check engine light

[spiral]

Probably a silly question...but oh well. I bought my bronco a couple of weeks ago. The only things I've done to it so far is have a Magnaflow exhaust installed and I put a K&N filter in today. The check engine light came on tonight. Is there any possibility that my minor upgrades could have confused anything?

 

[Seabronc]

Could be. Have you checked the codes?

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[BLADE262US]

Did you mess with the oxygen sensor when you changed the exhaust ? /emoticons/[email protected] 2x" width="20" height="20" />

 

[ocalabronco]

doing minor upgrades like that shouldnt have messed with the computer, since yours is a mass air style comp (adapts to changes better). you probably left out the 02 sensor or effed it up somehow. crawl under there and see if its loose, disconnected, or even present

 

[spiral]

I didn't do the exhaust myself....Exhaust Specialties in Tualatin Oregon did it. I had it done on Saturday. My check engine light came on last night (Monday night) at a little after 1 in the morning. Hasn't gone off since. I have an appt at the dealer for Thursday to check it out.

 

[Bronco89XLT]

AutoZone will check it for free!!! If you don't have one near you, I am sure another parts place will do it for you.

 

[BLADE262US]

I think I missed something here where do you see its a mass air system . In his/her signiture it says 96 with 351 V8 . To my knowledge and I checked alot ford never ever had a mass air system on a 351 only the 5.0 and only the really later models unless it came from california . Being a 96 I think there is an O2 sensor before and after the cat if they removed any of that it will throw a code . If you want to clear it ( I wouldnt do this if you already have an apointment ) you can disconnect the battery for awhile this will clear the EEC,s memory now the bad part of this is if the O2 sensor is bad the EEC will upon power up relearn all the sensors so if your O2 is bad it will learn bad return values . After it runs for awhile the EEC will keep looking at those values and they get compared to known good values stored in its ROM once it decides that the values are bad the EEC decides the sensor is bad and will throw the check engine light again . /emoticons/[email protected] 2x" width="20" height="20" />

 

[spiral]

There is indeed a mass air flow sensor. And yes, an O2 sensor too.

I'm going to call my Autozone today and see if they can read the code for me...I had no idea they would do that for free. Lovin' this forum.

 

[BLADE262US]

Very interesting do you know where that truck originated at and could you take a pic of the top of the intake ( a passenger side pic ) maybe the white info tag on the top of the core support . Thanks /emoticons/[email protected] 2x" width="20" height="20" />

 

[spiral]

Blade...I haven't gotten around to the pics yet, but I will. And I followed the Autozone advice. They read the code for me...there were two. It looks like I need a new O2 sensor. The first code read "Lack of HO2S switch-sensor indicates lean" and the other code read "The PCM has determined that the response time for oxygen sensor 1 in bank 1 was too slow during testing".

 

[ocalabronco]

umm, blade, not to sound like a know-it-all, but all bronco's, 93/94 and later had mass air, regardless of whether it was a 302 or 351. if you doubt, go check out www.fordfuelinjection.com

spiral- just go get new O2 sensors like your motor is telling you to do, install them, and i bet ya the light will go off after you reset it

 

[BLADE262US]

After I made that post I thought about it and I did remember the lightning 5.8 being mass air but I didnt know they did it on any of the others . Back a couple years ago I was looking for a way to do that using one of those motorsport mass air conversion kits and the tech told be that there were no production 5.8 with mass air except the lightning and some of the california trucks due to emmisions there . He then told me that he couldnt guarentee that the mass air kit for a 5.0 would work correctly some guys it did and some it didnt so I wasnt going to spend that much money on a gamble like that . I did go back to fordfuelinjection.com and look again and if you look on the computer chart http://www.fordfuelinjection.com/index.php?s=5.8 you see that there are only 3 computers that were mass air one the lightning and one the cobra R and one other that must be the one you have would be curious the part number on your computer if you had time to pull it to look and the code on the tear tag . Also if you look most all of the computers for the 5.8,s are SD or speed density which is what most all of them are . My F150 is a 95 and its speed density . I would have liked to have known about the non lightning computer back then ( thought the motorsport techs were supposed to know it all ) But then again I dont think you could use that computer with any tranny but an E4OD because the computer looks for signals back from the tranny for timing and other functions . I would like the part number off your computer if you had time though for maybe a later project . /emoticons/[email protected] 2x" width="20" height="20" />

 

[spiral]

Update....I brought it in to the dealer, they replaced the O2 sensor and reset the 'puter. Everything is fine again...and they did it for free /