5.0 Ranger Running Rich

[RonD]

Majority of the time when a CKP sensor fails there will be no code.
So if you think the wire may be to blame them same thing, no code.

CKP sensor signal shutting off would cause dead engine, spark and fuel would stop instantly, no chugging or slowing down, spark and fuel would just stop, literally like the key being turned off

 

[shr3dd3r 09]

That's exactly what happens. It does hesitate now and then, but when it does die it just goes completely dead instantly but will start back up after cycling power. It will crank and crank unless I turn the key of and then back on. Then it fires right up. I re-grounded the wires and it didn't help so I'm at a loss again. I'm going to check the wires going to the key cylinder to see if they are causing intermittent ignition faults. If that looks good I guess I'll try to find another engine harness.

 

[shr3dd3r 09]

So I've noticed when the Ranger hesitates it will go into open loop for a few seconds, and then go back into closed loop according to my ultragauge. It will sort of lose power briefly then go back to normal, kind of like a misfire. This is something I just happened to notice and thought I'd mention it in case it means something...

The idle speed also seems a little rough and seems to do a little bit of idle searching. Still no codes.

 

[shr3dd3r 09]

According to my tuner the open loop mode indicates the ECU is losing power. So now at least I might have a valid direction to go in. Guess I'll start with the fuse box and relays...

 

[shr3dd3r 09]

Fixed the problem. The switch cable plugged into the chip in my computer was apparently bad or not making good connection. I removed it and now it runs great. The cable was only there to allow me to easily switch between 87, 91, and 93 octane tunes so I don't really need it. Runs great now. Can't believe that was the source of all my headaches.

 

[RonD]

Good work

Electrical is the hardest problem to solve/find.