Low fuel pressure Duramax

It could just be a defective filter even though Wix is a good brand. Had it happen years ago on a 6.5 diesel. Try another filter first.

Are you sure the WIF plug is tight and the o-ring is in right. Might just be sucking some air. Did you make sure the old o-ring came off with the filter? And then, maybe RAS43 is right, occasionally there are bad filters.

I have had the exact same issue with my 07 Dmax. Happened the first time pulling a long grade last year, in the summer with my TT hanging off the back. It only does it when I'm towing.

I put a new fuel filter on it and it made no difference, indicating to me the problem is something else.

I posted a thread on this last fall. See it here.

I never did get mine fixed, as I haven't exactly pinpointed the problem, but research I have done points to an issue some of them have with the fuel line itself. I am told there is a rubber line that goes from the bottom up the firewall and it has been known to get weak and collapse, giving the symptoms of low fuel pressure.

Might be worth checking out more on this.

Mine did it again on a highway trip in Alberta a couple months ago when it was cold out.

Let us know what you find!

I would check the O-Ring, check the WIF sensor for cracks, or the nylon bleeder screw could be worn. If those are good, do you know if the fuel filter was ever overtightened? If so, it may have started a small crack in the fuel filter housing. I have replaced a few on buddies Duramax's that either tightened them to much (Hand tighten only)and cracked them, or took it somewhere where someone else overtightened it. They can be had for around $125 online.
BobsYourUncle - My BIL truck was doing exactly what you described. I replaced the fuel filter housing and he has not had an issue since.

What is the mileage of your truck? If your getting up there in mileage your CP3 could be getting tired. This is common in Duramax trucks. GM Duramax trucks are the only diesels that do not use a lift pump. They use the Injection pump (CP3) to deliver injection pressure to the rail and also suck fuel from the tank through the filter and up to the pump sitting at the motor. That is a long way to suck fuel. If you have any minor air leak you will get a loss in vacuum and starve for fuel. With any fuel maintenance you have to be extra extra clean. I can not stress this enough. Here are the steps I would take.
1...The easiest thing to check is a new filter. If you are using factory style filters you need to clean and maybe replace all seals along with it. This includes the water sensor gasket and the bleeder screw.
2...Is you are reasonably mechanically inclined you can rebuild the filter housing. Autozone, KOI, NAPA will all have filter housing rebuild kits for less than $50. It is all the o-rings and seals for the housing. The housings are very susceptible to dirt and debris at the primer plunger. If you are worried about the work involved you can buy a new housing also. If you get a new housing make sure it is for your year truck. GM slightly changed the hose routing somewhere in 2005-08.
3...Get a NICKTANE filter housing adapter and a Donaldson filter.
http://nicktane.com/osc/product_info.php?cPath=22&products_id=63

http://nicktane.com/osc/product_info.php?cPath=22&products_id=51

This will not always fix the problem. But if you have a week CP3 the larger filter will allow the pump to suck through the filter a little better.
4...The best solution is to install a Lift Pump back at the tank with a good water separator and filter built into one. These are expensive but once done are wonderful. AirDog 2 165 or FASS 150 are great options.
http://atptrucks.com/airdogii165-2001-2010-gm-duramax.html

Feel free to PM me with any questions. I will do my best you help.
good luck
Tony

I would think it it is one of the things already mentioned....bleeder screw. oring etc. I would also think you would be wise to stick with the OEM brand filter for your Duramax. The ac delco filter is darn good.

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

chevman

I found an interesting article regarding this problem.

See it here.

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.

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.