Check Engine Light - Because of Long tubes????

[bloopbloob]

Ok well i just had some lt's and OR x pipe put on a few weeks ago. When i get over 4000rpm, the check engine light comes on, but once i drop to 2000 it goes away. i have a feeling this may be due to the new location of the O2 sensors? Havent noticed any problems, but its still makes me a little uneasy.... anything else it could be, or how can i fix it? It seems to come on at even lower rpms now since i installed my 76mm maf w/true flow intake, and 70mm tb and spacer. Oh and i installed UD pullies, ac delete, new water pump and 180* tstat, and removed all smog stuff at the same time. I don't think its anything serious but it still bothers me to see a CEL at high rpms!

 

[gunmetal5.0]

Light shmight. Redline that bad boy.

 

[poneypower89]

How did you go about relocation the o2 sensors???

Did you cut/splice the wires? Use an extension harness? Or just move the sensors and pull the lines tight?

 

[bloopbloob]

first off, she occasionally gives the red a little smack or two, don't u worry! but i think thats outta my power range. more just me gettin a lil carried away and not watchin..... no real beneifit of doing that.
second, long tubes move the o2's further away from the engine. its just how they are made. i had to get an o2 extention for the passenger side for it to reach. i have heard if you lengthen the wires it can change resistance and possibly screw up readings??? could this be my problem? would installing my other extension on the drivers side maybe help, by evening things out? i don't think so, but maybe someone knows? anything else it might be? its only at high rpms... i dont think my other new mods would really affect that???...

 

[poneypower89]

Jricker will correct me on this if im wrong...

But I was under the impression that at WOT your o2 readings pretty much dont matter? Or maybe its something else that goes out the window... high HIGH rpms are we talking?

 

[bloopbloob]

really? i've never heard that before, but i'm pretty new to this. hmmm. maybe i should be worried? i've just heard that the o2s sometimes get bad readings with LT's because they are further away than they were designed to take the readings... and i figured that with higher exhaust flow at higher rpms the problem is just being magnified....
ok. before my maf and tb, etc (posted before), the CEL would come on at rpm over ~4700, only at higher speeds (above 80km/h - ??? 45-50mph????)) but disappear when i let off. That was right after LTs and xpipe. lately, since the tb and maf etc, it comes on whenever i get on it pretty good (at any speed), but disappears just after i let off.

 

[bloopbloob]

bump

 

[jrichker]

Do the obivious...dump the codes and see what the computer says is wrong…Codes may be present in the computer even if the Check Engine light isn’t on.

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great.

See http://www.troublecodes.net/Ford/
OR
See http://www.mustangworks.com/articles/electronics/eec-iv_codes.html

IF your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.

Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Wal-Mart.

Or for a nicer scanner see http://www.midwayautosupply.com/pc-7208-90-equus-digital-ford-code-reader-3145.aspx – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.

 

[bloopbloob]

whoa! i checked those threads and they are like a mile long and scare the hell outta me! i am not electrically inclined whatsoever! should i check with the engine running or off? i won't be able to test while the CEL is on because it disappears right way. Can i do these tests with a digital VM?

 

[iwashmycar]

be sure to jump the connectors [(46) to (48)] with a paperclip or wire with the KEY ON-ENGINE OFF and then the CEL will only show the codes. There is a Key On Engine On test too, and the CEL light will also just give you codes if the (46) and (48) in the above pic are connected.

just connect them....go into the car and turn the key on accessory or whatever it is (not running) and then have a paper and pen to write down the number of flashes.

Im just sayin it shouldnt "dissappear"

 

[bloopbloob]

ok. i meant the CEL disappears when i'm driving. i drove it today, and it's coming on more and more often! i was playing with my timing today but something is wrong there too! i'll probably resurrect an old post right away. i'm getting very confused! the light disappears whenever i let off the throttle. will it still be in the computer if i check without running it for a while?

 

[iLkYsPoNy]

ok. i meant the CEL disappears when i'm driving. i drove it today, and it's coming on more and more often! i was playing with my timing today but something is wrong there too! i'll probably resurrect an old post right away. i'm getting very confused! the light disappears whenever i let off the throttle. will it still be in the computer if i check without running it for a while?

HOLY CRAPOLA! I had the same problem! My CEL would come on under acceleration and then disappear. Well, I have BBK long tubes as well with the spliced extensions. It started coming on more and more often, then it stayed on. It's still on. I run rich and get 160 MPT, but who knows. I replaced the sensors them selves and redid the extensions. So, I think I may have a vacuum leak somewhere, just too lazy to check. I'm going to a new top end ( TFS TrackHeat) so I will just ride it out and replace all the vacuum **** then..... so long story short.... if you get in my position and figure it out let me know!

 

[jrichker]

Don't like the wires and paper clip? Spend $30 or so on a scanner. See http://www.midwayautosupply.com/pc-7208-90-equus-digital-ford-code-reader-3145.aspx

If you don't dump the codes you may never know what the problem is. Post the result of the code dump and I will try to help you.

 

[iLkYsPoNy]

I have that and it's awesome!:SNSign:

 

[bloopbloob]

ok well i went a picked up that exact one today, went to scan it, and nothing happens. 000. so i get looking, and one of the wires inside the harness on my car looks like it was broken off, so maybe they just moved it over. The scanner doesn't have anything that plugs into one the outlet on the far left (as in his pics). so now when i plug it in, one of the prongs is going to a dead end, but the is nothing plugging into the far left which does have a wire. Is this even possible for someone to have doen this? can i just get a new harness? would i just cut the old one off and solder the new one how is should be?
on jricher's pic of the connector, the far left terminal?? has a wire going to it, the one to the right is broken off and the inside looks like its missing one of those metal pieces, then the rest look fine.