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Putting a 94 4afe into a 91 Corolla


furias15
12-10-2006, 01:42 PM
A few weeks ago I posted a question regarding putting Gen 7 4afe (94) into a Gen 6 (91) Corolla and didn't get much info. Just got done with the job so I thought I would relate what I did in case it would help someone else. Physically the two engines enterchange nicely, which is no surprise. I had to swap the 91 throttle body onto the 94 engine as the 94 tps is not compatible with the 91 computer. You can't just swap the manifolds (which is what I would normally have done) as the two engines differ. The '91 has injectors mounted in the head, and the '94 has them mounted in the manifold. If you will use the vacum line placard on the 91 hood as a guide you will be able to mount the a/c vac relay and another vac relay (accs?) and modify the '94 vac line system. Do this out on the engine stand. You have to use the '94 airbox and throttle body intake hose assembly due to room constraints. A nipple has to be mounted in the bottom of the intake hose to pick up the abient air source for the above mentioned vacumn components. The heater hoses route differently on the '94 engine, I was able to use one of the original '91 hoses and used standard hose stock for the other. Themp switches were and issue. There are 4 mounted to the coolant manifold on the '91 and only 2 on the '94. I swapped the white and brown one from the '91 to the '04 engine and relocated the brown one to the bottom of the radiator. The wiring will have to be modified to allow for that. There is a single spade connector on the coolant manifold that relocates down by the water pump on the 94 and they wire has to be lengthened as well. You have to use the '94 Alternator as the mount on the '91 can't be used due to changes in the head. You will have to take the connector from the '94 engine harness and swap it over to the 91 engine harness. There is no cold start injector for the '94 engine, so I just installed the ingector on the wire harness so the EEC would see it and not set a fault code. It takes a little more cranking than normal to get it to fire off, but as this car was headed to FLA I hope it won't be an issue. You have to use the '91 distributor, due to wiring differences (I tried to use the '94 dist and it didn't work) which means you have to use the '94 wires. The wires must be modified by cutting off the top boot so that the rigid portion of the plug wire can go deeper into the head. I guess the '94 plugs are just a little further down in the head. After all that, it runs very well, the cooling fans come on when the temp gage shows 1/2 deflection and the a/c even works!! Hope this helps someone.
Steve

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