S-10 Forum banner
1 - 17 of 17 Posts

·
Registered
Joined
·
317 Posts
Discussion Starter · #1 ·
ok, i had my cat cut out, and now my check engine light is on!!!!
i disconnected my battery, and it went off, but came back on after about 60-70 miles.
i'm not sure how i can fix it. i had the cat cut out cuz it was bad and it was stankin. but does anyone know if maybe i can cut one of the wires or put voltage to it or something that will eliminate the check engine light????
PLEASE HELP!!!!!!!!
o ya, its a 2001 blazer 2wd 2door.
 

·
Self Portrait
Joined
·
1,632 Posts
Wasn't the cat under warranty? I have heard something about a dummy sensor you can put in the second O2 sensor to fool it....but I not sure...do a search of the forum to find that thread!

Hope it helps
 
G

·
Mine came on too, on wednesday.

My dad is a mechanic and hooked it up to the scanner and it aid some BS about the O2 Sensor but he just over rode it with his scanner but it came back today.

So I don't know what you can do.

BTW my truck still runs fine though.
 

·
Registered
Joined
·
317 Posts
Discussion Starter · #4 ·
ya mine runs fine too, but there's 3 O2 sensors.... and when one of them is bad, the pcm (i'm pretty sure its the pcm) resets to factory air fuel mixture settings. so instead of the air/fuel mixture adjusting to your exhaust and compinsating for u'r engine running lean or rich, it just gives u the factory setting all the time. so if u have mods, u get less out of them. like i know its probably only 5-10hp, but when my check engine light came on, i could feel the loss in power, not much but definatly there.
i'm trying to find a way i can make the pcm think it sees a change from the second O2sensor to the 3rd one which is after the cat. but i'm not sure how.
 

·
2 Litre Terror
Joined
·
1,964 Posts
4.3's have 4 o2 sensors. At least the 2000+ years do. First, why wasn't the cat covered under warranty?. 2nd, the truck will run better and have more torque with it on and 3, if you want it off that bad, check out thunder racing for the secondary o2 sensors that will trick the ecm. Also, on 2000+ trucks you need to disco BOTH battery cables as the electrical system works on a positive ground. Residual voltage will keep the ECM from clearing itself. Also, it can take as long as an hour to clear it. Hope this helps
 

·
Registered
Joined
·
317 Posts
Discussion Starter · #6 ·
how does having the cat on give me more hp???
are you talking about the simulator plug for the sensor?
 

·
2 Litre Terror
Joined
·
1,964 Posts
If you reduce backpressure past a certain point you will lose torque and to some degree Hp. The amount of Hp you are gaining is so small for the amount of work and cost involved that unless your running a high horsepower/ high RPM motor, it's nil. Yeah they sell a 02 sensor that is calibrated to tripping the ecm into thinking there is a cat there. Reason it goes into Check engine mode is the secondary 02 isn't being heated enough by the cat to give a correct reading. Hope this helps
 

·
Canadian Member
Joined
·
436 Posts
Here is my Exhaust system in a nutshell.

JBA Headers
Custom Y-pipe - 3 inch
Deleted cat- Straight pipe 3 inch
O2 sensor simulator.
Dynomax Ultraflo Muffler- 3 inch
dumped before rear axle.

After every mod on this truck I have raced here in Calgary. Each of these modifications has improved my times. DO NOT get hung up on this " back pressure is my best friend" stuff.

O2 sensor from Casper electronics are $42 USD. Mine works fine.
 

·
2 Litre Terror
Joined
·
1,964 Posts
To say don't get hung up on the beckpressure issue is doing everyone a diservice. I never said backpressure is your freind ??? It's been proven countless times that the 2k+ motors are much more sensitive to it. Your truck would likely benefit from the cat removal. Your '97 heads are different as well as your intake. Also, you say you raced the truck after every mod. exactly what was the cat removal worth? a 1/10th maybe 2. Here in the states, certain states it's illegal to run without one and also pass inspection. Like I said, for your year motor thats great....Your sig shows a 160 degree therm....Run that in a 2000+ truck and you'll notice a drop in Hp and torque. These trucks can sometimes be very year sensitive so if your running good, great for you and your combination. Doesnt mean it's gonna work that way all the time... By the way, with all the mods is 15.51 your best time. I'm curious becuase I have seen a 15.71 with the mods in my sig. Was traction an issue?. How hard were the headers to install.?

Bobby
 

·
Registered
Joined
·
3,094 Posts
not to call BS on anyone here...but Im runnin a 160 degree thermo in my '01 and I havent lost anything...yea, the SES light is on, but I knew that would happen...
 

·
2 Litre Terror
Joined
·
1,964 Posts
01, i got the light too. Just didnt feel like the truck was running as nice as it did with the 180......Did it take a while for the ECM to get it's **** straight?. If so I may go back
 

·
Canadian Member
Joined
·
436 Posts
Hey Bobby, I did not realize that the y2k were different to the degree that similar mods would not produce similar results. I also think that it is a diservice to downplay the benefits of a decrease in backpressure.

I do, however, agree that my experience lies only in the 97 w engine. I did not realize that the 2k engines were that sensitive.

As with any internet information I would suggest that anyone attempting a mod would do their research and talk to several people. (Never take one persons opinion as gospel, even mine LOL)

Bobby , you asked a few questions.

1- The headers were a technically simple mod but, VERY time consuming. 8-12 hours.

2- Here is a link to an example of my traction problems.
http://members.shaw.ca/simsnet/race1.avi

3-I ran on friday at Race City and got a 15.51 at 86.8 WITH my new drag radials, the track was still frozen as my 2.4-2.6 60 ft time will attest to. Keep in mind that I race at 3500 ft above sea level, this has a markedly detrimental effect on my times. At sea level I would be in the high 14s at 90ish MPH.

I think that with your current mods that mid-15s are probable, your additional weight should be at least partially offset by your gears. Your Altitude should help as well.
 

·
2 Litre Terror
Joined
·
1,964 Posts
Now see this is how posts should be done. Thanks bro. 2000+ motors are a little tricky. Keep me posted on times...:thumbup:
 

·
Registered
Joined
·
317 Posts
Discussion Starter · #15 ·
1-2 tenths off my 1/4 mile sounds worth the work. once i get that simulator plug i should be kewl with that. thanx guys...... i cant wait till i have those kinda traction problems!!!!!
 

·
Registered
Joined
·
1 Posts
hey man i read part of ur forum, i work for GM, since you have already cut out the cat GM will not cover it by waranty, the waranty GM offers is 8 yrs 80,000 mile waranty on all cats, you can however put an 02 sensor simulator that fools the second o2 sensor, so technically by this fooling the sensor bein read by the tech 2, you can run a straight pipe. Now on the 99 s10 like i have, you mock the headers too much you have to buy 2 more sensors for the headears because the sensors have to have a certain amount of feed goin through, but the dummy will solve ur problem. I have a V6 s10, im lookin for a simulator right now and ran across your post, good luck. Also, if you are interested in keepin your CEL out, make sure your charcoal canster is not to close to your exhaust, it is a diaster waiting to happen, it will melt your canister, keep it 6" away from the exhaust, because i know alot of people that bag S10s and decide to put it over the muffler.


matt
 

·
sold the dime :(
Joined
·
4,586 Posts
rip your dash out, pull out the gauges and destroy the little led that lights up behind check engine soon.. or just put tape over your gauges. i just destroyed the led. got annoying and im not paying for a new cat!!!!
 
1 - 17 of 17 Posts
Top