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Did Some Data Logging with TunerPro R/T

1-ton said:
I have an adjustable fuel pressure regulator that is currently set at 13-PSI. Do you think I should lower it?
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The answer to that question is why you are data logging. Based on the limited info you provided, if does look like you are universally rich. You could try backing it off a bit and then see how your data log looks. Drop 1/2 lb and see if your 105s become 115s...
Word of caution: you don’t want to ever run too lean at high loads - you can burn out your motor doing that.
To really do what you are trying to do, you should have a wide band 02 sensor and chip program capabilities.

Do you have a chip burner /are you going to be able to program your own ECM chips? If not, then fuel pressure may be one of the limited tools you have to make adjustments.
 
Keitha said:
The answer to that question is why you are data logging. Based on the limited info you provided, if does look like you are universally rich. You could try backing it off a bit and then see how your data log looks. Drop 1/2 lb and see if your 105s become 115s...
Word of caution: you don’t want to ever run too lean at high loads - you can burn out your motor doing that.
To really do what you are trying to do, you should have a wide band 02 sensor and chip program capabilities.

Do you have a chip burner /are you going to be able to program your own ECM chips? If not, then fuel pressure may be one of the limited tools you have to make adjustments.
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I am doing some data logging just to learn how to use TunerPro. I also wanted to see if my new crate engine is running at least half way decent. I am not having any problems with my engine. It seems to run just fine. I would like to get a chip burned for it some time. I may have somebody else do it because the equipment is expensive, and since my engine is only a daily driver engine I do not plan on doing a whole lot of tuning for perfection. Doing some data logging will help for having some info on how the engine is running if I have somebody else burn a chip for it.

I figured the fuel pressure was limited on any effect on any effect on my engine. No matter what the fuel pressure is the ECM will just re-learn and adjust the duty cycle.
 
1-ton said:
Yes, I found "History Tables" over the weekend, and did some data logging with it. It looks like you cannot save History Tables when done with data logging. It looks like the only way to save History Tables is to do a screen shot, and then paste it to Word Pad or something like it. Then save that as a file. It also looks like History Table only shows the highest and lowest BLM's, which allows the mathematical equation you already did . It also has a History Tables that shows the BLM average.
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Just take a picture with your phone and post it here with the “average” set. It can filter highs and lows or average. You don’t need to care about anything other than average if you’re just getting started.
 
bp71k5 said:
Just take a picture with your phone and post it here with the “average” set. It can filter highs and lows or average. You don’t need to care about anything other than average if you’re just getting started.
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I figured the BLM "Average" table would be the most useful. I will try to get around to that sometime this week.
 
1-ton said:
I figured the fuel pressure was limited on any effect on any effect on my engine. No matter what the fuel pressure is the ECM will just re-learn and adjust the duty cycle.
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Not really. Since the O2 isn't used on a cold engine (not that important) or under WOT (very important) the ECM can only adjust fuel based on O2 *inside* of those parameters, essentially when engine load isn't high.

There is a setting within the PROM for what the lb/hr is for the injectors. When you change fuel pressure, you change the effective lb/hr of the injector. The amount of adjustment the ECM is capable of, is limited. Generally that is why tuning is important if changing the fuel pressure...even under WOT that lb/hr information is used to calculate fueling. And since the O2 isn't doing anything, the adjustments based on load are only as good as the programming in the PROM.
 
dyeager535 said:
Not really. Since the O2 isn't used on a cold engine (not that important) or under WOT (very important) the ECM can only adjust fuel based on O2 *inside* of those parameters, essentially when engine load isn't high.

There is a setting within the PROM for what the lb/hr is for the injectors. When you change fuel pressure, you change the effective lb/hr of the injector. The amount of adjustment the ECM is capable of, is limited. Generally that is why tuning is important if changing the fuel pressure...even under WOT that lb/hr information is used to calculate fueling. And since the O2 isn't doing anything, the adjustments based on load are only as good as the programming in the PROM.
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Since I do not do a lot of driving at WOT, or in open loop I will be doing 90% of my driving inside the parameters you mentioned. The O2 will be sending info that the ECM will use to adjust injector pulse width.
 
I say WOT, it's not really WOT. All the PROMs have their own parameters to invoke open loop. If you've ever put a vacuum gauge on an engine, you can liken open loop to being some of the time the vacuum dropped during driving.

Yes, any adjustments like turning egr off, would be done with PROM tuning/burning.
 
1-ton said:
Since I do not do a lot of driving at WOT, or in open loop I will be doing 90% of my driving inside the parameters you mentioned. The O2 will be sending info that the ECM will use to adjust injector pulse width.
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I’ll tell you that you need the open loop parameters to be fairly close, otherwise it throws everything else off. The computer adjust the fuel up or down from the “default” values and uses the default values as-is for open loop.
 
bp71k5 said:
I’ll tell you that you need the open loop parameters to be fairly close, otherwise it throws everything else off. The computer adjust the fuel up or down from the “default” values and uses the default values as-is for open loop.
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I have read that the "open loop" tune is important, but I did not understand exactly why. Now I understand why.
 
One question I have about getting open loop data is do I need the open loop info when the truck is cold and warming up, or the open loop info after the truck is warmed up and idling in open loop?
 
1-ton said:
One question I have about getting open loop data is do I need the open loop info when the truck is cold and warming up, or the open loop info after the truck is warmed up and idling in open loop?
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You can’t really get any useful open loop data with the stock narrow band O2 sensor. What you should do is tune so the closed loop BLM cells are all close to 128. A BLM of 128 means no computer fueling adjustment is needed for that cell because the default values are close enough. “Open loop” is just a mode where the computer ignores the O2 sensor and doesn’t make ANY adjustments to the fuel table but instead just uses all default values.
 
I did some data logging with "History Table". This is just a 15-minute cruse up the freeway. The BLM's are maxed out on average, and It looks to be fighting a constant rich condition.
 
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Drop it as Keith suggested.

Honestly, having theoretically increased airflow on an otherwise stock engine and tune, you should be lean, not rich.
 
dyeager535 said:
Drop it as Keith suggested.

Honestly, having theoretically increased airflow on an otherwise stock engine and tune, you should be lean, not rich.
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How much do you think I should lower it to (maybe 11-PSI). The fuel pressure stock was 9-PSI. This engine also has a slightly bigger cam in it introducing more fuel into it that the stock one did.
 
GM spec is 9-13PSI. Those that have more experience than I have said that 9 is way low. In any case, I'd suggest what Keith said above, half a PSI, and immediately take an easy, short drive on flat ground with the engine up to temp. See if the numbers have come up.

Listen for pinging, and I'd check the datalog before/after for knock counts as well. SHOULDN'T be an issue, but it's prudent to watch any time you pull fuel. Pinging starts before you can hear it, so the datalog can show pinging without you hearing it.

If you can see the datalog, pick a turnaround spot, check the log, and decide what to do based on what you are seeing, then test any changes you make on the way back. Just make sure to save and label each datalog, in your case may be a good idea to label each log with the PSI used for that run.

Can't watch the video, but what's the O2 doing under full throttle? While the narrowbands are near useless for tuning, if it goes rich, and stays rich while under heavy throttle, it's likely you aren't going to introduce an issue by leaning out the fuel pressure a bit at a time. The ECM isn't using the O2 under those conditions, but the mV from the O2 is still valid for you to look at.
 
dyeager535 said:
Listen for pinging, and I'd check the datalog before/after for knock counts as well. SHOULDN'T be an issue, but it's prudent to watch any time you pull fuel. Pinging starts before you can hear it, so the datalog can show pinging without you hearing it.
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The knock count is only about 10 at WOT.

dyeager535 said:
O2 doing under full throttle?
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It is showing about 950 mV mostly steady at WOT. It flashes back and forth betweem 50 mV and 950 mV at light throttle. I have a 4-wire O2 sensor that appears from the data logging to be going into Closed Loop and Open Loop at the proper times.
 
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