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Discussion Starter · #1 ·
I'm running a '93 almost stock EFI 5.0L, with FFR/BBK 4-into-4 headers.
Hoping to attempt a first start in the next couple weeks.
I realize I can probably turn the engine over without the O2 sensors, but to really run the engine, I want to install them.
I know there is a big debate on the proper location (upper header pipe near the block, or after the 4-into-1 collectors, under the car.
After much consideration (and still not 100% confident with my decision), I'm going to mount them on the last header pipe (closest to the firewall, pipes 4 and 8) on each side, about 12" - 18" from the flange. What is the best orientation on the pipe? about 5:00, not straight down (6:00)?
similar to this:



Will this work? (Is there something better?)
Breeze - Bung, Oxygen Sensor, Stainless Steel #35374

What would a welding shop typically charge to drill and weld them? (Stainless to ceramic coated pipes, I'm assuming this will cost more)

I don't think the O2's on the '93 5.0L are heated or wide-band, correct?
 

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I put mine on the sidepipe before the collector on one of the tubes but car didn't run right. It ran much better after putting it after the collector. Only down side is you can see the wire when looking straight down between body and side pipe. Also when I took it in to get tuned they had to put another for their O2 sensor on the tuning machine.
 

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Innovate (LM-1 Wide Band) says: "The bung must be installed in the exhaust pipe at the side or the top, NOT the bottom...Best position is between 10:00 and 2:00" The concern is having water condense on the sensor and ruin it.
 

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I am thinking of going to the 4 into 4 headers too, but am a little concerned about the O2 sensor in only one pipe. If that cylinder's plug fouled, the sensor would read a rich mixture and lean out the whole engine. Maybe not likely though.
 

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I had mine welded into the side pipes after the collector. It runs great. I didn't want to do it twice. I drilled the hole right where I wanted it to be welded.
What don't you like about this location?
sounds like a good place, all four cylinders each side will read the sensor.

Mark are the side pipes finished, if not i think maybe John will weld the weldlets up for you, but i can't speak for him. may cost some beer and for me too, you still owe me more and more is good:icon18:

who better to weld a pipe than a pipefitter compliments of local 562:001_smile:
 

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Discussion Starter · #9 ·
Need a little more information before I order.
I'm running a '93 EFI, so I think these are narrow-band 02 sensors, correct?

I found these on Breeze, but they say "O2 Sensor Bung (weld-in). Required for installing a fuel injection system or a wide-band oxygen sensor with a 4 into 4 exhaust system. (M18 × 1.5 Thread)"
#35374, Bung, Oxygen Sensor, Stainless Steel

I found these on Summit, but they say "Oxygen Sensor (02) screw in extension 2 3/8" Long for Hemi & SRT8"
Kooks Headers 9003A - Kooks Weld-In Bungs

These look like they work best.
30743 - JEGS O2 Sensor Weld Fittings

Recommendations?

Also, while I'm at it, what Oxygen Sensor would you recommend?
I found these for a '93 Mustang:
Bosch Automotive 15716 - Bosch Premium Original Equipment Type Oxygen Sensors
but, I see others listed from $26 to $49.
 

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I went with the 4-wire O2 sensor Wade Chamberlain recommended here:

http://www.ffcars.com/forums/44-200...4x4-headers-02-sensors-possible-solution.html

This provides a separate ground for the sensor so it does not rely on the ground path through the engine-exhaust system.

I also placed it in the collector on the side pipes. One of the arguements for putting it in the headers is that the computer is expecting to see the data at at a certain point in the engine cycle but I would wonder if that is any better than seeing just one pulse per side instead of 4? The other arguement is the temp but many are running it in the side pipe collector without any significant issues (and the 4-wire helps).

If you do go with the side pipe then you have to be careful where you locate it. Not sure on a MK 4 because the body wraps under the car so if you locate and drill/weld before the body is mounted then you may have interference. You would want the pipes installed and levelled before locating them. You don't want to put it to low either since it can collect moisture and fail the sensor or get hit by road debris.

Cheers, Rod
 

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I moved mine up from being in side pipe. I mounted one in pipe #3 & #7 about 5 " down from each head mounting flange. Car goes into closed loop way faster now. I am not to concerned about reading all cylinders since if your engine is running good on all cylinders it really shouldn't make a difference. My engine used to die on initial start up until it built some heat. Now a push of the button and no having to keep foot on throttle until it warms.
 

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Discussion Starter · #12 ·
While I appreciate the additional information, I really want to stick with the 3 wire sensors on the headers. I don't like the sensors hanging down on the side-pipes and don't want to convert to a 4-wire harness and sensor either.

From what I've read, the 3-wire on the headers works fine and there is no significant advantage to moving it. Either will work fine.
 

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It's your car

build it the way you want it to be . . .

I, personally, built mine the way that ryanh (see post #6 above) had his built by a local shop.

All eight being sensed, all eight being controlled by EEC, no issues with starting cold or constantly running in open loop.

Just my 2¢

Doc :beerchug:
 

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While I appreciate the additional information, I really want to stick with the 3 wire sensors on the headers. I don't like the sensors hanging down on the side-pipes and don't want to convert to a 4-wire harness and sensor either.

From what I've read, the 3-wire on the headers works fine and there is no significant advantage to moving it. Either will work fine.
mmmmmmm:shifty:
carburetor engine

throw one on each side of the side pipes on the full tube
 

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build it the way you want it to be . . .

I, personally, built mine the way that ryanh (see post #6 above) had his built by a local shop.

All eight being sensed, all eight being controlled by EEC, no issues with starting cold or constantly running in open loop.

Just my 2¢

Doc :beerchug:
Either way you do it the injectors are not monitored or controlled individually. The computer takes the feedback from an O2 sensor and adjusts the whole side (head) accordingly. Therefore if you have 1 injector acting up (say it's stuck open), neither sensor location can compensate. If the sensor is in the collector you will get an average and the adjustments will be made to lean out all 4 injectors including the 3 that are OK. It's no better with the sensor in a single pipe. Depending on whether or not the bad injector is in the pipe with the sensor, the computer will either try to lean out all 4 injectors or it won't even know anything is wrong. (but you will).
Bottom line is that either location will work well as long the injectors are OK. Neither location will detect or correct problems with individual injectors.
 

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Discussion Starter · #16 ·
Guys, set the header vs collector aside, I've moved past that.

I need help with which bungs and sensors to buy.
Would appreciate recommendations.

Thanks!
 

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Either of the shorter ones will work. I got mine off the shelf at a local speed shop. I think they are all threaded the same. My wideband sensor also screwed right into the standard bung .
 

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Custom design

"Either way you do it the injectors are not monitored or controlled individually"

FWIW,
I always thought that the placement was required for O2 sensor heating from the exhaust, not because it would (or could) control eight injectors individually.

Ford places the factory installed O2 sensors in the small collector where the exhaust pipes transition to the down pipe in a stock mustang, 12 to 19" from the head.
By building 4 into 4's with a common plenum at that distance, we get the benefit of the 4 into 4 savaging coupled with a [somewhat] proper location for O2 sensor heating, required for closed to open loop transition.

I like that my sensors heat well enough to transition properly and I don't have the continual closed loop conditions that some have mentioned here. I do know my gas mileage went up when I first replaced my headers with this "unique" design.

But, again, that's just my humble opinion.

I got my bungs from Summit, along with my mufflers and the collectors.

Doc :beerchug:
 

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FWIW, I had my bungs put in the #4 and #8 headers about 8 inches from the flange. No issues in 8,000 miles until recently, I have had a slight miss when I give it some throttle at low rpms (in any gear). I pulled the plugs today, and the no 4 and 8 plugs were grundgy with tan burnt on something, but all of the other plugs were like new....????
 

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Sorry for getting off track. Here are 3-wire sensor numbers:

O2 sensor p/n’s
8” leads – Motorcraft p/n: DY605 Bosch p/n: 13942
16.5” leads – Ford p/n: E7TF9F472CA Bosch p/n: 13953


Got my bungs from Breeze (that just sounds wrong)

P/N 35374

Bung, Oxygen Sensor, Stainless Steel $7.00 ea
Stainless Steel Oxygen (O2) Sensor Bung (weld-in). Required for installing a fuel injection system or a wide-band oxygen sensor with a 4 into 4 exhaust system. (M18 × 1.5 Thread)
 
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