Underboost Code!!!

CyrusLoewen · Sep 9, 2015

A while back I swapped my 04 turbo for an 03 turbo. I bought it with broken shaft. I rebuilt it and put a billet wheel in. It seems to spool slightly faster but I can barely get it to 24psi. It will throw P0299 after I drive for a week or so. I checked the ebp line and it's clear. Just wondering if it's how the 03 wheel is or if it's a leak???

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CyrusLoewen · Sep 14, 2015

Bump

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6.0 Tech · Sep 15, 2015

Does it feel at all like the turbo is sticking? Especially at a 70ish cruise and back out and then get back into it? You should check athe map hose and fitting on the intake for restrictions or cracks as well. Also if you have a way of monitoring the pressures, monitor map, ebp, and baro key on engine off. They should be pretty damn close to eachother. Spec is 1.5 psi but usually see less than .5 psi difference. Ebp sensors are pretty common, and the pigtail can get corroded throwing off the readings.

CyrusLoewen · Sep 15, 2015

It's not sticking. But I don't have a way to monitor anything either.

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6.0 Tech · Sep 16, 2015

Did you check the map hose yet? I have seen that plenty of times. When you checked your ebp tube did you happen to notice the pigtail on the connector?

CyrusLoewen · Sep 16, 2015

I replaced the map hose and as far as i remember there was nothing wrong with the ebp pigtails. Is there a way to pressure test the cac system???

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6.0 Tech · Sep 16, 2015

Yeah you can plug up one side completely with a rubber cone, get another one and drill into it for an air fitting and use no more han 30 psi of regulated air and dunk it in a water tank or somethin to see if you got any bubbles. This is pretty similar to what we do at the dealer. A cac leak is usually pretty noticeable though. You'll hear a constant hissing noise. How are you measuring your boost?