Recent content by SteveX82

After driving the truck all weekend and putting on about 150miles, everything seems to be going great. I suspect that the "bad" new sensor might have actually been ruined in the brief few miles driven while the o2 heater fuse was blown. I am absolutely sure I measured +12v on the heater supply...

Both sensors have been made by Bosch. Have they been known to be problematic? And no, I only changed the upstream sensor. How expensive was your NTK? The Bosch set me back about $67 with tax.

As an update, I installed a new Felpro manifold gasket this afternoon hoping that it'd cure my problems. There was a slight exhaust leak from the crummy gasket that came with the new header, so I figured the leak might be fooling the o2 sensor. Unfortunately, I was apparently wrong. O2 signal...

As you're looking at the fuse block (facing the rear of the truck with the passenger fender to your left), it looks like F23 fits buckshot's description. I checked it again yesterday and the new fuse is still good. Pulling the fuse with KOER eliminates the voltage going to the o2 sensor heater...

Oops...I wasn't backprobing pin A25 properly. I am getting similar voltage to what I see on pin A24 (just over 4v). I've read a few unconfirmed statements about a 5v "pullup" voltage on the o2 signal wire that bleeds off as the heater warms up, but I don't know how trustworthy those statements...

It does not. I don't read any voltage at pin A25. Also, it turns out that the fuse that Buckshot500 referred to was, in fact, burnt out. Unfortunately, replacing it didn't change anything.

It looks like I may have narrowed down the source of my problem. I pulled pin A24 from connector C1 and plugged the connector back into the PCM. No voltage was seen at either end of the BK/DG wire, but I was able to verify that the PCM's corresponding pin for A24 was reading 4.23v. Before I...

With both connectors unhooked, there is no voltage at either end of the BK/DG wire. As soon as I plug C1 back in, however, I get ~4.23v at the o2 end. I'm unsure what the C1-end of the wire reads when connected as I haven't tried backprobing, but I can only presume that it also reads 4.23v...

Nope. This problem existed as soon as I purchased the Jeep, and it persists despite the replacement of the sensor and the new exhaust manifold. Sorry for the confusion.

Thanks a million for all your help, Sidewinder. From what you describe so far, it seems to me that seeing +4.0v on the BK/DG wire with the harness disconnected is a problem. I must have confused this reading with my experience with wideband sensors where a 5.0v reading isn't abnormal. The...

I was unable to edit my post #8, so I had to make my correction in post #10. I am reading ~4.0v KOEO on the BK/DG o2 signal wire.

I presume that means I've got a short somewhere along the BK/DG wire... Are there any particular closely-routed wires that I should disconnect one at a time while troubleshooting?

Ooops....I meant I was reading o2 signal between the BK/DG wire and battery ground.

Charles: What other sensors are fed by 5v source? Downstream o2, MAP, and TPS? Just to be clear, are you recommending that I disconnect all these sensors and then monitor the KOEO upstream o2 signal voltage as I reconnect the other sensors? Do you think that there might be a short in one of the...

I've attempted to "verify" o2 sensor and wiring as best as possible and have gotten the results listed in my first post. I'm not sure what to make of them at this point. Today I am going to verify continuity along the O2 signal wire from the harness connector to pin A24 at the PCM. The low-ish...