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2003 Mazda MPV STALLS WHEN WATER temp hits about 200 degrees +/-

I have a 2003 Mazda MPV I just replaced my engine and nearly all of the sensors on it.

The engine appears to run great until it warms up when the water temperature is about 200 + degrees Fahrenheit it stalls.

I have one error code for the bank 1 sensor 1 oxygen sensor I replaced the sensor and I am still getting this code I’m not sure if this is causing or has anything to do with the engine stalling when it warms up

I replaced the camshaft sensor crankshaft sensor mass air flow sensor water temperature sensor several solenoids in the vacuum lines for the EGR I have checked and cleaned the EGR valve and the IAC valve and they both appear to be working I have checked for vacuum leaks and have found none and I have new intake manifold gaskets and there are no leaks around the intake manifold
I am stumped and really have been pulling hair out trying to figure this one out``

Was this a used engine, a rebuilt engine, or a new engine from Mazda?

Perhaps your AIC valve that controls idle is at fault… When the engine warms up the idle is commanded to drop down… But this drop down should occur prior to reaching full temp…or this is usually the case.

Just an idea… I would be looking into the Air Idle control valve on this setup… Make sure it is clean and operational…see what you get. Otherwise it sounds like the system is trying to do the right thing…just might be getting hampered by something wrong with the AIC…

The engine was used (tested and running before pulled with a one year warranty)

I have cleaned (with carb cleaner and q-tips) and lubricated (with a burst of WD-40 on the shaft inside the valve) the IAC valve and even tried swapping out the IAC valve from my old engine after cleaning and lubricating that one with no change in the engine stalling when it heats up.

The idle drops down from just over a thousand RPM to 750 RPM with no problem and doesn’t stall as long as the engine coolant temperature is under 200 degrees give or take.

Does anybody know a definitive test for the IAC valve to make sure it functions 100% properly other than cleaning and lubricating it

What is the error code ? Pxxxx

So you have cleaned and employed your old functional AIC valve? This is good… How bout the throttle body? Are you using your old TB as well? If not… swap that over as well and see what you get.

The error code is P0031

I am in the process of cleaning and reinstalling the throttle body and if that doesn’t make a difference I’ll clean and install the old throttle body from the engine I removed. Today is my girlfriend’s birthday and she made me promise to do this work tomorrow so I’ll get back to you as soon as I find out

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You can clean the “newer” TB and try it however, do not alter or clean the old one that was functioning prior. We would want to see you simply bolt that unit on and try it… Don’t induce variables here. If the old one worked…then let it work as is. I’m sure you get the idea.

There’s your problem. You need coolant instead of water.

Sorry I misspoke I have a 70/30 mix of antifreeze & water I used the right antifreeze for the engine and the aluminum radiator.

I am pretty sure by the amount of antifreeze water mix that I put in that the engine is all purged of air… But I was wondering if there was any special trick to do it quicker then I did I took and made a 3L bottle “funnel” and adapter for the overflow hose (the one that connects directly to the radiator and goes to the overflow tank) and filled it up and waited until all the air bubbles bubbled out.
the radiator heats up top to bottom and there doesn’t seem to be any more air but I was wondering if there was an easier way…

The engine was used but tested before removal from the car it came from and came with a one-year warranty on all internal lubricated parts

I just received a brand new a i c valve and I’m putting it in today

I cleaned and replaced the throttle body and even tried to swap out the throttle sensor just in case that had something to do with it with no effect whatsoever I can’t swap to 2003 throttle body with a 2004 throttle body that came with the replacement engine because the 2004 throttle body has two vacuum lines that the 2003 did not have

i missed that part. you have a 2003 and put in a 2004 motor and the connections are not identical. well, perhaps that is a clue.

Actually everything on the 2003 and 2004 engines were identical except the throttle body. On a 2003 engine the throttle body has no vacuum lines, but on the 2004 engines the throttle body has 2 vacuum line connections. I talked to somebody in the repair shop at the dealership and they explained that the 2004 engine throttle body had additional vacuum lines that would not make any difference as they did not actually connect to the throttle body simply passed through it like a connector 2003 engine had an additional vacuum connection on a different spot separate from the throttle body it just moved on a 2004 engine to the throttle body I sent him pictures of how I had it hooked up and he said it was right as long as I was using the 2003 throttle body

Stating that the engines are the same isn’t exactly correct just judging from the differences you already pointed out. Im sure they are damn close however. What happens often is that the wire harness changes …even if the majority of the plugs are the same. They change the locations of wires often times…I have no clue why , nor do I care… I just know that it happens.

In 03’ the + wire for solenoid A is at Pin 37 Row D in 04’…its on pin 22 Row D… Something like that. Been there seen it… dealt with it.

Just keep this in mind.

Is there a way that I could find out about these wiring harness changes between years?