slow acceleration low vaccuum

[Lethermon]

ok so i recently put on a new pair of longtube headers and I disconnected the o2 sensor (i have a air/fuel ration gauge idk if the sensor is only for the gauge) and never put it back into the new headers(no bung for it). I was driving the truck to school and noticed the truck was getting jumpy while set on cruise control, looked down at my vac gauge and it was at 0 then the SES light came on as a code 32. I replaced the egr valve and it seems to run a tad bit better but my vac gauge is till low while under acceleration and doesnt seem to be as "responsive" as before. vaccuum is around 22 at idle. I have checked for vaccuum leaks and have found non. Any Ideas guys?

 

[GreaseDog]

Specs on the truck...

 

[Lethermon]

1990 k5 tbi 350

 

[87sierra]

the tbi system is very picky and every thing has to be perfect i would install the 02 sensor into the new headers but then again im not an expert maybe some one else has information that can help you

 

[smurph20]

MIght tune it a lil better now that you have the headers on it. IS the o2 just for the air/fuel gauge of was it a factory one for the OBDI computer?

 

[Lethermon]

thats one of my problems idk if it is to just the gauge or to both of em

 

[87sierra]

it might be for both since it is tbi and they are OBDI controlled

 

[89Suburban]

Running TBI without a O2 sensor is begging the gremlins to invade.

 

[Jims86]

Ther is no "Fuel/Ration gauge" on factory TBI.
You can not run TBI without the O2 sensor.
since you have long tube headers, you will need an 02 sensor from a 94-94 1/2 ton truck, and it must be a 3 wire sensor, and get the pigtail for it also. an exhaust shop will have to install an o2 sensor bung in the crvers side collector, and you will need to wire up the new sensor to keyed power, and ground.
Here isna good read on the wiring:http://sethirdgen.org/HO2S.htm

The heated sensor is needed because it has been moved farther away from the engine. A regular 1 wire sensor will cool off too much, causing the ECM to keep going into open loop, which wastes fuel, and effects power.
You should be good to go after that.
Also, this MAY clear up your code 32. the ecm also uses the o2 sensor to confirm a change in air/fuel ratio, to confirm commanded EGR operation, and for AIR injection, if so equipped. Get your o2 sensor squared away, and then we can see if that clears the egr code as well.
If you have your emissions sticker on the radiator support, post up a close up pic so we can read it, and see what type of egr you have.
What does the rest of your exhaust system consist of.....Pipe size, muffler(s)?

 

[89Suburban]

They make collectors with the bung installed already also right Jim?

 

[Jims86]

Ther is no "Fuel/Ration gauge" on factory TBI.
You can not run TBI without the O2 sensor.
since you have long tube headers, you will need an 02 sensor from a 94-94 1/2 ton truck, and it must be a 3 wire sensor, and get the pigtail for it also. an exhaust shop will have to install an o2 sensor bung in the crvers side collector, and you will need to wire up the new sensor to keyed power, and ground.
Here isna good read on the wiring:http://sethirdgen.org/HO2S.htm

The heated sensor is needed because it has been moved farther away from the engine. A regular 1 wire sensor will cool off too much, causing the ECM to keep going into open loop, which wastes fuel, and effects power.
You should be good to go after that.
Also, this MAY clear up your code 32. the ecm also uses the o2 sensor to confirm a change in air/fuel ratio, to confirm commanded EGR operation, and for AIR injection, if so equipped. Get your o2 sensor squared away, and then we can see if that clears the egr code as well.
If you have your emissions sticker on the radiator support, post up a close up pic so we can read it, and see what type of egr you have.
What does the rest of your exhaust system consist of.....Pipe size, muffler(s)?

They make collectors with the bung installed already also right Jim?

yeah, but if he is already running the headers, it would be more cost effective to have the 1/2" hole drilled, and the bung welded in.
I personally prefer o2 sensors istalled before the collector haskets....I is just "Monk" that way.

 

[Lethermon]

I have 3inch exhaust with a single flowmaster 50 series with a cat.
the PO did install a A/F ratio gauge thats why i wasnt sure what the o2 was for.

 

[Lethermon]

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the yellow wire goes into the cab and to the A/F ratio gauge. the o2 sensor was connected to the white plastic cap on the black wire but was torn off.

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[Jims86]

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the yellow wire goes into the cab and to the A/F ratio gauge. the o2 sensor was connected to the white plastic cap on the black wire but was torn off.

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Ok, you dont have a backpressure egr, you should be ok there. The wire that the O2 sensor from the ecm should be purple, and it should exit the harness around the back of the distributor somewhere.

 

[Lethermon]

yea it is and thats exactly where the other plug end is at . Is installing a heated o2 sensor going to make that big of a difference?