BigTex

iTrader: (16)

I installed my fuel pressure and boost gauge last week. Fuel pressure went right on with no problem, but I misplaced part of my boost gauge sending unit, so I didn't finish it up last week. I found the fitting yesterday, and guess what... no boost. Bad gauge, no... I felt the line and there was no vacuum or boost on it. I had the boost gauge line connected in the same fitting the fuel pressure regulator is connected to. Same spot the magna install docs say to connect to. Must be clogged up or something.

So this morning, I find another spot to plumb in the fuel pressure and boost lines. Instantly my idle went crazy and the boost gauge started working. With no vacuum, idle fuel pressure was 60psi. After the fix, it dropped down to near 52psi. Givving it throttle cused pressure to rise today, but it was falling off before the fix. So all my funny idle issues and tuning problems were caused be the fuel pressure regulator line tap.

There is probably a 10% difference in fuel pressure now at WOT. Even with the inline pump, it would drop to the mid 50s at WOT, but not its just over 60psi at WOT. I need to start my tune over again, as I'm overly rich at WOT now.

For what its worth, I'm seeing about 7psi peak at WOT, with 6.5 most of the way.

wkdivr

iTrader: (8)

Where did you tap into for these gauges?

Flyer

iTrader: (1)

The fuel rail is threaded for the fitting on the drivers side. There is a little plug in it. I used the compression fit and used a hole in the top of the manifold behind the blower. There was one with a hose barb that went to I think the fuel pressure reg, and another non used one. I took the plug out of that one and put the vacuum/boost gauge there.

BenKey

iTrader: (1)

I hooked my fuel pressure sending unit on the end of the fuel block where the allen head screw is. Worked easier for me at the time. Boost hookup was just behind the blower on the driver's side where there is a brass plug.

Glad you got it fixed. Time to up the boost a little

wkdivr

iTrader: (8)

I was thinking about going that route, too. What size fitting was that?

BigTex

iTrader: (16)

My autometer fuel pressure sender screwed right into the plug on the drivers side of the fuel rail. I had the fuel regulator connected to the hose barbed fitting on the drivers side. When that didn't work, I removed the brass plug next to it and screwed in a barbed witting there. Not sure why the original location didn't work.

I agree ben, time for more boost. It feels really good all the way to 6500, but when I move to the little pulley, I'b be well past 18000 rpms on the blower. I guess I'll pull the rpms back in favor of the extra boost.

Its frusterating that I've spent the last month tuning out problems that were caused with fuel pressure. Now I've got to put it all back and start fresh again. At least it will be right this time.

BigTex

iTrader: (16)

OK, is it better to have 20* timing and 7psi, or have to pull timing back some and go for 9 psi?

one03sierra

iTrader: (1)

man bigtex i have lost track of you mods lately. glad to see it is up and kickin. few less rpm's with more hp. man to me that sounds good. wish i could shift mine sooner with the cam and nitrous and make that happen.

BenKey

iTrader: (1)

Richard, how is the cam you have at maintaining boost up high? Any sharp dropoffs before your shift occurs, or still building at the 6500 rpm point? I know your original intentions on the cam were not boost in mind - just curious. You may have already posted about it somewhere else.

BlownChevy

iTrader: (20)

Yes try it and let us know.