Cat C-15 mxs fuel pressure ?

The older C-15 pumps can be shimmed by using copper washers under the spring not with a longer rod. The new ones can be done the same way, but be sure to check your fuel pressure afterwards.

 

What also happens is when the Safety relief cracks off is must compress the spring to do so and in doing so it creates a bend in the spring as its compressed and the spring goes a bit like a Banana. This causes the bend in the spring to rub on the side of the bore and wears the spring coils down slowly (depending on how often it cracks Off). This reduction in spring coil diameter also reduces the spring tension. That then reduces the Safety relief pressure and everything slowly gets worse and worse as its cracks off more and more at a constantly reducing rate.

You see excessive wear on this spring when Guys Shim the Crap out of the spring and its kinks the spring in the bore, even when the Valve is closed and wears..
The later CAT spring is not only longer but a heavier Gauge, so give the shimming away and use that later heavier spring.

Having the FAS fitted is a small bonus as it reduces the workload on the pump as it then only has to produce flow not draw from the tank.

 

MXS will respond big time to fuel pressure so if your old pump had the old spring and you fitted a new spring with your new pump you would mediately notice a big difference.

 

Something I’m not sure many are aware of and it’s very important in the injector operation.

The Plunger under the Injector Tappet isn’t connected to the Tappet like the OLD injectors or the 3500 Injectors.

Meaning when the spring lifts the Tappet back up after each stroke it doesn’t drag the Plunger with it.

These CAT injectors rely solely on Fuel pressure to push the plunger back up against the tappet to ensure a full stroke of fuel next injection.

“IF” the fuel pressure is low then the ability to maintain 100% plunger stroke is reduce which will affect the Fuel Volume delivered Next Stroke and also affect the Injection Timing (ret@rd it).

Explains why you have Low power and HIGH fuel consumption I guess!!!

 

When you replace the pump with the newer,better one. Did you have to do anything else to the system? Or it's just a simple remove and replace?

 

where do install the fuel gauge at. If you can mark in red.

 

Where do u install gauge. I’m just trying to get overall pressure. I’ve noticed my TPS only shows 83% in ET but also read this is normal any info??