P0087 at no load after warm

[sirmatthewt]

I have 2002 LB7. 230,000 miles or so. It's been throwing P0087. Will drive fine for 15-20 min then codes P0087 at a stop light and usually goes into limp mode. Never codes under load, only at like the 3rd stop light in a trip around town or pulling back into the garage after a run to the grocery store. Starts fine and runs fine when codes are clear, maybe down on power a little and the EGT's do seem high to me for the relative rpm and boost, and after driving for a few minutes I can't idle the EGT's down below about 350-375 degrees which I like to do before I shut it off. Idles fine no haze no smoke. Filter plunger stays firm and doesn't suck down. I've changed the filter, the two filter head hoses, siphoned and swapped out most of the diesel, and straightened a kink in the 1/2 supply back by the fuel cooler.

Any thoughts? I lean toward a weak fuel pressure relief valve. For $40 I think I may order a race plug and plug it. Leaky WIF plug maybe? Leaky bleeder screw?

 

[Bdsankey]

I have 2002 LB7. 230,000 miles or so. It's been throwing P0087. Will drive fine for 15-20 min then codes P0087 at a stop light and usually goes into limp mode. Never codes under load, only at like the 3rd stop light in a trip around town or pulling back into the garage after a run to the grocery store. Starts fine and runs fine when codes are clear, maybe down on power a little and the EGT's do seem high to me for the relative rpm and boost, and after driving for a few minutes I can't idle the EGT's down below about 350-375 degrees which I like to do before I shut it off. Idles fine no haze no smoke. Filter plunger stays firm and doesn't suck down. I've changed the filter, the two filter head hoses, siphoned and swapped out most of the diesel, and straightened a kink in the 1/2 supply back by the fuel cooler.

Any thoughts? I lean toward a weak fuel pressure relief valve. For $40 I think I may order a race plug and plug it. Leaky WIF plug maybe? Leaky bleeder screw?

A leaking relief valve won't show up at idle. My bets would be towards a weak pump not liking hot fuel. As the vehicle speed increases airflow over the fuel cooler picks up and intern dropping fuel temps.

How many miles? Lift pump? Tunes? Filling out your signature might not be a bad idea so people know what is done to the truck.

 

[sirmatthewt]

About 235,000 miles. Injectors replaced once before I bought it but I'm not sure the exact miles.

No, no lift pump. I was actually days away from installing one when it started throwing the P0087.

It has the old Edge Juice w/ Attitude programmer but no EFILive tunes.

Black smoke at hard acceleration but no smoke at idle. Idles smooth. Codes after driving about 10-20 minutes while waiting at a stop light or pulling in to park. Pull over and clear the codes and it'll be fine for a few stop lights or so. The EGT temp is noticeably higher than it's been. Like hitting 900+ degrees at 45-50mph at a low psi boost. It had normally been taking 10-15 boost going up a hill or hard accelerating to get the EGTs to run over 900 for any amount of time and pulling back into the garage a couple minutes of idle won't cool the EGT's to less than about 335-350. It used to take maybe a minute to cool back down to around 300 or less.

 

[THEFERMANATOR]

1st thing to try, completely remove the edge juice with attitude. They were notorious for problems, and are basically a glorified pressure box. Whenever one is there and a problem is present, you start by removing it so you know it isn't the problem.

 

[DAVe3283]

X2, remove the Edge temporarily. While removing it, look over the pins on the factory connectors closely to ensure they aren't bent or pushing out the back of the connector.

If it still throws the code, a return test should tell you if the pump or injectors are the problem.

 

[sirmatthewt]

Couple of things. 125-150,000 on the 2nd set of injectors. The first time it threw the p0087 was just after exiting the freeway. At the light there was a noticeable pop or sharp thunk and the CEL came on. Changed the filter and the filter to module hose. Light stayed off for a week or so. Came back Saturday. After changing the filter hoses on Saturday and the filter I changed the oil. It seemed thin to me. Paper towel test didn’t halo. The new oil, after probably 50 miles of drive time is very black and seems thin. It also seems to be making some oil. I’d say a quart or more over. All of this leads me to think injectors. I’ve read of CP3s leaking into the crankcase but it seems injectors are more likely. Again, there’s very little smoke. Some at accel from a light or on a hill. None, black or white at idle. Thoughts?

 

[sirmatthewt]

I say it’s injectors, in part, because it seems the answer to almost every question on an LB7 forum is “injectors”.

 

[WVRigrat05]

I say it’s injectors, in part, because it seems the answer to almost every question on an LB7 forum is “injectors”.

Two ways to fix it, burn it or buy an LLY and then burn it.