"Change Fuel Filter"- P0086 low fuel rail pressure

BlackSilver · April 13, 2014

2008 DMax 3500 pulling about 7 ton trailer.

At highway speed 65mph DIC says change fuel filter, engine went to limp and threw "generic low fuel rail pressure" code.

Erased the code, drove at reduced speed 55mph for about 100 miles to overnight stop with no problem. Changed out the fuel filter last night.

This morning hit the road again and got about 300 miles before a repeat performance. Reset the code, at highway speed got only a few miles and repeated. Reset the code and drove at 55 for about 100 miles to overnight stop without problems. All the above pulling 7 tons.

Should I change filter again and hope, or take it in to shop?

Prokopchuk_9 · April 13, 2014

Check the spin on head for leaks, any little bit of leaking or sweat around the filter head will cause issues...one of the most simple and most common fuel system issues with an lbz/lmm/lml

Prokopchuk_9 · April 13, 2014

If it is leaking you can buy a rebuild kit, i would recommend just deleting it all together and running a good lift pump...that way you have much better fuel delivery, more mpg, smoother running, quicker spool up and you can run as low as 2 micron filter. AND it's not a complete

a$$**le to change a filter. Not to mention a wAter separator as well.

If it's NOT leaking, check all other fuel lines. You're getting low rail pressure so it could be a few things, first I would check for any leaks. If no leaks I would check actual vs desired rail pressure (cp3 vital) if that was ok I would check out FPR voltage...

Check for leaks though, could be suckin some air or loose pressure

BlackSilver · April 13, 2014

Unfortunately I'm in the middle of a trip from Arizona to Minnesota, now holed up in OKC waiting for dealer to open Monday morning. Filter base looks dry.

One note --- when I pulled the first filter it didn't seem "full" because no fuel dribbled down my hand as I removed it. Perhaps it is sucking some air.

Prokopchuk_9 · April 13, 2014

Unfortunately I'm in the middle of a trip from Arizona to Minnesota, now holed up in OKC waiting for dealer to open Monday morning. Filter base looks dry.

One note --- when I pulled the first filter it didn't seem "full" because no fuel dribbled down my hand as I removed it. Perhaps it is sucking some air.

You're sure you primed it until NO AIR

At all?

Sounds like it's suckin air man! I bet it's filter head

Prokopchuk_9 · April 13, 2014

Got my fingers crossed for ya it isn't cp3, hope it's something quick and easy!

GMCustomerService · April 14, 2014

Hello BlackSilver,

I am sorry to hear that you are experiencing an issue with your vehicle while on vacation. I understand that you are waiting to have the dealership look at your vehicle. Please keep us updated on your vehicle situation and contact us if you have any lingering questions or concerns.

Jennifer T.

GM Customer Care

Prokopchuk_9 · April 16, 2014

What happened man?

BlackSilver · April 16, 2014

OK, the truck is rolling again without codes. Full new set of injectors. $7,200. Prolly could have nursed it home, but all were leaking so bad at high fuel temp under load that the pump couldn't hold rail pressure.

Prokopchuk_9 · April 16, 2014

OK, the truck is rolling again without codes. Full new set of injectors. $7,200. Prolly could have nursed it home, but all were leaking so bad at high fuel temp under load that the pump couldn't hold rail pressure.

No way!! Why did they all hang open? Odd for a LMM to have a major injector failure like this. Do you run any type of additive? Did you get bad fuel?

This is why I run a lift pump and run additive...$7200 bills scare me lol

BlackSilver · April 17, 2014

7 of the 8 were running way out of spec. Replaced the 8th one just to be safe. Don't recall the name of the test (balance?) but numbers were supposed to be within +/-4 ..... Unloaded all looked decent on the monitor, but accelerating on a grade they went all over the map. Tech suspected water/bad fuel. I don't run any additive except in really COLD weather. The initial incident was about 200 miles after I filled at a crappy looking station out in the boondocks east of El Paso. I dunno...... I really pushed hard the past two days from Oklahoma to Minnesota, and no more codes, so I'm pretty sure the injectors were the culprit.

Prokopchuk_9 · April 17, 2014

7 of the 8 were running way out of spec. Replaced the 8th one just to be safe. Don't recall the name of the test (balance?) but numbers were supposed to be within +/-4 ..... Unloaded all looked decent on the monitor, but accelerating on a grade they went all over the map. Tech suspected water/bad fuel. I don't run any additive except in really COLD weather. The initial incident was about 200 miles after I filled at a crappy looking station out in the boondocks east of El Paso. I dunno...... I really pushed hard the past two days from Oklahoma to Minnesota, and no more codes, so I'm pretty sure the injectors were the culprit.

Balance rate test...and ya supposed to be within 4 at operating temp. I would venture to say you got bad fuel, LMM injector failure isn't very popular at all...

I run additive in every tank, year round.

BlackSilver · April 17, 2014

I run additive in every tank, year round

Which additive? Sounds like cheap insurance (he says after shelling out 7-grand+)

Prokopchuk_9 · April 17, 2014

I run grey bottle power service in summer and white bottle power service in the winter (white = antigel + winter formulae)

I've also ran stanadyne, it is cheap insurance. Today's diesel is so dry it's wise to run additive in every tank IMO. ULSD has almost no lube for injectors anymore that it wears on fuel system parts faster. I'm religious with filters and additive.

Which leads me to this, blacksilver buy yourself a lift pump. Very easy to install, I bet you none of that would have happened if you had one. You can run 2 micron filters, have a water separator, inj pump doesn't have to work to pull fuel from tank, removes the air from the fuel which gives you better atomization at the injection pump which in turn provides longer pump life and in the long run injectors will stay cleaner, run smoother and last longer. Lift pumps should be on the truck to begin with from factory. Very smart addition to a diesel nowadays, best $600 you can spend on any diesel.

This is the pump I run, but with fleetgaurd (cummins...lol) filters

http://www.pureflowairdog.com/airdogII.php