Hi all,

My friend's old Mazda hadn't been run in a while. Charged the battery and it fired up right away. Idled and ran a little rough. She had a few parts from previous diagnosis efforts which she hadn't installed, which I offered to. They were a new Idle Air Control Valve and 2 O2 sensors. I started with the IAC valve.

I tested the old valve by pulling off the electrical clip while running and heard the RPMs dip which supposedly means the IAC valve is operational. Since she had the part I figured I'd replace it since she'd like the vehicle maintained as much as possible.

When i put the new IAC valve on, it started up, but i thought it was running rougher. I pulled off the electrical connector and did not see a drop in RPMs. I thought I'd just replace the old IAC valve and call it good, but when I did, the truck would not even try to fire up, it just cranked and cranked. I then put the new one back on again, same thing, just cranked and cranked.

I hear there's a relearn procedure for the PCM. I tried a couple methods, unsure of what was right, but the one that worked was disconnecting the battery for over 5 minutes. After cranking for a few seconds (longer than it took before any messing with the IAC valve), the engine turned over and fired up with some coaxing of the gas pedal.

I took it for a spin, it died down the block when I was starting up at a stop sign (manual, in 1st gear). I didn't think it was my fault as I slowly let off the clutch while giving it a little gas. At this point it didnt start up again and i had to tow it back. It just cranks and cranks, once again.

Does anyone know what could be going on? Maybe the relearn procedure didn't actually work? Anyone know the right procedure for the IAC valve?

Thanks for any help!

-Anthony

 

Welcome aboard