87 to 91 engine conversion
 

I just scored a real pretty 91 FC for almost nothing ($200.00 bones)

The motor is "supposedly" blown.

I don't really care even if the motor isn't blown because my 87 N/A has a fresh rebuild with only about 10,000 miles on it.

Can I take my 87 engine block and just put it right in the my new 91 FC?

Answer: no

Can it be done yes

The 91 engine is has similar parts but many changes. You would need change the wiring harnees ecu and various little things.

Well, I have to do it.

I must do it.

Oh yes, it shall be done.

So what do I have to do?

Work is not an issue.

If you do a search you will find all that information.

Well, lets get the facts straight.

Its a very possible swap, and no wiring or ecu changes should be required.. HOWEVER, if emissions are an issue, then it gets complicated.

Do you live in an emissions state?

Jarrett

No you don't have to change the wiring....but if you are going to pull the engine and remove all the wires and you have the wiring harness for the S4 and ecu. Why not. Plus u can label the either leave the wires on the engine or label them a hell of a lot easier.

Because the ECUs arent compatible with the different dashes. Its much easer to swap the S4 Keg into the car, then bolt up all the S5 goodies. Leave the S5 ECU in place. Unless rewiring the entire car is your cup of tea.

Jarrett

wtf I thought the Dash stuff was on a different harness??

No, the dash is controlled via the ECU. At least some aspects are.

I am really confused now. :-/ How the fuck do Microtech guys keep a working dash then?

I dont have any experience with standalones, so I cant answer that question.

Ah, there is a CPU that controls the dash..There are other compatibility issues. I was wrong on the dash portion.

Jarrett

woot :D

I say swap all the ECU junk with the engine

Yiou cant swap the ECU!! It wont work!!

Plus, why would you put the S4 ECU in anyways?!?!

If you retain the S5 ecu, and S5 upper half, you can retain your VDI.

;)

They are still not intechangeable. So whatever the smiley is about, I dont know.

Why dont all you knowledgable people bust out the pinouts and compare...

I made a thread and ask if I can change a s4 dash with a s5. They said no problem.

As long as you keep the
gauge
Logicon
and a/c

What else does the ecu control in the dash????

Microtech users sometimes keep the ecu and standalone together.

The ecu controls the a/c and other misc items and the microtech runs the engine.

Why wouldn't you beable to swap

The afm
engine
and engine and beable to use the s4 ecu.

alright....make him keep the ecu.

So the S5 ECU is going to control

S4 injectors
S4 rotors
and VDI

Also, remember to tell him that either the ecu is going to fry the injectors or the ecu.

Okay ERAUMAZDA... read above, I made a mistake on the dash portion. The pinouts for the 2 ECUs are different. This question has been asked several times before.

The S4 engine in the S5 car will work, and should work fine if the S5 upper half, and S5 ecu are retained. Although I cant understand why you would want to do that, the S5 motor has better HPs.

Jarrett

Well, that entirely depends on when in 87 his car was produced. Remember, the change from low to high impedance happened somewhere in the middle of 87 IIRC.

Jarrett

Alright alright alright...everyone shut up...

In order to put a wroking S4 engine into an S5 chassis you will need to do certain things to prep the block...short comments first:

Leave the damn ECU alone...don't touch it, don't think about it, don't breath in it's general direction.

While you're not thinking/touching/breathing anywhere near the S5 ECU remember to forget to mess with any of the other electronics as well.

You use the S5 injectors dolt, the ECU doesn't care which ones you use, it's the resistor bank that has a hard time with mix-matching low/high impedence injectors.

You'll either have to swap the front plates or run pre-mix.

Now, for the serious points. You need to remove both engines. You need to, while the engines are still in the bays, tear all of the intake assemply off including the rat's nest and primary fuel rail. After you have the intake and all off then pull the blocks, it's easier this way beings it'll all have to be torn down anyways. Once you pull the blocks mount the S4 block somewhere so that work can be done to it...DO NOT REMOVE THE FLYWHEEL.

First thing you need to do the the S4 block is remove the EGR. It gets in the way of the intake manifold. Once you pull the egr you'll need to make block off plates to fit the holes. If you're going to run pre-mix then you'll have to make a block off plate for the OMP as well. There is also a portion of the rear plate that will need to be ground off. I can't tell you exactly wher, you'll have to bolt up the S5 intake to the S4 block and just see where the UIM hits the block. Try not to take any more off than what's needed.

Now it's time to stick the S4 block into the S5. You should attach the exhaust manifold and the UIM before, it's hard to get to some of those bolts. With the block in the car now install the S5 fuel rail (I think...may have to use the S4, can't remember any fitment issues) with the S5 injectors and wire them up. Run your harness around to the sensors and shit that need to be hooked up before the UIM is installed. Once the UIM is installed bolt down the S5 secondary fuel rail and injectors. After that treat everything as though you were doing a run of the mill engine replacement.

All that and my answers were right anyways...Sheesh, why doesnt anyone listen to me?...:)

im sortof helping a friend do the same thing, he got payed to put a S4 turbo motor in an S5 GXL

n/a turbo swap issues aside, its still a PITA, All the harnesses are different, not to mention the auto seatbelts, AAS, and the T2 doner had ABS

its possible, just takes a while to do, there is alot to do

(so far.. our motor turns over.. no spark, no fuel =[)

J-rat...it wasn't a matter of saying you were wrong...but you're not entirely straight with your facts either. You keep saying you just keep the upper half, by this I'm assuming you're talking about the UIM, plenum, and TB. This is incorrect, you retain the ENTIRE S5 intake. I'm not saying anyone was wrong but no one was entirely right.

Here lets keep it REAL simple. Fuck it, throw in a Microtech or Haltech or whatever tickles your fancy and be done with all the stock bullshit. For the thousand dollars the standalone will cost you it's not worth all the trouble.