Odd check engine light

[pbmaster]

So I've noticed...that my check engine light likes to come on at random. Usually, when I do any sort of hard acceleration, like to pass. It doesn't stay on either, and all gauges are well within normal ranges. It doesn't do this often either...my vehicle runs great too! Also, it's a 1994 Mazda B4000 with ~136k miles. Oil was just changed, transmission fluid just checked and added, all fluids normal. Any ideas guys?

[JC316]

My guess would be something like the throttle position sensor, or a lean code. Something intermittent. Pre OBD2, the check engine light would kick on and store the code, then if the part started working again, it would go off. You need to retrive the codes. Usually you have to jump two pins together on the ALDL connector and count the number of times the check engine light flashes. Google how to read the codes, I am sure that something will come up in a forum.

[pbmaster]

OK, sounds simple enough. Thanks. I did think of this...my truck does leak a bit of transmission fluid, and there is a small leak on a radiator hose. Could the acceleration cause a sudden lack in something like that, and for that moment the light come on? Or no?

[JC316]

Check engine is usually reserved for a sensor malfunctioning somewhere. On occasion, it can be for the transmission, but usually not for lack of transmission fluid.

[pbmaster]

Just throwing it out there lol, I don't know a ton about cars. Thanks again for your help.

[Buck Nasty]

Does the light flash while it's on?

[Kreij]

The check engine light can come on if your gas cap is loose or not sealing properly too.
Too many sensors these days. lol

[JC316]

The check engine light can come on if your gas cap is loose or not sealing properly too.
Too many sensors these days. lol

OBD2 only. The OBD 1 systems were far too primitive to have gas tank sensors.

[Kreij]

Yup. my bad. Sort of glossed over the part that it was a '94.
Carry on.

[pbmaster]

The light stays on from anywhere from a few seconds to a minute. Never longer, and it doesn't flash.

[erocker]

Most likely an O2 sensor or EGR valve. There is most likely a place to run a jumper wire under your dash to retrieve the code which are what you need.

This is a illustration from a 94 Mazda it may or may not be the same for your truck:

http://i403.photobucket.com/albums/pp112/erocker414/42129986.gif

Here's a video on how it works:

EDEZ8PBp3X0


Post here what code(s) you get and I can look them up for you in AllData or try Googling them.

[Polaris573]

Just be careful doing it that way. You can fry your ECU if you short the wrong pins.