well here is the information from the person who figured it all out, so that many could follow, and as far as I know this info has been out there for along time now. do with it as you will.
The Original 95-99 Jbody Ecotec Swap How To
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You all wanted to know how to do it, Here you go.
** Disclaimer ** Anyone attempting this swap should be Mechanically Inclined, I am not responsible for any damage you cause to your vehicle as a result of this swap. This is only a help guide to show others what all is involved in swapping out a 95-99 Cavalier to an 02-05 Ecotec Motor. Use this FAQ at your own Risk.
It is strongly recommended that you have a wrecked vehicle that you are pulling the parts off handy. I picked mine up for $900.00, They are inexpensive and will save you making trips to an auto parts store or dealership looking for the parts you need.
There are quite a few parts that you can keep on the car that will also work with the 02-05 engine. Below is a list of the things that can stay in your car without having to swap out (unless you wish to its up to you).
Coolant Resvoir
Brake Master & ABS Unit (if so equipped)
Washer Tank
Lower Engine Mount (Dogbone Mount)
Engine Cradle
A/C System (I think you will need the Compressor & lines going to compressor I dont remember Since I just threw that stuff out)
Interior (except Gauge Cluster & Body wiring)
Moving onto the wiring section, Since I had a wrecked car that I purchased to do this. I took apart the whole interior of my car and set it aside. I did leave the steering column in since you dont need to swap that out, only if you want to. Make sure you keep the bolts in a plastic bag or something and label it as to where it goes. It will make your life alot easier in the long run. After you have your interior gutted, pull out all the wiring through out the whole car, including the engine bay all the way to the tail lamps. (If you dont have a salvage car then this wiring assy. will be very expensive.) You can get rid of your stock 3 speed shifter and shifter cables, if you have an automatic or 4speed if you have the Z version of this. I havent done this on a 5 speed so your on your own. As for the brake pedal, gas pedal and HVAC you can keep that all in the vehicle those havent changed. I do recommend that you pull the throttle cable off the gas pedal and swap it with the one from the donor car to work with your new ecotec motor, If i remember correctly I think they were different lengths. Also on your brake pedal you have 1 sensor already. with the 00+ vehicles there are 2 sensors which you can snatch it off your wrecked car. The HVAC unit hasnt changed what so ever. If you are swapping your dash to the new 00+ style it will still fit in the lower spot without changing it over to the new. Also I will note this, The door sensors that you have that allows your dome light to pop on when the door opens they are different from the new ones. I just removed mine completely but you can cut the wires a decent length from your old 95-99 harness and wire them into the new harness.
The most noticeable change that has happened from 95-99 would be the fuel system. You will have to swap out your old metal tank for the new plastic tank. You also need to remove your two fuel lines and evap. canister line from the system too and get the ones off of the 00+ donor car. You can keep your old brake lines unless you feel the need to replace them also. Your evap canister that is located in the passenger side fender of your 95-99 has also been moved from the front to right in front of your rear axle beam bolted to the frame. Make sure you grab the mounting bracket from your donor car. I did notice that on the 00+ vehicle that the fuel pump wiring and evap sys. wiring was mounted in a different spot than your 95-99 but it shouldnt pose a proble to just use the same spot like i did. Make sure you grab all of the components from the new gas tank. Like the fuel filler tube and hose, they are completely different than 95-99. The older style is bigger and wont fit on the new gas tank. Everything all mounts the same though for the filler tube, gas tank. If at all possible make sure you snag the fuel lines from the Donor because when I tried to use my old ones they wouldnt work, longer & bent different than the one for the plastic tank so I swapped those too.
At this Point your car should be just about completely bare with almost nothing in it. Now would be a great time to slap in that new fuel tank and run your fuel & evap lines, along with putting your new filler tube in & bolting up your evap canister to the frame. Moving along to the interior, if you grabbed the wiring harness out of your Donor vehicle, You can now put that in the inside of the vehicle and connect it to your fuel pump, evap system, rear brakes, tail lamps, and power trunk release if you snagged that off your wrecked car. The harness should mount exactly like your 95-99 harness. If you have the 95-99 pull handle for the trunk release you can go ahead and remove that cause you should have a power trunk button I would hope or atleast the LS Sport one stripped down did.. Go ahead and mount the BCM at the drivers side foot well (same location as the old one) and run your wires into the doors for your power windows / locks and mirrors if needed. Once you get all your interior harness' plugged in and your new shifter and shifter cables routed you can put your interior back together and call it done. Your about 75% done with the swap as it is now.
Moving along now to your engine bay, now would be a great time to pull your harness from the interior of the car to your engine bay. While you are also right there, Disconnect your Power Steering lines that should be just hanging there because you will need to use the ones off of the new Ecotec P/S Pump since it is mounted in a different location. At this point the only thing you should see in your engine bay is the ground. If you have A/C you should still have the A/C canister mounted on the firewall, and Coolant resvoir if you left that in along with the Brake Master & ABS Motorpack. At this moment, I ordered RK Sports lower dogbone mount and their Upper Ecotec Mount, You will not be able to use your stock upper mount from your 95-99 so might as well forget about it. If your modding up your ecotec now would be a good time to do it since it is out of the car and not installed yet. If not go ahead and lower your engine and transmission into the engine bay. If your ecotec is an automatic, Dispell all myths now because it will bolt directly up to your stock location as your 95-99 Auto. For a 5 speed you will need to order the front Trans bracket from Turbo Tech Racing, and the rear bracket from GM. Bolt your lower engine mount and tranny in. If you have the Ecotec upper mount you can bolt that in also.
Your engine should now be mounted in and looking pretty in your engine bay. Here is another myth that will be resolved right now. You cannot use your old driver side axle from your 95-99 2.2 OHV, You will need your Driver side axle from the getrag trans (personally I would get the axles from the donor). Now look for that wiring harness you pulled thru the firewall earlier (The Body Wiring Harness). Connect the Engine Wiring together with the Body Harness. You may now begin to plug in all your wiring into the engine and transmission. If you have it all routed good job. Take your ECM and mount it to the passenger side strut tower using your strut bolts. Run the wiring to that and plug it in. You may also want to hook up your new power steering lines to the new P/S Pump if you havent done so already, It is a Pain to get to underneith the car so I would do that now. Make sure you dont have your battery connected though. As for exhaust system. I purchased a catback exhaust and a high flow cat, You can use the ecotec stock exhaust manifold or after market ones fit very well in the 95-99 engine bay without rubbing anything on the new ecotec. Exhaust Manifold & Cat are very cheap to purchase if your donor doesnt have them.
Right now you should have Your engine mounted, all accessories plugged in, P/S pump hooked up & connected. Engine bay should look pretty damn full. Minus your Radiator and fan. Which you can now reinstall, plug in the connectors and rubber hoses. Here is where the fun comes in. At this point in time you have 3 options. You can now install 00-02 headlights and keep your stock hood, install 03-04 headlights and get a new hood, or keep your 95-99 headlights and just rewire them in. I personally wanted to go with 03-04 headlights since I purchased an 03-05 Urethane drift kit from ECC Motorsports. The 97 needed to be severely updated on its looks so I figured new engine new body kit new looks..
Now Reconnect your battery, turn your key to the on Position but do not start the vehicle. Your theft light should be on. (We do this all the time at work) so leave your key in the on position without starting for 20 Minutes. Your theft light should then be off after then. Now turn your key to the off position but do not take your key out of the ignition. You can proceed to start the vehicle and it should run if everything was done correctly. Congratulations. You have now joined me and a slight few others of having a 95-99 Jbody with an ecotec.
