Intermittent DTC 13

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majack82

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I got the ALDL cable in today, finally. Looking forward to learning what all I can do with it.

I did a test with the diagnostic readings on my '95 first since the A/C works in it. It's REALLY hot in Arkansas today and the 88's air is out, so it'll have to wait for now! As luck would have it though, the '95 threw a DTC 13 this past week too and it feels like it's losing power/hesitating whereas it wasn't before. The voltage reading on the O2 is dead at 446 mV. It might jump down into the 430s for a split second and come right back.

Lots of info to be read in TunerPro! I need to study up on what all it's telling me and if there's something else I should be aware of that isn't right with both trucks. I'm going to try to learn what I can, but I may have questions! I wish I could find this same kind of setup for my TBI Dodge truck.
 

majack82

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Conway, AR
I got updates. Finally got some nicer weather today, so I spent some time diagnosing the 13 in the '95 since it is my daily driver. Followed the testing flow chart in the service manual and everything checked out and pointed to a bad PCM ground. The ground itself (on the left side front manifold stud) looked fine, but a little tug on the tan wire and BOOM - pulled right out. Took it all apart, stripped and recrimped the wire, and my O2 is working great now. So, that led me to the '88. Same exact problem more or less, except the ground wire wasn't even connected. It was lost in the wiring loom and never got reconnected at some point when someone got crazy with some butt connectors. Hooked it back up and now both trucks go into closed loop without an issue.

I did go ahead and put a new Denso sensor in the '95. The one in it looked original so figured it would not hurt to change it for sure.
 
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