Low fuel pressure Duramax

[was_butnotnow]

I have a 03 Chevy Duramax and just replaced the fuel filter (getting ready to head for summer travels) and the next day after about 40 miles it went into limp mode with engine light on. Have enough power to drive but when I try to hit the foot feed it almost stalls for lack of diesel fuel. Got it to me local repair guy late on Friday and he took a engine code reading and it said low fuel pressure. Going to take it back to him on Monday.
Now my question why with a NEW filter this would happen?
We have replace these several times in the past without a problem. You learn when pulling a big 5er in the mountains and you go into limp mode to make sure your filter is good and you have a spare.
But now with a new filter it happens.
I bought a WIX filter 33960XE at $59.99 at O'Reilly auto parts so not a low end filter by any means.
Any ideas?

[tdeal823]

Good to hear you are back on the road.
Before you spend $4500, I would spend $600 on a lift pump. Just my opinion.
Good luck and happy travels.

[24fb_freedom]

glad to hear the good news!

[was_butnotnow]

Happy News...
The local mechanic called.... the new fuel filter did the trick. Power all back and I got it and drove it hard. Just like new. Took the fuel filter to O'Reilly Auto Parts and they were happy to refund my money.
The local mechanic said he didn't see much smoke at idle and not to worry about at this time. And since no fuel in the oil looks I'm good to go for awhile. Heading out on summer travels, but will check out new injectors this fall. I talked to Desert Diesel in Tucson and he was very friendly and if I want new injectors he has a deal that he changes everything fuel lines CP3 pump and all related parts (non off market injectors, the real deal) so it is all new so now problems later for total of $4500.
Checking around that seems like a very good deal. He came highly recommended by my mechanic in Benson, AZ who doesn't work on Duramax.

[Raften]

Could be bad fuel, has the truck not been used much. I am currently fighting algae in my tank because I did not add biocide over the winter.

[was_butnotnow]

OK got in the truck to take it to the mechanic and it stalled and died 1/8 mile and then I had a hard time even getting enough power to get ti 3 miles to the mechanic. Slowed to 5 mph going up slight hills. Still getting P0087 code and I called loves truck stop and they were kind enough to check back in their credit cared records for my fuel purchase and confirmed I bought gas diesel. So now the local mechanic is only going to replace the filter and we will see if that helps.
Next question if it comes down to needing new injectors how hard is it to change them. Not that I'm going to do it but for the Chevy dealer. I see online at Injector Wharehouse they are $200 plus core of $100. I called Chevy parts and they want $350 and $100 core.
Found this... guess this is not a DIY
The LB7 injector job is pretty significant. The injectors are buried below two layers of valve covers, each with a gasket that is both expensive and generally not saveable. Each injector also has a return washer that must be replaced. All of the FICM seals and water seals must also be replaced when performing this job. Gaskets and seals alone can be as much as $400! Add 8 injectors at $359 each (dealer price) and this job is pricey.

[RCMAN46]

was_butnotnow wrote:

larry barnhart wrote:
Have you pumped the filter when it is not running good to see if the filter is full?

chevman

Did pump the filter the mechanic said it was soft and pumped it some.... didn't help.

A soft prime pump would indicate to me there is air in the system. A small leak can cause the problems described and still possibly allow the truck to run with a light load.

The pump should go solid after the air has been bled out of the filter.

[GoPackGo]

The rattling sound is probably the water sensor float. It's plastic and slides up and down on a shaft, if I remember correctly.

So it sounds like you replaced the ENTIRE fuel filter and WIF assembly. Those are 2 separate pieces. Suggest that you make sure there's a good seal between them. Again, if I remember, there is a rather fat doughnut seal between the 2 pieces. It does not go around the perimeter but is located in the center. I don't remember if there is another separate gasket that seals the edge between them or not.

* Make sure there's only one 'doughnut' between the 2 pieces.

I've been away from these for a while now. Really need someone who replaces their own fuel filters to chime in to address the number and location of these gaskets.

Tim

[GoPackGo]

Yes, if that thing fails, you are stopped dead in place until you find a replacement. And it probably would not be a bad idea to carry a spare o-ring for it too.

I'm not sure this is the OP's problem because if you get air in the lines the engine will not start or run. But I suppose it's possible that an o-ring somewhere has a very slight leak and allowing a little air to enter. I would remove the filter and clean all gaskets/o-rings in clean diesel, then re-assemble and see if the problem goes away before doing much else. Same for the bleeder o-ring. Also possible the top gasket is twisted out of place somehow. Also check the mating between the filter and the bottom half water container.

These filters aren't he easiest to re-attach to the engine so it's easy for something to go wrong. I once had a real nice diesel leak due to the DEALER replacing the filter incorrectly. Didn't even get 3 blocks before the smell of diesel overwhelmed me.

One thing I've learned - When something goes wrong it's usually a problem with whatever maintenance was done most recently.

Tim

[tdeal823]

http://atptrucks.com/merchant-automotive-diesel-aluminium-air-bleeder-screw.html

Here is a link to what Tim is talking about. It is definitely a good idea.

[GoPackGo]

I had that *&*&^% NYLON bleeder screw actually break on my '02 Duramax. Luckily I had already ordered a new all-metal replacement and had it had just been delivered. My strong advice to all Duramax owners is to replace the plastic one ASAP. Why GM/Isuzu did this on such a nice motor is beyond my understanding.

Tim

[tdeal823]

How many miles are on your truck?
Being a 2003 LB7 truck if the mileage is high and the truck has only had factory filters you could have injector or CP3 issues starting.
Lift Pump with filtration..... Everyone hates to spend the money on one but they are a fuel system saver. You could add one now and get your injectors and or CP3 to last longer.

[was_butnotnow]

larry barnhart wrote:
Have you pumped the filter when it is not running good to see if the filter is full?

chevman

Did pump the filter the mechanic said it was soft and pumped it some.... didn't help.

[was_butnotnow]

OK I've been doing some reading thanks to you guys getting ready for the truck to go in the shop in the AM. One problem the shop does not normally work on Duramax diesels.
Ok I called my friend who did the filter change (who flew out of state in the meantime. I was taking him to the Tucson airport when this happened) if the old O-Ring came off with the old filter. Yes it did. He hand screwed it on and then gave it a 1/4 turn more. he has changed several in the past on this truck the same way.
Will talk to the tech about WIF sensor for cracks and nylon bleeder screw for wear.
Also it was hot down here in AZ (100 deg)Friday when this happened (about 40 miles into the drive) and the trans was reading about 200 deg so need to pay attention to a possible collapsing rubber fuel line. Forbid trouble with injectors as for the last couple of years we have been getting blue smoke at idle at times. Not effecting millage.

NOW talking to my friend he sez the guts of the NEW WIX filter rattled when he shook it. Is there anything that should be loose inside a new filter like that? If not I hoping it will turn out to be a bad new filter.

[DUO_CORE]

WIF or O Ring failure would cause air to be sucked in and the truck would SHUT OFF....ask me how I know lol.

I've experienced the poo87 when pulling heavy through the mountains. AirDog 165 II lift pump/filter-water separator has solved it for the last 5-6 years. Added a fuel pressure gauge so I could monitor filters. I run at 8-9 psi and when I see <6 I change filters. I usually get 12-18 months out of the Airdog filter. I go ahead and change the OEM filter while I'm at it. I run mostly bio-diesel for the last 115k or so.
Hope you get it fixed.