cat 740 starting problem

[Ruahines]

The boss bought a couple of these at auction. The first one has arrived and after moving off the float we can't get it to start regularly.
It has a fire supression system fitted which could be part of it but my thoughts are more along the line of transmission position switch.
When it does fire up it will then restsrt several times without fail. Come back later and no way Jose.

Thoughts or a circuit diagram etc would be greatly appreciated.
B1P00770

Thanks in advance

 

[Cmark]

So will it not crank, or cranks but no fire?

When it does eventually start, how do you achieve that? Just random chance or crank, crank crankitty crank until it goes?

 

[Ruahines]

Sorry I was a bit vague about that.
Will not crank, no sounds of any solenoid engaging. When it did start it was a random thing with no apparent reason.
I was not in the cab when this was all going on as "operators" were all over it like flies on the proverbial.
Since then I have been left alone and there is a fault code warning on the console.
Problem now is that it has fire protection and engine shutdown timer wired in.
So when I disable that and can read the code on the console I will post it.
I am assuming that is the standard on/off three times within ten seconds to read the code.

I am on my own today so it could be a while before I get a chance to do all this.

Thanks in advance

 

[Cmark]

Have you checked that the hoist lever in in the "hold" position?

 

[Nige]

For an electrical schematic PM me your email address. I can also send you the Diagnostics & Troubleshooting procedures for whatever Code you come up with. Here's the procedure for accessing Diagnostic Codes using the Monitor System BTW....

Turn the key start switch to the ON position in order to initialize the Transmission/Chassis ECM. When the IC begins the self test function (sweep of the gauges), cycle the key start switch from the ON position to the OFF position three times within ten seconds. The ECM will be reset, if the key start switch is operated for more than three seconds. Then, leave the key in the ON position. The displays are used to show active diagnostic codes and logged diagnostic codes. Event codes are also displayed in scrolling mode. When an event code is displayed, the letter "E" is shown in the left display. When a diagnostic code is active, the letter "A" is shown in the left display. The MID is also shown on the left display. The CID and the FMI are shown on the right display. When a diagnostic code is inactive, only the code is shown. Each code is shown for several seconds. Then, the display will show the next code. After all the codes are shown, "---" will appear. The display will show all the codes again. The scrolling mode will exit after three loops of the codes have been completed or the key start switch is placed in the OFF position.

 

[Ruahines]

Ok I got a chance this morning to look at it with no other tasks to cloud my tired old brain.
It felt like an inhibitor switch issue (I come from 30 odd years in the light vehicle game) common problem with older cars, so I stripped off the covers on the selector lever.
Pulled the plug off, cleaned, dried and re-assembled. This truck came from the Pilbara so it has red iron based dust everywhere, tried the starter and all good.
To be on the safe side I applied the usual electrical grease when re-assembling and did the same for many other connectors in the dash area.

I then disabled the fire suppression/shutdown timer and checked the error code display.
No active codes which I expected and amongst all the aother error codes were 702's(shift sensor) high and low current. That red dust is nasty stuff.
Many thanks for the assistance and the schematic which will be useful fixing some of the other little issues that the truck has.

 

[Ruahines]

A couple of weeks down the track and no starting problems so we can assume that it was the dust.

Both trucks are now out at work and so far no issues.
One truck had an operators handbook but unfortunately it is in Czech and I do not speak that language at all.
A pdf of an operators handbook or a link to download it will be appreciated. Google has not been my friend in locating one so far.

Thanks in advance

 

[Nige]

There won't be Operator's Handbooks on pdf as far as I know. They used to be available in that format as well as in paper and on-line in SIS-web but the pdf option was dropped a few years ago, dunno why because it made sense. Come to think about it that was probably the reason. You need to get your boss to bite the bullet and order SEBU7815 from your local friendly Cat dealer. It'll probably be about $50.