91 4afe to 93 7afe questions... Options

[Punisher]

Ok, bought a 93 corolla DX.. thought for sure it was a 4afe.. it's hard as hell to tell the difference between the 4afe and 7afe sometimes.. I guess I just have to take a peak at the ECU. The VIN says it's a 1.8L... however, checking the VIN both engines use an A as the 4th digit lol.

I got a 91 4afe for a 100 dollars.. was going to pick it up tomorrow.. 115K miles and a new timing belt.

So now my question is... I know I can use the 4AFE but what would I need to change on the motor to run the 4AFE with the 7AFE ecu/harness so this can be as quick and simple of a swap as possible?

The motor in the corolla has a hole in the block directly below the oil filter.. have no idea why.. didn't get to investigate yet. I stuck my fingers in though and I didn't feel a piston rod or anything strange.. lol.

The ever so small amount of power difference between the 2 motors doesn't bother me, this is more about economy and reliability than power.

[Bitter]

between 92 and 93 the engine sensors and heads changed. you can use the bottom end as its pretty much still the same between engine generations.


it will state on the emissions sticker if the engine in the car is 7afe or 4afe and the engine size. beyond that the physical differences can be hard to see.

[Punisher]

well I know for sure now that it's a 7afe. There was no sticker under the hood! I checked the oil pan though and it's a two-piece pan.. which is unique to the 7afe.

[Dr_Tweak]

I'm pretty certain that the 7AFE uses a knock sensor and the 4AFE doesn't so if you swap the 4AFE in, you'll either need to also use the 4AFE ECU, or tap/install the knock sensor.

OT: This is another good example of a thread that should stay in the engine/transmission/maintenance forum because it is related to Celica STs.

-Doc

[Punisher]

I'm pretty certain that the 7AFE uses a knock sensor and the 4AFE doesn't so if you swap the 4AFE in, you'll either need to also use the 4AFE ECU, or tap/install the knock sensor.

OT: This is another good example of a thread that should stay in the engine/transmission/maintenance forum because it is related to Celica STs.

-Doc

That is the only issue? I know that the 7afe uses a crank angle sensor.. 4afe also uses it? I read about other people saying that the 7afe harness and ecu will run the 4afe no problem... just wanted to be sure.

[Bitter]

they both use the same distributor when theyre from the same generation. between 92 and 93 is the split for the 4afe. both are called a 4afe but one is different from the other. 92 and earlier have a different head design and do not use an IAC motor, but use a waxstat to control idle speed and have a bypass valve for idle up.

[Punisher]

they both use the same distributor when theyre from the same generation. between 92 and 93 is the split for the 4afe. both are called a 4afe but one is different from the other. 92 and earlier have a different head design and do not use an IAC motor, but use a waxstat to control idle speed and have a bypass valve for idle up.

Dude I'm not talking about an older 4afe to a newer 4afe.. i'm talking about a 4afe to a 7afe.

[Punisher]

I finally figured it out!

When I had my 89 corolla coupe I did a 7afe swap on it when the 4af died... This has been buggin the hell out of me and I kept forgetting to look at the 7afe in this 93 corolla I just bought.. I was worried about putting the 92 (yea it's a 92 4afe not 91) 4afe in place of the 7afe.. What worried me was the crank angle sensor...

Well, whilst sitting on the john (yea great place to clear your head.. amongst other things...)

When I did the swap on my 89 corolla I remembered the I used a 95 7afe.. OBDII.. and I got a 93 harness and ECU, OBDI. I remembered that I had to buy a pre-95 distributor (To match my 93 harness/ecu).. because it's only on the OBDII 7afe's that they use a crank angle sensor.. OBDI 7afe's have the sensor built into the dizzy.. (cam angle sensor).

So now I know that I can go hog wild swapping parts from the 7afe to the 4afe and make a frankenmotor basically... so everything will work out just fine using the 4afe and 7afe ecu/harness!

[Bitter]

for all intents and purposes a 7afe is a bigger 4afe with a knock sensor, theres still the generational split you'd be dealing with by putting a 92 into a 93 and using the 93 pcm and harness.

and yes you are talking about putting an older 4afe into a car with a 7afe, which as i just said is basically a gen2 4afe with a knock sensor and longer stroke.