Whats up guys,

I have a FP question for you all, hopefully someone can help. I recently had my vacuum canister for my MEVI crack due to the heat and cause a bad vac leak. So what I did was just remove the vac canister and run the vac lines from under the valve cover straight to the actuator on the MEVI. This is just a temporary fix until my new vac canister arrives. Anyway, after I did this I noticed my FP at idle now reads between 28-30 PSI, it used to be at a constant 34 PSI at idle. The weird thing is when I turn the key to acc the FP gauge still reads 34 but as soon as I start the car it drops to 28-30 PSI at idle. Does anyone have any clue as to why this happened?

My fuel setup is:
AEM FPR
Walbro 255
Vortech FMU 6:1 (I believe)

Any help is greatly appreciated.

 

leaving work bump

 

You have a vacuum/boost gauge?

What's it say?

The FP is directly related to vacuum pressure via the FPR.

You may still have a cracked hose or vacuum leak somewhere.

 

my vac at idle is -20-22 in hg. The thing thats weird is that when I had a bad vac leak and a horrible idle the FP was solid at 34PSI. Now that I seem to have fixed the leak the FP has dropped. Thanks for your help.

 

The more vacuum the less FP.

When you press on the gas in normal operation, the vacuum goes to nearly 0 (or higher into PSI if boosting). As it gets closer to 0, Fuel Pressure raises.

So now that I think about it - what you're seeing is the effect of having more vacuum.

 

so Im seeing too much vacuum at idle? I didnt know too much was possible. What would cause high vacuum? Thanks Ian!

 

No, you're just seeing the right amount of vacuum at idle. (17-22Hg is spec).

I suspect that you're fine and your car just idles at a lower FP than most - not usually . a problem if it's just at idle. What FP are you seeing at redline?

 

around 90 PSI at redline (stock injectors) its hard to watch that gauge and the road. So you think its okay? Maybe it will go back to 34 when I put my new vac tank in. Which tank are you using? Thanks again

 

Anyone know to install an aftermarket FPR? I've heard you the new FPR replaces the stock FPR, how do I seal or replace where the stock FPR goes on the fuel rail?

 

I'm using a NAPA tank.

90 PSI at redline is about normal for your setup - I doubt that your boost pressure was affected since 1PSI still = 1PSI.

You're fine.