I have 150K miles on my LB7 Duramax and have been battling the SES Light, LIMP mode, and P0093 code for some time now. The only time I throw the code is when pulling a steep grade or towing a trailer (5K lbs), under normal operation conditions the truck runs great. The tough thing about the P0093 code is that it is generic and doesn't nail down the problem enough to remedy it. So, I took the truck to the stealer to get their opinion and they decided I needed to replace the fuel rail pressure sensor at $494.20. I agreed hoping this would resolve the issue. The truck ran fine as it always does when not under load until I put a trailer behind it. Throws a P0093, SES light, Limp mode, downshifting Allison. I take it back to the dealer (now with a new diesel mechanic) and he finds that I have low fuel pressure because I have diesel sludge caked to the inside walls of the fuel lines, a clogged artery, thereby causing the engine to not pull enough fuel in high demand applications. The fix is to drop the fuel tank, flush the lines, and replace the fuel filter at $658. I tell them we replaced a perfectly good fuel pressure sensor 3K miles ago and I would pay the difference between the sensor and the flushing of the lines ($163.80). The dealer agreed and started the work yesterday (7/3). They called me back and said the fuel line flushing would not work because of the gummy buildup was too thick and I needed to replace the fuel lines at $600 and that the injector pump should also be replaced at $1000 to ensure I do not have the same issue. $1600 is a little hard for me to stomach?

1. Do you think I am getting gouged here?
2. Shouldn't there be a way to flush the lines that works so I don't have to replace all the fuel lines?
3. Is it easy to replace an injector pump if I bought one myself and installed it?

I am just unsure of all of this and I'm not in a position where I can throw another $1600 at the truck at this time. Do you have any suggestions for me? Thanks for your help.

The lines are not that plugged! Unless someone prior had run nothing but WVO (waste vegitable oil) in the truck. I recommend running B20 Biodiesel to clean the lines, just keep a spare filter and all tools you need to change said filter. I ran B20 in my 01 after I bought it for three months and I was using a new filter every three weeks for two months, now I am on a regular interval. And the truck runs great! I still use B2 to maintain a clean system.

Here is a list of Biodiesel retailers in your area.
http://biodiesel.org/buyingbiodiesel/retailfuelingsites/showstate.asp?st=SC

Hope this helps,
Tony

I was going to say the same thing, but Tony beat me to it! Run B100 for a few tanks, and the Bio will clear the sludge in your fuel lines, tank, and the entire fuel system. Be prepared to changed fuel filters a few times. The Bio is a great solvant, and should break down anything in your fuel system. Keep us posted on your outcome! ;)

Been having this same issue and so have many others. For my story so far check the thread at http://www.dieselplace.com/forum/showthread.php?t=250142

The only Biodiesel in my area is B5. I dont have a clue of what that stands for and is the same price as DF. Should I every once in awhile run a tank of B5? And will this keep everything a little cleaner?

B5 is 5%

Thanks for the advice, gentlemen. Sounds like a cheap fix, not to mention that in SC biodiesel is a product of the soybean farmers here in the state. That keeps my money here as opposed to overseas and I like that. I'll just have to monitor my fuel filter and service it more frequently.

Do you think I need to replace the CP3 injector or will the B20 flush it as well? I want to be sure I don't have the limp mode, P0093 problem again.

Finally, the dealer dropped the fuel tank and removed some of the fuel lines to diagnose, what do you suggest I do?

Thanks for your much appreciated help.

i would tell them to put it back together. you should search around and find a better deal on the cp3 they arent that hard to put in if youre somewhat mechanically inclined. the POO93 is more than likely the cp3. went through the poo93 with all three of my duramaxes

Dodgedieseldad,

Even with the clogged fuel lines do you still think it's a bad CP3? I figure the code is getting thrown because the lines are clogged downstream causing low fuel pressure at the sensor.
Do you or anyone else know of any websites on how to replace the CP3 injector pump?

I'm going to investigate the dealer's estimate of $600 to replace the fuel lines (M&L).

Thanks, Mark

2500 I believe you are correct in your assumption. Let the bio do its work for a few weekes and se what happens after a month or two of running it. Two filter changes and you should be back in business. Give the bio some time to clean and lube the CP3, it should make it run better after a few days.

Tony

The 1093 could also be the product of a weak Fuel Pressure Relief Valve (It's under the GPCM on the end of the DS fuel rail). I was getting 1093's like crazy under heavy throttle until I replaced mine with a PPE Race valve. I'd probably either shim the existing valve or replace it with the race valve (which is actually a plug).

I met with the dealer this morning. I had the chance to inspect the fuel sending unit in the tank and the cup and lines that are a part of it. The fuel tank was clean when they pulled it. The fuel lines mounted to the frame were not easy to inspect to see how bad they really were. It's like trying to look down a spiral straw, you just can't see that far. I talked to the diesel mechanic and he said he had tried to flush the lines with brake cleaner and he had no success. If it was his truck he would replace the lines- $394 for parts, $180 for labor. I'm still like the idea of the B20, even though the mechanic said it would make it worse by dislodging the debris into the injector pump and module. I told him, isn't that what a filter is for? He also stated that the B20 would eat away all the seals in the fuel system. I just have a hard time buying it. Am I crazy or is this legit?

To correct my previous post, the dealer wants to replace the injector module, not the CP3 injector pump at a cost of $973.80. I don't know a thing about the module but it looks like it is an easy fix for a DIY. Could the module be affected by garbage in the lines? Could B20 flush the module as well?

I'm trying to buy time at the dealer to run this all by you guys. I've had a lot more luck and better knowledge of everything by posting on this forum, I really appreciate it.

Something smells fishy to me... I'd really take a close look at the FPRV... I suspect it would be lots cheaper for your dealer to replace that than all the other stuff, and I'd think it's more likely to be the issue than "cloged fuel lines"...