'64 GTO LS Conversion Help Needed

[JSchmitz]

Newbie to late model tuning needs help here. I just got done converting my ?64 GTO to LS platform. I bought a high mile 5.3 with harness and PCM from a friend. I stripped all the electronic trans, A/C, etc. wires from the harness. The injectors were all gummed up. I managed to get 5 freed up. I replaced three. It?s firing on all eight cylinders (verified with IR gun on header tubes). Engine is running pig rich at idle. It dies when I start it up cold. I must open the throttle to get it to keep running. Then it will eventually idle ok. It didn?t do that at first. But It may have been before I got the MAF hooked up. It?s a stock 5.3. It has 1-7/8? long tube headers and a 4? intake pipe. It?s running through a factory truck MAF. I don?t know if the MAF needs recalibrated or what. The A/F ratio seems to be ok when revved up. Then the fuel trims quickly creep up at idle. Five injectors are questionable. I?ve attached my tune and log file. Any help would be appreciated.

[JSchmitz]

GTO Engine.jpg

[JSchmitz]

2000 5.3 btw.

[JSchmitz]

This morning I started it with the MAF disconnected. It started and idled fine. Shut it off and connected the MAF. Started and idled fine. I had been disconnecting the battery each evening to be safe as I just rewired the whole car. Could this be resetting the fuel trims and starting over everyday not allowing it to "learn"? When I rev it up the trim goes to zero. It just seems out of whack at idle. I'm scared to drive it like this. But maybe that would be best thing to do? Here's a log from this morning.

[JSchmitz]

It looks to me like it is adding fuel at idle thinking it's lean when it's really rich. I don't think I have any exhaust leaks. I do have ball and flange collectors. Could it be leaking some oxygen in at idle making it appear lean? I'll post pics of the collectors and O2 sensors later.

[dhoagland]

At a brief look you o2 sensor voltage never moves so I'm not sure how trims can be moving. Maybe a channel logging issue?

[JSchmitz]

At a brief look you o2 sensor voltage never moves so I'm not sure how trims can be moving. Maybe a channel logging issue?

Ok. Would that mean bad sensors or wiring problem? Sensors are both new. Maybe scanner not set up correctly? I'm using the default scanner setup.

[JSchmitz]

Shouldn't I get a code if the sensor voltages are off? I don't believe I have reporting turned off.

[dhoagland]

When you connect the scanner try going to the Vehicle Tab, click it... Then Repoll supported parameters...

Then Click the add channels icon "little green +" Then look for o2 options.
Most people suggest not using SAE but if that's all available you have to

Then when you start scan Key on engine off your o2 voltage should be right at .450
If not its time to look at wiring

I agree with no codes being set, and in the one log the trims were moving, but based on what??

[JSchmitz]

When you connect the scanner try going to the Vehicle Tab, click it... Then Repoll supported parameters...

Then Click the add channels icon "little green +" Then look for o2 options.
Most people suggest not using SAE but if that's all available you have to

Then when you start scan Key on engine off your o2 voltage should be right at .450
If not its time to look at wiring

I agree with no codes being set, and in the one log the trims were moving, but based on what??

You're definitely onto something here. The sensor voltage is already added to my default scanner channels.. I looked at a log file of my truck and it's reporting it there. What settings should I look at in the tune to make sure I have my B1S1 B2S1 o2's set up correctly? It looks like I don't have the heater enabled for either. idk why. Is this a mistake?

[Matt Vardaman]

You have a wiring problem. If the O2 sensors are unplugged they read 450mv in the scanner. Your O2 voltage is reading 3mv the whole time, which is dead lean, so the ecm is trying to add 20% fuel in open loop, and 75% in closed loop at Idle! It should never go into closed loop like that, it should go into openloop fault since there is no activity. Verify your wiring. Your post said you stripped the wiring out that you didn't need, and the O2's no longer read, so start there.

Your tune file is basically stock, with only minor changes for PE ect. Your DTC list is correct for running only upstream O2's. I would bet you have pending codes for inactivity, and Lean codes. Since they are set to report on second error, and you are disconnecting the battery at night, the codes haven't showed up yet in the log details tab.

[Matt Vardaman]

When you connect the scanner try going to the Vehicle Tab, click it... Then Repoll supported parameters...

Then Click the add channels icon "little green +" Then look for o2 options.
Most people suggest not using SAE but if that's all available you have to

Then when you start scan Key on engine off your o2 voltage should be right at .450
If not its time to look at wiring

I agree with no codes being set, and in the one log the trims were moving, but based on what??

The Trims only moved when he touched the throttle. Which is strange, since the O2 voltage did not change. It's probably because he changed fuel trim cells.

[dhoagland]

The Trims only moved when he touched the throttle. Which is strange, since the O2 voltage did not change. It's probably because he changed fuel trim cells.

Makes sense, Thanks

[JSchmitz]

It turned out that I had the wrong o2 sensors. Don't know how I managed that. Lol! I got them early in the journey. Lesson learned. Put new ones in and it's working perfectly. Fuel trims are almost perfect so far. Now I need to drive it more. I checked all of the wiring first. Confirmed voltage and did continuity on all wires from PCM plug to sensor plug. dhoagland pointing out the sensor voltage led me right to the problem. Thanks for the help!

[dhoagland]

Glad to hear it

I see that was a cold start log but I think you will see similar once warmed up.
When you come off the throttle your idle dips low until adaptive idle kicks in.

So dial your MAF and VE then you can get to tuning IAC and Idle air. Once you get that you can Tune idle air from cold start (Russ K Method)

If your like me and can't leave stuff along, you can rough in your MAF & VE then try this link, and start over.
https://forum.hptuners.com/showthrea...g-with-Headers

[JSchmitz]

Yes, it was a cold start log. I took it for about a ten mile drive this morning. Everything looked and felt good. The idle is a tad bit low.

I have watched a ton of videos. Still haven't done my first attempt at MAF and VE tuning. I'm 55 years old and not the most computer literate. I'm very knowledgeable with carbs, curving distributors and all things old school. Working on another degree from the school of hard knocks. I guess I need to save a tune for MAF and VE tuning with all of the proper things turned off? Then start logging and making changes.

I'll take a look at the thread. I am pretty anal retentive about things also. lol

[JSchmitz]

Here's the log from my first "real" drive.

[JSchmitz]

Also thinking forward about getting a wideband. I guess I would need to weld in another bung (or two?). Or can you run the wideband in place of narrow band for tuning full throttle then switch back? I see, in the posted thread, someone reco'd getting AEM 30-0333.

[dhoagland]

Yes, it was a cold start log. I took it for about a ten mile drive this morning. Everything looked and felt good. The idle is a tad bit low.

I have watched a ton of videos. Still haven't done my first attempt at MAF and VE tuning. I'm 55 years old and not the most computer literate. I'm very knowledgeable with carbs, curving distributors and all things old school. Working on another degree from the school of hard knocks. I guess I need to save a tune for MAF and VE tuning with all of the proper things turned off? Then start logging and making changes.

I'll take a look at the thread. I am pretty anal retentive about things also. lol

I've got 2 years on ya. Completely understand where your coming from.
I read a bunch on HP, finally bought it, 2 months later wondered if I made a big mistake (that was 4 years ago)...

Yes if I was you I would do MAF only first as its easier...

[dhoagland]

Here's the log from my first "real" drive.

Doesnt look bad
Add MAF hz to your next log, that is needed for MAF error log