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

SOLUTION!

Well I replaced the camshaft and crankshaft sensor wiring with shielded 2 conductor high heat oil resistant 16awg all the way from the centers back to the computer, and it ran for longer… But still stalled when it warmed up…

So I took a scope and checked the cam & crank sensor wires … In between the pulses from the sensors was low level ac like noise… Which got real big and very noisy when the car warmed up…

THE ALTERNATOR was the culprit (and bad Shields on the sensor wires which I already replaced)

it was giving off a tiny little bit of noise likely from a bad regulator or bad diode but when the car heated up - the noise got so bad that the ECM couldn’t see the pulses from the cam and crank sensors!

Just putting this out there in case anybody’s having a similar problem check with a scope to see if similar noise is on the center lines and check the shielding on those lines

3 Likes

Nice ! glad you sorted it out. I wonder how many times ive come across a similar condition and tried to blame it on an overheated ignition component.

Excellent job and I will file this one away in the “possible culprits” category

Thanks for letting us know