Starter Hesitation....

JackConrad · April 24, 2009, 04:46:08 AM

Quote from: Iver on April 24, 2009, 12:19:28 AM
Gus,
Where is the other starter relay that you mentioned?
Thanks, Iver

Should be in the rear electrical panel. Sorry, I can't be more specific, but I don't see you bus make or model listed. Jack

gus · April 24, 2009, 05:04:19 PM

You said "Now I have developed a slight hesitation in getting the starter to engage." so I assumed it was a new problem, sounded that way to me.

As Jack says, knowing what bus you have will help find the relay. If it isn't an older GMC I can't tell you but someone else can.

Make and model should be in every post. Someday maybe it will be automatically included in each post.

bobofthenorth · April 24, 2009, 05:08:01 PM

IMO don't bother looking for a panel relay. Your first post said the starter engages and tries to turn the engine but it takes a couple of shots before it manages to spin it. If the primary relay was the problem the starter wouldn't engage at all. Go ahead and look for the relay just so you know where it is but don't bother trying any troubleshooting involving it because that isn't where the problem is.

gus · April 24, 2009, 07:07:39 PM

Bob,

You're probably right but if the relay has burned secondary contacts the solenoid won't get enough power or if the relay primary connections are badly corroded the same thing will happen, the relay secondary contacts won't stay together.

I always like to follow these events having had my share of them with both relay connections and battery cable connection corrosion. Never have had a solenoid problem.

Iver · April 24, 2009, 11:49:32 PM

Sorry, the coach is a MCI-9. I was having problems with the starting before the fuel fitting cracked. I haven't had a chance to check all the cables and grounds and will post again when I see if that resolves the problem.
Thanks, Iver.

JackConrad · April 25, 2009, 04:13:44 AM

We had a fuel pressure switch fail several years ago. We had similar symptoms. Apparently, the contacts in the pressure switch had become pitted and several attempts caused enough heat build-up in them to make them work. This can be diagnosed by bypassing this switch with a 12 gauge jumper wire between the switch contacts. or switch contact & good ground (depending on whether your switch has 1 or 2 contacts). Jack

buswarrior · April 25, 2009, 07:52:34 AM

Yes, fuel pressure switch in the starter circuit is a consumable.

Unless a busnut knows its age, buy a new one and screw it in.

Another obscure, yet crippling, preventive maintenance chore accomplished.

And another excuse to hoist a cold one.

happy coaching!
buswarrior

Iver · April 26, 2009, 02:37:09 AM

Jack,
My pressure switch has only one contact. I assumed that when the pressure switch is working properly, and there is fuel pressure in the system, it prevents the starter from engaging. So if the pressure switch is bad, it acts as though there is fuel pressure even when there isn't? And prevents the starter from engaging?
Buswarrior, Cheers..... I'll get a new switch just in case.....
Iver.

JackConrad · April 26, 2009, 05:17:56 AM

Quote from: Iver on April 26, 2009, 02:37:09 AM
Jack,
My pressure switch has only one contact. I assumed that when the pressure switch is working properly, and there is fuel pressure in the system, it prevents the starter from engaging. So if the pressure switch is bad, it acts as though there is fuel pressure even when there isn't? And prevents the starter from engaging?
Buswarrior, Cheers..... I'll get a new switch just in case.....
Iver.

If the contacts inside the switch are pitted, the problem can be intermittant. It is a electrical problem, not a mechanical (pressure) problem. Put a jumper wire from the terminal to a good ground. If the hesitation is no longer occuring, replace the switch. If the hesitation is still occuring, the problem is something else. Jack