411 Swap 383 Vortec Newbie To Tuning. Where To Start?

[supspt454]

Open the throttle body by turning the adjustment screw about 3 turns clockwise viewed from the front. Start it and warm it up. You want the IAC to be open minimally at hot idle. Look at the IAC counts at hot idle in park with no additional engine load like the ac. I shoot for around 15-25 counts at hot idle. After turning in the screw 3 turns clockwise with a torx bit, if the IAC steps are zero, bring the screw back out very slowly while watching the IAC steps until they rise up to ~20 counts. When performing this adjustment the TPS will auto zero to the lowest voltage the PCM sees. That is why I try to overshoot it higher than necessary at first and back off. If for some reason you are still over 25 counts, shut the engine off, go another 1 turn clockwise and recheck. I have found with this approach I often do not have to mess with the startup and friction airflow stuff, what was there just works.

So what does it mean if the wifi scanner is showing 130+ IAC counts? Someone jack with the set screw before I got the truck?

 

[L31MaxExpress]

So what does it mean if the wifi scanner is showing 130+ IAC counts? Someone jack with the set screw before I got the truck?

It is possible, however more than likely it is due to your 383 combination simply needing more airflow.

 

[supspt454]

It is possible, however more than likely it is due to your 383 combination simply needing more airflow.

Gotcha. I will make the changes you recommended as soon as I get done watching this massive tornado in SW Oklahoma.

 

[Road Trip]

Follow this guide for tuning your idle. There's a lot of steps and it'll take a while, but it'll give you a great running engine. Once you finish that, go through and tune your VE table, MAF, and then spark. I recommend you invest in a wideband sensor with a serial output otherwise you won't be able to tune the open loop portions of your tables, AEM makes some great ones. Once that's done you'll probably need to redo the idle tune, or maybe not.

It'll take a while to learn the ins and outs of tuning. @L31MaxExpress is a pro at it, I can also help you along the way. Also the HPTuners forum is a great resource.

If you'd like I can send you my scanner config that has all the histograms and data points you need to do just about any changes.

Thanks for sharing your pointer to that guide. Just gave this a brief read, and I
can appreciate the thought process. Nothing quite like looking over the shoulder
of someone with lots of experience -- it's good to have something like this to use
as a sanity check as I'm slowly picking up a new skillset.

 

[supspt454]

Thanks for sharing your pointer to that guide. Just gave this a brief read, and I
can appreciate the thought process. Nothing quite like looking over the shoulder
of someone with lots of experience -- it's good to have something like this to use
as a sanity check as I'm slowly picking up a new skillset.

Yes my thoughts exactly

 

[supspt454]

It is possible, however more than likely it is due to your 383 combination simply needing more airflow.

Okay. So a quick scan with dashcommand showed tps 0.4* and 145 IAC count. First started adjusting the screw clockwise and saw the tps increase but not much change in IAC. Slowly backed off the screw counterclockwise to 0.0* tps and the IAC dropped to 112-114 all at hot idle. That throttle body does have over 200K on it. Maybe that IAC is not traveling all the way and partially stuck?

 

[L31MaxExpress]

Okay. So a quick scan with dashcommand showed tps 0.4* and 145 IAC count. First started adjusting the screw clockwise and saw the tps increase but not much change in IAC. Slowly backed off the screw counterclockwise to 0.0* tps and the IAC dropped to 112-114 all at hot idle. That throttle body does have over 200K on it. Maybe that IAC is not traveling all the way and partially stuck?

The TPS will rise if the engine is running or the key on. It should auto zero otherwise on key-on. It is very possible it is gummed/carboned up. Same goes for the throttle body and throttle plate as well.

 

[supspt454]

The TPS will rise if the engine is running or the key on. It should auto zero otherwise on key-on. It is very possible it is gummed/carboned up. Same goes for the throttle body and throttle plate as well.

I cleaned the throttle body and blade real good before assembly but I did not remove the tps or iac so yeah I guess I do not clean it as good as I thought. You know what I’ll be doing tomorrow. I have a spare that I may take apart and clean. With everyone’s help we will get it. Thanks for everything and future questions in advance.