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Bank 1 shorted!!


Denisefwd93

Well-Known Member
Joined
May 20, 2015
Messages
2,261
City
South East PA
Vehicle Year
1994
Engine
4.0 V6
Transmission
Manual
Total Lift
stock, may get leveling springs in front "somday"
Tire Size
235
I found what I think may be the cause of my code 172!

Bank One connecting wire (all four of them) are pinched between the engine and the top of the bell housing near the one of the top bolts!!!

I can't get to it, will have to cut it and reroute

Techs if you're reading this where does it connect at the other end?

Just found it, and of course it started raining and it's really dark out there again,

This probably also shorted out and caused overheating alternator.
 
O2 heater Fuse should have blown if a heater wire shorted.
O2 sensor wires generate there own voltage, .1 to .9 so very little
But yes, under .2 volts from O2 sensor means Lean, so 0 volts would be lean, lol

Truck wiring side of passenger O2 sensor should have Black/white stripe wire, it runs to the computer, its the GROUND for the O2 heater
Light blue/orange stripe wire runs to heater Fuse in engine fuse box, usually 15amp

Both of these wires connect to O2 sensors "same color wires", i.e. if O2 sensors plug has 2 Black wires or 2 white wires then the above trucks wires connector to them, polarity doesn't matter since it is a Heater, so O2 makers just use 2 wires that are colored the same for the heater.

O2 sensor wires on passenger side are Grey/light blue stripe, it runs back to computer, O2 sensor #1.
And an Orange wire, it is the common wire for most sensors, computer Ground/Reference

Black/white stripe, O2 heater Ground at computer, pin 40 and 60
Light blue/orange stripe , O2 heater 12volt from fuse

Grey/light blue stripe, sensor voltage to computer, pin 29
Orange, sensor reference/ground to computer, pin 46 and 49


O2 sensor on Drivers side has the same Heater wires, in fact they are spliced in the wiring harness, so worse case is you can tap into those.

Orange wire for sensor is the same, spliced to other O2 sensors orange wire in the harness.

Only difference is the Grey/light blue stripe wire, computer knows that is the Passenger side O2
Red/black stripe wire is Drivers side O2 sensor, pin 39
 
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Thank you Ron! but it was so dark out there I couldn't even begin to see which way it runs, under/in the dashboard, or behind the engine, I have no idea yet but yes it's the passenger side I found it purely by accident!
 
still can't find the route . gad it's full sun out today still can't see in there!
 
Both O2 sensor's wires have connectors near middle of firewall behind the engine, and they go into the Main harness that runs across the firewall.

And since O2 sensor connectors are "universal" there is no passenger/drivers side connector, both are the same so WATCH OUT for that if you unplug both.
Had a shop reverse mine, engine ran poorly after warm up and got CEL
They want to charge me to diagnose it, lol.

Morons or Ripoffs, swapped them back and all was well
 
Thanks for staying with me on this Ron, I found #2 connector it's a gray plug still haven't found the other connector to bank one, the wires are definitely between the engine and the bellhousing.

I'm wondering at this point if we should loosen the bolts on the bellhousing, I guess now I know why I was only able to get one bolt in the top two holes of the bellhousing and yes, I was the one crawling on top!

(For those not familiar with the story we recently swapped out transmissions on this truck)
 
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Okay the sunlight helped this time around I can't find the plug because it's INSIDE the bellhousing, omg. No way that's going to back off enough and stay in alignment, someone will have to cut and splice. .
The cost of free help....
 
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The "plan"
loosen bellhousing bolts, (do not remove, pull up on the wires, and hopefully find enough slack to cut and splice above and right of the intake plenum, leave the plug in the BH assuming the flywheel already destroyed it. Order a new connector with wire pigtails
 
Just hit wrecking yard O2 connectors are fairly standard.

If funds permit get a new O2 sensor for passenger side and take it with you, or take your "good one" out and take it, get both connectors, O2 side and truck side
 
It probably wouldn't hurt to actually change that oxygen sensor maybe the wires aren't shorted even though they're clamped between the engine and bellhousing. But I don't have that kind of luck I never have LOL
 
Key OFF, just cut the wires as close to bell housing as practical.

O2 wires will be colored like these: http://www.aa1car.com/library/o2_wire_chart.jpg

So the two wires that are the same color are the Heater wires and there is no Polarity for those
So they hook up to Truck side Light blue/orange stripe and Black/white stripe wire

The sensor side does have polarity
Generally Black or Blue O2 wire would be the "+" signal wire, so hook that to truck side Grey/light blue stripe wire
Then remaining O2 sensor wire, grey or white, hooks to Orange truck side wire
 
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Thank you Ron very very helpful!

the nice thing about not selling my other truck I don't have to rush about getting these little items fixed on this truck.
The bad thing, I don't have the money from the sale truck to fix this truck lol.
 
update to report... no update! think I'm getting a mental block over this. Seems like because the trans is a M5OD the space at the top of the bell housing may be "safe" for the O2 plug that may or may not be shredded from the flywheel teeth.
 
I stopped by the garage that helped me on the fan clutch, apparently this happens a lot with do it yourself mechanics,. anyhow he's going to take care of next week. It's a bit humiliating but at least I can blame my friend Hank lol
 
@the shop as I write this, he backed off the bell housing, hopefully this issue will be put to rest, I had them leave the fender well liner out because we have to work on the AC anyway.
Edit
Drove the Beast home, no CEL! so my instincts (& $30, code reader) were right all along; it was the O2 sensor!
 
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