suspect overboosting

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suspect overboosting

Postby shane308 on Sun, 11 Feb 2018 10:39 +0000

Hey guys, I've got an 06 Hilux that I've recently put a new long motor and turbo in (both from Toyota), while I was swapping the engine and turbo out I also gave the & manifold & EGR a good clean of all the soot, I don't have a egr blanking plate fitted and don't have a chip or a tune, everything is standard throughout the engine except for the 3" exhaust that still has the muffler and cat fitted.
anyway the last couple of weeks I've noticed the turbo has been "singing" a bit louder than usual and I can hear a hissing noise coming from the engine bay while on boost like air escaping.
I plugged my scan tool into it and took it for a drive while watching the "intake manifold absolute pressure" number and it was regularly sitting on 159kpa (which I worked out was about 23psi) while just driving normally going through the gears, and is idling about 79-80kpa @ 800rpm, it hasn't thrown any codes related to this.
my question is..
#1 is "intake manifold absolute pressure" 159kpa the same as saying boost is at 23psi ?
& #2 has anybody else come across this and what was the problem/fix ?
I've done around 5000kms with the new engine and turbo with no worries and now this, I'm a bit worried about driving it if the boost is really sitting up that high.
any input would be greatly appreciated
cheers guys

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Re: suspect overboosting

Postby mitch_893 on Mon, 12 Feb 2018 9:54 +0000

Ok so when your reading map sensor data, you need to minus atmospheric pressure from the reading, so minus 101kpa.

So your boost levels are not high at all. Probably spot on for just cruising along. I’d be checking for loose hose connections for a leak if it sounds like that.

However, your idle reading is a bit suss. It should idle with a reading close to 1 atmosphere.
06' D4D dual cab SR
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