Steve's Megasquirt/tunerstudio Help Thread

a91what

I plan to eventually problem is time
Mod Dude
Apr 6, 2011
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I have a question in regards to the PWM idle valve (IAC). Can someone explain what increasing or decreasing the Valve Frequency does?

I have a weird issue that I have been chasing regarding idle. My idle control algorithm is set to Open-Loop, and with the tune being the same I get two different idle rpm of one being around 811 and the other 850 (these are averages over a few minutes) The AFR ratio is higher on the 811 rpm, which makes sense its getting less air and more fuel and the 850 rpm one is perfect. Of course, I am chasing the 850 rpm target as it gives a perfect smooth idle even with an E303 cam. The idle issue doesn't change during driving at all it stays the same the hole time. The idle s is a random idle issue too meaning that I can drive the car 3 times and the idle be at 811 and then the next time you drive the car its at 850.

Today I drove the car to work and it was perfect at 850, but yesterday it was at the 811. It is not due to headlights or voltage draw since both of those days where the same as well. This got me thinking that maybe its the valve frequency or the valve is going bad.

Any feedback would be great.
Pwm valve frequency is the Hz the valve will work at. I have found that in closed loop 279-311 Hz works well.
Typically the higher this is Set to the less precise the valve becomes, however at least my car the valve screams at lower Hz settings.

What are your mat temps on these different days? You could have ignition retard affecting idle speed. As little as .5* timing can lower and raise idle speed.
 
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stanglx2002

10 Year Member
Jul 7, 2005
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Pwm valve frequency is the Hz the valve will work at. I have found that in closed loop 279-311 Hz works well.
Typically the higher this is Set to the less precise the valve becomes, however at least my car the valve screams at lower Hz settings.

What are your mat temps on these different days? You could have ignition retard affecting idle speed. As little as .5* timing can lower and raise idle speed.
My temps are at 145-152 MAT, and I have the ignition set to 20*, and it doesn't change at all. I understand even a little amount of timing will mess with the idle.

I had the frequency set to 313Hz when trying to mess with CL, but just changed it yesterday to 92 Hz to see if this helps at all.

Edited:
All things stay the same:
- ignition
- fuel (VE)
- Idle PWM
 

a91what

I plan to eventually problem is time
Mod Dude
Apr 6, 2011
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Ok. I think I got it right if not please let me know what I am doing wrong. Thanks, My bad for the confusion. Newbie mistakes. lol
I'm not convinced that the WB is setup correctly OR maybe the WB upper range value is programmed wrong. I only say this because it looks as if 15ish AFR is the upper range value in the datalog. usually during a rev you will see lean spike somewhere, I don't see this in your log files. For some reason I cant convert the WB signal in to a raw voltage to double check on my end, can you get the part number off the WB or box for me so we can double check for you please. I jus want to ensure my tuning changes on this end are correct.

Until we figure that AFR issue out I richened the AFR table from 15.5 to 15 so the number are within the range I am able to see on this end. How is the car running so far?
 

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a91what

I plan to eventually problem is time
Mod Dude
Apr 6, 2011
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Hillsborough county
My temps are at 145-152 MAT, and I have the ignition set to 20*, and it doesn't change at all. I understand even a little amount of timing will mess with the idle.

I had the frequency set to 313Hz when trying to mess with CL, but just changed it yesterday to 92 Hz to see if this helps at all.

Edited:
All things stay the same:
- ignition
- fuel (VE)
- Idle PWM
Hmm weird I don't use open loop idle so I have not had this issue, I am jealous of your rock steady idle with the e303 cam however. with my very short port runner and non optimal injector angle [not to mention the reversion I get at idle] I get a nice idle between 875 and 925rpm
 

stanglx2002

10 Year Member
Jul 7, 2005
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Hmm weird I don't use open loop idle so I have not had this issue, I am jealous of your rock steady idle with the e303 cam however. with my very short port runner and non optimal injector angle [not to mention the reversion I get at idle] I get a nice idle between 875 and 925rpm
What do you have your AFR set with the E303 cam? I have found that it likes 13.4 with 20* of timing, and can it to go as low as 800ish steady idle

If you could think about any advice on the weirdness I am getting would be great. I will let you know if the frequency change helped or not.
 
Feb 6, 2012
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I'm not convinced that the WB is setup correctly OR maybe the WB upper range value is programmed wrong. I only say this because it looks as if 15ish AFR is the upper range value in the datalog. usually during a rev you will see lean spike somewhere, I don't see this in your log files. For some reason I cant convert the WB signal in to a raw voltage to double check on my end, can you get the part number off the WB or box for me so we can double check for you please. I jus want to ensure my tuning changes on this end are correct.

Until we figure that AFR issue out I richened the AFR table from 15.5 to 15 so the number are within the range I am able to see on this end. How is the car running so far?
2-1/16" WIDEBAND PRO AIR/FUEL RATIO, 6:1-20:1 AFR, PHANTOM

Product # 5778
Read more at https://www.autometer.com/2-1-16-wideband-a-f-w-sensor-phantom.html#yQ13pyobziYHc1CV.99

20180213_095021.jpg 20180213_095108.jpg 20180213_095145.jpg
I'm not convinced that the WB is setup correctly OR maybe the WB upper range value is programmed wrong. I only say this because it looks as if 15ish AFR is the upper range value in the datalog. usually during a rev you will see lean spike somewhere, I don't see this in your log files. For some reason I cant convert the WB signal in to a raw voltage to double check on my end, can you get the part number off the WB or box for me so we can double check for you please. I jus want to ensure my tuning changes on this end are correct.

Until we figure that AFR issue out I richened the AFR table from 15.5 to 15 so the number are within the range I am able to see on this end. How is the car running so far?
 

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a91what

I plan to eventually problem is time
Mod Dude
Apr 6, 2011
6,151
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Hillsborough county
What do you have your AFR set with the E303 cam? I have found that it likes 13.4 with 20* of timing, and can it to go as low as 800ish steady idle

If you could think about any advice on the weirdness I am getting would be great. I will let you know if the frequency change helped or not.
I idle around stoic 14.7 it is a fact that richening the idle will stabilize it but im stubborn and the leaner idle sounds amazing.

we can always try to set you up with closed loop idle.
 

a91what

I plan to eventually problem is time
Mod Dude
Apr 6, 2011
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Hillsborough county

stanglx2002

10 Year Member
Jul 7, 2005
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I idle around stoic 14.7 it is a fact that richening the idle will stabilize it but im stubborn and the leaner idle sounds amazing.

we can always try to set you up with closed loop idle.
We can't do CL with my car as I have tried for 6-months to get it to work. The issue is the AOD and how it activates. The warm-up setting works fantastic, and is super easy to maintain and setup
 

a91what

I plan to eventually problem is time
Mod Dude
Apr 6, 2011
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Hillsborough county
We can't do CL with my car as I have tried for 6-months to get it to work. The issue is the AOD and how it activates. The warm-up setting works fantastic, and is super easy to maintain and setup
I take it the car dies when you put it in gear? If that's the case then you can use the neutral safety switch input that's already in the computer Harness to tell The ECU when to add dashpot so the car stays at a steady idle when engaging the converter.

Pm me I can give you my # and walk you through the setup if you like but if open loop works well for you great. I have done many setups where this is the case.
 

stanglx2002

10 Year Member
Jul 7, 2005
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I take it the car dies when you put it in gear? If that's the case then you can use the neutral safety switch input that's already in the computer Harness to tell The ECU when to add dashpot so the car stays at a steady idle when engaging the converter.

Pm me I can give you my # and walk you through the setup if you like but if open loop works well for you great. I have done many setups where this is the case.
I may take you up on this when I put the new 4R70W transmission in the car. I was able to correct the dying when put into gear by increasing the "D" in the PID control, and increasing the throttle stop screw a little so you dont have to rely on the IAC.

I had a couple issues with CL:
1. Dying when going into reverse from drive (the neutral safety switch idea may fix this)
2. It activating PID at the wrong time (this is due to automatics lugging in low rpms making the computer think its idling and its not, so it actives dropping the duty below normal. When you get to idle the CL won't re-engage to bring the idle back up or dies)

#2 I may be able to increase the Load Threshold to right below in gear load rather than right below my out of gear. I was trying to get the idle at 850 for both in and out of gear situations. I don't think that is possible.
 
Feb 6, 2012
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according to the document the factory range is 0v=10afr 4v=20afr
you set yours to 0=10 and 4=18 did you go into the WB using the document page 4 BDG settings and rerange the WB???
according to the document the factory range is 0v=10afr 4v=20afr
you set yours to 0=10 and 4=18 did you go into the WB using the document page 4 BDG settings and rerange the WB???
To be clear are you refering to the acutal guage because you can only set BGD range setting mode hi to 19.7 or you refering to the AFR calabretion where you asked me to put 0=10 and 4=18?
 

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a91what

I plan to eventually problem is time
Mod Dude
Apr 6, 2011
6,151
3,673
204
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Hillsborough county
To be clear are you refering to the acutal guage because you can only set BGD range setting mode hi to 19.7 or you refering to the AFR calabretion where you asked me to put 0=10 and 4=18?
There are two of us whom have given information about the WB calibration and setup. I have always seen the gauge calibration and the tunerstudio calibration match, i believe somthing is amiss with the settings you have.
Since i am not the original adviser i will pass this back off to @5.0Thunder

I want to wait until this issue is resolved befrore moving forward
 
Feb 6, 2012
79
5
18
50
There are two of us whom have given information about the WB calibration and setup. I have always seen the gauge calibration and the tunerstudio calibration match, i believe somthing is amiss with the settings you have.
Since i am not the original adviser i will pass this back off to @5.0Thunder

I want to wait until this issue is resolved befrore moving forward
Ok thanks
 

stanglx2002

10 Year Member
Jul 7, 2005
551
240
84
There are two of us whom have given information about the WB calibration and setup. I have always seen the gauge calibration and the tunerstudio calibration match, i believe somthing is amiss with the settings you have.
Since i am not the original adviser i will pass this back off to @5.0Thunder

I want to wait until this issue is resolved befrore moving forward
@[email protected]

Here is the instruction manual I found for your WB: https://www.autometer.com/media/manual/2650-1143.pdf

Based on the brief review of the instructions it seems all the calibration is done within the gauge. What @a91what I believe is saying and I agree is that the wideband settings need to be the same from your gauge and TunerStudio for your readings to be correct.

Your gauge reads a 0-4V range and you set the low and high readings within the gauge.

Answer this two questions:

1. What is your low setting (aka 0V)?
2. What is your high setting (aka 4V)?
 
Feb 6, 2012
79
5
18
50
@[email protected]

Here is the instruction manual I found for your WB: https://www.autometer.com/media/manual/2650-1143.pdf

Based on the brief review of the instructions it seems all the calibration is done within the gauge. What @a91what I believe is saying and I agree is that the wideband settings need to be the same from your gauge and TunerStudio for your readings to be correct.

Your gauge reads a 0-4V range and you set the low and high readings within the gauge.

Answer this two questions:

1. What is your low setting (aka 0V)? low is 10
2. What is your high setting (aka 4V)?
hi is 18
On the gauge BGD range setting mode, Lo goes from 9.9 - 14.8
Hi goes from14.9 - 19.7
 

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a91what

I plan to eventually problem is time
Mod Dude
Apr 6, 2011
6,151
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Hillsborough county
No problem, maybe there is no issue.... twohawks what does your WB report when the car is idling? maybe your wb has a smoothing function i am not aware of on my end. as long as what i see in the datalog matches what you have on the gauge we are good to go.

basically the reading never goes above about 15.2 and never below 14.3ish. Thanks if this is found to be true then i can redo the tune real quick and we can move on.

How is the car responding to the tune files i am sending you? I need some human feedback from time to time. sensors only tell me so much