What if I just disconnect the EGR & AIR Systems in my LT1?

[vettered91]

I think since I took off the cats in my LT1 auto, I bought a one way ticket with no return into the no EGR & AIR Systems. Because after that, I'd put the long tube headers without the EGR connections. (they came without those little tubes) "Easy, I'll fix it latter" I thought, but days and months passed and more mods came...
The only things I did was to disconnect the AIR pump electrical connector and put on some rubber caps in the EGR tubes where they should be connected to the headers and that's it!
I don't get any "check engine" lights, I have all the O2 sensors where they should be (one of them after the right "cat"or where it used to be), I don't have a scanner to check if there's any stored codes in the ECM.
The vette is FAST but I think it can do a lot better if I just could do something to slow down the way it drinks gas! It started to run rich after I took off the cats and now it's worst!

1.-Does anybody knows if there's a decent way to cancel the whole EGR & AIR system or I'm I making the ECM crazy?

2.-Does anybody knows if there's a decent way to make my engine run the "magic" 14.7 air-fuel ratio?

Any ideas and/or experiences are welcome!


I don't have any problems with air tests down here so please don't take it in consideration for your opinion. I'm really the first one to want the vette very well tuned!

Thanks: George

 

[vettered91]

I could use some help...:cry

 

[78SilvAnniv]

Don't worry, someone will come along soon.
Heidi

 

[vettered91]

Thanks Heidi... I know

I just wish I have an easier one! :eyerole

 

[vettered91]

:z

 

[78SilvAnniv]

Sorry George...everyone else must be :z too.
Heidi

All ye, all ye, oxen free! Come out, come out wherever you are!!!

 

[vettered91]

Hi Heidi, You're always fresh air

You know... waiting for some help here gives me more time to fix my vette! I spend the last two days working on the red and my hands are full of scars!!!

:L

See you! (say hi to Kenny & Poquita)


Now I have the check engine Light!

And codes:31,33,35,37&62 :eek

Maybe I should start collecting them :crazy

 

[livinez]

Check with Summit

See what their tech line has to offer on this matter. Maybe call it racing set ups as they mention they sometimes tape their calls. They have a device for O2 elimination that keeps at least that code off. If you need more info I'll find in my catalog and pass info and part# along.
Otherwise I know NOOOOTHING!

 

[dremn2]

Vettered, I'd love to help you! But I though when you said you had removed the cats that you took your two 4 legged pets out of the car! Shows how much I know, If I gave you any advice it would be this. "Don't listen to Gary's opinions when it comes to mechanical problems!" LOL. Good luck bud, I'm sure someone has the answer!

 

[vettered91]

Re: Check with Summit

See what their tech line has to offer on this matter. Maybe call it racing set ups as they mention they sometimes tape their calls. They have a device for O2 elimination that keeps at least that code off. If you need more info I'll find in my catalog and pass info and part# along.
Otherwise I know NOOOOTHING!

Thanks livines, I'll start looking into my Summit catalog think I've seen those O2 eliminators. What I'm trying to find out with this thread is if I should go back and fix-connect the AIR & EGR systems of course without taking off my headers and other mods.
The other concern here is that my engine is running very rich and maybe this is a consequense (I don't know) of the turn off and canceled AIR &EGR. I know somehow all this stuff is inter-related and VERY COMPLICATED! :crazy

 

[vettered91]

Vettered, I'd love to help you! But I though when you said you had removed the cats that you took your two 4 legged pets out of the car!

:duh

How did you know that my hands look like some wild cats had a fight with me!

(and they won)

:L

 

[stumpy]

First, have you reprogrammed your PCM to reflect the mods you've done? I'm not talking about Hypertech, that's useless after a certain point and they're over priced as well! Make sure your PCM tuners knows about all of the mods you've done. Also, if you get the car dyno'd make sure to get F/A ratios and let the tuner know what they are. If you don't already have a PCM tuner then give PCMforLess a try. Brian is one of the best LT1 programmers around and his prices and terms are hard to beat.

Second, did you put in a cooler T-stat? If so you may be staying in open loop too long, or not coming out of open loop at all (not sure if that's possible tho). Also, how old are the O2 sensors? If you're running rich all the time it could be that the O2s are not working properly and are giving inaccurate "lean" readings.

HTH

 

[vettered91]

Stumpy;

Thanks a lot for your answer, I'll take a good look at the site in a minute! I have the 160° Tstat and I have the Hyper programmer.
My first fan turns on at 184° an off at 175° the second is on at 194° and off at 185° Most of the time I'm at 190° in the city and 175 in the highway.
I agree with you about the need of custom tune my PCM, I'm going to start looking for someone that can do it in a dyno down here!
I need the H programmer for the fans, the rear axle ratio change, RPM shifting points (it's an auto), etc.
The important thing is that you're opening my eyes with the sensors & open loop!
By the way two sensors are new, the one after the cat its an old one!
Maybe the only one that goes after the passenger cat it's sending bad lectures way out the parameters it should be to the PCM and that with the EGR & AIR systems not working...

I BET IT'S RUNNING IN OPEN LOOP ALL THE TIME

Does somebody happens to know if there's a way to know if the engine it's running in open or closed loop???

Thanks again stumpy!
;worship

 

[vettered91]

Does somebody happens to know if there's a way to know if the engine it's running in open or closed loop???

;help

 

[stumpy]

You have an O2 behind the Cat? Is this car running OBD-II? The rear O2s really don't get much wear, ie they're reallt there as a checkpoint for the PCM. But then you've removed the cats so I guess it may see more use. Man you really should talk to a tuner. You may be able to get rid of the rear O2 or get the dummy O2 from Summit.

BTW, you don't need the Hypercrap at all, a programmer can take care of the fans, shift points, bump up line preasure (do this for sure), speedo correction and so much more. Brian will keep your program on file and quickly update it without going through the discovery process again. In fact, if you are OBD-I then you can get updates via email and apply the updated code yourself. However, tnat does require an investment in a cable and program to access the PCM.

BTW, you only run in Open loop at startup and at WOT and Open loop doesn't use the O2s. It's highly unlikely that you're always running in open loop. However, the PCM monitors the temp sensor to know when to switch into closed loop. Hence the need to have the PCM reprogramed for 160 stat.

HTH

 

[vettered91]

Hi there!

You have an O2 behind the Cat?

Yes, I have one in the right side after the spot where the cat should be and one more up stream.

Is this car running OBD-II?`

No, it has OBD-I but with the OBD-II ALDL (16 pin), I understand that all the Vettes for export had the three O2 sensors and the 16 pin ALDL.

you don't need the Hypercrap at all, a programmer can take care of the fans, shift points, bump up line preasure (do this for sure), speedo correction and so much more.

I already have it and done all this for some months now but after seeing the link in your post I think I'm going to get the cable and a tuning program for my PCM.

However, the PCM monitors the temp sensor to know when to switch into closed loop. Hence the need to have the PCM reprogramed for 160 stat.

Most of the time my engine temps are between 190*- 210* the only time I see 160* is when it's on it's way to the 190*- 210*.
But anyway I would like to know if there's a way to know when the engine is in open or closed loop.

See you.

George

 

[vettered91]

Just one more thing,

Since the long tube headers & the MSD ignition control unit mods, the ASR it's not working.

All the old Trouble Codes are gone! Now it shows in the module 9, H62 & H72.

 

[SPANISHVETTS]

I just saw this thread. I can’t believe more folks have not jumped in!!!

1st. You need 3 wire, (heated), O2 sensors. With out Cats you will never get the O2´s hot enough to work. No voltage out of the O2 = NO closed loop = Bad gas mileage.

The Bosh 3 wire O2 sensor cost about $60. at most auto parts stores in the US. If you need the part # I will look it up for you.

The temperature advice is good. With a 160º T-stat and the stock chip I doubt that you will see much closed loop time. This is an ongoing problem with my car because it takes 20 min. to reach 160º with the water-less coolant I run. Since most days I drive 10 miles to the track and 10 miles back home I average about 8 MPG. Once the beast gets up to operating temperature I average 24-25 MPG at 90-100 MPH. I think that is OK for a 383 tuned for max Torque.

After you install the heated O2 sensors the stock prom might pull the mixture back into tolerance. If it was my car I would hold off on the new prom until you have finished all of the mods you plan on. Most of the prom burners will re-burn the chip a time or 2 for free but it is still down time while you send the chip away to be re-programmed.

Hasta la Vista Amigo,

 

[SPANISHVETTS]

But anyway I would like to know if there's a way to know when the engine is in open or closed loop.

Do a search for ¨field service mode¨ I remember reading about jumping 2 pins on the ALDL to check the open / closed loop mode but I do not remember where it was posted.

 

[tazdevl35]

Hello George,


Let me see if i can clear up some of this confusion....first , the cats are gone correct? You will need to put the O2 sensor eliminators in place of the O2 sensors so the computer will see the correct values...that is to say the ones it would normaly see if the cats were in place. Second... you have headers on the car now and have eliminated the stock manifolds with the AIR tubes that go to the AIR pump ....this is fine as long as the pump solenoid is disconnected the pump wont dump air out of the tubes that went to the manifolds...however, I would remove the pump as well and use a shorter belt..the pump is drag on you accessories and if its taking 2-4 horsepower to run it , its taking away from the overall horsepower. Remember small increases add up.You will need a different belt with the pump gone.Use a piece of string tied around the pulleys in the correct order to measure your new belt length taking into account the ammount of slack the belt tensioner has to take up. This measurement along with your old belt at a local parts store will get you the correct belt with the correct number of ribs in the correct size. As far as mileage goes the O2 eliminators will help with this but keep in mind without "live sensors" in place the mileage will never be as good as it could be because the computer cant fine tune the mixture.But it will be better with the eliminators in place.As far as the ASR system....asr retards timing and backs the throttle off for slip regulation....you could have removed or bypassed something necessary to the proper operation of the ASR system. With out actually seeing what you have there i cant offer any help in that area. Once you have done all these things, clear any codes and start over. You will need to reprogram you computer with someting besides hypercrap. I have used their products and they didnt "blow my skirt up" so I would have a custom program designed and flashed into your PCM. This is the best and only way to get the best performance out of the mods you are doing.I always recommend to everyone to do mods that are emissions legal, high flow cats, emissions friendly cams,etc. This makes life so much easier...or better yet install a better exhaust and a supercharger kit....you still get reliability, mileage and a kick a$$ power increase. I know its more expensive but I prefer the tried and true methods that work with the on board systems.


Taz :t :t