LBZ Throwing P0087 and blowing black smoke on light acceleration/highway cruising

[fergymoto]

I have a 2007 Silverado 3500 Classic 2wd with the LBZ/Allison. It has 234k miles on it. It is a little down on power and blows smoke under light, normal acceleration around town and at highway speeds it is worse. The only code it is throwing is P0087 Low Rail Pressure.


The guy I bought the truck from said the dealer told him it needed a new CP3. I don't buy that being it blowing fuel smoke. I was leaning more towards injectors. I really need to correctly diagnose the problem and spend the money the right way so I'm looking for some help.

It already has a new fuel filter on it and Diesel Kleen has been run through it.

Here are some balance rates that I used the PPE Programmer from my LB7 truck to get. They were taken at idle in gear, brake on. Just like if you were sitting at a stoplight.

1: -1.1
2: -2.4
3: 1.4
4: -.02
5: -0.1
6: 0.0
7: 0.3
8: 0.1


What do you guys think?

[LtEng5]

change the fuel filter for the P0087 to go away.

order up a set of new injectors and you should be good to go

[fergymoto]

As said in my post the fuel filter is new. I do not want to just throw parts at it like some of the more sorry mechanics out there would. I'd like to diagnose it correctly first.

[bnowlin001]

When you say smoke, do you mean an excessively large amount? I ask this because I had a turbo vain position sensor go out and I had similar symptoms. I believe it has it own code though.

[fergymoto]

Yeah it's excessive for sure. The guy I bought it from said it did throw a turbo vane sensor code but he didn't know the code number and when I scanned it there was no stored code. Only the p0087.

[LtEng5]

was the P0087 stored or current CEL. If it did throw the vain position code it could have been clearedi and now you have to wait for it to re-code. do you have access to a EFI scan tool or a Tech II some how. you will be able to follow vain position with either scanner.

[fergymoto]

I don't have access to either and don't have any connections at shops or dealerships around here unfortunately. I do up in PA but I live in NC now where I know no one lol

[bnowlin001]

I'd put in a BIG vote for the vain position sensor. It's easy to change, but there's a learn procedure you have to go through to make it work right after installation. I believe I found the instruction here when I changed mine.

[jasperb21]

you might try cleaning the mass airflow sensor mine started smoking a lot and lost all power when it got dirty. its a cheap thing to try i think a can of cleaner is like 7 bucks at an auto parts store. and maybe a new fuel filter you might have caught some dirty fuel you never know.

[fergymoto]

I'll clean the MAF tomorrow but I really don't see a dirty MAF causing this serious of a problem.


Well here's more info and the story changes a bit. This truck has a Knapheide steel flatbed on it and the exhaust was just dumped underneath, behind the rear tires, going straight back. So from the driver's seat, I guess I couldn't get a good perspective on how much it is actually smoking.

I just put a tail pipe on it with a 90* bend, the way it should be, so it exits out the right side of the truck behind the rear tires. Now that I can look in the side view mirror and actually see it come out, it is smoking like a freight train upon acceleration, and I am talking very mild acceleration, not romping on it.

It seems to be worse at highway speeds. at 70mph the truck is pretty much putting out a steady stream of smoke and probably pissing off a lot of people behind me. When you go up a slight grade it gets worse, even without increasing throttle.

I thought I couldn't hear the turbo working before, but I can.

It is also throwing a P2563 now. I was unable to get it to do that before but the previous owner said it was throwing a turbo vane sensor code. When I first got the truck, the code was not stored. Now it is, along with the P0087 still.

Again, this truck is BONE STOCK. No chip, no tune, no cold air intake, no drop in K&N or similar, stock exhaust system. The smoke is way excessive. It will actually blow out quite a lot of black smoke if you just rev it in the driveway.

I don't know where to go from here with this thing. I can't afford to just throw parts at it, but I don't have the best means of diagnosing it either being I don't have access to a Tech 2 or similar. I wouldn't mind paying someone a fair price to diagnose it for me so that I can repair it, but I don't know anyone around here off hand and I don't have enough faith in the dealerships around. Scratching my head.