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Mazda MX-3 SE to Mazda MX-3 ZE

Step-By-Step Procedure By Moray MacDearmid

Before I get too heavily in to the description of what I've done I want to take a chance to thank all the contributors to and all the other mx3 web sites. The information I gleaned from these sites, and from corksport has been invaluable and has made what should have been daydream into reality.

In the following piece I will try to give you a detailed instruction on the work I carried out on my car. This is a much-abbreviated version as it misses out all the errors, screw-ups, back tracking, cursing and time spent puzzling that occurred in real life. If some of this seems over-simplified it is not because I think the reader is going to need it, it's just that the writer did. I hope what follows is of some use.


The first thing I set about sorting was the handling. I bought Mazdaspeed front & rear anti roll bars (corksport), Koni shocks, Eibach springs, Red Dot grooved front discs & pads (demon tweeks), and 16" alloys with 215/40*16 rubber.
To date the only items not fitted are the anti roll bars. I got a garage to fit the springs & shocks as the Konis are replacement inserts and I didn't fancy hack sawing my old shocks and making a mess of it.

Engine & Gearbox

The next thing for me to address was the engine and gearbox. The engine is a KLZE and was sourced from corksport, they also supplied me with a Millennia inlet manifold & gaskets, a KL47 throttle body & reprogrammed ECU.I sourced a used 626 2.5 air flow meter (VAF) from intapart. I got new mx3 gaskets for the throttle body & ex-manifolds. A K&N Hi-flo mx3 replacement air filter (demon tweeks) was bought to increase airflow. All other engine parts or ancillaries were robbed from my old 1.8(I'll detail them later on).
I got a used mx6 gearbox from intapart and bought a new mx6 clutch assembly (don't know if its any different to an mx3, but if it is, it should be stronger).

I decided to replace all the rubber drive shaft boots while the engine/box was out and also had to buy a new circlip for retaining the passenger side drive shaft.

The final purchase before starting was all the necessary fluids i.e. brake fluid (for bleeding clutch), gearbox oil, power steering fluid, coolant/anti-freeze, WD40 or similar (absolute lifesaver), engine oil & filter (standard mx3 is ok).


As a general piece of advice tag everything you remove, disconnect, unplug, unscrew, or loosen with a piece of masking tape and write a description of where it goes on the tape, & bag all bolts with each component. The engine bay looks a bit stupid with white flags everywhere but it helps highlight everything that needs attention.
It might seem a bit much but it was the only way I could cope since I didn't have a handbook.

Disable any alarm / immobiliser.
Remove bonnet.
Remove strut brace across engine.
Disconnect throttle cable and unbolt retaining brackets.
Jack front of car, put on stands (don't restrict movement of axles & suspension, and allow space to roll the engine hoist in and out).
Remove wheels.
Remove 2 plastic undertrays.
Remove battery & battery tray.
Remove air intake above radiator, air filter box, VAF (probably has JE50 stamped on it and p/n 197200-0060 or similar), & air intake duct.
Drain radiator, disconnect hoses, unplug electrical for fan, unbolt black metal retaining trim and lift out radiator, disconnect quick release hoses at bulkhead for heater.
Unplug, unbolt, and remove starter.

Go round engine & gearbox disconnecting the remaining electrical connections labelling them as you go. These are them as I remember :

Earth strap from inner wing to engine mount.
Front loom - alternator (1), oil filter (1), front exhaust sensor (1), distributor (2), starter(2), fuel injector rails (2)
Back loom - under coolant filler cap (1), beside coolant filler cap (4), power steering (1), earth strap (1), VRIS-solenoid on inlet manifold (2), rear exhaust sensor (1), behind throttle cable bracket-solenoid (2), EGR connection (1), throttlebody (2)
Over the gearbox - air filter box (1), VAF (1), radiator fan (1), gearbox (3), earth strap on gearbox (1)
Unclip and unbolt the loom from the front & back of the engine and peel it away to one side of the engine bay. Take care while doing this in case any wires still connected.

Disconnect hydraulic clutch pipe from just below the bulkhead, under where battery tray was.
Remove filler cap to release pressure from tank, disconnect fuel pipes, from tank to fuel filter (1), from tank to front fuel rail (1)
Release tension on accessory belts and remove.
Disconnect hose going to power steering reservoir. You may need to remove this hose to ease removal (It is bracketed to side of engine and bolted to power steering pump)
Disconnect pipe to top of power steering pump shrouded in silver heat shield hose). If you can't get this removed as I couldn't then you may have to undo bracket retaining p/steer pump to side of engine (4 bolts).
Disconnect the two levers for the gearchange.
Unbolt the exhaust downpipes front & back and from the cat.
Unbolt the shock absorbers from the hubs. This gives enough freeplay to pull the driveshafts.
Drain the gearbox oil.
Remove the bracket holding the driver-side shaft to the back of the engine. This shaft should now pull clear of gearbox. The passenger side shaft should also pull clear but more effort is required as it is retained by a spring circlip. Bag up shaft ends to protect them.
Disconnect any remaining hoses to engine, intake manifold to brake servo (1), from solenoid on bulkhead to back of throttlebody (1) (be careful with hoses on solenoids, the pipes on the solenoids are very fragile), from charcoal filter to solenoid on bulkhead (1). Some small hoses remain connected but it should be between solenoids and fuel injector rails.
Remove the charcoal canister (not necessary, but it gets it out of the way)
Move the hoist into place and sling the engine. Put enough tension on to make sure sling doesn't catch on anything delicate as it tightens up.
Undo nuts for the mounts from gearbox to subframe (the rear is a pig to get at but it is possible with a ring spanner)
Then lift enough to take engine weight.
Recheck security of the sling and if ok undo mount above gearbox and the engine mount.
Slowly lift and remove engine & gearbox (it's a tight fit!). Watch for any pipes cables still connected or snagging.
While it's in the air remove the small plate on the bottom of gearbox, just below the engine (3 bolts). It allows gearbox past flywheel.
Prop up on blocks of wood on floor, support on engine leaving gearbox free to pull away, take care not to crush sump or to trap the sling.
Unplug & remove old ECU, it's bolted down behind the kick panels at the side of the centre console.


Next I compared the engines & gearboxes and stripped off any unnecessary brackets from the KLZE and the mx6 gearbox.

Now I swapped all the necessary ancillaries, brackets and sensors from one engine/gearbox to the other (remember at the end of the day you want the new engine & gearbox to tally with available connections, in number & position, in the engine bay). A list of parts I swapped follows :

Power steering pump, alternator, starter, EGR, distributor & leads & plugs, exhaust manifolds, Throttle Position Indication Sensor, fuel filter & bracket, hoses for radiator, hoses for heater, hoses for fuel, engine mount, flywheel, gearbox mounts (3), gearbox sensors (3), stud that holds gearlever to gearbox (original too short), hydraulic pipe and cylinder for clutch, engine knock sensor (only cause wire was broken), accessory belts, and all brackets possible for supporting pipes or wiring looms.
This should now give you an engine and gearbox that has all the right connections in the right places except for :


On the wiring loom find the two VRIS solenoid connectors and you'll find one is shorter by maybe 5-6 inches. Put in a splice long enough to make it the same length. It's only two wires.

Inlet manifold

Remove EGR and blank the holes this leaves.
Fit blanks to vacuum pipes, small (2), large (1) on back of manifold.
Fit KL47 throttlebody and connect small coolant pipes to underside, and if necessary fit the Throttle Position Indication Sensor from the 1.8 throttle.

The small bore hoses between the solenoids behind the throttlebody, the solenoid on the bulkhead, solenoid on the airbox, pipe on the fuel injector rail & pipe on front of inlet manifold are connected the same as they were on the 1.8 with these minor changes:
Extend these hoses by approx 6 inches, hose to side of top of airbox, hose to metal pipe on solenoid on side of airbox, hose to pipe on front of inlet manifold. The hose from the fuel inj rail to the plastic pipe on the solenoid on the side of the airbox just needs unclipped from other hoses.

Removed throttle cable bracket supplied with new manifold and fitted 1.8 one. In order to get the cable lined up for the throttle at a better angle I drilled a new hole for the lower bolt further back on the bracket.

The hose which goes from the top of the front rocker cover to the front of the neck of in-manifold on 1.8 has to be extended approx 10 inches to pipe over back of the neck on intake on new manifold.

The hose that loops over the fuel inj rail and tees into the air intake duct need extended but I left that till it was back in car with air intake system fitted to allow me to trim them accurately.

Once I had ascertained which of the rigid pipes on the brackets at the back of the new manifold I needed, I cut away the extra ones as neatly as possible. I salvaged a short section of rigid pipe that stepped down from large bore to small bore & used it to connect pipe on top of throttlebody to hose from solenoid on bulkhead.


The refit is pretty much a straight reverse of the removal except for the following points :

Fit new circlip to passenger side driveshaft.

When lowering in engine I found it difficult to keep it dead level, so when it was almost in the mounts I supported the gearbox end with a scissors jack and this kept it level so the studs on the mounts go through the subframe cleanly.

Bleed clutch before fitting air intake system.

Fit new VAF & air filter to airbox.
Check air inlet duct for holes or cracks as this plays havoc with the smooth running of the engine.

In the engine bay, find the bracket that is the forward mount for airbox, remove one of the bolts retaining it so the bracket pivots. This allows air box a bit of movement when fitting the air intake system, as it is pushed further over with the new intake manifold angle. Even with this it is still a tight fit.

There is a bracket halfway along throttle cable that used to attach to back of 1.8 in-manifold. Trim off the square shaped lug on the side and then you can bolt down bracket using one of the bolts retaining the VRIS solenoids bracket.

Of the two loom retaining brackets used on the back of the 1.8 manifold only the one on the back right can bolt to the new manifold.

There is a large blanking plate atop the new manifold with two lugs projecting out of it. You need to cut off or file down the lugs and replace the front bolt with a countersunk screw/bolt. This is to stop damage to lining in bonnet.
The engine strut brace almost fits, and only need slight adapting to fit (i.e. lengthening one of the indents in the underside by approx 3 inches, to clear top of intake manifold).


Top up all fluids : - Engine oil, gearbox oil, brake fluid, power steering fluid.
Try to start car, it will take a moment or two for the fuel to get sucked through but it should go.
Top up fluids again, especially power steering.

Set-up Idle
Warm up the engine (i.e. till fan cuts in).
Switch ignition off.
Open lid on small Diagnostic connector box
Inside lid there is a diagram of the pins on the connector. Use something to connect pin TEN to pin GND (I used a paperclip). This will put the car in diagnostic mode.
Restart car.
Now adjust idle speed by turning the large Philips headed screw in the top of the throttlebody.
Set the idle speed about 150 rpm below your desired idle as when out of diagnostic mode it will idle higher.
Switch off ignition.
Remove paperclip.
Restart car, and hopefully it idles OK.

If you still have problems, you could try this, remove negative battery cable and press brake pedal for 30 secs, then reconnect battery cable. This wipes the past history from the 'learning' part of the memory of ECU.
Then go through the idle setup again.
And that should leave you with a running vehicle.

Any further problems and I usually look at the bulletin board, it's a mine of information.

Oh, and is it worth the hassle? You better believe it, it is astonishingly fast, loads of pull in every gear, masses of torque right through rev range, and with the suspension changes, a real blast to drive!
The only jobs I've left are fitment of the anti roll bars, stainless steel exhaust (cat back) & hi-flo cat, and hopefully that ain't too far away.

Parts Suppliers:
corksport (USA) Tel: 503-252-5700
intaparts (UK) Tel: 01327-310511
demon tweeks (UK) Tel: 01978-664466

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Last modified: October 26 2007

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