also have cheaper ones that will do both 6V & 12V

Re: Engine won't start

Reply #11 – December 14, 2022, 05:35:28 pm

Measure voltage on AUX Start solenoid located on isolator panel. The small connector gets 12v when ignition switch is turned to 'start' position. One large terminal gets 12v from start battery, other large terminal sends 12v to small terminal on starter mounted solenoid when the AUX Start solenoid small terminal has 12v.

To crank engine, you could put 12v on small AUX Start solenoid to bypass the ignition switch and neutral-start relay mounted on front dash 12 panel. You could also touch a jumper between large terminals on AUX Start solenoid.

Re: Engine won't start

Reply #12 – December 14, 2022, 05:44:16 pm

If you hear a click but no turn over- battery ground is loose.

Re: Engine won't start

Reply #13 – December 15, 2022, 09:27:32 am

Quote from: 18360 – December 13, 2022, 10:14:54 pm

I haven't started my coach for about 4 months. I was going to take it somewhere today and it wouldn't start.
It was at first very slow in turning the engine then the starter just clicked. The battery reads 13.5 on my meter. But could it
still be bad.

I checked the voltage on the starter (the large starter wire) and it was 13.5. I tried to get a reading on the smaller wire as someone was trying to start it, but it read 3. 2.. That doesn't sound right. Shouldn't either be zero or the same as the larger wire.

Too many unknowns. Your second sentence wold indicate a discharged battery, but the voltage reading tells us otherwise: But is there some sort of battery maintainer running providing electricity? "I" would start by taking a battery terminal brush to the battery posts and connectors bringing back that fresh lead shine.

Regarding "the small wire," I believe that your describing the wire to the starter solenoid, the 3.2V measurement indicates a bad connection between where you measured the voltage and the negative terminal on the battery. The coil in the starter solenoid doesn't take much current so the resistance may not be very much. There's math.

The voltage readings that will mean something is the voltage at the starter terminal, the big connection on the starter itself, while the engine is being cranked. Then a measurement from that connection to ground, again while cranking the engine.

Re: Engine won't start

Reply #14 – December 15, 2022, 10:14:20 pm

Well, I took one battery up to the auto store. It was fully charged but it was dead. I got 3 Optima Red Top Batteries. On my coach it is really easy to take the old ones out and install the new ones. I read the literature. It said to attach the positive on the first battery first then attach the negative on the last battery. So that is what I did, and it worked out fine.
After installing the batteries, the coach started right up. The batteries that were in there apparently, were just regular car batteries.
They were 7 years old.
Nothing like the sound of a purring diesel engine. (And the aqua hot for that matter).

Thanks

Re: Engine won't start

Reply #15 – December 15, 2022, 10:42:03 pm

When checking voltage is with the starter turning is what gives the answer how the batteries
are.

Re: Engine won't start

Reply #16 – December 15, 2022, 11:04:02 pm

STILL.. clean the terminals at the batteries. Even though there is no visible corrosion they need to be shined lead. I do that every year for regular terminal and cable maintenance.

Re: Engine won't start

Reply #17 – December 16, 2022, 08:40:29 pm

7 years on three car batteries is pretty phenomenal I guess you could say. When my optima batteries died I went with Odyssey AGM batteries instead. Instead of three batteries I only needed two. I had to reconfigure the battery box a little bit and well should have had it welded, I didn't have access to one at the time and I went with bolting it together works great. I have never worried since then about my coach not starting.
Until of course it doesn't.
I think pretty much without putting a voltmeter on just cranking and hearing that sound tells you pretty much one of two things. The batteries aren't able to provide any type of load or the connections are bad. If you try to jump it from the battery terminals and the same thing happens now you know that it's your connections to the starter.
Wouldn't it be nice if there was a panel when you opened your engine compartment that gave you access to measuring all those kinds of things? I'm sure somebody a lot smarter than me can come up with something like that.
Now make sure you have some kind of trickle charger to keep your batteries from discharging while sitting again. Protect your investment.

Re: Engine won't start

Reply #18 – December 22, 2022, 09:12:49 pm

You should add a trick-L-Charge for the start batteries to keep the voltage up, engine batteries are only charged when the engine is running and the engine computer is constantly using power when the engine is off,
Three months is a long time for the batteries to remain charged

Re: Engine won't start

Reply #19 – December 23, 2022, 09:45:39 am

Having a similar starting problem,went to start before the zero degree hit us,heard a brief click sound then nothing,when I turn the key now I get nothing and the trans keypad does not light up,hooked to shore power and all batteries charged,will do more checks
in a couple of days,trying to get thru the zero degrees,when I tried to start it was in the 40's,wonder if a solenoid went bad,will get
the diagrams out and look,any ideas?

Re: Engine won't start

Reply #20 – December 23, 2022, 09:58:40 am

Quote from: John44 – December 23, 2022, 09:45:39 am

...when I turn the key now I get nothing and the trans keypad does not light up...

First guess: Check the ignition solenoid (located IIRC on your coach behind the removable panel in front of passenger seat).

See first post in thread linked below:

Need dash solenoid I'd please

Re: Engine won't start

Reply #21 – December 23, 2022, 10:03:30 am

Quote from: Chuck & Jeannie – December 23, 2022, 09:58:40 am

First guess: Check the ignition solenoids (located I believe on your coach behind the removable panel in front of passenger seat).

Yup, anytime the chassis battery is 12+ VDC and turning the key elicits none of the normal responses (Allison shift pad doesn't illuminate, gauges don't come up, dash HVAC fan doesn't work) the IGNITION SOLENOID is high on the suspect list.

Giving it a sharp, light rap may temporarily put it back among the living.

And, the work-around is super simple-- merely remove the wires from one large lug and ADD THEM to the other large lug. Disconnect to turn off ignition!

Re: Engine won't start

Reply #22 – December 23, 2022, 10:06:06 am

Heck, I used to use "percussion persuasion" way back in the late 50s on starter solenoids. Still a good emergency option today.

Re: Engine won't start

Reply #23 – December 23, 2022, 10:16:45 am

Will check that today,then give feedback.

Re: Engine won't start

Reply #24 – December 31, 2022, 01:38:41 pm

Ignition solenoid is on the isolator panel,tested and both big lug terminals have voltage,diconnected cables from start batteries
and am in the process of cleaning the ends,have a new cole hearse solenoid in hand.

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