Why Do Fuel Regulators Fail?

Is your common rail diesel engine surging at idle or light load? It doesn't matter if you have a Cummins Duramax, Powerstroke or another flavour of engine your fuel regulator can be the cause of this, as Nick Priegnitz of Duramaxtuner and HPA diesel tuning course material explains.

The first part of knowing how something failed is knowing how it is supposed to work correctly which is why Nick is quick to pull a CP3 regulator apart to show you the inner operation, including a tip on current draws between LB7 and LBZ applications which is an easy adjustment once you know there is an adjustment to be mate.

Also covered is how to quickly test your regular to check if it has failed, along with 2 of the common reasons why they fail and cause our issues which are more noticeable at lower loads due to the bigger power difference percentage-wise getting more or less fuel than required will cause in this area of the map/calibration.

So what is the fix? Honestly, a new regulator is the go-to here, but understanding how these things work and the issues they can cause us can and will save us a ton of time and money chasing issues in the wrong places instead!

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TIME STAMPS:
0:00 - Surging & Hunting
0:49 - CP3 Regulator Example
1:10 - Housing & Plug
1:42 - Testing The Regulator
2:39 - Good Regulator Sound
2:42 - Bad Regulator Sound
2:47 - Regulator Control System
3:55 - Fuel Flow Slide Control
4:37 - LB7 Slide Example
4:47 - LBZ Slide Example
4:55 - Shape Changes Current Requirements
5:15 - Slide Functionality
5:57 - Potential Cause 1: Wear
6:44 - Low Vs High Load
7:48 - Regulator Failure Causes
8:34 - Potential Temporary Solution
8:58 - Potential Cause 1: Lift Pump
9:35 - High-Pressure Issue
10:09 - Potential Solution
10:33 - Thanks Nick! Have A Beer Mate!