Slow cranking diesel in the morning

[passerby]

Has anyone suggested to use the house battery booster along with chassis batteries.
If house batteries are up that should rule out battery as the problem.

[AtlantaRick]

This morning - started up on the first try. My wife was watching the wall meter and after it started I pushed the 'boost' button and it made no difference in the voltage.
So that means my boost solenoid is bad I presume. Could that cause an intermittent loss of volts when it is cold in the morning... and then back to normal voltage after the engine starts and it heats up from the current passing thru it?

[GGC]

The boost is to aid in starting, not after the engine is running.
The volt meter is showing the voltage as the batteries are being charged with the engine running.

[RobRoy]

Have you yet determined that the voltage that what you are reading inside the coach is the cranking batteries? Because my guess is that is NOT and that your reading the house batteries voltage and not the Cranking batteries.

Have you properly tested you cranking batteries as of yet?

Failing to do so IMO will only lead to a guessing game and yes sooner or later you will probably get lucky and find your issue.

Hopefully this doesn’t come off as being critical I / We are just trying to be helpful.

A simple logical and well thought out diagnostic strategy along with a Digital Volt Ohm Meter with a ( Min- Max) function and a set of very long homemade leads will lead you to the promise land and most likely pretty quick.

The diagnosis starts with knowing whether the CRANKING the batteries are indeed Good and to the proper spec.
So if the battries are tested properly and to mfg spec and they are GOOD , we then take our volt meter and do voltage drop test from the positive and negative battery POSTS to the starter positive POST and starter case. Battery voltage drop tests are very simple to do.

So at this point you now know that the batteries are capable of doing their job properly and that the electrical connections are capable of doing their job from the cranking batteries to the starter.

My guess is that you will have your answer in these simple tests and pretty quick.

If not? On to some starter motor tests.

Cold ambient temps cranks slow …….after warm is O.K.

hmmmm engine oil weight issue perhaps? I doubt it but just a thought.


Happy Hunting

[dix39]

I'm also thinking that the judicious use of a multimeter could save a lot of time and get answers more quickly.

Also, load testing the batteries will sometimes give very different results than just checking for voltage with a multimeter. I learned this after checking my Metro battery for voltage, then replacing the starter and several other components. Finally in frustration I had the battery load tested and found that was the problem. Along with a new battery I also bought a load tester.

I recently had a similar problem as the OP, but mine was with the house batteries. When checked with a multimeter the batteries were good, but individual load testing indicated one of them was weak. I replaced both batteries rather than have the "good" one fail in a year or two.

Here is a link to some information about testing for voltage drop; Voltage Drop Testing. A search will also turn up a lot of "how to" information if you need it.

Best of luck.

Steve

[Skip426]

JMHO: 880 CCA batteries may be marginal for your coach . I'd think 950s would be the minimum.
If your wait to start light is coming on for more than the 3 second bulb check when you turn on the key , with temps in the 60s , there could be an issue with the intake air temp sensor; that is causing the intake heaters to cycle when they shouldn't , at that temp (60s) the intake air cycle indicator ; the wait to start light ; shouldn't come on after the bulb check.

Also ; with the problem happening as it does; three days or so; then testing the batteries before they sit for three days without being charged ; might give a false good reading. Remove the batteries and let them sit for the 3 days then have them load tested.

[Cdnw30]

Originally Posted by AtlantaRick;3036330[COLOR="Red"

If] the coach sits for 2-3 days [/COLOR]I have a problem starting it in the morning. Temperatures are in the 60's so it is not a cold morning. It cranks real slow and I have to cycle thru the 'wait to start' 3-4 times. It eventually starts but barely. Then for the rest of the day it starts just fine.
I took the battery's to NAPA for a complete load test and not just the quick test. They both came back fine. 880 cca each. They show 12.8v on the inside meter

I removed the battery cut off switch and bolted the wires together but that made no difference.

Any suggestions? Starter? Fuel pump?

I just had the oil changed last week and they replaced the fuel filters but it was doing this with the old fuel filters too.

If this is happening after the coach sits for 3 days, more than likely they are draining some and causing your slow cranking. After you have it running it seems to work better for you the rest of the day, because they now have a full charge.

[xydial]

I own a 2005 Knight, the sister to the Ambassador. I am curious where you are reading the chassis voltage. On my Knight the voltage display on the control panel is for the house batteries only.

The only way to check the chassis battery voltage is with a Voltmeter or you can turn on the ignition switch and get an approximate number from the dash.

Good Luck

[Randyman1]

I'm going to give my 2 cents worth and bet it is the starter dragging. On my coach, which charges the chassis battery when plugged in, I could start pretty easily when breaking camp or leaving home as long as the night before it was plugged in. If boon docking I would get the slow crank and barely start scenario. I replaced the batteries with 1,000 crank capacity thinking this would help. Same problem. Now my coach was known for a weak starter, but I wouldn't listen, so I spent all sorts of money changing batteries and still had the problem. Replaced the starter finally with the Denso gear reduction starter that everybody said would fix the problem and I'll be darned if they weren't right all along.

[AtlantaRick]

xydial - the meter on the wall shows both house and chassis batteries. Push up on the button to see one and down on the button to see the other. Weird that yours doesn't do that too.

This morning after sitting for 3 days I had my wife watch the chassis battery gauge. It was 12.8 before I put the key in. Then dropped to 11.6 when I turned the key on. I didn't get a reading while it was cranking but it fired right up in 2 seconds!

My big problem is that we keep traveling and trying to find a place to look at it is pretty hard. We are in Roswell, NM today till Tuesday so I will look here.