too lean at wot
09-02-2015, 08:49 PM
#1
Teching In
Thread Starter
Join Date: Sep 2015
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
too lean at wot hi i have a lq4-4l80 combo in a 1955 chevy truck- xr275hr cam -headers- cold air intake-walbro 255 fuel pump with corvette regulator. i took it for a dyno tune today the guy said he could not get the wot fuel setting below 14 on the wideband using hp tuners. fuel pressure was 58lbs at the rail at wot injectors were at 60% duty cycle what are i missing or should i find a new tuner
09-02-2015, 09:09 PM
#2
Crappy Vette fuel pressure regulator is my guess. I have had wix and gm and store brands stick open or regulate at wrong pressure or not flow enough volume. In your case I would lightly pinch the return line and see if your pressure raises. Fully blocked off return, your pump should hit about 100 psi. You may have a weak pump. I don't use the Vette regulator any longer and use the eBay $21 adjustable regulators with an efi in line filter from a 88 Vette. They have worked fine for years of use.
09-02-2015, 09:43 PM
#3
Moderator
iTrader: (11)
Join Date: Mar 2002
Location: East Central Florida
Posts: 12,605
Likes: 0
Received 6 Likes
on
6 Posts
Check plug gap, and for any signs of misfiring; too much
gap can make fail-to-fire or an incomplete burn and then
the excess oxygen freaks the meter. Look also at the
NB02 output voltages as a consistency check (just on
the chance the meter is whack or the sensor is in a
place where it's getting some outside air).
gap can make fail-to-fire or an incomplete burn and then
the excess oxygen freaks the meter. Look also at the
NB02 output voltages as a consistency check (just on
the chance the meter is whack or the sensor is in a
place where it's getting some outside air).