Still have low O2 millivolts

2

2QWIK4U

Member
Joined
May 27, 2001
I've been chasing a low O2 millivolts problem. I only get to work on my GN every month or so due to work and parenting so it may take me awhile to try different solutions.
I started noticing O2 counts in the 460-550 range at WOT with Turbo Tweak street chip ,50 lb injectors and a mild 12-25 lbs of boost. Fuel pressure would not go over 50 psi at wot. I installed 140 alternator,no change. Just finished installing new Racetronix fuel pump and fixed a bad connection to pump. It is hot wired. Now fp will rise to 58-60 lbs at wot but millivolts were only 464!!!! With 1.6 kr.
Tried to adjust fp and now it won't move off 46 at idle. Checked vacuum on fp regulator and it'll only go to 15 and starts dropping.
Is this my problem and where can I get a rebuild kit for it?
 
That should read 12-15 lbs of boost and need to mention I installed new DENSO O2 sensor with no change
 
I can't recall where I bought it but I think it was ATR or Conleys years ago Its black with 4 Allen head bolts holding it together. I did notice a few minutes ago that it will now raise fp but go no lower than 48 psi.
bpman1234 said:
What fuel pressure regulator do you have ?
Click to expand...
 
Atr? Think there's a rebuild kit for it the diaphram must be leaking if you can't get fuel down also check for restriction on return line.
 
During the install of new pump today there seemed to be alot of fuel draing from return line. I don't recall that the last time I had tank out but it's been a long time. I went ahead and replaced fuel filter with new Delco also. I dont think there's any way the lines are hooked up wrong as someone asked me earlier.
What's the easiest way to check the return line?
 
If your fuel pressure is 60 psi when you're on it I don't think that's the problem. That's the correct pressure for 15 boost. Low o2 could be from a missfire, unburned air fuel mix goes out the exhaust and is read as lean. Do you think it might be misfiring or breaking up?
 
Doesn't seem to miss or break up at all. It pulls hard but I let off the gas quick since counts are so low.
Has new NGK plugs,10 mm wires and coil/module aren't very old
 
You must log in or register to reply here.

Similar threads

SteveZ82
Chasing KR still
2 3
Replies
54
Views
5K
SteveZ82
SteveZ82
Tim Cucci
Tip and stumble at at stop and go. Red lights , Stop sign. Normal driving.
Replies
8
Views
862
Tim Cucci
Tim Cucci
R
Fuel PSI not increasing with boost after E85 conv
2
Replies
38
Views
2K
Mr.Spool
M
Dan SS2471
Using too much fuel
2 3 4
Replies
66
Views
6K
Phoneguy
Phoneguy
Jonesy
Been addressed before but.....
Replies
9
Views
1K
Jonesy
Jonesy
Top