Lb7 high return rates
Injector return flow is high but not near as excessive to cause that drastic of a fuel pressure drop. Max return per bank usually runs about 4-5ml. According to the test procedure on Mitchell, and GM's bulletin, with my fuel API at around 40, it says max return is 40ml per bank. I beleive (someone verify) that each injector should return about 3 ml during 15 seconds of cranking. Thats 12 ml per bank for you math majors. All you do is capture the fuel and measure it. If you follow the return fuel line at the driver side firewall, that will help,you chase where you need to grab the return fuel. Run the lines into 8 measuring cylinders and measure the return rate. They should all be the same. This test is tricky too because you have to get all the air out first. This is how we diagnose injectors with excessive return volumes and the balance rates usually coincide with high return volumes. This is a quick reference test to determine if there are possible issues w injectors OR cp3 pumps in the LB7 Duramax. lb7 injector return rates balance rates cp3 failure rail pressure relief
Buy DEF LB7 Injector Return Line Bolt for 2001-2004 GM 2500 Diesel 6.6L Duramax Return Fuel Line 8 Pcs: Fuel MATERIAL: Stainless steel,10.9 level high strength bolt. Shipping Weight, 4 ounces (View shipping rates and policies).
25 Nov 2015 Injector balance rates are only measured while the truck is in neutral, or in drive with the foot on the brake. Back leakage/return flow; Solenoid response time; Reveal external leakage issues (common on LB7 engines) And InjectorsDirect. com, we test all of our injectors using the highest standards, and Leaking ball seats will show up better at higher rail pressures than they do Return rates is the amount of fuel each injector returns to the tank during a I have used this method for finding more bad LLY injectors than LB7's. GM 6.6L LB7. Duramax high-pressure side of the fuel system is pressurized up to 23,200 PSI and the injector wiring inaccurate injector balance rate results. 4. DTech fuel Torque the injector return pipe banjo bolts to 12 ft-lb (16 Nm). 16. 18 Oct 2018 IN-DEPTH LB7 DURAMAX HEAD GASKET AND FUEL SYSTEM REPAIR system with a high pressure CP3 injection pump that made everyone a skeptic. can disconnect the injector return lines to check fuel return rates.
Typical LLY Duramax injector failure is high fuel return rates, which cause hard The LB7 Duramax built from 2001 – 2004.5 is known for injector failure.
LB7 Trucks came from the factory with a 200K mile, 7 year warranty on injectors. The job pays 16hrs to replace them on top of about ~2300 in parts. It's a big job, it's important to diagnose correctly! I replaced the last high positive and all of the rates dropped to +/- 1. Checking the returns rates is the first thing to do since it's so simple and if they are all ok, then I would add them up and if negative, replace the highest neg first. If positive, replace the highest positive first. If the returns rates are bad, you have to fix those first. High Pressure Testing (LB7 Example) Before starting, it is important to note that the high pressure fuel pump must be able to produce a minimum of 2500 to 3500 psi while cranking during the carbon on the nozzle tip then balance rates should be high on that cylinder. 5. Some LLY engines have a reflash that addresses rough run, miss, and smoke concerns. Check to make sure the ECM is up to date. Dilution. 1. Cracked injector 2. Injector return lines are under the valve cover on LB7 engines. Pressurize the return If your making oil, chances are your return rates are way out of spec causing fuel to leak into the crankcase. In other words, you most likely need injectors. LB7's are notorious for injector issues, the injectors and injector cups carbon up and they don't perform as intended. IF they are out of spec, don't just replace the bad ones do them all. 1) High-Yield Savings Accounts. When it comes to low-risk investment options, a high yield-savings account is one of the best ways to invest money. Although the potential for high earnings is typically lower than it is in the stock market, up to $250,000 of your money is insured by the FDIC per account – provided you deposit the money with an
Run the lines into 8 measuring cylinders and measure the return rate. They should all be the same. This test is tricky too because you have to get all the air out first. This is how we diagnose injectors with excessive return volumes and the balance rates usually coincide with high return volumes.
Over time, this ball seat erodes and no longer fully seals. When an LB7 injector begins to leak, you’ll notice the truck hazing at idle and you’ll also be able to observe abnormally high injector balance rates (the amount of fuel each injector contributes to maintain a smooth idle) with the appropriate diagnostic equipment. What You Need to Know About Duramax Balance Rates The Duramax has proven to be a reliable engine since its introduction back in 2001. Generally, most owners and service techs are well aware of the importance of keeping a clean fuel system by running clean, high quality fuel, lubricity additives, and routine fuel filter changes along with all The fuel rate should be at least 8MM3 of fuel, but the fuel rate is 3MM3 of fuel for this example. So we need to add -5 to all of these balance rates to get the actual numbers(the displayed fuel rate is 5MM3 of fuel low, so it is -5 off). GM only provides a specification for return fuel when cranking for LB7 engines, however, we have done some testing on a good running LB7 and found that injector return flow at idle from one bank was 95 – 110 ml in one minute at 21,000 PSI.
If your making oil, chances are your return rates are way out of spec causing fuel to leak into the crankcase. In other words, you most likely need injectors. LB7's are notorious for injector issues, the injectors and injector cups carbon up and they don't perform as intended. IF they are out of spec, don't just replace the bad ones do them all.
18 Oct 2018 IN-DEPTH LB7 DURAMAX HEAD GASKET AND FUEL SYSTEM REPAIR system with a high pressure CP3 injection pump that made everyone a skeptic. can disconnect the injector return lines to check fuel return rates.
Injector return flow is high but not near as excessive to cause that drastic of a fuel pressure drop. Max return per bank usually runs about 4-5ml. According to the test procedure on Mitchell, and GM's bulletin, with my fuel API at around 40, it says max return is 40ml per bank. I beleive (someone verify) that each injector should return about 3 ml during 15 seconds of cranking. Thats 12 ml per bank for you math majors. All you do is capture the fuel and measure it. If you follow the return fuel line at the driver side firewall, that will help,you chase where you need to grab the return fuel. Run the lines into 8 measuring cylinders and measure the return rate. They should all be the same. This test is tricky too because you have to get all the air out first. This is how we diagnose injectors with excessive return volumes and the balance rates usually coincide with high return volumes. This is a quick reference test to determine if there are possible issues w injectors OR cp3 pumps in the LB7 Duramax. lb7 injector return rates balance rates cp3 failure rail pressure relief