Starting hesitation

[Adam Hicklin]

Thanks for the discussion.  I really didn't think it was a problem until I saw Mike's question in another post.  I asked it hoping someone would chime in and say it's just an idiosyncrasy of the C12 (I never get that lucky!) but to answer some questions, my coach is always plugged in while sitting.  I'll pay more attention to the battery condition before starting and have the chassis batteries tested.  I'm sure a cleaning is order at the very least. 

[Mike Groves]

Adam,

Thanks, that might also tell me that my issue is simple cleaning as well - though I thought perhaps it might be the solenoid in the electrical bay going bad. 

The battery compartment is fine, but I've never even looked for the starter.  If I face my coach from the rear looking in on the engine, no doubt the starter is beneath the engine but is it to the left or right? 

I guess when I go to pacific shores next week, I'll roll under and take a look.  I've heard others say they've worked on their coaches while parked at Pacific Shores.  Will I be breaking any rules doing so?

Thanks,
Mike

[Steve Huber Co-Admin]

Mike,
The stater on a C12 should be on the right (passenger) side as you face the rear of the coach.
Steve

[Mike Groves]

Ok, I'll take my crawler on vacation with me, and spend some time under there.  I know the oil breather exits in the rear right (engine nearest me when I stand back there) part of the engine, and I guess that stuff can go anywhere, and could coat anything so maybe my terminal is simply dirty.

Thanks Steve,
Mike

[Adam Hicklin]

I picked my coach up today. Chassis battery voltage was 13.3 and still the hesitation.  I'll clean all the contacts first and if it persists, I'll delve deeper.  But 13.3 should be adequate, correct?  As Gerald said, may have some bad cells and not have the cranking amps behind it but when it has been run for a little bit, it will start without the hesitation. 

[Edward Buker]

Adam,

13.3V would indicate a full charge so that is good. When you start the engine cold, the oil is thicker, and parts are not as well lubricated so the engine is more difficult to crank. That translates into higher current need to crank the engine and in your case that results in slower cranking speed. There should be no hesitation if all is well. Between warmer oil, lubrication, and some additional charging the cranking speed improves.

Later Ed

[Mike Groves]

Adam,

Since we have similar coaches (pre-2000) at which time, evidently, there were some changes made, I'll work on this issue as well, and let you know what I find.  Please let me know what you find out as well, and we'll compare notes.

Thanks,
Mike

[Adam Hicklin]

Will do, Mike.  Thanks everyone for the help and encouragement.

[Gerald Farris]

Adam,
It is possible that you have cranking batteries that are just not up to the task of turning over a cold C 12, regardless of their age or charge state. That is one of the reasons that I told you to have your batteries checked for CCA (cold cranking amps). A cold C 12 will need in the range of 1600 to 1800 CCA to start it without hesitation.

I just looked at the Interstate Battery website and found four group 31 batteries that they make that will fit your coach as a cranking battery. They run from 660 CCA to 1000 CCA per battery. So a pair of the lower end cranking batteries will total to 1330 CCA when brand new, and they will probably cause a problem when cranking a cold C 12 from lack of capacity, even when new. However, a pair of the 1000 CCA batteries, at 2000 CCA, will crank a cold C 12 without hesitation, even after several years. All batteries are not created equal, and just because a battery is new that does not mean that it is up to the job. 

Gerald     

[Adam Hicklin]

Gerald

The batteries I have are rated at 950 cold cranking amps at 0 degrees. 1185 CCA at 32 degrees. They are almost 5 years old.  Do you think they are at the end of life?  I'll pull them out and have them tested.

[Mike Groves]

Adam,

I'll horn in and say, well, have 'em tested, but I had this problem BEFORE and AFTER the new batteries.  I think I will change out that ignition solenoid in the wiring bay.  My logic is, if it can suddenly wig out, ie fail completely and turning the key does nothing, might it also, as it fails, fail in some cases to immediately provide a load to the starter, thus the hesitation. 

Anyway, if I do it, then I'll be doing it next week, and see if at least I am no worse off.

Mike

[Gerald Farris]

Mike,
There is no chance that the ignition solenoid is causing the hesitation when cranking your engine cold. The only current to the starting circuit that goes through the ignition solenoid is to the starter solenoid, and if the ignition solenoid had a open, the starter would not engage instead of slowing down in speed. These are two totally separate, and unrelated conditions.

Gerald

[Mike Groves]

Gerald,

Perhaps it is true, but the problem I am experiencing, and I believe Adam is, as well, is NOT a slowing down of the starter motor.  Its a temporary total cessation of anything, then immediately the starter turns and in my case immediately starts the engine.  It's just that "dead space" or as Adam says, "hesitation".

Now, given that you know now that our problem is NOT a slowly turning starter, but instead, a hesitation, are you saying that it still couldn't possibly 100% be a failing circuit in this solenoid? 

The sound is like HEAVY CLUNK (which sounds like the starter moved, but immediately stopped), then hesitation 1/4 to 1/2 second perhaps, then starter starts engine.  As Adam said, it's more of an annoyance and he was going to ignore it, until I reported it, and no one else seemingly has had the issue but us. 

Even if not many of us have experienced the problem in our coaches, most have probably experienced something similar in our cars.  I did, in my jeep, and after several months in that case the starter eventually got replaced, so that may be the issue here as well.

Thanks,
Mike

[Edward Buker]

Mike and Adam,

The fact that you turn the key to the start position and then you sense hesitation has nothing to do with the ignition solenoid in the electrical bay. That is not a device that draws enough current to get any hesitation even if the batteries were a bit low in capacity, it simply makes or breaks contact to turn on the ignition buss. The starter solenoid and starter can certainly provide a hesitation when low voltage and low current being supplied. I'm sure this issue has happened before with cars you have owned when a failing battery or a low charge due to a failing alternator occurs. Those that have lived in cold climates have crossed that threshold of hesitation and lack of starting as battery capacity lowers due to the cold and engines become harder to crank due to thickened oil.

Five year old batteries as a diesel starting source is a bit long in the tooth. Over three years and you are doing well but it depends on the battery capacity to start with as Gerald points out. I have had several batteries fail in two years on my C12 and some will make it to 4 or 5 years. All of this depends on how deeply the battery was cycled during its life, the less deep cycles and the higher the charge state is maintained the more life you will get out of it.

Later Ed

[Adam Hicklin]

Tomorrow I will take the batteries loose, clean them up and take them to be tested.  I have two new ones on standby should I need them.  The new ones are 950 CCA at 0 degrees.  Will those be adequate Gerald?

I did try the battery tie switch today.  Held for 30 seconds as suggested by Ed (last time I tried it I just pushed it and turned the key) and it started without hesitation.  Seems that would suggest a battery problem.  I don't want want to spend $300 on batteries, but as my wife says, I can't take it with me!  Standby.......