Check Engine Light

[unccpathfinder]

ok just took the truck out for another test drive and a couple times before...the other times i didnt have an O2 sensor in so it wouldnt set off the ses light till it warmed up...tonight it came on and stayed on as soon as the truck was cranked...i looked around on the FSM and cant find what exactly sets this off...i do know since the previous drives i have disconnected the temp sensor and i broke the oil pressure sending unit wire tonight while swapping out starters...i would imagine these both have an oil light and possibly a check gages light for the temp (i have a gage for it but i didnt know if they had a light to say hey dumb dumb look at the gages)

 

the SES light is that more for emissions stuff or what?...i didnt have time to test it out but i was going to disconnect the O2 to see if that makes the light behave as it has before...

 

i also did a TB job but need to go back and verify the timing but im pretty sure its right...as well as check the plugs and all that...but i was mostly curious to what would set it off right away...

[mws]

Aren't their two engine temp sensors - one for gauge/light and one for ECU? If the ECU sensor is disconnected, it will definitely trip the SES light as the ECU is getting grossly conflicting information and can not figure out the proper amount of fuel to inject. It will make it's best guesstimate to compensate, but that is a compromise.

 

In general, the SES light comes on:

- when any of the sensors the ECU needs to make accurate decisions is providing readings outside of the programmed allowable parameters

- when O2 sensor is detecting levels outside of allowable parameters

- when other sensors related to emissions (fuel tank vacuum) are giving readings outside of allowable parameter

- Other causes as defined by ECU programmer....

 

Is this the '87 or '95?

Edited April 4, 2007 by mws

[unccpathfinder]

the 87 with the 95 harness, engine and dash...

 

Thanks for the input though on that temp gage cuze i know there was a tab that looked like a ground and the actual temp probe for the gage so i think this might be part of the problem...it started getting dark so i didnt have time to really inspect it but i did want to take it for a really quick spin around the neighborhood since she hasnt moved in 2 months

 

im really doubting its an the O2 b/c it usually runs that closed loop for 5 mins or so until it reaches operating temp then it starts running an open loop...

 

i just hope its easy to figure out cuze i really want her up and running full strength with no issues