Steve's Megasquirt/tunerstudio Help Thread

Ok thanks. The stock o2 sensors are unplugged.

twohawks777@cox said:

Ok thanks. The stock o2 sensors are unplugged.

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When you get a chance, go to your tunerstudio projects folder (inside "my documents") and copy the whole project folder that you're using and zip up the copy, then send me that zip file so I can look at the whole project in context.

Looks like 5.0thunder has it covered for now just checking in been busy.

tag teeeaammmm

Ok

5.0Thunder said:

When you get a chance, go to your tunerstudio projects folder (inside "my documents") and copy the whole project folder that you're using and zip up the copy, then send me that zip file so I can look at the whole project in context.

Click to expand...

Receiving this error when I try to send file.
The following error occurred
Security error occurred. Please press back, refresh the page, and try again.

Cobra.zip
Can I email it to you?

twohawks777@cox said:

Ok


Receiving this error when I try to send file.
The following error occurred
Security error occurred. Please press back, refresh the page, and try again.

Cobra.zip
Can I email it to you?

Click to expand...

Of course.

problem I see..

Should be speed density and not %baro. This is a big deal, unless Steve intended this?

5.0Thunder said:

problem I see..

Should be speed density and not %baro. This is a big deal, unless Steve intended this?

Click to expand...

Yes intended, %baro works well in all installations besides turbo. It takes into account the baro pressure in the original fuel equation rather than an add on table, however a turbo adds ALOT of backpressure beyond atmospheric so the standard speed density equation must be used.

If this is a turbo car I must have missed the build sheet on ot.

May want to keep the exchange of email info to a private message. This is to protect your information. Thanks

5.0Thunder said:

problem I see..

Should be speed density and not %baro. This is a big deal, unless Steve intended this?

Click to expand...

See any issue with the wb setup? If not maybe the issue is with the programming of the wb itself. Maybe a over the phone walk thru of the wb setup is needed to straighten this out.

a91what said:

Yes intended, %baro works well in all installations besides turbo. It takes into account the baro pressure in the original fuel equation rather than an add on table, however a turbo adds ALOT of backpressure beyond atmospheric so the standard speed density equation must be used.

If this is a turbo car I must have missed the build sheet on ot.

Click to expand...

Ah, okay. Speed Density is the only thing I've seen used in these cars so far, thanks for verifying.

a91what said:

See any issue with the wb setup? If not maybe the issue is with the programming of the wb itself. Maybe a over the phone walk thru of the wb setup is needed to straighten this out.

Click to expand...

I didn't specifically see anything wrong with the WB setup. You can see in the calibrate AFR settings that he's got it set on 0-4 = 10-18 and as long as the wideband is set up similarly, it should be fine. I think either way, it shouldn't be flat-lining at 14.7AFR for such an extended period of time. I wonder if the sensor itself is having an issue.

Is this a used/old sensor @twohawks777@cox?

These are what my WB settings are on the programmable gauge are presently.
AFR: 14.7
ALT:10.0
DSP: HI 18.0 / LO:10.0
HTR: on
Sensor is at least seven yrs old , but car was not driven much. I am leaning towards the sensor. It never drops below 13.5 and never above 15.4 when pressing the accelerator.

That's the only thing I can think of at this point.

Well. I have tested this Wideband sensor several more times and it seems to be failing. It is not going to full lean when I open air test it and only It goes to 15.1. It only goes to 11.1 when you do a brake fluid on the rag test. It takes at least three minutes to do this. Just ordered a new sensor. I will reconvene when I have sorted this WB out. Thanks

Well sorry to hear about the bad sensor but hopefully it will fix the problem and we can move forward with the tuning.

Good to at least pinpoint the issue. These autometers are generally very easy to set up. You can get a good sensor for I think $45-$50 if you shop around (don't buy a knockoff).

Guys, this is killing me! I cannot figure out how to get the transient tables right.



From top to bottom, you have the top relatively steady yellow/orange line which is the commanded AFR. The other yellow line with repetitive twin-peaks" is the Actual AFR. The blue line is my TPS. the red "mountains" is the RPM graph, and the pink spikes line is the dMap Correction. Finally, barely visible above the windows toolbar is the accel pump correction.

First I spent a while with the "accel pump" transient table which only takes the tps into account. I would just tap the throttle repeatedly and then add to the accel pump cells I hit until the actual AFR never crossed the desired AFR. Once it seemed to stay on the rich side, I started playing with the "power valve" fuel table, which is the dMAP correction table.

This one of my final attempts. I went for broke and made the top of the dMap table 300%. I don't understand why it kicks in, richens the mixture and then cuts back out and goes lean again. I mean, this is so much extra fuel, I can hear the car stumble when I go heavy on tip in. It's killin me. Transient tables are a PITA. Worst tuning issue I've head. Everything I've read makes it seem easy, but it sure isn't to me.

Hmm... i will liken this to the MS version of accel enrichment.

I see the pumpshot happen and the dmap or powervalve fuel, but I do not see a maintained change in AFR.

Imho I would back off the dmap enrichment, how do you handle main wot enrichment? The ae should only cover transients.... Looks to me like you are relying on it for complete wot fuel.

I like to see a full point AFR drop when I mash the pedal and then I have it set to taper off, after that the main fuel table takes over for wot enrichment.

I assume the power valve or dmap setting is your wot enrichment?

Steve, insightful as always. Is it right to try to get that point drop out of that accel pump shot? Or, is it a combination of accel and dmap?

I honestly don't understand your first question. For "main WOT enrichment," I don't think you're asking about the main VE and AFR tables, but I'm not sure what you mean. So, I guess I'll run through the list. The BS3 uses the following transient tables and I'll include a snippet from the manual for each as well as my actual table (might need to go to the next post to get all of them):



1. Run time correction - only influences the Positive dMAP and dTPS Correction Values for a short period of time after the engine is running. (i.e. up to 8 minutes). So, that's not gonna help. Mine is zeroed out. Skipping the pic.

2. AE Position Correction: like a carburetor’s accelerator pump “cam” profile. modifies the size of the Asynchronous Pulse Width (APW) relative to the throttle position at which the dTPSdt event occurred. - My guess is that this reduces the pump shot when you're already at part throttle.



3. Accel Pump Shot. I think we're on the same page on this one already. Here's mine, after today. I may add some more now that I'll be looking for a 1 point drop:



4. Power valve fuel. I added a ton to this with 240 and 300. There's a maximum of 500, but at 300 it was like I took that back out when it only resulted in the twin-peaks thing you're seeing instead of a flat lean 15.9 AFR.



5. dMap RPM Modifier: modifies the dMAP correction based on RPM. The positive or negative percentage (%) is applied to the dMAP Correction table relative to the RPM. I've done nothing to modify this table from the way my other car was programmed. However, I did test pulling out the negatives just to see any observable difference. I didn't see one and put them back.



6. MAP AE Decay rate. determines the decrease to the Positive dMAP correction value after accelerating (throttle tip-in) the engine at a given coolant temperature. The ECU decrements the dMAP correction by the MAP AE Decay Rate. A MAP AE Decay Rate of 6 represents a decrease of the dMAP Correction by 6% every crank interrupt until it reaches zero. In other words, if you input the number 6 into the table, after 1 crank interrupt the dMAP Correction will decrease 6%. The 6% per interrupt continues until the dMAP correction reaches zero.

So, this may be helpful, because it could explain why you can see the correction and then it goes lean again. As I was playing around today, I went the wrong way! I went from 6 up to 20 thinking it took 20 rotations of the crank for each reduction of 1%. It's the other way around. 6% for every crank interrupt. I may reduce this to 1 and see if it keeps it richer. Still this isn't the end all, because it's going rich (edit: I meant lean) before the dMap correction.



7. Map AE Increase Rate: Same thing in reverse. Controls rate dMap fuel negative correction is added back in.



Sorry for the length of the post. If nothing else, rereading the manual helped me clarify the confusion on the decay rate table.

with incorrect corrections in these tables you should see....
A lean tip in that eventually tapers down to main fuel enrichment. Ie. You should start lean and then richen up, this is tuned SD correct? If so the 've table should take over fueling directly after the transient event (throttle increase).

-Your pumpshot setting is the same as a tps based enrichment, rule of thumb set this to twice your idle pw value for right off idle (left side of the table) and quadruple at the top (right side of table)

The rest of the settings look like map based acceleration enrichment settings, I don't even have these enabled in my tune file, after the tps based enrichment my 've table takes over for fuel. Usually I choose to use one type or the other to tune from (tps or map based ae) some setups work well with a blend of both although I have never tuned this way.

Now with all that said, you should still be able to get a maintained rich (or at AFR taeget) fuel with all of these turned off from the main fuel table.
These settings are to correct lean tip in only.