Loss of Power in Boost?

[Selli160]

Got a basically stock 99 RB25Det Neo Stagea. Just recently had to replace all the coil packs because one had failed so I got some brand-new spit fires for the old girl. About a week after installing them stated to feel like the car was down on power a little when I got on boost. After driving around for a bit I could tell something was up. first gear almost felt like the car was NA with what felt like no extra power when I got on boost.  Second wasn’t as bad had a little extra power on boost but still nowhere near where it was before. 3rd 4th 5th Also sort of felt off (But it’s kind of hard to tell in the high gears). To sum it up Car feels Absolutely normal driving around normally (Not getting on boost). But as soon as you get on boost there is no power. The car sort of hesitates and throughout the rev range the power will tend to fluctuate come in and out a little bit. I’ve been driving it sparingly for the last week and have also noticed that some days it feels like its NA with almost zero power. Others its not so bad. And one day this week the car feels almost normal. So, it’s a little intermittent. Not too sure what’s going on

My first reaction was "it’s probably just a boost leak" but my boost gauge was still siting on 12psi like normal and I’ve got the reference line for it coming directly from the intake manifold so there’s no funny business going on in between.   

Other Thought was it had something to do with spark.  so, I got all new sparkplugs and just got a brand-new set of coils.  I just left the plugs with the stock 1.1mm gap and tested each coil pack/coil pack wire and plug to see if I’m getting a nice blue spark which I am. So that’s crossed of the list

From what I can tell I must have something to do with fuel. Not sure exactly what could be only guess is dying pump, blocked fuel filter, blocked injectors. Note about 3 weeks before all this I used some of that liquid injector cleaner that you put in your fuel tank. possibly dislodged a bit of gunk somewhere in the fuel system and is causing issues?? I have no real way to test the fuel pressure let alone the whole system. Haven’t really messed around much with fuel stuff all that much in my time so any ideas or tips or tricks for trouble shooting would be greatly apricated.

Could it be possible something is stuffed with the ecu???

[Ben C34]

Can still be a boost leak.

Turbo will be working its   guts out, heaps hotter intake air and higher back pressure..

to test for boost leaks you need to pressure test.

My vote is boost leak.

 

[Selli160]

Hhmm Yeh could still definitely be possible. I might have to look into a pressure test. Still it’s a substantial loss of power just for some higher intake temps. Plus its only the stock turbo and I’ve already got it basically maxed out at 12psi. If it had to work any harder it’d probably disintegrate.

[KiwiRS4T]

Replace the fuel filter under the bonnet. Cut it open to see if it is full of crap. While its off turn on the key to see if a decent spurt of fuel comes out. You really need a fuel pressure gauge.

Pressure test the system ...make up a plug with a tyre valve in the end and put it in the  outlet pipe from the turbo and see if it will hold 20 psi.

[GTSBoy]

2 hours ago, Selli160 said:

Still it’s a substantial loss of power just for some higher intake temps

It's not just higher intake temps. EMAP will go through the roof, which means that your 12 psi of boost = nothing or less.

[kimbod]

Also close the plug gap up to .8mm

[Selli160]

What’s EMAP?

[GTSBoy]

Exhaust Manifold (Absolute) Pressure

It's important. It's the opposite of boost. It's what makes the spinamathing chooch.

Edited December 27, 2019 by GTSBoy