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Old 06-11-2018, 12:30 PM
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Bdsankey Bdsankey is offline

Join Date: Feb 2018
Location: Oshkosh, WI
Posts: 553


Originally Posted by sirmatthewt View Post
These symptoms mirror what my LB7 is doing right now. Will drive fine for 15-20 min then codes P0087 at a stop light and usually goes into limp mode. Never codes under load. Starts fine and runs fine when codes are clear, maybe down on power a little and EGT's seem high 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. 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.

OP, did you figure out your solution? Anyone else have any thoughts? I lean toward a weak fuel pressure relief valve. For $40 I think I'll 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 drops fuel temps.
Current Rides:
1) Toy: 2005 LLY ECSB, Leather, Sunroof
-820hp/1748ft-lbs @ Duramax Tuner (6/25/18) - Old 475/87/1.00 setup
-Built Motor, Forced Inductions Billet ETR 480/96/1.10 T6, Modded Exergy 250% Injectors, Exergy 14mm Street Pump/LBZ CP3, Goerend J Converter, Billet Trans, Fuelab Supply Pump/Reg, RCD Sump, Front E-Locker, TrueTrac, Yukon 4340 Rear Shafts, Traction Bars, DHD Center Link Brace, DHD Lower Crossmember Support

2) DD/Tow Rig: 2002 LB7 CCSB, Leather, Loaded
-Bosch NEW Injectors, FASS 150, 3" Downpipe, 4" Downpipe Back, RCD Sump, PPE Sleeves, DHD Centerlink Brace, DHD Lower Crossmember Support, Steering Wheel Radio Control Swap
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