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Jchism3406 · 08-28-2026, **(Subject: 0482 )**

I’m getting code 0482 pid 94 fmi 1 on a cm570. I’ve done replaced the check valves, fuel pressure regulators, a new filter and new screen inside the ifsm and a new pump. I did the 5 gallon bucket test and used a supply hose and ran it from there. The fuel pressure is 245 at idle. Soon as you hit the pedal and hold it open it’s drops down to 180 which is activating the code. Once you left off the pedal the code goes inactive. I also checked fuel pressure with a manual gauge and it still drops. What’s next. Any help would be greatly appreciated

Rawze · 08-28-2026, **(Subject: 0482 )**

A snapped shaft inside the gear pump would cause this.

Jchism3406 · 08-29-2026, **(Subject: 0482 )**

When you say gear pump you are talking about the piece that bolts to the ifsm? If so I installed a reman one from Orlando cummins. If you are talking about the ifsm idler gear I took off the ifsm and checked the gear inside. It’s got some play. I took a video but I’m not sure if the play is good or not. Also I looked in quick serve. And reading through I see there’s a check valve inside the supply side of the ifsm and mine wasn’t there. But I also do no have a primer pump on this engine

Rawze · 08-29-2026, **(Subject: 0482 )**

gear fuel pump is known to sometimes have its shaft snap internally and make pressure at idle, but slip when it has to work harder. The pump cannot keep up properly when this happens.

also if truck has clogged fuel filter, has collapsed fuel lines, or is sucking air, etc. it could cause what you describe too.

Jchism3406 · 08-31-2026, **(Subject: 0482 )**

Good morning yes. That’s why I’ve eliminated all the easy stuff. Is it possible for the injectors to cause a low fuel pressure ? Also my fuel gets dark. Wasn’t sure if that’s normal

Rawze · 08-31-2026, **(Subject: 0482 )**

(08-31-2026 )Jchism3406 Wrote: Good morning yes. That’s why I’ve eliminated all the easy stuff. Is it possible for the injectors to cause a low fuel pressure ? Also my fuel gets dark. Wasn’t sure if that’s normal

does it pass injector leak bubble tests?..
info: https://rawze.com/forums/showthread.php?...8#pid67948

Rawze · 08-31-2026, **(Subject: 0482 )**

popping back thru the intake can also be a severely clogged exhaust manifold, either due to turbo too high position at idle, or a different clog like cans not hollowed out properly after de-mandate, clogged exhaust or muffler, etc.

It can also be an intake butterfly valve slamming open/shut, or an EGR valve doing this.

If the engine is demandated, the intake butterfly valve should have had its butterfly removed, and crank case filter gutted or removed as well.