'82' High performance 'chip'

[Rmodeler]

Just purchased an 82 Vette(1st. one). Along with it was what the previous owner said was a high performance chip that came with the car when he bought it from the original owner. It's in a GM box, about 6-8" sq. and about an 1¼ thick. It has a couple of plugins. I don't see mention of it anywhere. Does it replace the original computer box(?)

 

[wishuwerehere82]

It sounds like a replacement ECM box. Yours is in front of the battery in the battery box behind the drivers seat if you want to take a look at it for comparison. It will have a part number on a paper label on the box.
I am not aware of any "High Performance" replacement ECM, just the ROM chip that goes into it. All of the other updated ECM's that are faster than the stock ones have to be re-wired to be compatible with the existing wire harness because of different connectors to the box. The high performance "Chip" plugs into the ECM inside the little door on the side of the box facing the battery.
The stock units have two card-edge connectors that plug into the bottom edge of the ECM box. My guess is that it's a spare for your car.

 

[JohnGrawcock]

It sounds like a replacement ECM box. Yours is in front of the battery in the battery box behind the drivers seat if you want to take a look at it for comparison. It will have a part number on a paper label on the box.
I am not aware of any "High Performance" replacement ECM, just the ROM chip that goes into it. All of the other updated ECM's that are faster than the stock ones have to be re-wired to be compatible with the existing wire harness because of different connectors to the box. The high performance "Chip" plugs into the ECM inside the little door on the side of the box facing the battery.
The stock units have two card-edge connectors that plug into the bottom edge of the ECM box. My guess is that it's a spare for your car.

I wounder if the HiPo chip is already installed in the replacement ECM. If so it will probably have some aftermarket name on it such as Hypertech. I'm not sure that these chips make a difference on the 82 though. I haven't tried one, but the only feedback I've herd was negative.

 

[Twin_Turbo]

If it's that thin it's probably an 84 C4 ECM or a later model truck ECM, what's the # on it? 1225550 is the stock 82, 1227747 is the late model tbi one, can't remember the C4 # off the top of my head

 

[Rmodeler]

The number on the part is EM7747. This is all new to me, as this is my first Vette. I'll probably have more questions as I get into it more. The 'emissions' pump by the a/c has been disconnected, lines blocked. Shouldn't this be operating, so the engine will run more efficient. Doesn't the computer sense this and adjust the engine running accordingly?

Thanks

 

[wishuwerehere82]

The AIR pump on the 82's inject air into the exhaust manifolds and exhaust pipe. This was done in 82 to dilute the exhaust gasses to reduce tailpipe emissions. It does not make it run more efficiently, since it takes power away from the engine to run the pump, but it does allow it pass emissions tests for an 82 Vette.
Depending on your state's emission testing, this may not be a problem. It will definitely run faster and smoother with it off.

 

[jdp6000]

Wish...

I have all that polution control stuff and don't need it. No Emissions test on my car here. Anything I need to know about removing it? Taking the parts off is a no brainer but what do you do about the electrical connectors and where the hoses coonected??

Jim

 

[wishuwerehere82]

Jim,

I still have mine on, but you could check with the other board to see what is involved. http://www.crossfire.homeip.net/
I know the hose connections at the manifolds have to be plugged(welded) shut. I think the electricals can just be unplugged.

 

[Twin_Turbo]

The number on the part is EM7747. This is all new to me, as this is my first Vette. I'll probably have more questions as I get into it more. The 'emissions' pump by the a/c has been disconnected, lines blocked. Shouldn't this be operating, so the engine will run more efficient. Doesn't the computer sense this and adjust the engine running accordingly?

Thanks

that's the 7747 ECM, a TBI ECM which' code is well hacked and available on the internet, there bins are out there so you can (w/ some learning) program your own stuff (burning proms, or buy a prominator and forget prom burning and erasing), is it a turbo city ECM (hefty overpriced 7747 w/ crimp on connectors supplied requiring you to cut original wiring, if so check out the harness adapter module to go from pin to edge card style, plug & play. http://www.speedtronics.net is where you find the ham and the prominator)

wishuwerehere82The AIR pump on the 82's inject air into the exhaust manifolds and exhaust pipe. This was done in 82 to dilute the exhaust gasses to reduce tailpipe emissions. It does not make it run more efficiently, since it takes power away from the engine to run the pump, but it does allow it pass emissions tests for an 82 Vette.
Depending on your state's emission testing, this may not be a problem. It will definitely run faster and smoother with it off.

The pump pumps air into either the exhaust system or air cleaner housing, this is handled by the 1st switching valve and the air cleaner is used to vent when letting off the throttle to prevent popping in the exhaust.

the 2nd valve switches between headers and cat con. During warmup/open loop when the system runs off the prom without feedback from the O2 sensor it switches headers to quickly heat up the O2 sensor so closed loop/o2 feedback can be entered. then the valve switches to the cat con because it needs the oxygen for the oxidiziung bed (the 2nd one, the front/first is the reducing section) you will notice the O2 sensor is forward of the cat con air injection pipe so the o2 doesn't catch a false lean signal from the air being pumped to the cat con. that's why it's important for the valves and reed valves (and exhaust self to be leak free) to be in working condition, otherwise you get a very rich running car due to a false lean signal. It has nothing to do with dilluting the exhaust gas.

 

[jdp6000]

Twin,

Are you saying i should leave the airpump on??? Did all 82 cars have it?

Jim

 

[Twin_Turbo]

all catalytic converter equipped cars have the air pump to feed air to the oxidyzing bed so yes, all 82s have it as it's part of the emissions control system. Do you have to elave it on? No not really but your cat won't function properly without it, only the reducing section will be operative and it shows in the emissions, I removed mine also, it's not a problem for the fuel injection system, the emissions stuff (AIR valves) is controlled, not monitored for proper operation.

If you want to haev a functioning cat con, yes then elave it on and the header tubes aid in O2 sensor warmup, you can do without them, just run the 1st switch valve to air cleaner and directly to the cat con, bypassing the 2nd valve (eliminating it) however it would be smart to install a heated sensor then, doing it in the collector would be a good choice (assuming you want to run headers, the only reason to do away w/ the air pipes)
The best way to activate the heater is to run it off the 12V power feed for the pump that comes off the oil pressure sender (when you start the car the relay momentarily powers the pump but shuts off, by then the oil pressure is up and the pressure sender/switch will have taken over the job of supplying 12V to the pump, it's a safety feature so the car won't run without oil pressure),that way the heater is only operative when the engine runs, not when the ign. is on (which it would be if you ran it off an ign. switched source...w/ a relay, always use a relay!!!)