Help diagnosing a cat320d starting issue

[Shivan Dookeran]

Hey everyone, I have a cat 320d serial kgf 00768 that recently started giving some problems , operator shut off for lunch one day and it refused to start . Tumbled for about 30 sec before it started .Since then on on morning where it used to start in half tumble its takes about 10 sec before it starts. When it heats up it will not start without the help of a spray of quick start. The machine is throwing no codes and I've checked for bubbles in the return line, even tried plugging it to see if it's air or a plugged check valve. What pressure do I need to see for the machine to start ? How can I rule out if it's fuel pump or injectors?
Sorry if it's a long read I'm just trying to cover everything .

 

[Simon C]

Have you changed out the fuel filters and put air into the fuel tank with an air blower nozzle into tank and holding back 1PSI of pressure with a rag ball over opening of tank. Disconnect the furthest the fuel line runs then try again and see if fuel rushes out of line. Have you blown air back into tank. Maybe your filter housing is partially plugged in an elbow by dead flies or who knows what.
Try something and let us know.
Simon C

 

[ahart]

What you’re likely going to need to do here is get an ET connection to the machine and record actual vs desired rail pressure when cranking. You very likely have an injector or multiple injectors that are dumping high pressure fuel.

 

[Shivan Dookeran]

Thanks ,will do that tomorrow , when you say dumping ,is it bypassing via the seals ?

 

[ahart]

No, internal part of the injector is sticking open allowing high pressure fuel to leak into the return.

 

[Nige]

Shiv, just be aware that the lines from the rail to the injectors are (allegedly according to the manufacturer) single use only. If you remove one you’re supposed to replace it with a new one. So if you do have a bad injector you want to make double sure you know which one it is before you start disassembling stuff.

 

[heymccall]

Let's go basic.
The circled drain plug MUST have the thumbwheel flush with the water bowl boss. I've changed many when they won't thread all the way in.
Secondly, the seal ring the arrow is pointing to must be present and I've also seen two in there. With out the ring present, it'll give the same symptoms as listed above, yet not really leak.

Also, hours on your machine aren't listed. How many hours on machine?
Have you drained the water and such from the fuel tank? What came out?

 

[heymccall]

Tamk sediment and water drain.

 

[Shivan Dookeran]

Ok machine is doing 12800hrs all filters were changed about 3 weeks ago by me and tank is drained once or twice a week ,the sediment filer is clean , haven't tried pressuring the tank yet .tomorrow I'll walk with my laptop and get the readings both when it's hot and cold

 

[Simon C]

Did see a collapsed fuel line on a truck with 8000 hours this winter that took a while to diagnose. It would run perfect for 1 hour and then all hell would break loose.
If they are original consider changing them.
Will have to eventually one day anyways, But handy to see pressure drop when problems happen.
Simon C

 

[Shivan Dookeran]

So all tests points to injectors so I'm in the process of ordering in a set of injectors and lines, is there a washer like the 3126 as I'm only seeing a o ring seal part number 294 1803 and a gasket 1r 6573? Also is the 326 4756 injector been replaced with any newer numbers ? Thanks for the info in advance .

 

[Nige]

s there a washer like the 3126 as I'm only seeing a o ring seal part number 294 1803 and a gasket 1r 6573?

What's referred to as the "gasket" 1R-6573 is actually a copper washer.

I would check your injector Part Numbers physically before ordering. I see two Part Numbers, 326-3756 & 326-4700, and they don't appear to cross over from one to the other. Whichever one it is there is nothing any newer as regards Part Number.

12k+ hours on original injectors is pretty good IMO.

 

[ahart]

Based on your serial number, you have an engine arrangement of 305-4776 which uses injector PN: 295-9130 which updates to a 326-4700 which has a reman option of 10R-7675 gasket/seal numbers you listed are correct.

 

[Nige]

Based on your serial number, you have an engine arrangement of 305-4776

I suggest to double check that with the engine S/N plate details.

 

[Shivan Dookeran]

When changing injectors do I need to input the trim files found stamped on the injector?mechanic kno2s what he is doing but I'm asking for my own information

 

[ahart]

That is the correct way to do it, yes.

 

[heymccall]

While putting in trim files, be sure to download the entire product status configuration? files. My 320DLRR at 6k hours decided to forget everything, especially joystick button configurations for the auxiliaries. I was fortunate enough to have the download data from a previous service visit. Without the download, it would've taken forever to program the configurations back in, and, they probably wouldn't all be correct.
I'm told Caterpillar doesn't have that info saved anywhere.

 

[Nige]

While putting in trim files, be sure to download the entire product status

Excellent advice. Before touching anything download a complete Product Status Report. Then download another one when whatever service work has been done is completed.

I'm told Caterpillar doesn't have that info saved anywhere.

It's a coin toss whether all the info would be there, or even be the correct info. Should be in TMI but don't bank on it.

 

[Shivan Dookeran]

Forgive my noobiness since this is my first injector change with this excavator , previous ones were 3176 but the product status is found under configuration in ET?

 

[Nige]

Forgive my noobiness since this is my first injector change with this excavator , previous ones were 3176 but the product status is found under configuration in ET?

I think it's in the Status section of ET as part of the drop-down menus. Either way it won't be that hard to find because there aren't that many menu options. IIRC it's titled "download Product Status Report" or something like that. It is the option to download a PSR as an Adobe pdf file. The complete PSR could easily run to 10 pages. The automatic file naming is somewhat clunky, we used to change the name to the machine Serial Number and the date.

Don't forget that if you change 6 injectors you're going to need 6 new injector lines as well.