Computergeekguy

I just purchased a dulley 4x4 6.6L Chevy silverado 3500.

When i first saw it in the lot it looked good drove good and was in exalent condition.

It had TONS of power and tore down the street.

Well i liked it enough i bought it for a not so nice price but that is how it goes.


Later I went to take it on a big job of moving hay from Minnesota to where i live in Missouri.

The trailer with the hay would haul up those big hills like they were not even there.

I was pretty happy with the truck than all of a suddan the check engine light came on and all my power left.


Ever since than it has been a nightmare.

If i turn off the truck and turn it back on it is fine and drives like nothing happend .

I changed the fuel filter hoping that it was bad fuel or somthing.

The problem has persisted for a while now.



Let me describe what happens.

The check engine light comes on i loose power.

The engine will not go above 2000 rpm in any gear.

I barely crawl up the hills at 20mph.

The engine dosent sound bad evrything sounds right but the truck just wont go.


I have reaserched and found that several people have this problem and it has earned the name "Limp Mode"

It is not a permanant problam as soon as you turn it of and restart it is fine again.


I have gotten to the point were i think it is some problem with the truck computer.

I dont know the codes for the engine light yet but ill try to get it soon.


Now some ideas i have had is if it is a computer problem were it switches to this "Limp Mode" for some reason how to i turn it off.

Modern technologie allows for people to plug something into the OBD-II slot called a power programmer were it overrides to trucks computer to add power or increase fuel econamy.

I heard of a guy that got a OBD-II to usb and hooked it up to his computer and was able to use his computer as the power programmer.

What i want to know is how do i use my computer to talk to the truck computer via the OBD to usb cable to ether learn how to fix this problem OR Flash the trucks computer (Wipe evrything) and reinstall the updated computer software.

Bottom line i want the truck fixed. Please help Thanks.

Computergeekguy

Evry time this has happened to me i had cruise control on and i was usally pulling a hill if it wasn't able to maintain the set speed would it trip somthing freak out the computer and kick me into limp mode?

Edit: Something else i would like to know. What causes the car to go into limp mode. If i know what causes it than i can try to avoid it. So if someone happens to know the things that commonly cause limp mode to engage i would love to know what they are.

Thanks

Computergeekguy

I just got the code.

It is P0087: "Fuel Rail Pressure Too Low"

So what does that mean? I didn't have enough gas to keep up the demand?

Its not the fuel filter so i can scratch that off my list.

Any way i saw that many people have had the exact same problem i do.

This is a common problem. Haven't found any common fixes yet though.


So what do i need to do to get it the fuel it need's I dont think it is a problem with clogged this clogged that. But i dont know anymore.

Could i put in an extra large fuel pump maybe with a higher flow or something?


Could the cruise control still be the problem? Cruise will try to maintain it at the set speed no matter what so if it start to slow down wouldn't it try to push enough gas to keep it up there and when it can't (because im hauling a big load up a hill) Would it not lose fuel pressure and freak something out?

Thanks for any answers on this.

ericnottelin

Is it possible the fuel pump is going?

Computergeekguy

I have worked on fuel pumps before. They are a pain to deal with. So if im going to replace the fuel pump i would like an over sized after market pump. Would that work?


The pump i worked on was an old gmc 1996. It would sometimes pump and sometimes not. Leaving me stranded until i could get it to pump again. I replaced it now it is fine.


What things in the fuel system could gum up the works.

In my old gas truck the fual system was: fuel pump, fuel filter, fuel injectors, engine.

I dont know much about desal as this is my first time owning ANY desal so you will have to fill me in. I know the turbo is in there some ware lol

Thanks.

Computergeekguy

I think i have found a solution.

I found it on this forum: trouble code p0087 - Chevy and GMC Duramax Diesel Forum


Apparently on the truck there is a pressure release valve also know as a PRV.

On the trucks in my time range like 05-07 the PRV gets week over time letting gas back into the gas tank before it is suppose to. When it does that while you are under a heavy load the pressure drops too low giving you the (P0087/limp mode) problem.

Some solutions are 1: A PRV shim kit. costing around $10 where you shim your original PRV somehow making it hold more pressure. Link: PPE PRV Shim Kit 04.5-10 GM Duramax

Or buying a more powerful after market PRV that doesn't weaken over time.

What do you guys think?

I hope this helps other people having this problem.

I guess we will see soon if it helps me

bradcalhoun77

What landed up being your problem? My truck is doing the same thing. Ive replaced the injectors an the problem still remains. Just curious thanks

Computergeekguy

For me, it turned out to be a combination of problems.
1. I replaced a fuel pressure plug and installed a race plug. They don't cost much. They cost like $10-$20 depending on who you buy it from. Basically there is no more safety relief valve as the race plug is solid. Race Fuel Rail Plug "2004 5 2010 GM 6 6L Duramax LLY LBZ LMM" | eBay My engine is an LLY so this is what I purchased. You will want to find out what your engine is as you might not have the lly. Just warning you, this part is a pain to install. You will feel like you unbolted the entire truck by the time you are done. Also, you will need to learn new tricks to keep from dropping any bolts. It would be wise to look for videos on youtube.
2. Second I discovered that my external fuel tank had rust and water. It clogged my fuel filter
3. If you are using cruise control, stop using cruise control and see if that helps. It did for me.

Now, non of these suggestions might apply to your truck. This is just what I had to do to fix it. It would most likely be best if you start your own thread with a good supply of details.
Thanks