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Discussion Starter · #1 ·
Hey forum,

new guy here. Couldn't find a thread w/ similar signs, if there is one pls lmk.
Got my srt4 passed down from my brother. Pretty much stock except, intercooler, intake, exhaust and a few things that shouldn't have impact.

Here's what's going on - first, second, third... WOT it only goes to 9 psi, stays there for a sec or two, drops 1 psi and holds at 8. My brother said it used to go 15-19.

Boost gauge looks fine - goes to 0 when car is off, -14 vacuum when idling. Car appears to move fine, except for that lower boost.
Checked and tightened a few connectors. Replaced a hump hose right before BOV (had a crack) - no change.

Any ideas, suggestions and links will be appreciated. Lmk if i missed any info.
 

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Discussion Starter · #3 ·
No I have not.. Did a bit of reading on it and started putting together some stuff to make shift a rig from a Halloween smoke machine and some piping. I'm a bit afraid because it uses corn starch and does leave a bit of sticky residue (don't want to coat the inside with it).
Seen many vids, but everyone seems to have different points where they attach the rig, so i'm not sure where to start - any suggestions ?
 

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05 srt-4 white
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Even if you make something like this. This is all you need and some soapy water. Smoke machine yeah sure might show you every last lil leak easy as pie. But I wouldn't recommend. Best leak detector I've found is good old soapy water and air.
 

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Also another bit of info for you to look into. The stock wga spring I belive is 8psi or less can't remember off the top of my head. It needs the boost control solenoid working to get that 15 to 19 psi of boost. So sounds to me like your boost control solenoid isn't hooked up/or working properly.
 

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Discussion Starter · #6 ·
I'll give the water soapy water a try - a lot of connectors to check unfortunately.
Also will look into how to troubleshoot the solenoid.

Thanks guys, will give feedback when i check
 

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I'll give the water soapy water a try - a lot of connectors to check unfortunately.
Also will look into how to troubleshoot the solenoid.

Thanks guys, will give feedback when i check
14 inches of vacuum.. assuming the gauge is right...does it have stage cams or something? my car normally runs 20-23 inches.

low manifold vacuum can indicate issues with timing, or major engine problems.

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Discussion Starter · #8 ·
No stage cams as far as i know. And i believe the gauge is working fine - found a vid showing what to look for if a gauge is bad, none applied.

That low manifold vacuum and major engine problems has been giving me nightmares since u posted it :D
 

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No stage cams as far as i know. And i believe the gauge is working fine - found a vid showing what to look for if a gauge is bad, none applied.

That low manifold vacuum and major engine problems has been giving me nightmares since u posted it :D
well, id check to make sure there are no leaks, then timing. if its timed then id do a relative compression or a leakdown test.

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I had the old school Crower stage 4 cams years ago. The amount of vacuum you are seeing is about the same amount I was seeing myself. 14 to 18 vac. When I had them I no longer do now. So back to stock cams and 20 to 24 vac.

I would say it's normal on bigger cams to have less vac for some reason. I wish I still did have them stage 4 cams now that I have a bigger turbo though but..... sigh
 

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I had the old school Crower stage 4 cams years ago. The amount of vacuum you are seeing is about the same amount I was seeing myself. 14 to 18 vac. When I had them I no longer do now. So back to stock cams and 20 to 24 vac.

I would say it's normal on bigger cams to have less vac for some reason. I wish I still did have them stage 4 cams now that I have a bigger turbo though but..... sigh
per op's original statement

"Got my srt4 passed down from my brother. Pretty much stock except, intercooler, intake, exhaust and a few things that shouldn't have impact."

no big cams.

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Then yes 14 vac is quite low. For not having a bigger cams.
 

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Discussion Starter · #13 ·
I had the old school Crower stage 4 cams years ago. The amount of vacuum you are seeing is about the same amount I was seeing myself. 14 to 18 vac. When I had them I no longer do now. So back to stock cams and 20 to 24 vac.

I would say it's normal on bigger cams to have less vac for some reason. I wish I still did have them stage 4 cams now that I have a bigger turbo though but..... sigh
So my concern is not the vacuum, but rather it only boosts to 9 PSI and stops - used to get 15-20 in boost.
 

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So my concern is not the vacuum, but rather it only boosts to 9 PSI and stops - used to get 15-20 in boost.
I would test or even replace the wga solenoid if you can't test it here's a link to purchase a new wga solenoid. Also are the factory boost lines/vacuum lines on and present?

 

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Discussion Starter · #15 ·
I would test or even replace the wga solenoid if you can't test it here's a link to purchase a new wga solenoid. Also are the factory boost lines/vacuum lines on and present?

I'm getting stuff i'll need for pressure leak test this weekend. Not sure how to test solenoid though.
All vac lines are present, but no zip ties at the end :D (which shouldn't be the problem as that's how they've always been).
 

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I'm getting stuff i'll need for pressure leak test this weekend. Not sure how to test solenoid though.
All vac lines are present, but no zip ties at the end :D (which shouldn't be the problem as that's how they've always been).
Cool do the test then we will see what you come up with. 👍
 

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So my concern is not the vacuum, but rather it only boosts to 9 PSI and stops - used to get 15-20 in boost.
You are focusing on the wrong thing. it's like cutting your finger off cause your head hurts.

The reason you are boosting to 9 lbs may be the same reason you dont have appropriate vaccume. Late timing and burned valves will prevent you from creating enough pressure to spin the turbo to 15lbs, it will also lead to catastrophic engine failure if not corrected.

but, its your car. :)

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You are focusing on the wrong thing. it's like cutting your finger off cause your head hurts.

The reason you are boosting to 9 lbs may be the same reason you dont have appropriate vaccume. Late timing and burned valves will prevent you from creating enough pressure to spin the turbo to 15lbs, it will also lead to catastrophic engine failure if not corrected.

but, its your car. :)

Sent from my SM-G988U using Tapatalk
Dude wow man just wow!!! Smh....
 
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