Gretch

Is there a way to do this with it off the car? I would like to test a spare one I have. The two white wires are hot, correct?, and the black one is the signal wire.....so what is the power feed to the two hot wires.....not just a steady 12 volts I suppose.....

some one here educate me....

I was thinking about using a seperate o2 sensor to drive the AFM gage....so I wouldn't degrade the signal going to the computer by splicing the gage feed into the signal wire....

Thoughts?

Jim R.

Gretch,

I don't know about the testing of the spare, but as far as worrying about degrading the signal to the computer I would not worry about it. I have mine soldered in and have had no issues. Runs clean enough to pass NY emissions not just at idle, but under load on a simulated road dyno with accelleration, decelleration, hills, etc. (original factory cats still in place).

Did you fix the running rich problem yet?

Jim

Fabio421

The two white wires are not both hot. They are for the heater. They make a circuit. Power goes in through one and out through the other after going through a resistor (heater). It shouldn't matter which is which.

Garth S

The power of google ..... To test an O2 sensor,

"Use a high impedence DC voltmeter . Clamp the sensor in a vice, or use a plier or vice-grip to hold it. Clamp your negative voltmeter lead to the case, and the positive to the output wire. Use a propane torch set to high and the inner blue flame tip to heat the fluted or perforated area of the sensor. You should see a DC voltage of at least 0.6 within 20 seconds. If not, most likely cause is open circuit internally or lead fouling. If OK so far, remove from flame. You should see a drop to under 0.1 volt within 4 seconds. If not likely silicone fouled. If still OK, heat for two full minutes and watch for drops in voltage. Sometimes, the internal connections will open up under heat. This is the same a loose wire and is a failure. If the sensor is OK at this point, and will switch from high to low quickly as you move the flame, the sensor is good. Bear in mind that good or bad is relative, with port fuel injection needing faster information than carbureted systems.
ANY O2 sensor that will generate 0.9 volts or more when heated, show 0.1 volts or less within one second of flame removal, AND pass the two minute heat test is good regardless of age. When replacing a sensor, don't miss the opportunity to use the test above on the replacement. This will calibrate your evaluation skills and save you money in the future. There is almost always *no* benefit in replacing an oxygen sensor that will pass the test in the first line of this paragraph."

.... and that's all there is to say about that ...

Gretch

So Fabio421, how does the "signal" get generated....?

Never mind.....THANKS Garth.....man what a great place this is.....I will get my propane torch out this weekend.....HOO RAH

Jim, I think the sensor I had installed was toast....DR is sending me some rotors and disti caps and when I get this and the tune up all done I will then check how she is running......I am sure it will be fine.....BTW what is your fuel pressure at idle? You have both vacuum and boost bleed off screws down tight on the Dual RRFPR, right?

In the meantime I topped off the oil in the tensioner and checked the belt tension with my Kempf tool.(which is a hell of a lot easier task with the air pump gone.....)...I spent a great day tinkering on my shark on Saturday.....DR sold me a GTS shift **** with his special insert....I put that in too. Looks good. I made my hotel reservations for SITM today....don't forget to do that.

Jim R.

Gretch,

FP at idle 32 psi on the fuel rail gauge. As far as the Super FMU, I left it exactlly as Tim set it up. I have not touched any adjustment other than setting the idle fuel pressure-really don't know where the other adjustments are set. The AF gauge "hunts" at idle and cruise, goes rich at WOT.

My next fun is to R&R the clutch assembly-the pilot/throwout bearing are noisy and done. Just have to decide on which unit to use ( GTS or Carl F.'s HD unit).

Jim

Fabio421

The third wire is the signal wire.

FlyingDog

If you're worried about the sensor signal, get a 4-wire O2 sensor and run the sensor ground (grey) to the same ground as the LH and the A/F meter. It really shouldn't matter.

Gretch

Jim, I have the same set up (fuel pressure 32# and bleed off screws seated) and it ran like a champ until last fall when the AF meter stopped hunting (still ran strong, just rich all the time).....thus a new O2 sensor...I had my clutch replaced several years ago and went with the GTS clutch, and it is still good......though with the kinda torque we are putting out, pretty much any clutch can be made to slip if you put your foot into it before you let the clutch hook up....DR sold me a brandy new clutch kit last year, which I have sitting on my bench looking pretty.....I am not gonna put it in until it needs it.....as long as Gretch continues to smoke the sneakers in the first 3 gears I figure I am fine.....

perrys4

Not to hijack but when the O2 goes bad does the car run rich or lean or niether?

FlyingDog

IIRC, common mode of failure is low signal voltage which indicates lean condition. The computer will compensate by adding more fuel causing the car to run rich while thinking it's lean. However, it can fail to lower voltage, higher voltage, or be accurate but very slow to make changes.