Fuel pressure fluctuation?
Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Fuel pressure fluctuation?
How much should the fuel pressure fluctuate during acceleration,,,, any at all, some etc?
When I rev the throttle body the fuel pressure will drop down 2-4 psi, is this OK?
I bought a Walbro 3450 used and I wonder if this thing is no-good
Thanks for the help guys!
When I rev the throttle body the fuel pressure will drop down 2-4 psi, is this OK?
I bought a Walbro 3450 used and I wonder if this thing is no-good
Thanks for the help guys!
Drifting
Joined: Nov 2001
Posts: 1,783
Likes: 2
From: Latham NY
Re: Fuel pressure fluctuation? (ld85)
Your pressure should increase as you rev because there is less vacuum at the regulator. Try this: disconnect the vacuum line to the regulator and monitor the fuel pressure at idle and with revving. It should stay the same if the pump is good.
Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Re: Fuel pressure fluctuation? (ld85)
Incredible,,, the Aeromotive Fuel Pressure gauge leaks at the thread so when I would rev the car with the vacuum line connected, the fuel pressure would actually drop instead of increase.
I put some thread seal on the threaded areas and the FP is now stable.
Its always something !
Thanks guys!
[Modified by ld85, 9:05 AM 5/29/2004]
I put some thread seal on the threaded areas and the FP is now stable.
Its always something !
Thanks guys!
[Modified by ld85, 9:05 AM 5/29/2004]
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Re: Fuel pressure fluctuation? (ld85)
This came up once before, so I did a check of mine.
When I reach over and quickly open the TB butterflies, my fuel pressure instantly increases 6 to 8 psi. It never drops when I rev the engine.
At idle, my Accel fuel pressure gauge is rock steady.
Jake
When I reach over and quickly open the TB butterflies, my fuel pressure instantly increases 6 to 8 psi. It never drops when I rev the engine.
At idle, my Accel fuel pressure gauge is rock steady.
Jake
