weird boost issue

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sliverumble
First Gear
Posts: 79
Joined: Sat May 29, 2010 7:02 pm

weird boost issue

Post by sliverumble »

Ok ive got a legacy ss with a td04, prosport mbc, hks fcd, 06 wrx tmic etc. I had a bad connection with my cam and crank angle sensors so i wasnt getting spark. Ive since then fixed those but now its not boosting at 14-15 psi as it was before. It even acts like its having issues building boost pressure, it will only boost about 7-8 psi. I did notice the inlet tube off the turbo where it branches off to the tb area and t's to the block looked like it had a crack in it so im thinking thats a possibility. Anyone have another idea what it could be?
92 SS
-TD04
-3" dp/ turbo back w/HKS can
-wrx/legacy susp combo
-Tribeca Front Sway
-whiteline rear sway
-wrx front brakes
-sti lip
-ver.4 sti tranny w/rear diff
-wrx tmic
-mbc @14.5-15psi w/HKS FCD
-Apexi turbo timer
94SS_Canada
Third Gear
Posts: 851
Joined: Mon May 12, 2008 4:19 am

weird boost issue

Post by 94SS_Canada »

I'm assuming you have a boost gauge?

What is the vacuum reading at idle?
FastRust
sliverumble
First Gear
Posts: 79
Joined: Sat May 29, 2010 7:02 pm

Re: weird boost issue

Post by sliverumble »

Yeah i have a boost guage, its reading 20 inHg at idle. It goes to 25. Usually unless im decompressing downhill it doesnt hit 23-24 inHg
92 SS
-TD04
-3" dp/ turbo back w/HKS can
-wrx/legacy susp combo
-Tribeca Front Sway
-whiteline rear sway
-wrx front brakes
-sti lip
-ver.4 sti tranny w/rear diff
-wrx tmic
-mbc @14.5-15psi w/HKS FCD
-Apexi turbo timer
kimokalihi
Fifth Gear
Posts: 8360
Joined: Mon Nov 06, 2006 3:41 am
Location: Tenino, WA

Re: weird boost issue

Post by kimokalihi »

What's your intake pre-turbo made up of? Another member on this forum just recently installed a td04 and was having a similar issue where his hose before the turbo was collapsing under heavy load from the vacuum. He was using a cheap water heater hose instead of a silicone hose. If you think a hose is cracked take if off and inspect it/pressure test it. No sense looking for other problems when there's other suspects already.
98 Metro Hatch Daily Driver :)
91 SS EJ20G Engine/Tranny/Diff Swap Build Thread Here
"Your testes are close to your bottom but you still play with them all the time." Jeremy Clarkson
sliverumble
First Gear
Posts: 79
Joined: Sat May 29, 2010 7:02 pm

Re: weird boost issue

Post by sliverumble »

I have a 90 deg silicone hose, I figured out the issue. I was running my boost controller though my factory boost solenoid and my boost solenoid i think took a poo. I didnt know you could totally bypass the solenoid so I did and now the car pulls hard. Ive got the boost at 14-15psi when my foots buried.
92 SS
-TD04
-3" dp/ turbo back w/HKS can
-wrx/legacy susp combo
-Tribeca Front Sway
-whiteline rear sway
-wrx front brakes
-sti lip
-ver.4 sti tranny w/rear diff
-wrx tmic
-mbc @14.5-15psi w/HKS FCD
-Apexi turbo timer
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