Low o2 problem

[jamericaniSS]

The car has a pretty much new denso o2 and im having a problem with getting low readings, in the mid to high 600's...The alky kit is finally up and running right. Running a 23/21 chip, alky knob at 12 o'clock, 22lbs, zero knock. I started the boost at 17, all else staying the same, got readings of highs 6's maybe low 7's on the o2's, zero knock. Progressed with the boost and the o2's dropped into the mid 6's, 640, zero knock, 22lbs. Car felt pretty good, but i think it could feel better.

My buddy said it could be a sign of the fuel pump taking a dump. Initially when i had the kit running before running into a rocker shaft problem, o2's were in the 8's, high 7's...After resolving the issues, they are now in the mid 6's, low 7's, but no knock either case. There is no sign of a hotwire kit and i have no idea what pump is back there, the owner never told me. I do know it has been replaced, he did give me the old one, i will check through the reciepts of the car.

What should i do, keep running it or what? I would really appreciate you guys imput, as i am getting the itch to turn up the boost. Only running 36's and a 44, so i wont go past 24, expecting the 60's this week.

 

[Razor]

Did you fix/replace your fuel pressure regulator?

 

[jamericaniSS]

Yep, i sure did replace it, took me an hr bc im slow....I was driving the car and like i mentioned earlier when it was hot outside boost at 22 640 o2, tonight going home cooler air same boost 02 was 610-605, while on the highway, no knock still.

The car is definetly moving. Im going to check the connection at the back of the passenger head.

 

[Razor]

Change the O2 for an AC Delco AFS20.

You dont run leaded.. the stock O2 will live for a long time. Its only 30 bucks.. lot better than pulling your hairs for hours..

Then check grounds..AND hook up a fuel pressure guage and extend it into the car.. make sure its increasing FP lb per lb.. you could be leaking air at the TB distribution block not allowing FP to rise correctly..

 

[jamericaniSS]

No problem, i will get on those changes right away.

 

[dvernst]

Does that seem to happen a lot with the Denso o2? Sometimes when i'm just lightly getting on the throttle it will give me readings like 150 or 180. Under full throttle it seems normal, but seems weird everywhere else. I run leaded fuel, and the readings were normal for a long time. Then I started getting low o2's, so I figured it was getting sluggish. When I put the new one in I was getting similar readings. Sorry to hijack your thread.

 

[jamericaniSS]

Well the update on the situation is that i found that one of the lines on my vacuum block was cracked so i changed them all. I also went back to the ac delco o2. Car seems to idle a little better, however it did not cure the problem of the low 02 readings. That car is still running very strong and not experiencing any degree of knock.

Im waiting on the new fuel pressure meter so i can get an accurate reading of my fuel pressure.

The car does have an exhaust leak somewhere b/c it is audible but not very distinctive b/c the car has a cam.

The car does not have a hotwire kit and with the 60 lb injectors coming i will add that and check to see if it have a walbro back there.

The only other think i have yet to check is the grounding at the back of the head. Other than that are there anymore suggestions

 

[jamericaniSS]

Well i didnt get anything done today but i now found a new problem.

When going into the boost neither the turn on led or power injection bulbs light up. What could cause this when the system was working perfectly yesterday.

I checked the vacuum line to the maf it has vacuum. Im going to check the volts on the wiring to see if it checks out.

It seems everytime i get something fixed, something else pops, strange, but i can deal.

 

[jamericaniSS]

Yes i know its 4:14 a.m. but i just got back from testing and tuning the car. I found the problem and it turned out to be a loose wire. Went to my personal 2 miles stretch of diserted street and worked my way back up to 24lbs. Made 6 passes and the car feels really good.

Since im still tackling the low 02 problem it hard to tell if im too lean or not. I did not get any knock, even on the shift, at 24lbs. I maxed the rjc boost knob so i cant go any higher. I think the car has a heavy duty actuator but 24lb is enough for me, it rains too often and im already squirley doing regular driving.

Since my goal for the car is strictly daily driver status, i will find a way to fix these o2's. I still have not checked the back of the head yet, will get to that soon.

 

[jamericaniSS]

Bringing back from the dead. I found the problem a few weeks ago. It was the dreaded o2 wire on the back of the passenger head. It was hard to tell since there were like a million wires on that bolt.

 

[Pronto]

Was it split or just off the head? Have the heads been off?

 

[jamericaniSS]

It was off head