4.8 with truck norris nsr need some help tuning.

[elcamino85]

Have a stock 4.8 and just put in a truck norris nsr came and cant seem to get it happy idling always wants to die, any help would be greatly appreciated thanks.

[Fast355]

It requires a lot of tuning, especially in a DBW setup. It also needs a converter in a 5.3L much less a 4.8L.

[elcamino85]

Thank you for the reply my setup is dbc at the moment. I think I may have an issue with my map sensor or the wiring, it throws a code right away before I even try to start it.

[elcamino85]

Any suggestions with the tune would be greatly appreciated.

[dave w]

Any suggestions with the tune would be greatly appreciated.

Can you post the 4.8 Flash?

What error code is being set?

All Fuel / MAF / Spark related error codes need to be resolved before any tuning is attempted.

[elcamino85]

I was getting a P0107 code l replaced the sensor and it’s reading properly now. I also need to replace my maf because iat was reading -37f l live in Canada but it’s not that cold lol. Strange issues it was a running engine. Here are both bins that l tried there are changes made to both with what l got from youtube videos. The cam is Truck Norris NSR

[2xls1]

Guessing this is a swap? What transmission are you you using. First file has it set to non electric auto, second file has it set to 4L60. Vin and OS IDs as a 01 Silverado 4.8L with a 4L60. Did everything come put of that vehicle? Give as many details as you can about what you are using. And you must get the IAT reading correctly before you go any further. IATs very rarely go bad so before you just replace the MAF check the IAT wiring closely.

[elcamino85]

Iat is reading properly now. This is a swap going in a 71 cutlass engine is 4.8 with 706 heads everything is stock on the engine besides new cam and cold air. . Dbc and th350 trans. I can start the motor on the stand but it won’t idle on its own it seems to surge a lot I have to keep it up in the rpm’s to keep it running, it sounds good up high just doesn’t idle. Thank you all for helping.

[2xls1]

I've never understood why people try and run EFI engines on a stand and attempt to tune it without everything hooked up like it will be in the car but if you are running open exhaust with the O2 sensors installed you can't do that. If you must run it unplug the O2 sensors so it stays in open loop. You can't run closed loop with O2 feedback with open exhaust. And with a T350 transmission I would start with a 4.8L OS for a manual transmission that isn't looking for any transmission behind it.

[elcamino85]

I have a 4.8 in the car with a stock tune and it works great I have another 4.8 with the cam in it and I at least wanted to get it to idle and start and run before I pulled the engine out and then I would be a car down because I can’t get it to run. I agree no the best idea but at least I can still drive the car while I sort the canmed engine out.

[2xls1]

You will need bigger injectors than the 24 lb that are in it.

[elcamino85]

Ok thanks I will look into that. I was under the impression that a no springs required cam would be ok with stock injectors.

[2xls1]

24 lb injectors are barely adequate tor the airflow a stock cam provides. You are increasing the airflow especially at higher rpms. Your injector duty cycle will be really high around 54-5500 rpm. NSR cam just means you don't have to change valve springs. But as weak as stock valve springs are and as cheap as LS6 springs are I would change those too even though Tooley says NSR. Are you using the stock 01 fuel rail with the vacuum referenced regulator with a return line going back to the tank? What is the fuel supply with the engine on a stand?

[elcamino85]

I have an evil energy in tank pump set up with filter. And yes all stock with regulator and return. I understand at high rpm fuel may be an issue but you would think even with the stock stuff I should be at least able to get it to idle. Yes I agree I will be taking your advice and doing the springs.

[2xls1]

You never answered if you are trying to run it on the stand with open exhaust. Meaning are there active upstream O2 sensors close to open exhaust? There are a few things in your files that are problems.