What is code P1093?

Error Code P1093 is set because the fuel rail pressure is low. Meaning, there’s a problem in the fuel pressure relief valve. This is quite a common problem among diesel engines. The valve is a small plug at the end of the driver’s side fuel rail.

What should the fuel rail pressure be on a lb7 Duramax?

Note that the fuel rail pressure is at 24,053 psi. As stated previously, the fuel pressure with the Ignition relay unplugged needs to be a minimum of 2500 to 3500 psi during cranking for the return rate test results to be valid.

What is the fuel pressure on a 6.6 Duramax?

27,550 psi
Use common sense safety practices when servicing any diesel system: While maximum control oil pressure on a Power Stroke can reach nearly 4,000 psi, the Duramax fuel system is pressure-relieved at a blistering 27,550 psi.

What causes P0087 Duramax?

DTC P1093, P0087 causing limp mode is common with this issue. Low rail pressure may or may not cause an MIL (check engine light). This is a very common problem that we hear about from our Duramax customers. Actual fuel rail pressure is not keeping up with desired fuel rail pressure.

How do I know if my fuel pressure regulator is bad on my Duramax?

The symptoms of a bad regulator usually manifest as a surge when idling, though sometimes the surge can happen at speed while driving. Other symptoms include power loss on acceleration or hard starting. Sometimes it can get bad enough to force the truck into limp mode with a low rail pressure warning.

What causes low fuel rail pressure in a 6.6 Duramax?

It could be a restriction or a leak on the supply line between the fuel tank and the injection pump. It could be a weak injection pump not able to increase fuel pressure up to the maximum under load. It also could be one or more injectors have high return rate.

How do you know if fuel pressure regulator is bad?

Symptoms Of A Bad Fuel Regulator

1. Engine misfires/poor acceleration.
2. Black smoke coming from the exhaust.
3. Spark plugs appear black.
4. Reduced fuel mileage.
5. Gasoline in the vacuum hose.
6. Engine backfires.
7. Engine won’t crank.
8. Excessive fuel pump noise.