Cummins ISL 450 Starter

[Doc007]

How should one...shop or owner...diagnose a starting problem? A to Z...batteries, ignition switch, relays...starter itself...

A new starter was recently put on my coach but I am wondering what they should have checked before installing it.

The symptom was that it started up one day and the next day it did not crank. Batteries are new and show 13.5 v.

[Skip426]

I'd lean toward , battery first then starter ( by jumping the terminals on the starter to by-pass the relay and ignition switch) if the starter works with the relay and ignition switch by-passed then, onto testing those components ; if it doesn't work , replace starter .

[Skip426]

BTW: 13.5 volts is an indication that the batteries are being charged .
Was the coach plugged into shore power when you checked?
Chassis batteries in good condition ( at rest ; no charging for over 2 hours ) should be holding 12.6>12.8 volts.

[Doc007]

Originally Posted by Skip426

BTW: 13.5 volts is an indication that the batteries are being charged .
Was the coach plugged into shore power when you checked?
Chassis batteries in good condition ( at rest ; no charging for over 2 hours ) should be holding 12.6>12.8 volts.

Actually it was 13V. It was unplugged using solar panels to house batteries and Echo Charger on to chassis batteries. Sorry

[Doc007]

Originally Posted by Skip426

I'd lean toward , battery first then starter ( by jumping the terminals on the starter to by-pass the relay and ignition switch) if the starter works with the relay and ignition switch by-passed then, onto testing those components ; if it doesn't work , replace starter .

Using your method, what if the starter doesn't move but gets hot? With the ignition and relays bypassed then this would definitely indicate a bad starter...yes?

[Skip426]

Originally Posted by Doc007

Using your method, what if the starter doesn't move but gets hot? With the ignition and relays bypassed then this would definitely indicate a bad starter...yes?

Correct. With power supplied to the starter solenoid terminal directly from the main cable terminal the starter should turn the engine over; if it doesn't then there are internal issues in the starter .
Removal and bench testing the starter for a possible solenoid problem is next but most shops don't do that ; it's a hold over from the days when we used to rebuild starters and alternators in the shop , not just install a new/rebuilt unit.

[bubby124]

Check your ground connection use a jumper cable from ground on battery to frame if starter works you have a bad ground

[akadeadeye]

Our ISL 400 did the same thing and the culprit was the starter solenoid.


Don

[Skip426]

Originally Posted by akadeadeye

Our ISL 400 did the same thing and the culprit was the starter solenoid.
Don

Don ; was the issue the solenoid attached to the starter ; or the neutral start/ starter relay ( that some refer to as a solenoid ).

[akadeadeye]

Originally Posted by Skip426

Don ; was the issue the solenoid attached to the starter ; or the neutral start/ starter relay ( that some refer to as a solenoid ).

It was the solenoid attached to the starter.

[Ray,IN]

Originally Posted by Doc007

Actually it was 13V. It was unplugged using solar panels to house batteries and Echo Charger on to chassis batteries. Sorry

Batteries should be off charging or draw for 1 hr before testing, otherwise you just wasted your effort.
As to the starter; I'd suspect the starter relay switch, and/or a loose battery cable connection.

[153stars]

These have pilot starter solenoid is most often fail in the electrical chain. The ignition switch will usually pull a small cube type relay, next to Pilot starter relay solenoid, that pulls in the Bendix solenoid that is the high amps relay on the starter. You can usually jump the pilot starter solenoid, but for the cost of having a spare on hand I would just grab one as a spare. All of the solenoids for the 12 volts are kind of don't last forever fail item across all brands. The house disconnect referred to as a Salesman switch, the Boost combined solenoid and the starter pilot solenoid. Sometimes a couple of taps on the pilot relay will get her to hit, I have done this on dozens boats, jet skis and engines.

[vito.a]

Many of us are switching to the new Delco gear reduction starter. They require less amps and spin over much faster.

[n2zon]

Originally Posted by vito.a

Many of us are switching to the new Delco gear reduction starter. They require less amps and spin over much faster.

We did this, um, involuntarily. What a huge improvement!