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help! no o2??? wtf?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by tacoma, Mar 14, 2006.

  1. tacoma

    tacoma 1/2 ton status

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    ok. So I've got two 89 Chevy's, a Blazer and a 3/4t Burb. Both are TBI'd.

    The Burb is leaking and probably about to lose a head gasket. My plan was to just swap the motor from the Blazer into the Burb, since the Blazer is getting a 454 this summer. HOWEVER

    the 3/4t Burb has no O2 sensor, and I cant' find a stub on the harness for it. I need to do the swap QUICK so no dicking aroudn looking for new exhaust studs and all that when they break off LOL

    Question: will the no O2 motor run w/the computer from teh Burb? Will the O2 motor run in the Burb with no harness for the sensor?

    OR should I just say the hell with it, pull the heads and hope for the best?
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    It's supposed to have an O2 sensor, it will run, but it will never go closed loop and that's not going to be a good thing.

    There are only two sensors that I KNOW were not used on all TBI applications, one is an Inlet Air Temp sensor, (cars only) the other is a Knock Sensor. (big blocks didn't use)
     
  3. tacoma

    tacoma 1/2 ton status

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    well where is it supposed to be?? the Blazer has one in the driver's side manifold. The Burb has a flat for one, but it isn't drilled/tapped. And none in the pipes either.

    I am perplexed and more than a little miffed LOL HEY WAIT A MINUTE! you're in Stuttgart! LOL
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    Without looking at it, pretty hard to tell what's going on.

    I've never heard of a manifold without the flat drilled out. Any chance it's on the passenger side, or maybe moved further down into the exhaust pipes for some reason?

    I've never owned one of these things with stock TBI, but I have a few manifolds from TBI stuff, all are drilled/tapped.?
     
  5. tacoma

    tacoma 1/2 ton status

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    It's not there. The only thing I can think of is that it's some kind of 49state heavy duty emissions deal??? Not sure. It is definitely not drilled or tapped, and there is no O2 sensor anywhere.
     
  6. HarryH3

    HarryH3 1 ton status Author

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    Some GM's have the O2 sensor installed in the exhaust pipe, close to the cat.
     
  7. HarryH3

    HarryH3 1 ton status Author

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    Oh yeah, it isn't originally from Canada is it? They didn't get O2 sensors until a few years later than the US did...
     
  8. Thunder

    Thunder 3/4 ton status

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    Yeah. Check the exhaust pipe. Most 3/4 tons I have seen have the 02 down the pipe before the cat. Not at the manifold like the 1/2 tons
     
  9. tacoma

    tacoma 1/2 ton status

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    hey now there's an idea!

    I haven't checked that far down the line LOL it's been a bit cold w/35mph wind in the driveway.

    Thanks guys, I'll check there in the AM.
     
  10. dyeager535

    dyeager535 1 ton status Premium Member

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    My only thoughts to this whole "lack of O2 sensor" idea is that it's kind of pointless to even be TBI if the engine can never use the O2 sensor to correct fueling. I know they did weird stuff for export (and to a lesser extent, Canada) but doing injection in open loop isn't something that would seem to be beneficial in any way.

    Two things I already mentioned I know are "optional" on certain TBI setups, but I don't think an O2 sensor could have been one, regardless of destination. Just doesn't make sense. :confused:
     
  11. mouse

    mouse 1/2 ton status

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    It does seem useless to have TBI and no O2 sensor. I would like to see a pic of the non-drilled manifold. Thats something I have not seen before.
     
  12. HarryH3

    HarryH3 1 ton status Author

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    They did it because other countries were still using leaded gas, which would just ruin the O2 sensor. Had to run open loop all the time. :( There's a section about it in my '87 Corvette shop manual. :doah:
     
  13. dyeager535

    dyeager535 1 ton status Premium Member

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    Was Canada still running leaded gas then too? Stateside was early 80's total auto ban IIRC?

    Makes sense now, what a fricking waste though lol. :)

    Somewhat related, why is it that Canadian cars (it seems) are able to come across the border easily, while Mexican cars are not? I'm just thinking of things like the G-body Monte Carlo SS made in Mexico that was a manual trans. (not available in the US at all) Probably emissions related.

    Interesting to see where this one goes.
     
  14. Blue85

    Blue85 Troll Premium Member

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    There are some vehicles that don't pass US crash testing regulations, but can still be sold in Mexico. Sometimes a car just isn't heavy enough or just does poorly in a certain test. Other times it just has to do with the market. For example, Dodge sells a full-size SUV down there (based on RAM truck).

    As for the O2 sensor, you can run FI open loop, as we all know, but with lower efficiency/higher emissions. But think about this: carbs are open loop and they work OK. Then the CCC setup came along, closing the loop and didn't really work any better.:doah:
     
  15. HarryH3

    HarryH3 1 ton status Author

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    Sure makes ya wonder about those Dodge boys. I think that a Cummins-powered Suburban-esque rig would sell like hot cakes in the US! :doah:
     

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