2003 Silverado VE Tuning Problems

[Fastmike91]

1 bar OS since you have a 1 bar MAP sensor. If you want 2 bar from 1 bar you'll have to write entire your current tune then go to 2 bar. Save your tune somewhere safe.

Pull the throttle body and do a thorough cleaning. Remove the IAC and clean the passages.

It's also possible that you have a vacuum leak. STIT is bringing BRAF much lower than I'd expect.

When you decide to put on the TBSS intake be sure to change out the knock sensors and harness while you're at it. Don't forget to RTV the gasket plugs, buy new steam tube gaskets, and get new intake manifold gaskets.

Ok cool I will swap over to the 1 bar OS. I thought I had to write entire to do that no matter what? I will pull that apart this weekend and clean it all really well. I was wondering if it had a vacuum leak too so I will investigate that as well.

I did a log on the way home and the idle definitely drops down faster. At the end of the log I was backing in my driveway and pressed the clutch in and the truck died. It looks like the WB was either not reading or reading super rich.

Again, thanks for all the help man.

2003 Silverado 5.3 vE log 13.hpl

[SiriusC1024]

Yes you have to write entire when changing OS. The point is to go from 1 bar to 2 bar it's 1bar>original>2bar. Can't go 1bar>2bar.

[SiriusC1024]

It looks like there is a fueling problem causing all this. It holds idle fine in a few spots, but in others it stalls. That's inconsistent. Rich AFR is stalling it out. Look at the wideband and O2 voltage (not trims).

I've adjusted O2 crossover and idle CL settings. Hardware-wise I'd look into leaking evap purge. This could also be a source of vacuum leak through the tank. Another thing could be something with the regulator such as sticking or the vacuum line.

In the beginning of the log MAP reads 91-92kPa during your pull. Engine stalled reads 97kPa. Intake restriction of some sort. Decent 15-20hp power gains to be had here, and it should be an easy fix .

I've adjusted a few other things as well. Tune is not SD OS yet.

[Fastmike91]

It looks like there is a fueling problem causing all this. It holds idle fine in a few spots, but in others it stalls. That's inconsistent. Rich AFR is stalling it out. Look at the wideband and O2 voltage (not trims).

I've adjusted O2 crossover and idle CL settings. Hardware-wise I'd look into leaking evap purge. This could also be a source of vacuum leak through the tank. Another thing could be something with the regulator such as sticking or the vacuum line.

In the beginning of the log MAP reads 91-92kPa during your pull. Engine stalled reads 97kPa. Intake restriction of some sort. Decent 15-20hp power gains to be had here, and it should be an easy fix .

I've adjusted a few other things as well. Tune is not SD OS yet.

Alright Im ordering the rest of the stuff this weekend to put that intake on haha I was thinking when I first got it that the FPR was giving me issues.

I just loaded the new tune and logged on the way to work. It feels the strongest its been and every thing seems good but the idle hangs a lot when its cold. I think you can see in the beginning of the log where it was hanging and towards the end when it dropped down right away. For some reason it seems like it pulled way harder than it has been.

2003 Silverado 5.3 VE log 14.hpl

[SiriusC1024]

Haven't seen cold start yet. Probably needs BRAF lowered at those temps.

Well then why don't we call it there until after you've installed parts? What all do you plan to change?

[Fastmike91]

Haven't seen cold start yet. Probably needs BRAF lowered at those temps.

Well then why don't we call it there until after you've installed parts? What all do you plan to change?

Sounds good. I was going to say the same thing.

I'm going to put the tbss intake on. It's brand new and came with stock injectors and I have an edelbrock 90mm TB for it. I'm going to change the intake tube also because it's all the stock stuff. That's about it for right now other than the obvious stuff that goes with the tbss swap.

If I got rid of the MAF on the intake tube should I wire in a IAT sensor in the tube?

[SiriusC1024]

Yep gotta wire in an IAT and update the IAT sensor cal in the tune. Same for the injectors if you're using the ones from the TBSS. Don't forget knock sensors and stuff while you're in there. Plan on changing the reg or evap purge?

Here's a good setup for the new TB.
https://www.pcmofnc.com/2021/03/05/i...throttle-body/

[Fastmike91]

Yep gotta wire in an IAT and update the IAT sensor cal in the tune. Same for the injectors if you're using the ones from the TBSS. Don't forget knock sensors and stuff while you're in there. Plan on changing the reg or evap purge?

Here's a good setup for the new TB.
https://www.pcmofnc.com/2021/03/05/i...throttle-body/

OK cool. Yep I usually get some gm knock sensors. I think I'm going to run an aeromotive regulator since we have had good luck with them at work. I want to get rid of the purge valve to clean it up a little bit and to not have to deal with it.

[SiriusC1024]

Right on. That should take care of it.

[Fastmike91]

Here is the log from today and the tune file. You can see in a couple different places it goes really lean as I take off from a stop. At around 22-24 seconds is the worst I believe. I had just fired the truck up and took off.

2003 Silverado 5.3 TBSS.hpl
WORKING TUNE SD_8 1 BAR SD 2.hpt

[SiriusC1024]

Idle adapt is running it out of IAC. Close the throttle body adjustment screw so that TPS voltage reads .45V.

Load this, clear LTFT's, then log.

[SiriusC1024]

So I was thinking about your idle problem. New 90mm throttle body and intake swap. BRAF is unusually low, and it hasn't changed since parts were put on. It's almost half what should be expected.
braf.png

See here in the log. Engine is up to temp. As rpm is decaying to idle MAP increases. IAC closes and no more air can be subtracted. Idle spark begins to compensate.
idle airflow.png

First step is making sure the throttle is closed or barely cracked. Next do a TPS relearn. Turn ignition on then off. Unplug TPS and IAC. Turn ignition on for at least 5 seconds. Turn off then reconnect.

If the problem remains check for vacuum leaks. TBSS intake was just installed, and I hope you used new gaskets. Check the vacuum lines. There could even be a leak in the brake booster or the PCV valve is stuck open.

Monitor IAC counts to indicate if you've fixed the problem.

Also, the knock sensors. Did you end up replacing them with genuine parts and torqued to spec? You're getting KR where there shouldn't be any.

[Fastmike91]

So I was thinking about your idle problem. New 90mm throttle body and intake swap. BRAF is unusually low, and it hasn't changed since parts were put on. It's almost half what should be expected.
braf.png

See here in the log. Engine is up to temp. As rpm is decaying to idle MAP increases. IAC closes and no more air can be subtracted. Idle spark begins to compensate.
idle airflow.png

First step is making sure the throttle is closed or barely cracked. Next do a TPS relearn. Turn ignition on then off. Unplug TPS and IAC. Turn ignition on for at least 5 seconds. Turn off then reconnect.

If the problem remains check for vacuum leaks. TBSS intake was just installed, and I hope you used new gaskets. Check the vacuum lines. There could even be a leak in the brake booster or the PCV valve is stuck open.

Monitor IAC counts to indicate if you've fixed the problem.

Also, the knock sensors. Did you end up replacing them with genuine parts and torqued to spec? You're getting KR where there shouldn't be any.

So the TPS voltage was .71 and I could only get it down to .55 Its an Edelbrock 90mm. I did the TPS relearn and I'm going to monitor IAC counts now and see if its better.

I absolutely used new gaskets I wouldn't reuse them even though most people say you can.

My buddy replaced the knock sensors with GM ones about 3k miles ago when he did the swap. They looked to be in great shape and so was the harness.

It has a catch can on it so no PCV valve.

[Fastmike91]

Alright I got the IAC counts pretty good by adjusting the throttle blade and it seems way better. I need to transfer the VE data from the log to the tune one more time and I think it'll be good. I was pulling like 10-12% when I first started with the file you sent over.

Couple questions now, does the CEL need to be enabled for the mass air flow (p0103) for SD to work even though I am running the SD os now? I hate having the CEL on haha

Also.. one time while I was out logging the IAC counts went up to like 130 and would stay there until I came to a complete stop and then they came down. Most of the time the stayed around 40-50 coming to a stop and it was ok. What would cause this? Im fairly certain I don't have a vacuum leak.[

WORKING TUNE SD_8 1 BAR SD_3.hpt
2003 Silverado 5.3 TBSS 5.hpl

[SiriusC1024]

You can uncheck the box for SES light. Keep it set to MIL on First Error.

IAC is changing like you're describing due to throttle follower and throttle cracker.

And what do you mean it has a catchcan so no PCV? Is it setup like a breather off the valve cover, or is there still vacuum to the catchcan?

[Fastmike91]

Yeah it has two hoses, one from each valve cover that go to the catch can. No vacuum to the catch can.

So I'm not seeing any KR at this point would you think its safe to add some more timing? I removed a little bit when I was seeing that KR.

[SiriusC1024]

The catchcan goes to one of those small filters to atmosphere? PCV vacuum capped off?

[Fastmike91]

Yeah there is a vacuum port on top of the intake that I capped off. There is the vacuum port in back of the intake that goes to the vacuum pump and then the vacuum booster. I don't have the evap purge valve on the intake anymore either and I have that port capped off.

So 2 hoses 1 from each valve cover to the catch can that has a filter on top of it.

I drove it a while today and for some reason it randomly wants to die like not enough air flow. Seemed more when I was pulling into parking lots a slow speed. Sometimes too it will hang the idle until I come to a stop or under say 1-2 MPH. Unfortunately I didn't get a log today but I will on my way to work and I'm sure it'll do the same thing.

I will have to double and triple check for vacuum leaks. Maybe I'll throw the smoke machine on it. It's getting really frustrating because sometimes its all good and sometimes its not haha I don't know what else it could be at this point. I'm wondering too if its a fuel pump issue?

This is the current tune on the truck.
WORKING TUNE SD_8 1 BAR SD_4.hpt

[Fastmike91]

Hey man here is the log from today. It didn't die at all but in the beginning it was really lean.

2003 Silverado 5.3 TBSS 6.hpl