Engine / Transaxle Swap

agent00F

Member
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Mazda Protege 2003/LX
Hope you guys and gals could help with an interesting problem.

Currently I own a 2003 Protege LX manual with some $$ issues but a good engine/trans, and I have the opportunity to buy a 2002 Protege5 manual with a bad engine for not much $. So I figure I could do a transplant from the LX to the P5 and end up with one good car.

My question is whether this would be a realistic project for someone without much experience but free spare time, who could borrow some tools. I gather I would need at least an engine hoist and maybe jack stands.

Any info would be greatly appreciated, like how long it might take for a noob and what to look out for, whether its best to replace the transaxle as a unit or engine/trans separately, that I'm nuts for even trying it, or anything you can think of.

Much obliged!
 
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This is possibly the easiest swaps to do. All you have to do is unplug everything, remove the axles, pull the engine and transmission together and put them back into the other car. Not the most descriptive but if you've ever pulled an engine its pretty straight forward.
 
That is the easiest situation to learn in, with ample spare parts and bolts, plus an easy reference point if you forget how something goes together.

Unplug everything, pull the harnesses out of the way, remove the axles and shifter linkage, and pull the engine and trans together.

You could do it in a weekend, someone with experience could have them apart by lunch and back together before dinner.

Its all nuts and bolts, nothing too difficult.
 
Thanks for the advice and encouragement. I pondered on it some more, and maybe the best start is to try detaching the engine/trans in my heap before committing to anything. That way at least won't end up with 2 broken cars right away, and hopeful the protege5 and sedan use same electricals/plugs.

What might be the best detailed steps to the operation? Cus honestly the steps in brief to a noob sounds a bit like "start by sketching the owl's head", "then draw the rest of the owl", lol. One shop I called to see how long it would take them said there could be some "alldata/mitchell" guide down at the local library, but they also said it's about 20hr billable job for them.

Thanks.
 
It is best to leave the engine and trans together while removing. after its out you can switch trans if you want or whatever. It is really a 4 to 5 hour job if you are experienced.
I would just remove the slave cylinder by just unbolting it and let it hang there.

Unbolt the exhaust down pipe from the exhaust header.

Drain the radiator and unplug the fans. Remove the radiator by disconnecting the lower and upper radiator hoses.

Remove the heater core hoses

Take the radiator and fan out as an assembly.

Remove the battery and battery tray.

You need to remove all wiring connections on the motor and from the starter, speedo sensor, reverse sensor, knock sensor, oil pressure sensor, the alternator plug and battery connection to the alternator.

Undo the throttle cable from the throttle body.

Remove the air filter box and plumbing.

unplug the brake booster hose from the intake manifold.

Unbolt the slave cylinder, remove the clips that hold the slave hard lines and move it out of the way.

You can leave the ac compressor attached to the lines but you have to unbolt it from the engine. You will have to remove the ac/power steering belt.

Unbolt the power steering feed line from the top and remove the hose that connects the pump to the reservoir.

Drain the transmission, remove both axles but leave the half shaft in the trans.

Remove the front tie bar/plate from under the exhaust.

Remove the lower trans sub frame assembly with the 4 bolts.

Unbolt the shifter stabilizer from the trans, remove the shift linkage from the trans.

Support the engine with an engine hoist and remove all of the bolts that hold the rear mount to the engine.

Remove the bolts that hold the mount above the trans to the frame.

Remove the passenger side engine mount and lift the engine out.

The install is the opposite of the removal. Make sure that you replace the rear trans mount if it is bad. You cannot do this if the engine is in there or it is extremely hard to do.
 
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Ok, hit first snag on the "good" engine. But first a further disclosure on my car: it met with a pole near the lower A-pillar, right behind the wheel, scrunching the body inward there and the sidewall some. It did angle the strut tower a bit towards the engine, but nothing touches and no fluids leaked.

The engine starts up but revs right away to about 3.5k and stays there. Throttle works to rev it up higher, but it will settle at ~3.5 instead of the usual 1.5 or so on startup. I disassembled the intake system up to the throttle body and the throttle position appears normal, maybe a few deg at most, so I'm not sure how/why it's revving so willing without much air going in. I turned off the cruise button at the wheel just to be sure. I tried leaving the hose to the throttle off to see if the throttle is opening by itself, but the engines dies right away after starting presumably because the airflow sensor detects no flow.

Now seems something happened in the collision, but what? The car can be driven with this throttle issue, though it's clearly not normal.

Suggestions/diagnosis?
 
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Ok, I went back to mess with it some more:

I did a battery disconnect to reset the computer or whatever, and then the idle went to normal on start, starting at 2k and going back down to <1k quickly. But not so fast, after about half a min it started gradually creeping back up again. I kept it running and went to look under the hood again, and saw the throttle inlet hose was slightly loose, so I went to put it back on tight. But in doing so the idle actually went UP! After a bit it's back to the 3k or so. By now the engine's slightly warm, and the idle starts fluctuating rhythmically between 2.5 to 3k. I retighten the throttle hose clamp, restart it, and it still does the rhythmic 2.5k to 3k dance.

Help.
 
Check your throttle cable and the one from the cruise control unit.
They might be binding or need adjustment.

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