Compression Ignition Addict
Join Date: Jul 2012
Location: Sacramento area
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P0299 turbo underboost
Hey all, itís been a long time since Iíve been on the forum, and true to firm I need some help. I have a code with no symptoms that I need to get to the bottom of. A little history first:
I had an open glow plug circuit in cylinder 6 throwing a code, so two days ago I replaced all my glow plugs and my glow plug harnesses. That was a pain, but solved my problem. I have also had an intermittent hard start situation for years. Sometimes it just cranks forever before it starts, and usually I need to try multiple (2-3) cycles of the key with the injectors buzzing to get it to fire up. Happens hot, cold, summer, winter, after sitting for days, or after sitting for a few hours. No rhyme or reason, but itís never stranded me.
This morning after sitting for an entire day I started it up and it fired right up but sounded terrible for a minute bucking and missing as it came to life. I thought I might have an issue, but it smoothed right out and didnít throw any codes.
Iím late with my registration because I have to get the truck smuggled, and I was waiting for all the monitors to reset from clearing the glow plug code. I parked, checked the monitors and it wasnít throwing any codes. When I restarted the truck out of nowhere I got a CEL and P0299 Turbo Underboost. It started right up with no hesitation and ran smoothly out of the gate, but gave me the CEL instantly upon startup.
Now I was all over the place snaking the glow plug harnesses, so I figured I must have screwed something up. I checked all over, and cant find an issue. I cleared the code and drove it for a while, no new CEL. Then I romped on it on the freeway to make sure my turbo vanes were getting a workout and I instantly got the same P0299 CEL.
I fired up my monitor (I use Dashboss) and Key On Engine Off my various air pressures matched. Exhaust Back Pressure, MAP and the Barometric pressure all matched. I fired it up and watched the MAF, EBP, and MAP move up and down upon acceleration/deceleration, so it seems my sensors are working properly. Iím pretty confident I got the air filter and turbo intake all put back together properly.
Sorry for the novel, I just wanted to let you know what I have done already. Any advice is greatly appreciated. Thanks in advance.
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