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1984 corvette oxygen sensor

 
kenyes1
I love my Chevy Chevette!
Posts: 8
Joined: 02/12
Posted: 03/12/12 05:37 PM

sorry for not stating the year in prior post. As i have stated i have looked everywhere for the oxygen sensor with no luck  could the prior owner have eliminated it when he put headers on the motor.   and if so could it be the issue with motor performance i am still having problem with a long cold start.
   
  thinking that it might be the fuel line draining back once the car sits for a while i installed a fuel line check valve at the gas tank. I also changed the fuel filter this weekend,and looking back im wondering if i should have put the check valve just after the filter rather than at the tank  

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waynep7122
I mow my lawn and find Chevys
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Joined: 08/09
Posted: 03/12/12 07:35 PM

start with this info..

84 cross fire models have 3 obvious temp switches...

in the left head.. between the #1 and 3 cylinder spark plugs is the ENGINE TEMP SENDING UNIT.. this controls the GAUGE on the dash board...  it has ONE GREEN wire on it..
this is the temp sending unit in the left head
TU66


in the RIGHT cylinder head.. between the #6 and #8 cylinder spark plugs is the radiator cooling fan control....

this looks very much like the early design ECT sensor. but it is actually the RADIATOR fan switch..  on the 84 . ONLY this and the high pressure switch on the AC control the radiator cooling fans..

you will see that this has a single contact PIN..  not the dual that early Coolant temp sensors have..
Radiatorfranswitch S500sideview

Radiatorfanswtichtopview



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

stuck into the FRONT of the intake manifold down under the smog pump is the ENGINE COOLANT TEMP SENSOR...
this has usually a  black and a yellow wire on it..  this tells the computer how hot the motor is.. so it can set the PROPER FUEL MIXTURE for engine operation..   sorry i don't have a decent picture of the original coaxial type of coolant temp sensor..  they are replaced by the version below...

you have to remember. this is electronic fuel injection..    NOT A SIPHON system where the speed of the air pulls fuel up and over..  the COMPUTER HAS TO decide to SPRAY the fuel and HOW MUCH to spray...


you can see the coolant temp sensor in this image..

82Crossfire


this is the AZ stores SU102... under 20 bucks. goes in the front of the intake. please install harness also.. both can fail.
Su102  

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waynep7122
I mow my lawn and find Chevys
Posts: 1114
Joined: 08/09
Posted: 03/12/12 07:42 PM

oh.. the oxygen sensors are in the exhaust manifolds...

there are collector adaptors that can be installed to allow oxygen sensors to be installed.. without damaging the headers...

oxygen sensor bungs can be welded into almost any collector..

i would worry about some coatings preventing proper welding of the bungs in...

you can see the Oxygen sensor as item E at the top of the drawing ...


84Vettecrossfireenginelocations

the Crossfire only needs ONE oxygen sensor as far as i recall..

it has to have the sensors to work the fuel trim..  or it will be really really rich .. to protect the engine...  

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waynep7122
I mow my lawn and find Chevys
Posts: 1114
Joined: 08/09
Posted: 03/12/12 07:56 PM

the item at #41 or 42 is the oxygen sensor.. it goes into the OEM short header just above the flange..

840Crossfireemissioncomponents  

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waynep7122
I mow my lawn and find Chevys
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Posted: 03/12/12 08:11 PM

bump....  

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kenyes1
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Joined: 02/12
Posted: 03/13/12 02:36 AM

thanks for info  but none of the diagrams came thru please send again   and what about the location of the fuel check valve  

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waynep7122
I mow my lawn and find Chevys
Posts: 1114
Joined: 08/09
Posted: 03/13/12 04:27 AM

if the diagrams are not visible..   you have the settings on your browser set to prevent them from being viewed... i have had that happen to me..     what browser are you running..   IE,  firefox, safari??


the fuel pump check valve is in the end of the electric fuel pump that is mounted inside the fuel tank..

its less than an hour to change the in tank pump from ABOVE..   you do not have to drop the tank on this one..

the fuel pressure regulators in the top of the injector housings also hold pressure.. when blown . they will leak fuel into the intake..  

Gp Sorensen/Throttle Body Rebuild Kit (TBI)
For your 1984 Chevrolet Corvette 5.7L TBI 8cyl
Part Number: 96-629
 

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ctoneal55
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Joined: 04/12
Posted: 04/11/12 09:29 AM

My switches on both cylinder heads look identical does that mean i can buy two of the same switches or are they different an just look alike?  

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waynep71222
My first time was in a Chevy
Posts: 181
Joined: 04/12
Posted: 04/11/12 03:36 PM

NOOOOOO!!!!   did the images above show up???? i went to a LOT of work to post them..

the switch on the right cylinder head on an 84 is the ONLY control the radiator fan has.   it is the RADIATOR FAN SWITCH..


the switch in the LEFT cylinder head.. Drivers side.. is the TEMP SENDING UNIT this is for the DASH BOARD DISPLAY...


the switch with 2 wires Black and yellow is the Engine coolant temp sensor..  for the ECM...

each one works DIFFERENTLY..   you cannot INTERCHANGE them.  it you want the car to work properly..  

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Dan1952
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Joined: 10/12
Posted: 10/07/12 07:08 PM

My buddy has a crossfire in his jeep and I,m trying find out witch TB gets the fuel supply line and witch one gets the return line. I have not yet found a diagram. Any thoughts?
Thanks a bunch
Dan  

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waynep71222
My first time was in a Chevy
Posts: 181
Joined: 04/12
Posted: 10/07/12 08:49 PM

this should help....

17 is the fuel inlet...

15 is the fuel return to the tank...

830308GM03 124
Chevrolet 1984, Corvette, Fuel system-exhaust-emission system, 1984   Y THROTTLE BODY INJECTION/CFI-5.7L V8 (MODEL 400)(L83)   (GM03-124)  

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waynep71222
My first time was in a Chevy
Posts: 181
Joined: 04/12
Posted: 10/07/12 08:52 PM

oh,,  click on the image for a big image...

the inlet is on the side of the front passenger side throttle body..

the return is on the front of the rear left side throttle body..  

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briando
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Posted: 10/27/12 10:37 AM

i'm starting to learn more and more that even in a corvette, most sensors were installed because a lawyer wanted them there and the only time they go off is when they themselves have failed or broken  

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waynep71222
My first time was in a Chevy
Posts: 181
Joined: 04/12
Posted: 10/27/12 01:35 PM

Icon Quotebriando:
i'm starting to learn more and more that even in a corvette, most sensors were installed because a lawyer wanted them there and the only time they go off is when they themselves have failed or broken

these cars have as few sensors as possible...

the crossfire cars were mostly a conventional TBI system..  and the GM TBI system was used on cars from 1983.. 82 if you count the C3 models.. up through 1995 ..  thats MILLIONS of cars and trucks..

if gm could do the job without it.. they would...

look for a cam position sensor on a saturn.. its not there... they look at the spark feedback signal from the coil to see which cylinder has compression to figure out where #1 compression stroke is ..

there is a great inside story from the mid 90s... when gm went to electronic shifted transmissions..  caddy owners were complaining that on right turns their car would not have power until the transmission shifted back down from overdrive..

what was happening is the owner punched the throttle to hang the right turn.. then had to slow down to merge into traffic...  at this point the transmission has upshifted because of the programming for MPG..

the hydromatic devision had a group meeting... a few other division engineers also attended...  when the problem was discussed... one jr engineer spoke up and said.. why not use the lateral acceleration data from the air bag system... the hard core transmission guys said... WHAT data stream???   that guy went home and over the weekend wrote a program... it worked. fixed the issue... got rid of his JR engineer title..

in some aftermarket and factory repair manuals.. there is a section that discusses each of the sensors and their job.. if you get a chance to read that... might take 20 minutes to an hour... there is also a video i might be able to find a link to... slightly over an hour on fuel injection tuning and fuel trim calculations...  

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