'07 having issues tuning, Probably time for an intercooler.

[lawrence.jerel90]

I was glancing at my wideband during a WOT and saw it going toward 11.6! Fuel pressure is ok and I have bosch green giant 42s installed. When I watch the injector duty cycle PID, the duty actually drops when the lean spikes happen so the computer is actually pulling fuel. I looked through my tune file a few scans back and actually found a couple screw ups I made while adjusting fueling. I thought I fixed them though.


Yes I'm reaching 9psi it's probably time for an intercooler. I attached my latest log and tune files. Any help?

3.69
VS cam
108 thermostat
42lb injectors
Fenderwell Intake
Headers
autolite 104s
double roller timing chain
105 Springs
3.4 pulley
no cat

Just a list of mods.

[5FDP]

Seeing 10.0 is too fat, I'd try to stay around 11.0-11.5 for that boost level.

I can't see anything in the tune that would cause the injector duty cycle to drop like that.

[lawrence.jerel90]

Thanks for taking a look! I'll trim the fueling. Stock, the RPM adder table dumps fuel over time and I assumed that was used as a form of cheap backward intercooling. I am aiming for 11.5 or so to start and fatten to 10.8 after a couple seconds. I chose to do this because I don't have an intercooler and I'm well into 9psi. I'll take any advice I can get I'm learning and open. I'm going to set it for 11.2. I really don't want to blow this thing up so it makes me feel better about myself to stay on the richer side heh. I'll post another log in the AM on my commute to work.

[5FDP]

Even at 9psi that isn't that much boost. The GEN V supercharger is far more efficient than the previous GEN 3 supercharger. The same psi on the smaller less efficient blower is going to make more heat. The only time an intercooler would really come in handy is in the middle of summer because the ambient temps are already way up around 80-100 degrees and the underhood intake temps are higher. In this cooler weather with intake temps well below 90-100 degrees the need for a intercooler is far less.

If this was pushing like 12+ psi I'd think about an intercooler or a mix of E85 and 91/93 octane.

I never ran an intercooler on my 2000 GTP with 9-10psi of boost. Just used 93 octane and a air fuel ratio right around 11 with timing in the 12-15 degree range. I could have ran E85 but I didn't want to buy larger injectors when I had the car.

[lawrence.jerel90]

Good mention on the timing. Almost left it around 17-18. 11.2 AFR and 15 Deg timing. I also only run top tier 93. I like having the 3.69.

[lawrence.jerel90]

I drove some and made a couple of adjustments today and the lean spiking is back. It is making me nervous with the AFR set to 11.2 because when it spikes it goes into the 12s now. My histograms keep showing a need for leaning, but I don't like taking fuel from these areas where the spikes happen. There are a couple spots at 14minutes and 15minutes where you can see the injector duty drop. Either way, I'm going to keep working on it and post results.

[lawrence.jerel90]

Whoop whoop. Getting closer. Feels good. Please don't blow up..... come on 3.2 pulley. At least once though I noticed a lean spot go to 12.5 then 11.8 another. I go to the block on the MAF table that lines up at the same Airflow vs. Output Frequency block and add an extra percent of fuel there. Should fix that. We'll see. I have an AFR error histogram, but I don't copy and paste multiply by whatever. I just make adjustments at most 3 percent at a time. When the % error is 5% positive or negative I only adjust 1%.

I really need to pull this trans and overhaul it. Probably jinxing myself right now.

So the plan is to get down to a 3.2 pulley and 10ish lbs and i'll be happy if I can keep her together with that setup. Most of the time I stomp I only have enough room for 5k to 5500 rpm by my scans and I don't race or anything. Just a nice surprise when I put the pedal to the metal and hold me over until I can afford my CTS-V.

It's weird that I entered 11.0 in the Power Enrich Fuel Base vs. ECT table, but my commanded AFR in the scan is 11.1. This may be because I have the equivalence ratio commanded pid chosen and the math converts that to AFR.

I chose that because I have the wideband reading equivalence with the math converting the data to AFR so my AFR error math would work properly. Long winded. Hopefully some good info for a researcher.

Thanks 5FDP for the input. What do you think about the 3.2 pulley? I'll definitely be pushing my luck then. The heat index gets up to 120 in the summer so that will be trouble. Maybe I'll give in and get an intercooler after tax time. If there's still a US then.

[RoninDusette]

Based on what you were describing, I had an idea/suspicion, and I am pretty sure I have the solution... Your VE table is terrible. Like, really, really bad. If you look at the screenshots, the places where your IDC does like stepping thing (climbs a bit, stays flat, then climbs, then stays flat, etc) looks the same as where your kr is being graphed. Plus the HUGE rich spike when you let of the throttle... that shouldn't be happening. It seems at high RPM you are running like 16 degrees of advance while boosted, which isn't bad per se, but I cannot see your alcohol/eth % in your channels so idunno what percentage of ethanol you are running. That being said, looking at your VE table alone, that is where your problem is. At least that is what I am seeing is the issue. Your VE table should be tuned VERY well before doing anything related to WOT pulls, as it's going to throw everything off. It's the base upon which everything adds. My advice, for what it's worth cause what do I know, would be to set your ride to tune SD with your STFT WITH PE ON, but try to stay out of it and tune up to like 4k. Nice light driving. Do it over and over, all day if it takes, until it looks nice and smooth. I am telling you it wont seem like much when you first do it, but when I tune someone's car, one of the first things they notice is how smooth it runs before they get into the power, and that is because of taking the time to tune VE. Your timing and fueling all starts on a proper model of airflow, and that is what the VE table(s) is/are.

chart-knock.PNG
screwed-vve-knock.PNG
stftvve-knock.PNG

[lawrence.jerel90]

Back. Yes I do need to work on my VE table. I'm having trouble keeping the car out of closed loop. I disconnect the signal wire instead of unplugging the MAF so that hp tuners can calculate cylinder airmass and fill my knock retard map properly. I also set the closed loop enable temp to 283, but after the car warms up short and long term calculations come in. I have also tried setting PE to 0% TPS and setting the commanded afr to 14.7 and taking off the blower belt while driving under those conditions.

[lawrence.jerel90]

Also should I zero out all of the startup AFR correction tables? Tuning cold starts has been another pain in my ass.

[RoninDusette]

ok. So lets take this one step at a time.

To keep your car in open loop, set your o2 readiness voltage to the lowest it will go, and closed loop enable to as high as it will go, if you have those tables. And yes, I would set all of your fuel adders/multipliers/modifiers to 1.00 so that they just do what the VE table is doing and you target 1 lambda. Instead of unplugging your MAF at all, just set the maf fail high freq to 1. That way as soon as it start reading, it will throw an error and DTC, causing the car to fail into speed density. Also, not sure why you are worrying about MAF to do anything with the KR table. All you do is graph your KR and make the table just like the KR table in Editor, then just drive it. If you see KR in that table, then copy the whole table and paste special -> subtract to subtract that timing out of the KR table. It's very straightforward and as far as I know it has nothing to do with the cylinder airmass. Your VE table is the model of your cylinder airflow. You should modify this by logging in SD closed loop and use your STFT to get it done. It's generally accepted practice to do that and then tune WOT with your wideband.

DO NOT mess with the PE table or rape it like that. Set it to come in where you want it to come in, and set it to the afr you want it to hit. PE goes off of your VE table too. Whatever your car is commanding, it will try to reach PE on top of that. If it's off, your VE table is off.

If you want, I will modify your tune and post it here so that you can use it to tune properly for SD. Actually I am bored so I am going to do it anyway. Be back in a few with the one modified for SD closed loop and tuning your VE table. You NEED to do that before you tune anything else. Your VE table is the basis of most, if not all of your fueling.

[lawrence.jerel90]

The lean spikes when I let off the throttle are decel fuel cutoff I think. This model uses that for engine braking and I'm not sure there is a way to stop that. I shouldn't want to right? I just adjust my histograms to record data over 5% throttle. No alcohol channel. Just a 2007 Grand Prix supercharged and I just run good quality 93 nothing special. I'm writing a file with all start up afr adjustments turned off and air fuel aiming for 14.7. Taking the belt off for safety because there are a lot of steep hills. I'll post scans and tune files if the car keeps trying to go into closed loop to try and show what I'm talking about.

[lawrence.jerel90]

Because the MAF sensor has the intake air temp sensor in it and that is needed for the cylinder airmass calculation. It maps it against the spark table I took from the tune file so I can see where I'm getting KR and plot against a map that looks like my spark table. Thanks for taking the time to look through the file too!

[5FDP]

It's a MAF based computer. I've never tuned the VE on a 3800.

And that computer does not support flex fuel or an alcohol percent channel.

[lawrence.jerel90]

I just had a better idea actually. I can set commanded AFR to 14.7 and use the TPS fuel adder table to command 11.2 above 35% throttle. The transition will be a little difficult to tune, but I should be able to drive in open loop and tune cruising and boost safely.

[lawrence.jerel90]

Yeah what he said.

[RoninDusette]

oh ok. Well, I know the MAF has an air temp sensor. I was just saying to leave it plugged in and set the MAF to fail properly so that it will default to SD and not use the MAF to help calculate airflow. I am going to set it up in a minute for closed-loop speed density. Just waiting for my tuning laptop to charge a bit.

[RoninDusette]

ok. so I did see that you cannot set the MAF fail freq on this ecu, but the way it's set up, if you disconnect the MAF signal wire like you did, it will throw a DTC/CEL for the MAF, which should keep it out of the equation. In your logger, make a graph that mimics your VE table, and filter out anything under 5mph and under like 5% accel pedal position. This will help you not log when you are not actually using the pedal and when you are not moving or having no load on the engine. Then make sure to set minimum cell count to like 20 or 25 and in the cells of the graph log your STFT or LTFT. LTFT will take longer. Make sure to reset your fuel trims before each log. Go out and gently drive it, with no big pedal changes and try to keep out of WOT. Then once you have filled in as many cells as you can up to 4k, copy that and paste special -> multiply by % to your VE table. Do some basic smoothing. It doesn't have to be perfect, but a smooth table is ahappy table when it comes to how it drives. Keep doing that until your logging VE shows +/-5%ish. Again, doesn't have to be perfect, but it should mostly pe there. Then do some WOT pulls with a WB and log that to your VE graph instead of fuel trims. Then apply that to your VE table in the relevant areas. It takes a while, but it's very worth it. If it's streetable, I would just log every time you go to the store or for a short drive and a couple of days later it should be MUCH better. That should help a lot with your strange fueling. Then once you get that all set back up, open the stock file as a compare file, and set your fuel adders and other stuff back to where it should be.12-8-20 Lean dips and Knock_SD-CL-SETUP.hpt

[lawrence.jerel90]

I was waiting for you to come back and say you couldn't fail the MAF haha. I'll pull the signal wire and work on the speed density tuning in the morning and update the thread.

[RoninDusette]

Word. That was the first one of those ECMs that I have looked at. I am used to looking at the GEN V ones, like my e78, which has more tables than I care to every deal with, but are not so bad once you get the hang of it.