Duramax Update...

Well, after much of a battle, the engine is back together, and last weekend we got it back into the truck and fired. Have a small transmission issue we are chasing now, but other than that, everything WAS seemingly good. Took it out for a drive, threw the exact same P0093 "Fuel Leak" code. AGAIN.... This is the same code that usually leads to injector failure. After a couple days of thinking, we finally decided to test the CP3 Injection Pump this morning. Communicated to the ECM of the truck with a Tech II from GM, commanded the pump to full operating pressure (21,000 PSI at IDLE!), it made it to a hair over 16,000 before it quit. So, just ordered a $600 CP3 pump! Now I get to tear the top of the engine apart. Again! :/

Also ordered a fuel filter adapter that will allow me to run a CAT 1R-0750 , 2 Micron filter on the truck. From what I have read it is a very popular option. GM's stock filters are about 5 Microns. Either way, the adapter kit is about $50, and the CAT Filters are $17. The GM Filter is around $50. I like the sounds of that!

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Some gremlins are found in small hurds. Some are more of a flock. Best of luck, jim

I think I found the mother ship?? Oh well. Going to be an awesome truck when done.

You're gonna get pretty good at working on those motors!

I understand that those 2 micron filters can be problematic during north country winters.

A friend that was the machinest at a local auto parts store would not sell a rebuild kit unless you sent in pump and injectors for test and repair, and also new head bolts. As he said all it takes to ruin a rebuild is one slobbering injector. Good luck.

Hope you don't have injectors leaking, that will show low pressure in the system with a good CP3 pump. Used to use a cap on Cummins to locate a leaking injector by removing each injector line one at a time and cap the rail outlet. When the engine then starts on five cylinders with the leaking one out of the system the culprit has been found. In most cases it's best to replace all injectors, usually the others are not far behind. Remember, pressure is caused by resistance to flow. Have seen CP3 pumps replaced before when one or more injectors are the culprit.

Well, we put a full set of injectors in it before, when it set the code the first time.

Bryce, Keep up the good work. Just look at all the good experience you are obtaining. Good for you Good Luck. Mt. Man

I am so glad that we did not order a diesel in the last four trucks.

i had 2 duramax trucks. good motors, expensive to fix. glad i have 4 cylinder Farmalls i can work on them

bass
53superC

Got to admire you for sticking with it,I think I'd of given up long ago.

It will go quicker the second time.... We've all been there at one time or another.

I love my Duramax!

I also have the adapter and run the CAT fuel filters. You will just leave your WIF sensor wire unplugged as you will no longer use it. Whole you have it apart, might as well delete the EGR, or at least block it and do the PCV re-route as well. No sense in dumping all that back into your intake again now that you have it all cleaned up!

Do you live in a state that does emissions testing? If not, I would pull your catalytic converter. I run an MBRP 5" stainless turbo back exhaust with their muffler. Kit is very nice but if I had it to do over, I would go without the muffler too. Check your transmission cooler lines as they are prone to leaking. I am running Alligator Performance lines and would recommend them. Also check your transfer case over good for signs of pump rub. I installed the Merchant Automotive pump rub fix kit before mine put a hole in my case.

Before you go pulling the pump, what are your balance rates on the Tech 2? In my experience, any one over positive 5 can cause the low rail pressure code, two over 5 and an LB7 will have starting issues. Then you need to do a return rate check on each bank, if one bank is high, there is a suspect injector on that bank. Just because the injectors were replaced doesn't mean they are good. Aftermarket injectors are universally junk. If I open up an LB7, it gets genuine Bosch or GM. Did you clean or replace the rail to injector lines? Not doing that can take out even the best injector. Other things to look for are the fuel supply lines, I have been seeing them start to kink at the nylon flexible sections at the left valve cover, I think due to sagged engine mounts. I would highly recommend installing an Airdog, or other fuel supply system, to convert it to pressure lift system. The vacuum lift system is the Achilles heel of the Duramax. Fuel system 101 says never install a fuel filter on the vacuum side of a fuel system, but yet college edumacated engineers put right where it shouldn't be. The aftermarket supply systems also clean up the engine by eliminating all factory supply lines and filter housing on the engine. To end my ramblings, I don't see a lot of CP3 failures on the LB7s because it isn't worked to capacity. I would bet you have a supply restriction or a high return rate on an injector.

Well, on and 01 chevy, they didn't have and EGR system, which is one reason I liked it! I went with a bigger down pipe, and a 5" straight pipe all the way back with a 7" stainless top. Looks hood, and rumbles pretty good.

Good luck, your perseverance is commendable, and you will learn a lot.

How much will you have in the engine when done?

Don't know off hand for just the engine, but right now I am sitting at about 12,000 for the entire truck. Rebuilt lower end of engine, 2 new cylinder heads, injectors, pump, bigger exhaust and a small turbo upgrade. Truck had stainless simulators, New paint, New tires, and a few other goodies.

It has been a long process, but the reality is that there is no way I could buy this truck, in this condition, for the 12,000. It is pretty close to new!?

Cali models of the LB7 do have EGR, even in '01. You are lucky yours does not have it, total craper of a system.

Ya I know... I actually went to look at a 2002 LB7, and it DID have an EGR system, that was what made the deal a no go for me. Didn't want to mess with that on that old of a truck. It was a Cali model.

The EGR system on an LB7 actually won't run the nessassary monitors to pass emission testing in Cali. GM and Californistan have an agreement to let them pass emission testing without the monitor showing pass. The system works, just won't show it is. Problem only cropped up after the trucks had lots of miles and the codes are cleared.