[spittoon]

My current setup is the Howell TBI with the 258. I'm in the market for a 6-into-1 header, no cat setup. Do i need to continue using the O2 sensor and weld in a bung on the downtube, that was there from the old manifold setup?

 

[walkerhoundvm]

I'd think so, it's what the computer uses to determine injection parameters, along with block temp. I'm not sure what would happen if it was unconnected - bad things probably.

I'm about ready to do the same thing you are, and I'm having a bung welded.

 

[73jeep]

Yes you do need to have the o2 sensor hooked up. It provides real time data to the ecu on the air/fuel mixture. From there it either increases or decreases the fuel into the engine. This the major advantage to EFI, precise mixture control. If you omit the O2 sensor you might aswell put your carb back on.

 

[bdb86cj]

you need an O2 sensor for TBI. Mast after market exhausts have an O2 bung already welded in. If its in the header get a 3 wire heated O2 sensor if your harness will accept it or you can fab the connector. If its in the down pipe or you just dont want the 3 wire one any single wire universal o2 sensor will work.

 

[1986cj]

Yes you need a o2 sensor for it to run right. If you have a Howell system it already has only the basic parts needed to run and get into closed loop. I would think with out the o2 , when you reach operating temp it would run in open loop or limp home mode and never go into close loop. Howell has already turned off the rest of what the ecm is capable of doing in the chip they burn for their system. 2X on what 73jeep said, no o2, you might as well go back to a carb.

 

[spittoon]

awesome, thanks for the advice and explanation guys...

 

[Chewtoy]

btw, the 3 or 4 wire O2 sensor is worth the extra couple bucks. Put it down in the collector so it gets an average reading of all your cylinders vs just one. A 1 wire will not stay hot enough to work correctly that far way from block.

 

[bdb86cj]

btw, the 3 or 4 wire O2 sensor is worth the extra couple bucks. Put it down in the collector so it gets an average reading of all your cylinders vs just one. A 1 wire will not stay hot enough to work correctly that far way from block.

this is not true, once the engine gets up to operating temps the exhaust in the down pipe will keep it more than hot enough. Only difference in the two is the heated gets readings faster. Placing the O2 after the headers is a good idea though.

 

[Chewtoy]

this is not true, once the engine gets up to operating temps the exhaust in the down pipe will keep it more than hot enough. Only difference in the two is the heated gets readings faster. Placing the O2 after the headers is a good idea though.

Well if you say so. It did not work for me on a 304 and there are lots of other posts on here and binderplanet that will tell you if you move a 1 wire O2 sensor down to the collector it is far enough away from the motor that sitting at idle (stuck in traffic or at a long stoplight) is often not enough to keep the O2 sensor warm enough to stay in closed loop. Make is a hot summer day in AZ, sure, no problem. Make it a cold winter day in ID, MT or WY and not so much. Just for clarity, the 1 wire is not going to "malfunction", it just may not keep you in closed loop as often as a 3 or 4 wire.

Sup to you, a 1 wire will work well enough. IMHO it is better to stay in closed loop as long as possible. A 3 or 4 wire gets you there faster and stays there in more situations, plus is only a few dollars more.

Either way, keep the rubber side down :2thumbsup:

 

[spittoon]

Hmm, so i'm finally to this point in my build. Should i weld the bung on the collector? or can i weld the bung to the exhaust pipe? I'd rather not have to drill a 7/8" hole in the collector. The pipe would be easier. I've never had to weld on a header before, is that cast? Any idea what setting i would use on my Lincoln 135 handler?

 

[CSP]

As it's been already said, unless you're using a heater oxygen sensor, the collector is too far from the engine.

Sure it will run that far downstream, but it will go back and forth between open loop (cold O2 sensor) to closed loop (hot O2 sensor) at every traffic stop. It will also take longer to go into closed loop when the engine is cold.

Headers are not cast. It's steel tube.

 

[aero mech]

I have a one wire in my tbi set up and i located it just aft of the collector in the exhaust pipe. I haven't had a problem with mine going back into open loop once it warms up. This was varified by down loading all my info with the data link on a laptop. I am using a 4.0 cherokee factory manifold. I haven't run it in cold weather yet but so fare so good. If it does you can always upgrade to a 3 or 4 wire with no problem.

 

[mtnbikeidaho]

Hmm, so i'm finally to this point in my build. Should i weld the bung on the collector? or can i weld the bung to the exhaust pipe? I'd rather not have to drill a 7/8" hole in the collector. The pipe would be easier. I've never had to weld on a header before, is that cast? Any idea what setting i would use on my Lincoln 135 handler?

You have a 258? Stock exhaust manifold? If yes, your 1982 to 1986 manifold has an O2 port on it already.

Aftermarket...is another story.

 

[walkerhoundvm]

Put it in the exhaust just downstream of the header, and use a heated O2 sensor. If you put it in one of the header pipes, it's not going to get an accurate reading of what's going on in the entire engine - just that one cylinder.

But that may be what you have to do if you don't have a heated O2 sensor.