Deleting cat=loss of low end torque?

[jamesco329]

The reason I’m deleting them is because of theft. We have had a few vehicles by my work have theirs stolen. I’m only doing this because if I don’t remove it, someone will probably do it for me…. Otherwise I’d throw a high flow cat on my truck.

I deleted mine for the same reason. And because the epa is a joke. I'm just looking to get the idle back to a smoother level. I replaced the headers back. And put in eliminating plugs. I think I need to reprogram it. But I'm not sure where to look.

 

[kylenautique]

I deleted mine for the same reason. And because the epa is a joke. I'm just looking to get the idle back to a smoother level. I replaced the headers back. And put in eliminating plugs. I think I need to reprogram it. But I'm not sure where to look.

Woah bringing my thread back from the dead! You leave the up stream o2 sensors installed. You need to delete the rear o2 sensors from the ECM. I think there is a resister trick that makes the ECM think everything is fine, but the best way is to program them out. I noticed more power as soon as I removed them. Its not a "HOLY S*IT" difference, but its noticeable.

 

[jamesco329]

Woah bringing my thread back from the dead! You leave the up stream o2 sensors installed. You need to delete the rear o2 sensors from the ECM. I think there is a resister trick that makes the ECM think everything is fine, but the best way is to program them out. I noticed more power as soon as I removed them. Its not a "HOLY S*IT" difference, but its noticeable.I

Woah bringing my thread back from the dead! You leave the up stream o2 sensors installed. You need to delete the rear o2 sensors from the ECM. I think there is a resister trick that makes the ECM think everything is fine, but the best way is to program them out. I noticed more power as soon as I removed them. Its not a "HOLY S*IT" difference, but its noticeable.

That's my 64 thousand dollar question. Where can I get the reprogramming kit/software?
BTW, like Goonies. Threads never say die.

 

[99xcss4]

Where can I get the reprogramming kit/software?

if you have a 98-00 gmt400 black box or 0411 swap your options are hptuners efi live jet dst or mail-order if you have a 96-97 black box your only option is jet dst you might still be able to get mail-order if you have a 96-97 and want to use hptuners or efi live you will need to to the 0411 swap

there are listings on ebay for 0411 pcms with l31 tunes with 4l60e/4l80e and non e-automatic/manual transmissions

 

[kylenautique]

That's my 64 thousand dollar question. Where can I get the reprogramming kit/software?
BTW, like Goonies. Threads never say die.

Ha! Love it! I have a Black Bear tune, so I had them remove it when Justin tuned my truck. Any local tuner that can access the black box ECM should be able to help you. HP Tuners, TunerCat, EFI Live... are some software's that work with the black box ECM. 1998 is the only year that can be fully tuned. 1996-1997 have some adjustments available, but not a ton. There are ways to solder in a resister on the rear o2 sensors to trick the ECM into thinking they are working properly. I've personally never done it, but you could give that a try. Lots of info on it via Google..

I see that your location is Washington State. If you are close to Vancouver, David the owner of Old School EFI can do this for you. [email protected]

 

[L31MaxExpress]

Ha! Love it! I have a Black Bear tune, so I had them remove it when Justin tuned my truck. Any local tuner that can access the black box ECM should be able to help you. HP Tuners, TunerCat, EFI Live... are some software's that work with the black box ECM. 1998 is the only year that can be fully tuned. 1996-1997 have some adjustments available, but not a ton. There are ways to solder in a resister on the rear o2 sensors to trick the ECM into thinking they are working properly. I've personally never done it, but you could give that a try. Lots of info on it via Google..

I see that your location is Washington State. If you are close to Vancouver, David the owner of Old School EFI can do this for you. [email protected]

96-97 can be tuned as much as a 98-2000 black box. I have Tunercats OBD2 definitions for both. That being said the 0411 and P59 have far more tables because they are much more advanced than the OBD1 era LT1 based controller that GM crammed some rudimentary OBD2 code into the already overwhelmed processor of to run our hacked together EFI. Needless to say I throw the black box in the scrap bin as quickly as possible along with the OEM poppet injector garbage. With an 0411 or P59 and the MPFI update spider using the proper injector data for them these engines run so much better. They start quicker, idle more smoothly, have much better throttle response, make more torque and hp as well as get great mileage.

The 0411/P59 is much more user friendly with modifications as well. When I put the 383 in the van, I took the old tune I had been running the 350 on, changed the cylinder volume to match the 383, increased the base running airflow volume by the % displacement increase, copied back in the VE table since increasing the displacement scaler adjusts the VE table lower, flashed the PCM, turned the key and it popped right off, idled and had throttle response.