Electrical - where to begin

[Moosemoon]

If you want to, take a look in your scanner for the short- and long-term fuel trims (STFT, LTFT) for both banks. Post up all 4 values at warm idle, then also at 1500-2000 rpm.

I got values for the 02 sensors but it was during a scan after I tried resetting the Ksenors and seeing if the light came back on. No Light but code pending ….
O2B1S1
1: Rich to LN Threshold = 0.540 (V)
2: LN To Rich Threshold = 0.540 (V)
3: Low V for Switch = 0.250 (V)
4: High V for Switch = 0.625 (V)
5: Rich to LN Time Value = 0.040 (S)
Min = 0.000 (S)
Max = 0.132 (S)
6: LN to Rich Time Value = 0.036 (S)
Min = 0.000 (S)
Max = 0.140 (S)
O2B2S1
1: 0.555 (V)
2: 0.555 (V)
3: 0.250 (V)
4: 0.625 (V)
5: 0.040 (S)
0.000 (S)
0.125 (S)
6: 0.028 (S)
0.000 (S)
0.136 (S)

Hope this is sorta what you were asking for. I don’t think I understand what I’m looking at other than volts and seconds. Thanks

 

[Moosemoon]

I got values for the 02 sensors but it was during a scan after I tried resetting the Ksenors and seeing if the light came back on. No Light but code pending ….
O2B1S1
1: Rich to LN Threshold = 0.540 (V)
2: LN To Rich Threshold = 0.540 (V)
3: Low V for Switch = 0.250 (V)
4: High V for Switch = 0.625 (V)
5: Rich to LN Time Value = 0.040 (S)
Min = 0.000 (S)
Max = 0.132 (S)
6: LN to Rich Time Value = 0.036 (S)
Min = 0.000 (S)
Max = 0.140 (S)
O2B2S1
1: 0.555 (V)
2: 0.555 (V)
3: 0.250 (V)
4: 0.625 (V)
5: 0.040 (S)
0.000 (S)
0.125 (S)
6: 0.028 (S)
0.000 (S)
0.136 (S)

Hope this is sorta what you were asking for. I don’t think I understand what I’m looking at other than volts and seconds. Thanks

Well shoot now that I reread your post - I don’t think this what you asked for at all. Sorry

 

[Fless]

Well shoot now that I reread your post - I don’t think this what you asked for at all. Sorry

The fuel trims will be expressed in percentages; most scanners will read between -25% and +25% and not outside of that range. Good numbers are within +/- 10%, but if you can grab them let's take a look.

 

[Doubeleive]

The harness was replaced with the knock sensors. One set o’reilly; latest AC Delco .Dealer says they are working. There are other codes suggesting some electrical issues and now the radio will not turn on. Instrument panel light is dim - brightened once when I hit just the right bump.

HOWEVER, I’ve read that 50% of ac delco sensors are also bad out of the box. Have no idea if mechanic(s) tested ks before closing up and hoping for the best.

no radio and cluster dim could reflect a poor connection somewhere, where exactly is the tricky part. most commonly it's the ground to the battery.
I would ohm check the ground cable as a place to begin. from "negative battery post to ground point on engine block/head" it should read 0.00
you may have a smaller cable that also splits from the main ground cable and goes to the frame check that as well.
on the back of the engine I think drivers side there is a ground strap there as well it can be difficult to reach you may want a stool or something to give you a lift up.
I know you said you checked the grounds before but a ohm test will confirm they are good

 

[Moosemoon]

no radio and cluster dim could reflect a poor connection somewhere, where exactly is the tricky part. most commonly it's the ground to the battery.
I would ohm check the ground cable as a place to begin. from "negative battery post to ground point on engine block/head" it should read 0.00
you may have a smaller cable that also splits from the main ground cable and goes to the frame check that as well.
on the back of the engine I think drivers side there is a ground strap there as well it can be difficult to reach you may want a stool or something to give you a lift up.
I know you said you checked the grounds before but a ohm test will confirm they are good

Thought I did that but will do again. Yes, the trick is where did slow guy connect things and how badly did it mess up everythin.

 

[Moosemoon]

The fuel trims will be expressed in percentages; most scanners will read between -25% and +25% and not outside of that range. Good numbers are within +/- 10%, but if you can grab them let's take a look.

Think I have some of that from a freeze frame. Will chk

 

[Moosemoon]

Think I have some of that from a freeze frame. Will chk

This is FF from when the engine light came on when on the way home from ksensors & harness being replaced along with O2 sensor. Supposedly all ac delco
STFT B1 = -3.1%
LTFT B1 = 7.8%
STFT B2 = -3.1%
LTFT B2 = 9.4%

veh speed 68mph
engine temp 183F
RPMs 2401

 

[Fless]

This is FF from when the engine light came on when on the way home from ksensors & harness being replaced along with O2 sensor. Supposedly all ac delco
STFT B1 = -3.1%
LTFT B1 = 7.8%
STFT B2 = -3.1%
LTFT B2 = 9.4%

veh speed 68mph
engine temp 183F
RPMs 2401

So those are good at speed, very acceptable. Typically one would add the ST and LT FTs together for each bank. Bank 1 is -3.1 + 7.8 = 4.7%. Bank 2 is -3.1 + 9.4 = 6.3%. Anything under 10% is good, the closer to zero the sums are, the better. But nothing wrong with those.

Positive fuel trims mean that the engine computer is adding fuel since the O2 sensors are reading the mixture as lean. That's what it does, within reason.

They could be different percentages at idle, but I doubt that has anything to do with your knock sensor issue.

 

[Baja_Bob]

I am no engine expert but did this "technician" replace your spark plugs and wires for you? Newer engines with high-energy ignitions need resistor spark plugs, electrical noise/interference may affect surrounding sensors. (like knock sensors). Just a thought.

Check your schematic, the radio and instrument panel might share a common ground inside the dash somewhere, it may be loose, corroded or broken.

 

[Moosemoon]

So those are good at speed, very acceptable. Typically one would add the ST and LT FTs together for each bank. Bank 1 is -3.1 + 7.8 = 4.7%. Bank 2 is -3.1 + 9.4 = 6.3%. Anything under 10% is good, the closer to zero the sums are, the better. But nothing wrong with those.

Positive fuel trims mean that the engine computer is adding fuel since the O2 sensors are reading the mixture as lean. That's what it does, within reason.

They could be different percentages at idle, but I doubt that has anything to do with your knock sensor issue.

Thank You. Good to know info whether or not affecting knock sensor.