Swapping a 2zz-Ge into a Mk3

[Jiff Lemon]

Some thoughts on "re-pinning"

Part of the appeal of this swap for most people, is the minimalist amount of wiring that needs doing - "just repin the ecu"

So whats involved? Well, I'd suggest practicing lots before attacking your ECU. If you broke the car yourself, save 6 inches of the ecu wiring to practice on.

Here's a standard looking ECU plug:


or another angle showing the locking bar....



If you look carefully the locking bar is strip across the top of the plug. Using a small screw driver, you can lever it up...





So when you insert you small screwdriver into the larger holes



You can pop out the wire, making it easy to pop into a blank space



And that, is re-pinning 101. Practice it.

[Jiff Lemon]

So, that's pretty much all the prep work covered off - You could obviously change things like the timing chain, head gasket and valve stem seals etc, but the above should be considered as the essentials. Other stuff you're going to need:

WD40 (other lubes are available)
Exhaust/cat gaskets
Copper slip
thread lock
Taps/dies - If you struggled to get a bolt out, clean the damn threads before putting it back in!
Security bits / Chisels
Engine oil/coolant/gearbox oil
Coolant Bleed tubes
Cable ties
Some sort of dolly/wheeled engine holder to allow you to slip your engine/box assembly out.

The bulk of the actual swap is standard MR2 fodder. The engine and gearbox come out from underneath, meaning you need to lift the rear as high as possible to clear the dropped engine/gearbox assembly. My swap was a little more long winded, as I was also swapping out the exhaust, so did some additional bits (removing the heatshields, rear bumper etc). I was also fortunate enough to have access to a 4 post ramp which makes life oh so much easier!

1) Drain the coolant, drain the engine oil, drain the gearbox oil. Coolant can be drained via the drain plugs at the front of the car on the metal pipes if you wanted to try and save the coolant. They could also shear off giving you a whole new world of pain to deal with.



2) Decide whether your going to keep your subframe in or out. Out will give you more space to work, in means you can keep the car mobile.

3) If you've got aircon and you're keeping it, you're going to have a world of pain and have my sympathy - prepare for skinned knuckles.

4) Remove, in no particular order: Battery, battery tray, rear lights, Airbox, charcoal cannister, throttle cable and Unplug your O2 sensors, then remove the Cat.



Take a long hard look at your subframe - They're prone to rotting. Poke and scrape and rust. Hopefully, you'll have something like this:



5) Get inside the car, remove the N/S door bin, Bin and remove the ECU plugs. Push the wiring through the bulkhead and into the engine bay.Take a long hard look at your ECU - It's probably got a cover holding it in and that cover is secured with security bolts. If they've not already been mullered, you can remove them with the correct security bit. Otherwise Mr Chisel or Mr Drill will have to come out to play.

6) Lift the cover off the fusebox, undo the 10mm bolt and pop the starter wiring up and out.

7) Crack off the Wheel nuts, hub-bolts (if your taking the subframe out).

8) Unplug the ABS sensors and push them back through into the wheel wells, and undo the 10mm body bolt.

9) If you've aircon, get the drive belt off. If not, you can leave it on.

10) Now's as good a time as any to get the thing up in the air, wheels off, axle stands in place.

11) Brake calipers off, strut to hub bolts off. Cable tie your calipers to the springs. Undo the forward tie bar and you should have a Hub that can flop about.

12) Get underneath and get the forward gearbox mount undone - take out the centre bolt before undoing the mount from the body and sliding off. This means you can then undo the gearbox side which also mounts the Clutch slave without undoing the clutch hose, which means a LOT less hassle - Cable tie the slave mount up to stop any strain being placed on it.

13) Undo the fuel Hose - Its a squeeze fitting and will drip a small amount of fuel on you. You may as well undo the coolant hoses in front of the gearbox and from the thermostat too.

14) Move the rear mount from the subframe.

15) Aircon people - here comes the pain. The lower two bolts are nice and easy to get to. Only you can't actually get them out without rocking the engine on the mounts. Then there's one more upper one... Don't try that until the engine is in a semi lowered state or you'll lose the will to live.

16) Remove the gear linkage cables from the gearbox and pop the cables out of the holders. At the same time, remove the earth strap from the gearbox. You'll find a few more coolant hoses to undo too.

17) Dolly in place, we can lose the remaining engine mounts and subframe mounts. Lower down gently get the remaining aircon bolt and cable tie it back up to prevent strain.

18) And that's it out!

[Jiff Lemon]

With the engine out, the first thing to do is to strip the essentials off it

You will need:

The wiring loom, the dipstick,The fuel rail, the idler pulley. (sump is an optional)

The wiring loom is straightforward enough. At the same time, add in your additional 2zz looms (the lift sensor wiring and the Oil temp sender) - I opened up the loom and tucked it inside the orginal tubing for that OEM look.

You may want to do the wiring adjustments at this stage or once it's all back in the car - You'll see why soon. Take your time and you should be able to get everything laid out and bolted down as if it were a 1zz. Clearance along the top is very tight once installed, so pay close attention to securing it down.





The dipstick will take a little threading through the inlet manifold and if you've got a spare inlet manifold gasket, it's as easy to give yourself some room and take it off.

It also makes it easier to deal with the first of the pipes you'll need to bung. The heater hose has a small outlet that needs bunging. Other bungs include the outlet on the inlet manifold and water pipe outlet next to the heater hose.





Finally, there's a tiny vacuum hose that needs blanking on the inlet manifold.

If you're reading through this and planning ahead for a swap, I'd actually recommend buying a spare 1zz loom and dipstick meaning you can effectively skip this part. It takes a frightening long time to swap the loom and associated bits across. If you want the actual swap time to be a short as possible, there's considerable savings to be had here.

Fuel rail swaps over with two bolts - remember you want the 2zz injectors, not the 1zz ones.

The idler pulley can be a bit of pain to remove and refit - Lots of WD40/cleaning & Copper slip rewards here. It goes in the same position on the 2zz engine as it does on the 1zz. Don't over tighten as the front casings have been known to snap the lugs off.

If you're not using AC you can fit the drive belt now - 2zz Tensioner is used, not the 1zz and the belts are the same (assuming you're not using the MWR underdrive kit). AC also uses the 2zz tensioner, you just can't fit the belt yet. The belt follows the standard routing:



Fit your swap exhaust manifold (and bracket if you made one), your new clutch and hybrid gearbox and wowsers, we're ready to go back in.



Refitting, as they always say in the haynes manuals, is the reversal of the removal.

Gotcha's to watch for? Yup, that bloody AC pump is a nightmare. Top bolt in first whilst you're halfway in before you consider the bottom ones.I'd also leave putting the bridge mount on until it's in the bay, as it can catch on stuff as you wiggle the engine into place.

The driveshafts and especially the mid bearing can be fun - patience is the key to all of this, don't try to rush.

You'll also have a spare O2 sensor. So, use a short one in the Post cat position (conecting under rearlamp), the long one can go in the precat position (use the timing chain end plug) and everything is hunky dory.

With the lump back in and secured down, its time to tackle the wiring.

Remember I said to leave it till it was back in? Well, believe it or not, the 2zz will actually fire up on the 1zz ECU! Don't expect it to run like that, but if you bought an engine you hadn't heard running, here's a moment where everything is still reversible!

[Jiff Lemon]

Before we venture into the ecu, lets start off with the TPS sensor on the throttle. There's 3 wires.
Brown is ground and doesn't go to the ECU
Blue/red stripe is VC, goes to the ECU
Yellow/green stripe is VTA, goes to the ECU.
Swapping VC and Ground will reverse the polarity, which we need to do but with the ground not going to the ECU it has to happen at the plug on the tps, not at the ECU.

So, instead of your 3 pin going Yellow/Blue/Brown it'll go Yellow/Brown/blue.

Next up, the ECU. Lets first, clarify our plugs.

Plugs A and B are the body Loom.They're the two that don't come off with the engine loom. The two plugs on the engine loom are C and D.

Plug a has 22 pins
Plug b has 28 pins
Plug c has 24 pins
Plug d has 31 pins

If you looking at the pins, with the clip at the top, pin 1 will be the top left. If you're in anyway forgetful, get a sharpie pen and label them!



Start with Plug B, the body loom. On the Celica, the post cat Ecu is so far away from the engine, its on the body loom. So, we need to move the roadster post cat sensors here.
So, take the wires from engine loom C8 and C9 and move them to B16 and B25. Insulate and tape up the B16 wire (was a red/yellow tracer on mine) and B25 wire (Was blue/pink tracer) so they're safe.

Onto plug C: Celica C6/C7 are the Outputs for the Lift Sol Wires. But the roadster plug has these for something else. C6 is Direct Ground in the Spyder Harness and C7 is Missing. Pull out C6 (white with black tracer on mine), but label it - we'll use that in a moment. Add your lift Wiring from the engine loom. Remember that bit of loom that you used for practising Re-pinning on? Well, I found that the loom was little short, so I pulled the pins from the cut loom to give me the extra length I needed (and because I'm OCD, matched the colours too!)



C21 will now be used to detect the Oil Pressure Switch of the Lift Solenoid. Again I added a bit of extra loom and then insulated and taped up the Existing black wire.

That C6 wire you've got labelled? That's an earth and the Celica Ecu wants to see earth on A7 and B12, so use it here.

[Jiff Lemon]

Shifter swap - Half an hours work for shift perfection.

They say you can mod the 5 speed shifter to make it work.Grind a bit here and there, but why bother when you can just swap the parts over?



First obvious difference is the gear lever - straight on the 6, cranked over on the 5. But there's more...



Notice the crank arm difference between the 6 speed (left) and 5 speed (right).

Shifting gears, and more importantly, getting reverse, is now simplicity.

[Jiff Lemon]

One final piece. The rain cover on the MR2 will divert rain very nicely into the spark plug channel on the top of the engine.



This will lead to misfires and no end of trouble if you don't prevent it. Some people have modified the 1zz cover to fit (nice for a sleeper look!), some have modifed the FWD celica cover to fit.
Me? I turned to lotus for the solution:



Amazingly, the part direct from lotus, was under £20 delivered! Lotus part number is B120E0022F