datamaster values
- Thread starter unluckyty
- Start date
02 millivolt readings
at startup - should be rich/slightly rich (02 is not warmed up, but warms up quickly, and engine needs to be rich at start/warmup)
at idle/cruise once warmed up, you will see 02 values flicker all over, crosscounting across 450mv.
at WOT/full boost, you should see them in the 900-1000 range. I've seen them in the 800s, but for the *most* part, 900s is safe. You need to watch your truck and apply other tuning skills to find out what works best for your truck
Knock retard - want to see zero, but hardly any trucks see this. A couple degrees during shifts is normal, but ideal is zero, again.
Integrator
128 is neutral (zero), this will change on the fly a lot once the truck is warmed up and in closed loop. I'd say the normal range is 100-140. Datamaster gives you the option of using S terms (short term fueling trim). 128 is zero, 141 is 10% richer, 115 is 10% leaner, for reference. Crosscounts or xcounts is a running counter of the number of times the 02 readings have crossed 450, going lean, or going rich. This number will overflow at 255 and begin again. At closed loop, this value should be moving pretty fast. It is a good indication of how well your closed loop system is working (or not).
BLM - Block Learn Memory
This value is an attempt by the computer to try to adjust for long term fueling adjustments, due to engine wear, or anything that may change the fuel needs of the motor. We have only 2 cells in our trucks, open or closed throttle. So you may see your values change when you open or close your throttle. 128 is neutral, once again. I'd say you have some issues that need looking at if you are outside the window of 115-140.
Timing - you will see 20-30 at idle/cruise, and should see 12-15 at WOT/full boost. Racier chips will push the timing values at WOT to 17-19 possibly.
Wastegate duty cycle -
100% is the solenoid is fully closed, 0% is fully open. Think of it this way, at 100%, the ECM is desiring more boost, at 0% the ECM is desiring less boost.
AFR target is NOT an air fuel reading. It is a programmed value in the ECM for a fueling multiplier. So at start/warmup, you will see richer AFRs until it is warmed up, when you will see it go to 14.7. Once you go into Power Enrichment mode (you floor it), the AFR will go richer, to 11-12:1 ratios, depending on chip programming, and based off of RPM.
IA temp /MAT
20-40 degrees above ambient are typical. You can watch this value increase with heat soak, or if an intercooler pump is dead. EGR will raise air temps as well, usually 40-60 degrees above ambient.
EGR stuff -
EGR duty cycle will kick in during light cruise conditions, unless it is disabled in the chip, or not enabled due to other conditions.
IAC - 10-30 at idle is about normal. Adjusting the throttle stop can manipulate this value, as you are creating a slight vacuum leak.
Battery voltage - 13s are good, at WOT is very important, 13.4+ being very good at WOT. This will have huge effects on performance.
I believe these to be the most important ones.
Watch when trouble spots are occurring, during WOT, during shifts (graph RPM vs MPH), at boost spikes, at knock, at lean spots (02s dip horrendously). Finding correlations is a start for identifying problems, but be sure it is a cause and not a symptom. (I have low 02s because I have lots of knock...) Watch the changes you can make on a datalogger with actual changes to the truck. Make performance logs to document what helped or hurt. Take notes so you learn from your experience and can share, or at least know your truck better.
Brian G
at startup - should be rich/slightly rich (02 is not warmed up, but warms up quickly, and engine needs to be rich at start/warmup)
at idle/cruise once warmed up, you will see 02 values flicker all over, crosscounting across 450mv.
at WOT/full boost, you should see them in the 900-1000 range. I've seen them in the 800s, but for the *most* part, 900s is safe. You need to watch your truck and apply other tuning skills to find out what works best for your truck
Knock retard - want to see zero, but hardly any trucks see this. A couple degrees during shifts is normal, but ideal is zero, again.
Integrator
128 is neutral (zero), this will change on the fly a lot once the truck is warmed up and in closed loop. I'd say the normal range is 100-140. Datamaster gives you the option of using S terms (short term fueling trim). 128 is zero, 141 is 10% richer, 115 is 10% leaner, for reference. Crosscounts or xcounts is a running counter of the number of times the 02 readings have crossed 450, going lean, or going rich. This number will overflow at 255 and begin again. At closed loop, this value should be moving pretty fast. It is a good indication of how well your closed loop system is working (or not).
BLM - Block Learn Memory
This value is an attempt by the computer to try to adjust for long term fueling adjustments, due to engine wear, or anything that may change the fuel needs of the motor. We have only 2 cells in our trucks, open or closed throttle. So you may see your values change when you open or close your throttle. 128 is neutral, once again. I'd say you have some issues that need looking at if you are outside the window of 115-140.
Timing - you will see 20-30 at idle/cruise, and should see 12-15 at WOT/full boost. Racier chips will push the timing values at WOT to 17-19 possibly.
Wastegate duty cycle -
100% is the solenoid is fully closed, 0% is fully open. Think of it this way, at 100%, the ECM is desiring more boost, at 0% the ECM is desiring less boost.
AFR target is NOT an air fuel reading. It is a programmed value in the ECM for a fueling multiplier. So at start/warmup, you will see richer AFRs until it is warmed up, when you will see it go to 14.7. Once you go into Power Enrichment mode (you floor it), the AFR will go richer, to 11-12:1 ratios, depending on chip programming, and based off of RPM.
IA temp /MAT
20-40 degrees above ambient are typical. You can watch this value increase with heat soak, or if an intercooler pump is dead. EGR will raise air temps as well, usually 40-60 degrees above ambient.
EGR stuff -
EGR duty cycle will kick in during light cruise conditions, unless it is disabled in the chip, or not enabled due to other conditions.
IAC - 10-30 at idle is about normal. Adjusting the throttle stop can manipulate this value, as you are creating a slight vacuum leak.
Battery voltage - 13s are good, at WOT is very important, 13.4+ being very good at WOT. This will have huge effects on performance.
I believe these to be the most important ones.
Watch when trouble spots are occurring, during WOT, during shifts (graph RPM vs MPH), at boost spikes, at knock, at lean spots (02s dip horrendously). Finding correlations is a start for identifying problems, but be sure it is a cause and not a symptom. (I have low 02s because I have lots of knock...) Watch the changes you can make on a datalogger with actual changes to the truck. Make performance logs to document what helped or hurt. Take notes so you learn from your experience and can share, or at least know your truck better.
Brian G
Tooky
Serious about performance
If it is not 13.4 at WOT, what can be done to remedy it? If there was a low voltage issue at WOT, how might it manifest itself? Also do you know any trucks I can check (in a boneyard perhaps) to swap alternator pulleys with, because I want to verify if mine is the correct stock diameter or if it is an underdrive pulley. My voltage drops to like 11.5 at idle and my headlights get dim. Thank you.
New alternator, alternator mods, overdrive alternator pulley.
Check to see that Datamaster is reporting correct voltages, using a voltmeter. If not, try a different ECM.
Clean up all grounds & refasten, possibly installing new grounds.
If you go low at idle, chances are you are very low at WOT.
BG
Check to see that Datamaster is reporting correct voltages, using a voltmeter. If not, try a different ECM.
Clean up all grounds & refasten, possibly installing new grounds.
If you go low at idle, chances are you are very low at WOT.
BG
Daron
Active member
I am not as bright as BG, but I have some thoughts on the O2 in our application. Go with what your plugs are telling you. Your experience with the O2 is why associating a numerical value with the proper operation of the O2 can be confusing. The job of the O2 is to cycle from rich to lean, and do it rapidly. The high number you see has little to do with actual A/F ratio, but is likely an indicator that it is old. My original O2 ( 80,000 mile) used to read over 1000 mv at WOT no matter what I did. The cross counts were a little slower than other O2's but not bad enough to set a code. I eventually replaced it, and my new O2 read in the low 900's at WOT with no other changes to the truck.
This is what I wrote a while back, about what I use O2's for:
"As o2 volts go, I don't look for a specific number, I look for a "trend" of sorts. For instance, if my truck starts knocking at 3500 rpm, at a certain boost, and my O2 takes a dive from its normal WOT state, and a fresh plug check shows real knock has occurred, I may consider looking into a fuel related issue. "
Just my 2 cents, I am positive Brian can explain it better than I can though.
_________________
Daron
1992 Typhoon Blue/Gray
1991 Syclone Best 1/4 12.42 @ 106.1
Member Of Freakin' Ohio (MOFO) SyTy
<font size=-1>[ This Message was edited by: Daron on 2001-11-26 12:14 ]</font>
This is what I wrote a while back, about what I use O2's for:
"As o2 volts go, I don't look for a specific number, I look for a "trend" of sorts. For instance, if my truck starts knocking at 3500 rpm, at a certain boost, and my O2 takes a dive from its normal WOT state, and a fresh plug check shows real knock has occurred, I may consider looking into a fuel related issue. "
Just my 2 cents, I am positive Brian can explain it better than I can though.
_________________
Daron
1992 Typhoon Blue/Gray
1991 Syclone Best 1/4 12.42 @ 106.1
Member Of Freakin' Ohio (MOFO) SyTy
<font size=-1>[ This Message was edited by: Daron on 2001-11-26 12:14 ]</font>
Tooky
Serious about performance
If anyone gets a chance under their hood, could they do me a favor and measure your alternator pulley (if you have a stock one?) I just went out and measured mine, it is exactly 3" in diameter from the outside edges. Thanks in advance.
PS: I am hoping yours is significantly smaller than mine cause then I am just a pulley away from some type of improvement! :smile:
PS: I am hoping yours is significantly smaller than mine cause then I am just a pulley away from some type of improvement! :smile:
unluckyty
Member
Thanks Brian, my #'s all fall within the ones you stated. The ty is running great!! Just was worried about the injector DC going over 80%, datamaster doesn't show a lean condition at WOT.
Tooky, my alternator is 2 1/2", to outside edges.
Once again, thanks to all on the board that have helped, so new G-tech pro #'s for ty2216
0-60 in 4.9
1/4 in 13.74@100
Tooky, my alternator is 2 1/2", to outside edges.
Once again, thanks to all on the board that have helped, so new G-tech pro #'s for ty2216
0-60 in 4.9
1/4 in 13.74@100
Methuselah
New member
Brian,
Is it possible for you or someone you know to make a FAQ out of this. A Datamaster reference on Sportmachines.com or something along those lines?
Thanks.
________
Pissing Movies
Is it possible for you or someone you know to make a FAQ out of this. A Datamaster reference on Sportmachines.com or something along those lines?
Thanks.
________
Pissing Movies
Last edited:
Tooky
Serious about performance
Joe I don't really know for sure but here is what I have concluded from observation.. it seems to increase by 1 every time your knock retard goes over a certain threshold, let's say it is 5 degrees. So if your Datamaster data frames read like this "0.0, 1.2, 3.4, 5.5, 2.0, 6.7, 0.0" then it might increase 2 knock counts (because of the 5.5 and 6.7). But like I said, I'm not sure and it doesn't seem real consistent. I have seen some knock like 8 or 10 and it doesn't increase a knock count. But I have also seen when 2 or 3 degrees of knock can increase the knock count by 1. Strange.