Need help with 383 TBI

[Hellbilly]

I've asked questions here before, but I now have the engine built and in the truck. It's ready for fluids and start up. A little about the build, its 383 with 9.5:1 compression, AFR 195cc Enforcer heads, Edelbrock Performer TBI intake, Lunati roller cam with 206/215 duration at .050" 112 lobe separation .470"/.489" lift, 1.5 roller rockers. Heads, intake, and headers where port/gasket matched. SPR Perfomance throttle body with 1" spacer, and intake ports matched to throttle body. Truck is a 93 K1500 4l60e on 35s. 3.42 rear gears (I know, they'll get changed by the end of the year.)
I played around with Tuner Pro for a while before I pulled the old engine out and got familiar with how to use it for the most part. I have all the Moates hardware. I installed a bung to add a wide band later (when I have the money). This is the first time I've built an engine start to finish on my own and tuning is new to me too. Besides the engine constants, what else do I need to change from the stock tune to get fired up? Once its running, I know how to get the VE tables dialed in, but I know I can probably add some timing with the aluminum heads, right? I would just like some help, to make sure I'm not missing anything before I try to start this thing this weekend. For now I Just need it running but at some point I'm going to need to tune it really clean for emissions test and would like to be able to just swap chips back for daily driving/performance. Anyone able to help me with this?

[tayto]

the only timing i would be worried about is your initial, and then idle timing. get fuel dialed first, WB is necessary now IMO. has the engine been broken in yet?

[Hellbilly]

the only timing i would be worried about is your initial, and then idle timing. get fuel dialed first, WB is necessary now IMO. has the engine been broken in yet?

Right. So initial timing at zero. And get idle timing before fuel? And no, engine has had no brake in. I built this thing in about 10sq ft of space in my garage and swapped it in my driveway. I don't really have access or the money to have it broke in on a stand or anything like that. So what WB would you recommend? I know there was one recommended by moates if that's still available. Should I get that set up before trying to run my engine?

[tayto]

i generally don't use 0* for initial, but whatever you decide on it needs to match whatever is in your calibration. there are lots of good WB out there, stick with a "big name" and try to order from a real vendor, counterfeit wideband sensors are a real thing. i am a big believer of getting a motor properly broken in, get it hot,do cam break-in if required, and then full wot pulls to seat the rings. if you are not comfortable getting the fuel table dialed in very quickly I would just throw a carb on it to do breakin then tool around with EFI after. maybe I'm being too anal but everything i build goes on the dyno now. installing and engine and not have to worry about cam or ring break is worth the few hundred bucks to have it done.

[Hellbilly]

Ok, that's the kind of advise I'm looking for. What range of initial timing do you suggest? I'll order order a wideband from Summit, and look into what my options are for break in. I think I can get fuel table done pretty quick, but again, I've never done this from the ground up. Probably just psyching myself out. I've never had anyone teach me more than how to change brakes and oil on a car. Everything I've done, I taught myself by trial, error and the internet. I struggled to match parts up, building this thing, not realizing how many differences there was in gen1 SBC parts, but here I am with it complete. Thanks for the help

[steveo]

its really hard to hurt or blow up a well built smallblock. i wouldn't really stress over it, you just need to make sure your general fueling is between like 11:1 and 15:1 so you don't rinse the rings clean, and the timing at a range so it doesn't go click click boom, then tune from there.

[Hellbilly]

its really hard to hurt or blow up a well built smallblock. i wouldn't really stress over it, you just need to make sure your general fueling is between like 11:1 and 15:1 so you don't rinse the rings clean, and the timing at a range so it doesn't go click click boom, then tune from there.

How far off should I expect the stock fuel/timing tables to be though? I learned how to use TP on my bone stock engine, but have no experience in what happens when you change heads, stroke, ect.
If I take the stock tables, set initial spark, and change engine constants, are tables going to be close enough to start/run so I can go from there? Or do I need to adjust anything first? Idle RPM?
Sorry, I really have started over stressing this, and second guessing every little thing.

[Fast355]

its really hard to hurt or blow up a well built smallblock. i wouldn't really stress over it, you just need to make sure your general fueling is between like 11:1 and 15:1 so you don't rinse the rings clean, and the timing at a range so it doesn't go click click boom, then tune from there.

10:1 won't even hurt it at WOT. Better to have it a bit rich than too lean. GM ran alot of truck calibrations in closed loop at WOT.

[Fast355]

How far off should I expect the stock fuel/timing tables to be though? I learned how to use TP on my bone stock engine, but have no experience in what happens when you change heads, stroke, ect.
If I take the stock tables, set initial spark, and change engine constants, are tables going to be close enough to start/run so I can go from there? Or do I need to adjust anything first? Idle RPM?
Sorry, I really have started over stressing this, and second guessing every little thing.

Set the injector flow rate, set the displacement, raise the idle to ~750, add some fuel (10% or so) to the VE above ~60 KPA. It should run well enough for initial startup.

My 383 TPI ran well enough on the TBI 350 stock tune to drive and load on the trailer when I brought it home.

[Kitch]

What are you doing for a fuel pump and what fuel pressure were you going to use as a base setting?
My Vortec headed Comp Cam TBI 350 first fired and idled with the stock TBI fuel pump and pressure but even with altering the VE tables the stock pump will be highly unlikely to keep up with any W.O.T runs.

[Hellbilly]

What are you doing for a fuel pump and what fuel pressure were you going to use as a base setting?
My Vortec headed Comp Cam TBI 350 first fired and idled with the stock TBI fuel pump and pressure but even with altering the VE tables the stock pump will be highly unlikely to keep up with any W.O.T runs.

I put a vortec pump in it and fuel pressure is set at 18.

[Hellbilly]

Set the injector flow rate, set the displacement, raise the idle to ~750, add some fuel (10% or so) to the VE above ~60 KPA. It should run well enough for initial startup.

My 383 TPI ran well enough on the TBI 350 stock tune to drive and load on the trailer when I brought it home.

Thanks, good to know

[Hellbilly]

Went ahead and fired up, set initial timing, but having ignition issues. By recommendation, I used Accel distributor (performance replacement) and wires (superstock spiral core). Pertronix Flamethrower coil. Plugs are BKR5E. Anyone see this happen before? I tried putting the distributor from my old engine in it and it did the same thing18848

[1project2many]

This is usually because the definition file is reading the wrong values for spark or has the wrong math to convert the computer data to correct spark numbers. The way the numbers change appears to roughly match a spark table but the values are incorrect so I would suspect wrong math.

Which definition are you using?

[Hellbilly]

This is usually because the definition file is reading the wrong values for spark or has the wrong math to convert the computer data to correct spark numbers. The way the numbers change appears to roughly match a spark table but the values are incorrect so I would suspect wrong math.

Which definition are you using?

Advanced $0D TP5 v251

[1project2many]

There are notes that instruct the user to make a change to the conversion math. You can use those notes to make sure the math in your file is set up for zero degrees distributor angle.


There are two values that need to be set for your engine, Initial Advance and Injector Flow. Initial Advance: After loading A217 $0D TP5 v250.adx into your definitions menu, and opening, go to the Acquisition menu and open Edit Definition. Click on the + sign beside the word Values. An expanded menu will open. Drop down and click on Spark Advance. Then click on the Conversion tab at the bottom of the screen. Next click on the Set button at the top and change the last number in the equation to the Initial Spark Advance. This can be found at 4133 in the bin file. The Initial Spark Advance should match the advance set at the distributor. This will correct the Spark Advance display. If you decide to leave this as is, then you will need to add the appropriate amount of Spark Advance to the displayed amount when viewing, as the definition is set-up for 0 Initial Advance

[Hellbilly]

There are notes that instruct the user to make a change to the conversion math. You can use those notes to make sure the math in your file is set up for zero degrees distributor angle.

Thanks! I missed that, somehow, I'll check it out this evening

[Hellbilly]

I cant figure out the ignition issue... when it first starts up the advance is normal. As it starts to warm up and lower RPM, it starts flashing back and forth between normal and over 23000 degrees advance. By the time it gets up to normal temp, it never shows a normal advance. I've tried replacing distributor with the one out of my old engine and also the original coil. I've reburned chips, even tried the original calibration with nothing changed except engine constants. I checked for spark at each cylinder, and put fresh plugs in. I'm running out of ideas. When it shows a normal advance value, it runs pretty decent, but once the advance goes haywire, it starts missing and backfiring if you try to give it throttle to fast or Rpm go above 3000. Both the old, Known good parts and the brand new parts act the exact same way. I do have a knock sensor fault but I think it might be the wrong one... if you look it up on Summit, it shows like 3 different ones and doesn't say what the difference is. I can swap that out with my old one but I don't see a knock sensor causing this problem. I can try another temp sensor, but temps seem to be working correctly. No other data is going haywire like advance is so I'm at a loss with what would cause this. The PCM shouldn't even be able to calculate that range, right?

[Hellbilly]

These are the files I'm using
18868

18866
18867
18868

[Fast355]

I cant figure out the ignition issue... when it first starts up the advance is normal. As it starts to warm up and lower RPM, it starts flashing back and forth between normal and over 23000 degrees advance. By the time it gets up to normal temp, it never shows a normal advance. I've tried replacing distributor with the one out of my old engine and also the original coil. I've reburned chips, even tried the original calibration with nothing changed except engine constants. I checked for spark at each cylinder, and put fresh plugs in. I'm running out of ideas. When it shows a normal advance value, it runs pretty decent, but once the advance goes haywire, it starts missing and backfiring if you try to give it throttle to fast or Rpm go above 3000. Both the old, Known good parts and the brand new parts act the exact same way. I do have a knock sensor fault but I think it might be the wrong one... if you look it up on Summit, it shows like 3 different ones and doesn't say what the difference is. I can swap that out with my old one but I don't see a knock sensor causing this problem. I can try another temp sensor, but temps seem to be working correctly. No other data is going haywire like advance is so I'm at a loss with what would cause this. The PCM shouldn't even be able to calculate that range, right?

What you are seeing is the result of a bad mathematical equation in the scanner definition file. It is a known issue that has been floating around for a while. When you are seeing that 23000 value the commanded timing is actually negative. Nothing is wrong with the actual PCM, distributor or anything like that. A knock sensor fault can cause the PCM to command less timing. Most modified engines are going to run like poop if the timing is negative.

[Hellbilly]

What you are seeing is the result of a bad mathematical equation in the scanner definition file. It is a known issue that has been floating around for a while. When you are seeing that 23000 value the commanded timing is actually negative. Nothing is wrong with the actual PCM, distributor or anything like that. A knock sensor fault can cause the PCM to command less timing. Most modified engines are going to run like poop if the timing is negative.

Ok, that makes sense I guess. I'll get the knock sensor taken care of and see what happens.

[Fast355]

Ok, that makes sense I guess. I'll get the knock sensor taken care of and see what happens.

Given that the PCM has to be able to make the engine knock to test the knock sensor, I am not sure I would mess with it yet. Those non swirl port aluminum heads need a good chunk more timing than the stock cast iron swirl ports. I would start with putting an appropriate advance curve in the engine.

[Hellbilly]

Given that the PCM has to be able to make the engine knock to test the knock sensor, I am not sure I would mess with it yet. Those non swirl port aluminum heads need a good chunk more timing than the stock cast iron swirl ports. I would start with putting an appropriate advance curve in the engine.

Maybe I haven't drank enough coffee yet. If the knock sensor fault is going to cause PCM to pull timing, which it has been showing 4-5* knock retard at any given RPM, then what is adding timing to the main spark table going to do?
Just trying to understand this better before I go mess with it, because there's obviously something I'm missing or don't understand (that I thought I knew lol).

[Fast355]

Maybe I haven't drank enough coffee yet. If the knock sensor fault is going to cause PCM to pull timing, which it has been showing 4-5* knock retard at any given RPM, then what is adding timing to the main spark table going to do?
Just trying to understand this better before I go mess with it, because there's obviously something I'm missing or don't understand (that I thought I knew lol).

It may sound crazy, but you can actually get spark knock from having too little timing. Less timing causes the engine to run hotter, especially the cylinder heads, which can actually lead to more real knock.

Years ago before I was tuning, I put a TBI setup on top of a 305 that had 601 casting non swirl port heads on it. To get it to run well on the stock TBI tuning took 10* initial advance at the distributor. The swirl port heads have a drastically different burn rate than any other head. They burn more quickly than even Vortec heads. Those aluminum heads will want at least 30* of timing in my experience and maybe as much as 34-38*. The calibration for the TBI heads might have 20-24* of timing at high rpm and actually goes negative in places from the factory. Too little timing can cause drivability issues not limited to overheating, no power, backfiring into the intake and more. Best to get the timing curve closer to where you need it to be then work on fueling. Timing changes will affect the fueling on a speed density system anyway. I broad brush more fuel into the tune to make sure there is enough fuel, let the 02 sensors trim out what is not needed while tuning the VE tables.

I have a feeling you will also likely have to lie to the computer on injector size. You have an engine that is probably capable of more than 100% VE near peak torque. You will need to tell the computer that the injectors are smaller than they actually are to get the pulsewidth up enough to be able to control the fuel with the VE table. VE table maxes at 100%.

[Fast355]

Those AFR Enforcers are the same Chinese casting that I had LLoyd Elliot port for my 11:1 383 in my Express van. I am very familiar with the timing they require and can give you a few points to work the timing table around. On 91 octane this is where I am.

Idle 16-18*

Cruise timing @ 50 kpa
RPM Advance
1200 27
1600 31
2000 32
2400 33
2800 35
3200+ 37

WOT 90-100 KPA (remember the stock PE adder adds 2-4* to the main timing table)
RPM Advance
800 6
1200 14
1600 19
2000 24
2400 27
2800 28
3200+ 29

Moderate throttle 75 KPA
RPM Advance
800 8
1200 14
1600 20
2000 24
2400 27
2800 29
3200+ 29

[Hellbilly]

It may sound crazy, but you can actually get spark knock from having too little timing. Less timing causes the engine to run hotter, especially the cylinder heads, which can actually lead to more real knock.

Years ago before I was tuning, I put a TBI setup on top of a 305 that had 601 casting non swirl port heads on it. To get it to run well on the stock TBI tuning took 10* initial advance at the distributor. The swirl port heads have a drastically different burn rate than any other head. They burn more quickly than even Vortec heads. Those aluminum heads will want at least 30* of timing in my experience and maybe as much as 34-38*. The calibration for the TBI heads might have 20-24* of timing at high rpm and actually goes negative in places from the factory. Too little timing can cause drivability issues not limited to overheating, no power, backfiring into the intake and more. Best to get the timing curve closer to where you need it to be then work on fueling. Timing changes will affect the fueling on a speed density system anyway. I broad brush more fuel into the tune to make sure there is enough fuel, let the 02 sensors trim out what is not needed while tuning the VE tables.

I have a feeling you will also likely have to lie to the computer on injector size. You have an engine that is probably capable of more than 100% VE near peak torque. You will need to tell the computer that the injectors are smaller than they actually are to get the pulsewidth up enough to be able to control the fuel with the VE table. VE table maxes at 100%.

Thanks for the detailed info. I guess I was being conservative when I tried adding timing, because of knowing the knock sensor not working, was scared of hurting it that way. I'll go over what you've said and try to come up with something. I've never started this from the ground up and guess I didn't expect it to be that far off from a stock calibration. Live and learn I guess.
I really appreciate the help man. I'll try to get back on here tonight with an update

[Hellbilly]

ok, so after a little playing around, the truck actually makes enough power to drive... not WOT yet or anything crazy. I'll try to put the file and log here if anyone wants to look at it and make suggestions. its obviously gonna be way off in some areas still

[Fast355]

ok, so after a little playing around, the truck actually makes enough power to drive... not WOT yet or anything crazy. I'll try to put the file and log here if anyone wants to look at it and make suggestions. its obviously gonna be way off in some areas still

I adjusted the whole spark map, brought down the injector size to give you more room in your VE table. Should get it more to drink with the injector size being programmed smaller. As such I roughed in a VE table that is smoother than a plateau of 100%. I also disabled the EGR since the AFR Enforcers do not have EGR passageways to feed the valve.

Test carefully while listening for audible pinging.

[Fast355]

I just noticed something else. Is your distributor set at 5* BTDC with the EST wire disconnected? That is what the Initial Timing Value is set at in your .bin file and I did not alter it.

[Fast355]

If your distributor is at 5* BTDC use the one above, if it is at TDC or Zero, use this one. Having the initial value in the BIN not matching your initial value at the distributor, offsets the timing advance by that amount. They should match.

[Hellbilly]

I adjusted the whole spark map, brought down the injector size to give you more room in your VE table. Should get it more to drink with the injector size being programmed smaller. As such I roughed in a VE table that is smoother than a plateau of 100%. I also disabled the EGR since the AFR Enforcers do not have EGR passageways to feed the valve.

Test carefully while listening for audible pinging.

Wow, thanks. Yes, distributor is set at 5*. I hadn't smoothed anything out yet, that bin was just where I ended at yesterday, by changing a few cells at a time till I got to where it would go down the road. I also forgot what you said about lying for injector flow and had just added 15% to the factory tables, and smoothed out a little... wasn't actually planning on needing anymore than that when I went out.
I noticed you also changed the AE, I was going to ask if I should do something with that. And also what is the reason for changing the AFR stoich?
want to make sure I understand the reason behind changes, so I can get better at this.

[Fast355]

Wow, thanks. Yes, distributor is set at 5*. I hadn't smoothed anything out yet, that bin was just where I ended at yesterday, by changing a few cells at a time till I got to where it would go down the road. I also forgot what you said about lying for injector flow and had just added 15% to the factory tables, and smoothed out a little... wasn't actually planning on needing anymore than that when I went out.
I noticed you also changed the AE, I was going to ask if I should do something with that. And also what is the reason for changing the AFR stoich?
want to make sure I understand the reason behind changes, so I can get better at this.

Change stoich because almost all fuel you will find now has 10% ethanol. Just corrects the fueling from the alcohol content being added to the fuel. I did bump up the AE modestly to get it some more to drink when you open the throttle. The AE is all pulsewidth based and proportional to airflow. If you have more airflow you need more fuel.

I decreased your injector flow rate in the tune because I noticed the INT and BLM rising in areas you already had the VE table at 100%. The injectors were still showing the pulsewidth and duty cycle to be fairly low. I reshaped the VE tables to try to get them more in line with what I feel the VE probably is on your engine given its specs. Adjust from there.

I am sure it will probably run, how good I cannot say since its more or less a startup tune I would flash into my Autoprom and modify from there.. I also raised the idle just a bit to keep the cam happier.

If it is globally rich, increase the injector flow rate in the tune. If it is globally lean decrease it. Once you get the BLM and INT in the 128 or less ball park, you can fine tune the VE table from there. My typical BLM target is 124. Keep it slightly rich and let the computer pull fuel as it sees fit. Prevents the fuel curve from having random lean hiccups.

Not sure if you noticed that I also brought your open loop air/fuel ratio table more inline with what it needs to be. GM programmed them to command 16:1 during warmup and they tend to run very lean set that way.

[Hellbilly]

Ok, cool. I haven't had time to mess with it yet... hopefully this evening. I am concerned that I'm not going to here knock over my exhaust though. It's pretty loud with true dual, headers and flowmaster 40s. The last time I messed with it though, I had exhaust popping in some areas. Would that indicate a need for more or less timing? At the times it happened I still had enough fuel. I found out the knock sensor I put in was for a manual transmission if that makes any difference (besides throwing a code) I'm going to order the right one and a wide band on Friday.

[Fast355]

Ok, cool. I haven't had time to mess with it yet... hopefully this evening. I am concerned that I'm not going to here knock over my exhaust though. It's pretty loud with true dual, headers and flowmaster 40s. The last time I messed with it though, I had exhaust popping in some areas. Would that indicate a need for more or less timing? At the times it happened I still had enough fuel. I found out the knock sensor I put in was for a manual transmission if that makes any difference (besides throwing a code) I'm going to order the right one and a wide band on Friday.

The manual trans knock sensor is the same as the older one. It was used on the trucks that had a seperate ESC module as well as the Vortec 350s. Make sure you torque it to 15 ft/lbs. The torque value is critical for it to work accurately.

Every engine setup is different but if it pings a little at part throttle it won't typically destroy anything. Detonation at higher rpm and WOT is what kills things. Stay out of the throttle until you get it dialed in better, have a knock sensor and a wideband. If your narrowband is in the 880-930 mv range under load its not really lean anyway.

There are plenty of SBCs in service without knock sensors. Just have to be a little more conservative on the timing.

[Hellbilly]

Little update: I got the knock sensor replaced this week and got the truck running good enough that I drove it to work a few days. Had a few issues I was having trouble figuring out. But, Friday, my MAP sensor decided to quit working, so I put the new one back on. This one seems to read about 5-10KPA different than the old one did, but now I'm chasing non-engine related issues. Rear axle seal leaked into the drum, so I gotta get that fixed.

Some of the issues I was having: When coming to a stop, it gets to about 1000RPM and kinda hangs out there, making it feel like the engine is trying to push through the brakes. Until you get to below 5MPH and it switches to idle timing. Would the fix for this be less timing at 1000RPM or raise the max MPH for idle timing?

The other issue is, at idle, I've noticed that the IAC is going all the way to zero and hangs out there till I accelerate again. I've sat in the driveway at idle and played with timing and VE but, it seems like no matter what, it idles 750-775RPM, IAC at 0, and 5 degrees advance. What am I missing?

If it makes any difference, I've had Power Enrichment and DFCO turned off while trying to get VE dialed in. I can get a log to upload today, if you want but I have a feeling everything is going to be a little off again, because of this MAP sensor reading a little different.

Also, I got a wideband, but don't have everything to install it yet. Have to double check PCM connectors, but I don't think I have a wire on the pin needed to log AFR, so I'm gonna have to buy some pins. Or I guess I could steal one from the EGR solenoid wires

[Fast355]

Little update: I got the knock sensor replaced this week and got the truck running good enough that I drove it to work a few days. Had a few issues I was having trouble figuring out. But, Friday, my MAP sensor decided to quit working, so I put the new one back on. This one seems to read about 5-10KPA different than the old one did, but now I'm chasing non-engine related issues. Rear axle seal leaked into the drum, so I gotta get that fixed.

Some of the issues I was having: When coming to a stop, it gets to about 1000RPM and kinda hangs out there, making it feel like the engine is trying to push through the brakes. Until you get to below 5MPH and it switches to idle timing. Would the fix for this be less timing at 1000RPM or raise the max MPH for idle timing?

The other issue is, at idle, I've noticed that the IAC is going all the way to zero and hangs out there till I accelerate again. I've sat in the driveway at idle and played with timing and VE but, it seems like no matter what, it idles 750-775RPM, IAC at 0, and 5 degrees advance. What am I missing?

If it makes any difference, I've had Power Enrichment and DFCO turned off while trying to get VE dialed in. I can get a log to upload today, if you want but I have a feeling everything is going to be a little off again, because of this MAP sensor reading a little different.

Also, I got a wideband, but don't have everything to install it yet. Have to double check PCM connectors, but I don't think I have a wire on the pin needed to log AFR, so I'm gonna have to buy some pins. Or I guess I could steal one from the EGR solenoid wires

Have you adjusted the Minimum Air Rate screw on the throttle body? If you have not, I suspect a possible vacuum leak. The IAC counts should be low at idle, but not zero. I would say probably 5-15 counts at idle is enough for the PCM to be able to lower the idle as needed.

Less timing will allow the engine to idle lower with the same IAC counts FWIW. Retarding the timing while the engine is decelerating will make it return to idle more quickly.

[Hellbilly]

Have you adjusted the Minimum Air Rate screw on the throttle body? If you have not, I suspect a possible vacuum leak. The IAC counts should be low at idle, but not zero. I would say probably 5-15 counts at idle is enough for the PCM to be able to lower the idle as needed.

Less timing will allow the engine to idle lower with the same IAC counts FWIW. Retarding the timing while the engine is decelerating will make it return to idle more quickly.

Ok, so I finally got brake issues worked out so I could drive the truck. But the ignition timing is making me feel like a complete idiot. I keep adding timing to open throttle table, or taking away were I get knock retard, but I feel like I've added way more to the majority of the table than I should have and it doesn't seem to have any effect on what the truck actually runs at. Except that I noticed after adding a bunch of timing to idle table it revs really high and holds it at initial start up. Once it gets into closed loop it goes back to the normal timing that it always runs at. I know its not going to run the exact numbers that are in the tables, due to coolant bias and whatever other bias's it has, but the tables literally seem to have no effect on closed loop. Is this normal or am I completely missing how to tune ignition on these things? When I tune fuel, I turn off power enrichment, DFCO, EGR ect. and can get it close that way. Do I need to be doing something similar with ignition tuning? the truck is running good enough to drive through town, but has its quirks still, and the timing tables don't look anything like what I think they should. But I can literally sit in the driveway with my Ostrich plugged in and add 5* to the table and nothing changes.

I've looked on here and other places online, looking for a tutorial on ignition tuning and can't find anything that's helped me. I get the idea of the timing shelf before knock occurs, but cant seem to actually get the truck to run more or less timing than what its doing on its own, except at initial start up. I data logged my drive home from work, and I'll add the BIN used. I put the idle advance table you sent me back in to keep it from running at 1200 RPM at start up, but you'll see that I have a lot of timing in the open throttle table, and its not actually running near that advance and its not knock retard taking it out.

I've appreciated you help so far, I'm not looking for someone to do this all for me, I want to learn to do it myself. I'm just not understanding how the PMC is correcting it, I guess. Thanks