total loss of boost
 

hey all. So 99 twins in simplified seq with AzEknights solenoid kit. Has been working rock solid for over a year. Yesterday Driving home from work I get on it a bit. No boost. So i slow down to 35 leave it in 3rd gear and floor it. 0 psi all the way to 7500 rpm. When i let off i usually hear a psst from the BOV. But i got what sounded like a wet fart. I looked at vac lines last night. Didn't see anything out of the ordinary. But what else could cause a complete loss of boost?

Thanks
Carl

One big ass boost leak, do you hear hissing when you accelerate?
Check to see if there intercooler piping hasn't come loose.

Yep, boost leak. It doesn't take much to lose all boost.

BOV connections, intercooler couplers, ANYTHING in the air path from the turbos all the way to the throttle body.

Dale

Sounds like a big boost leak. I found the coupler to the Y-pipe can slip out sometimes if you have an earlier Y-pipe.

i was getting 1-2 psi this morning. I don't hear any hissing. '99 y pipe and all aluminum pipes. 4 couplers (elbow to intercooler pipe to intercooler) (intercooler to pipe going to y pipe). All 4 are solid no splits. I'll pull them all off tonight and reset all 4. I have always heard the turbo's spooling but nothing that sounds like a boost leak. Like a said only weird sound coming off full throttle is that wet fart sound instead of that quick PSST from the blow off valve.

If you have enough of a boost leak, you won't hear anything. There's no resistance, only a restriction or a resistance will make any noise. Also, with no boost going into the engine, it lowers the exhaust pressure to drive the turbo, making even less boost - it's all a system.

Another possibility is the throttle not fully opening or sticking.

Dale

Well i broke 2 of the clamps.. Have new t-bolt clamps all around now nice and tight. Inspected the couplers and all 4 are good. Inspected/removed all the hoses for the BOV's all are good. Went for a drive same thing. no boost. How do i test the bov's? that sound is what has me thinking it's one of those.

You need to do a boost pressure test. There's tons of info on how to do it, here's a video -


Pressurize the system and look/listen/feel for leaks.

Also possible to have a major exhaust restriction or a wastegate that's wide open or not connected.

Dale