6G Celicas Forums

I have swapped engines and transmissions and am running into some questions for someone that has done it. Please let me know if you have.

What questions do you have? I'd be happy to help you out.

-Doc

I have an engine, transmission, wiring harness, and ECU/ECM all from different sources. They don't seem to be as compatible as I originally thought.
The engine has a crankcase position sensor connection that has no corresponding connection on the wiring harness. Do I need it?
The wiring harness does not connect to the ECM/ECU - is there an adapter harness?
CA specs seem different and I am on my fourth harness without having one that has every connection for the engine/tranny combo and the ECM/ECU.
The car is not starting and I think I need another harness?

This post has been edited by Bikeman982: Aug 1, 2006 - 1:22 AM

Just use your stock 4AFE harness and distributor with the 7AFE engine and injectors.

-Doc

The stock harness does not have the correct connections for the engine or transmission either.
It also did not have a connector for the engine's crankshaft position sensor.
It would fit the ECM/ECU, but that is supposed to be different for 1.8L 7A-FE.
The distributor part number is also different for the 7A-FE engine.
I have a distributor and that does not seem to be a problem, except maybe that it needs to be set for correct timing.
Do you know the stock number for the ECM/ECU for CA 7A-FE specs?? - should be 89661- something.
It is 89661 -02140 for the 1.6L 4A-FE engine.

This post has been edited by Bikeman982: Aug 1, 2006 - 4:25 PM

Upon further examination I have discovered that the engine wiring harness does connect to the ECU/ECM, however the connector that comes from under the dash (part of the cars internal wiring) has the wrong connector and does not fit the ECM/ECU. It is similar to what goes into the ECM/ECU for the 4A-FE. I don't know what all the wires go to, or how to change the connector/wiring to fit the 7A-FE ECM/ECU.

hey bike, it sounds like you have an ob2 harness maybe.

The simplest thing for you to do is use the 4AFE harness and just swap over the 7A connectors where you need to. And use your 4AFE distributor. Basically use all the 4A parts you can.

What car is the 7A from, and do you have the whole harness and ECU?

-Doc

The engine/tranny and wiring harness - ECM/ECU came off a 1995 and the car is a 1994. The reason I changed the harness was due to the transmission having a different park/neutral connector on it and the harness for the 4A-FE was different. There may have been other connectors that were different as well. Since the majority of changed parts were 7A-FE from a 1995 I was trying to keep it all 1995 compatible.
The ECM/ECU has three connectors on it and on the 4A-FE there is a 12 Pin connector whereas on the 7A-FE there is a 22 Pin connector.
As Bitter has said - I may have a harness that is for an OBD2 car and not from a OBD1, but the harness is the same and it is the cars connection to the ECM/ECU that appears to be different.
I don't know if the donor car is still at the junkyard, but I can check the connector on that car. It was a 1995. I took both the ECM/ECU and the wiring harness from the same car - but the cars internal wires must be different. I will have to check it out.

This post has been edited by Bikeman982: Aug 3, 2006 - 7:03 PM

You're doing it the hard way. You don't need to swap harnesses or ECUs or anything like that... the 7AFE can run alright on the 4AFE ecu and wiring. All you need to do is to swap over the sensors from the 4AFE to the 7AFE... and ignore the sensors on the 7AFE that the 4AFE doesn't have. That way you can just plug in your old 4AFE harness and not have to worry about anything else. There shouldn't be too big of differences between the two... at the most you might need to splice injector plugs and swap distributors. It should be a very straight foreward swap... cause I'm pretty sure the 4AFE uses about 90% the same sensors as the 7AFE... except for a few different plugs here and there.

What about something similar - I swapped the engine/tranny and wiring harness - can I use the old 1.6L 4A-FE ECM/ECU, since it plugs right in?
What about the wires that are not on the 12 pin connector from the car that are used on the 22 pin on the 7A-FE ECM/ECU?
What about the engines crankcase position sensor - just ignore it?
Someone has told me that the 1.6L 4A-FE engine uses a hydraulic shift transmission, while the 1.8L 7A-FE engine uses a computer controlled electronic shift transmission - is this true? What does that mean as far as the swap? Don't both use the ECM/ECU to electrically control shifting??

This post has been edited by Bikeman982: Aug 3, 2006 - 7:53 PM

Use your old 4AFE engine harness and ecu... and primary sensors that have different plugs. Avoid using the 7AFE harness and ecu.

Refer to above. Don't change the engine harness... use your exsisting 4AFE harness.

Is it automatic? All autos are computer controlled mostly for speed inputs and stuff... manuals are either hydro or cable... but toyota did away with cable trannies in the mid 80's... so this should not be a factor. The 5 speeds are the same. Ignore the crank sensor.

wouldnt the 4afe ecm make the 7afe run lean since its got .2L more displacement that the PCM doesnt know about?

No, because the 7A injectors are a little bigger.

-Doc

What about the problem with the connector and transmission wires - totally different on the 7A-FE? - hence the reason I changed the wiring harness.

What wires and what do you mean? The only wires attached to the trannies are the reverse light, neutral safety switch (I'm not even sure if toyota intergrates this into the tranny), and speedo sensor. At the worse... you do some splicing.

Why not use your old tranny?

This post has been edited by Kwanza26: Aug 3, 2006 - 11:52 PM

The wires I am referring to connect to the Park/Neutral switch on the tranny.
The old tranny had a smaller connector and different switch.
I tried to use the old tranny from the car, but it was incompatible with the 1.8L 7A-FE engine, therefore I changed transmissions.
I think the 1.6L 4A-FE engine uses the A131L tranny and the 1.8L 7A-FE engine uses the A245E tranny. They are not interchangeable (both are automatic).

This post has been edited by Bikeman982: Aug 4, 2006 - 1:46 AM

http://www.corolland.com/forums/index.php?...30&#entry131312

bike, based on that i dont think the 4afe pcm will contol the a245e trans at all. it'll goto its defaults if not plugged in, which is to sit in 4th gear with a unlocked torque converter. it'll move but you have to floor the pedal and wait about 20 miles to get to 10mph.

Which leads me back to why I need to get the 7A-FE ECM wired in. It would seem compatible with the engine and transmission, but needs whatever the wiring (and connector) is inside the body of the car.

But what's wrong with your 4AFE tranny? If there's nothing wrong with it... there is no problem. The 4AF trans does fit on the 7AFE if you swap flexplates. It's not all that complicated... and I think that's where your fitment issues are. The whole ordeal of messing with wiring isn't worth something mechanical.