Roughy idle and zero power

Abel661

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Sep 12, 2023
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Went to replace the turbo horn and when I went to start it my truck didn’t sound the same at idle. Back down the drive way and wouldn’t go above 2k rpm’s. Went around the block slow and it barley pulled itself back in the garage. Next day still starts fine but wont rev up and all just stumbles and smokes white. Smells like fuel. Removed the intake tube with maf still in it during install. Removed pressure sensor. Unbolted hard fuel line bracket to move out of the way Unplugged vac line to waste gate. Installed new horn extended map sensor wire. Verified it still had 5V. Put everything back. Plugged in maf. What did I mess up along the way?? I tried cleaning the maf sensor didn’t help. Is it possible the maf went bad when I had it out? On my cts2 mad is only reading 18 or so and map is reading 6psi at idle. I ordered a new maf and new pressure sensor but I don’t see why unplugging and moving them would make it go bad. Also verified maf has power.
 

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2004LB7

Well-known member
Dec 15, 2010
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Compare that to your boost sensor. Should be the same when the engine is not running. Off the cuff, it almost looks like you're running at high altitude. Rag in the intake?
 
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Abel661

New member
Sep 12, 2023
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Compare that to your boost sensor. Should be the same when the engine is not running. Off the cuff, it almost looks like you're running at high altitude. Rag in the intake?
This is engine off. And intake and turbo are clear. Turbo wheel spins fine and has no play.
 

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DAVe3283

Heavy & Slow
Sep 3, 2009
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Boise, ID, USA
Yeah, you should see MAP match Baro with the truck off (which you do, so the sensor is OK) and with the truck idling (which you don't). Since it's low at idle, something is restricting airflow prior to the intake. Did you take the intercooler tube(s) off and leave a rag in them?

I'd disconnect the cold side intercooler tube and idle the truck without it installed, make sure the MAP reading matches Baro then. Bet it stops smoking at idle with that tube disconnected.

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