93 5.0 Microsquirt with Stage 3 trickflow tuning issues

marxpreston11 · Jun 22, 2026

I have been fighting the tuning battle with this car for too long. Any help would be great. I believe all of my ignition settings are correct. My idle is awful and I really think I got a awful tune from the microsquirt factory. I got it to idle great for awhile at one point but the car would not drive at all wihout intake backfiring. My AFR seems to be all over the place. I cant get timing stable. I really dont have the money to pay someone online 500 dollars to tune it. Car hasnt been running in a few years. THe car has a stage three trickflow. Attached is the data log of the car running when at operating temps. As well as my piss poor tune that I have loaded onto it. Thanks again

Mustang5L5 · Jun 22, 2026

Can't open tune yet on this PC so will need to look later.

What size injectors are you running?

marxpreston11 · Jun 22, 2026

Mustang5L5 said:
Can't open tune yet on this PC so will need to look later.

What size injectors are you running?

I'm running 24lb injectors with a matching MAF

Mustang5L5 · Jun 22, 2026

Tune is a mess. The AFR table it too lean, and your VE table is not smooth. You have high numbers next to low numbers. That's going to swing your AFR wildly. You also do not have EGO correction turned on, so the EGO won't make any adjustments.

I made some changes. I added a bunch of fuel and tried to smooth it out a bit. Also, richened up your AFR table as it was way too lean. Also fattened up your warmup-enrichment, and your after start enrichment. Turned on your EGO correction to 10% starting at Coolant temp 170 degrees.

I can't tell if this will work for you but it should be a bit richer and smoother. You are going to have to adjust the VE cells where your engine idles at (once it's fully warmed up). Basically if your idle is hunting you want to raise and lower the VE numbers a tad to try and smooth that out. You might have to play a bit with what AFR it likes to idle at. For example, i idle my engine at 14.0 and play with the VE cells to keep it smooth right around that AFR. Any leaner and it makes it unstable. If your cam is pretty rowdy you will likely need it a bit richer at idle as well.

But you are going to need to find a tuner, or need to really know how to make adjustments. DO you have the paid version of TS with VE analyze? Once you get the idle set you will want to tune your WUE and then start to drive around and make adjustments to the VE table.

There's a lot of other stuff to go through as well. I'm not a tuner, so I didn't spend a whole lot of time refining this as i couldn't really check your log file. For some reason you don't have AFR as a logged profile and I can't seem to see why? I have MS3, so there are some differences with what i'm used to vs megasquirt.

You can do a "compare tunes" and see the changes i made and compare to your tune. I just drafted up that VE table based on some educated guesses, but it won't be perfect, so don't fire it up and start romping on it. It will need work

marxpreston11 · Jun 22, 2026

Mustang5L5 said:
Tune is a mess. The AFR table it too lean, and your VE table is not smooth. You have high numbers next to low numbers. That's going to swing your AFR wildly. You also do not have EGO correction turned on, so the EGO won't make any adjustments.

I made some changes. I added a bunch of fuel and tried to smooth it out a bit. Also, richened up your AFR table as it was way too lean. Also fattened up your warmup-enrichment, and your after start enrichment. Turned on your EGO correction to 10% starting at Coolant temp 170 degrees.

I can't tell if this will work for you but it should be a bit richer and smoother. You are going to have to adjust the VE cells where your engine idles at (once it's fully warmed up). Basically if your idle is hunting you want to raise and lower the VE numbers a tad to try and smooth that out. You might have to play a bit with what AFR it likes to idle at. For example, i idle my engine at 14.0 and play with the VE cells to keep it smooth right around that AFR. Any leaner and it makes it unstable. If your cam is pretty rowdy you will likely need it a bit richer at idle as well.

But you are going to need to find a tuner, or need to really know how to make adjustments. DO you have the paid version of TS with VE analyze? Once you get the idle set you will want to tune your WUE and then start to drive around and make adjustments to the VE table.

There's a lot of other stuff to go through as well. I'm not a tuner, so I didn't spend a whole lot of time refining this as i couldn't really check your log file. For some reason you don't have AFR as a logged profile and I can't seem to see why? I have MS3, so there are some differences with what i'm used to vs megasquirt.

You can do a "compare tunes" and see the changes i made and compare to your tune. I just drafted up that VE table based on some educated guesses, but it won't be perfect, so don't fire it up and start romping on it. It will need work

I will definitely load the tune it there. Yes I do have the paid studio version so I will see what auto tune does for me.

I was told by a few people to turn it off to try and fix something I can't remember. But they wanted me to turn it off until I fixed the ignition I think actually. Must not have turned it back on.

I will let you know and thank you very much for the help, I'll be putting tune in the second I get home.

marxpreston11 · Jun 22, 2026

Mustang5L5 said:
Tune is a mess. The AFR table it too lean, and your VE table is not smooth. You have high numbers next to low numbers. That's going to swing your AFR wildly. You also do not have EGO correction turned on, so the EGO won't make any adjustments.

I made some changes. I added a bunch of fuel and tried to smooth it out a bit. Also, richened up your AFR table as it was way too lean. Also fattened up your warmup-enrichment, and your after start enrichment. Turned on your EGO correction to 10% starting at Coolant temp 170 degrees.

I can't tell if this will work for you but it should be a bit richer and smoother. You are going to have to adjust the VE cells where your engine idles at (once it's fully warmed up). Basically if your idle is hunting you want to raise and lower the VE numbers a tad to try and smooth that out. You might have to play a bit with what AFR it likes to idle at. For example, i idle my engine at 14.0 and play with the VE cells to keep it smooth right around that AFR. Any leaner and it makes it unstable. If your cam is pretty rowdy you will likely need it a bit richer at idle as well.

But you are going to need to find a tuner, or need to really know how to make adjustments. DO you have the paid version of TS with VE analyze? Once you get the idle set you will want to tune your WUE and then start to drive around and make adjustments to the VE table.

There's a lot of other stuff to go through as well. I'm not a tuner, so I didn't spend a whole lot of time refining this as i couldn't really check your log file. For some reason you don't have AFR as a logged profile and I can't seem to see why? I have MS3, so there are some differences with what i'm used to vs megasquirt.

You can do a "compare tunes" and see the changes i made and compare to your tune. I just drafted up that VE table based on some educated guesses, but it won't be perfect, so don't fire it up and start romping on it. It will need work

I just loaded in the tune and fired it up, letting it warm up to temps. how long should i let it idle with the ego control making adjustments before making any of my own? It idles way smoother thats for sure, still a tad rich around 11.5 to 12 with a 13.8 target.

Mustang5L5 · Jun 22, 2026

Warmup will be rich. Probably will be around 12.0 when it first fires, but as warmup enrichment tapers off, you should start to get to 13.0-13.5 AFR as you approach 180 degrees. I had to guess a little so I purposely went rich. You’ll prob need to take out some fuel

I set the o2 correction to only start at 170
Degrees.

But if you are at 180 degrees and still
Under that AFR target, go into your VE table and find the cells you are idling at and pull a tiny bit of fuel out and let it settle. Remember your starting point in case you need to go back. But don’t change anything under 180 otherwise you are fighting the warmup enrichment adder as well

Once you get a stable idle, with the engine warmed up go into the auto tune and have it adjust all cells except idle. There is a way to LOCK your idle cells so it is not making changes to those and screwing up your idle. I just usually say no changed under 1500rpm and 180
Degrees. Then drive around easily and let it adjust the cells

It won’t get it perfect but it will get you close.

I did not touch your timing table. I think that could be adjusted as well. A little less timing near idle.

You might have to change the AFR target at idle. Batch fire setups tend to like mid 13s AFR. I did 13.8 but if it starts to get a bit unstable might have to shoot for 13.5 at idle.

marxpreston11 · Jun 22, 2026

Ok, wife called me inside... I'll message around more tomorrow, do you have any idea how the best way to make sure my throttle blade is set correct?

I had target idle at 850 and it was in the 1000s. I didn't really want to mess with the fuel table with the idle being that high.

I set base timing, have the offset set correct and verified with timing light. I slightly backed out the screw on the throttle adjustment, and it died.

Mind you I have the stock ecu and it idles perfect and sounds amazing right around 750-800.

Thanks

Mustang5L5 · Jun 23, 2026

You have your closed loop idle RPM set for 1200-1100 at startup, and to come down to 875 by 140 degrees. So if you want to make changes to your idle RPM, this is the menu to do it from. But from what I see 875 is your target RPM over 140 degrees coolant temp.

Since you moved your throttle blade, you'll want to recalibrate your TPS again

There are other factors that come into play here as well like idle advance settings, but you had yours turn off.

What is the RPM once warmed up?

marxpreston11 · Jun 23, 2026

Mustang5L5 said:
You have your closed loop idle RPM set for 1200-1100 at startup, and to come down to 875 by 140 degrees. So if you want to make changes to your idle RPM, this is the menu to do it from. But from what I see 875 is your target RPM over 140 degrees coolant temp.

Since you moved your throttle blade, you'll want to recalibrate your TPS again

There are other factors that come into play here as well like idle advance settings, but you had yours turn off.

What is the RPM once warmed up?

Idle once it was fully warm was still around 1000-1100. It did not want to drop. I did changed the throttle blade set screw and recalibrate the tps at idle and full throttle.

Mustang5L5 · Jun 23, 2026

What was your AFR when it was idling high? If rich, you can try pulling some fuel out and that might lower your idle a bit.

If the AFR is close to target, pull a little timing out from those cells and see if that makes a difference. I saw you were at 22 degrees? Try 20 degrees or 18 degrees

Just keep in mind until you adjust the above curve, your warmed up target is 875

marxpreston11 · Jun 23, 2026

Mustang5L5 said:
What was your AFR when it was idling high? If rich, you can try pulling some fuel out and that might lower your idle a bit.

If the AFR is close to target, pull a little timing out from those cells and see if that makes a difference. I saw you were at 22 degrees? Try 20 degrees or 18 degrees

Just keep in mind until you adjust the above curve, your warmed up target is 875

Afr was around 12 with target of 13.8. Timing was at 22. I was just worried about adjusting the fuel with it being so high at idle.

Would you recommend putting stock ecu in and getting the throttle blade set perfect and getting it to idle perfectly, then putting the microsquirt back in and then changing fuel?

marxpreston11 · Jun 23, 2026

Mustang5L5 said:
What was your AFR when it was idling high? If rich, you can try pulling some fuel out and that might lower your idle a bit.

If the AFR is close to target, pull a little timing out from those cells and see if that makes a difference. I saw you were at 22 degrees? Try 20 degrees or 18 degrees

Just keep in mind until you adjust the above curve, your warmed up target is 875

I bumped spark to 20 then to 18 like u said, helped alot. its idle is alot lower, still surges just a little nut not nearly as bad. My ve table i only adjusted the cells that it idles in. Now there is a steep jump from 40s, to high 60s. I still have not taken it for a drive. just wondering what you think. here is my data log and my tune file as it stands. Also, I will compensate you for this good sir. PM me and we can talk more

Also, I will add. The start up hot and cold is pretty rough, bounces on the starter a little. Then stumbles and runs for a few seconds then the idle picks up.

Mustang5L5 · Jun 23, 2026

Oh i'm not a tuner. I know enough to be dangerous but that's about it. Not sure how much more help i'll be here.

For some reason your datalogs are missing a lot of info when I view them. For instance i cannot see your AFR. I dpn't even see it as an option under your datalog logging profiles. For that reason i'm having trouble looking at your logs to suggest a next action

That's a pretty choppy cam if your idle kpa is in the 60-70kpa range. Pretty low vacuum. That might present some challenges in turning your idle. You might want to change your AFR target to 13.5-13.7 and see if that helps stablize it a bit. You might also need a little more timing in those cells

One thing else to check is your AFR target cells. SInce this is what you are modifying for idle you might be fighting yourself and EGO correction trying ot hit these target. You might have to blend this all in to something like 13.5 and play with your VE cells to see if that results in a more stable idle. I know this is what I gave you, but i was basing it on an idle kpa in the 45kpa range. SInce your idle KPA is higher, need to pull those cells up but also modify them for a more appropriate AFR target. Your cam probably doesn't like 14.1 it might need 13.5

Mustang5L5 · Jun 23, 2026

Try this. Made some adjustments to your AFR table and VE table based on what kpa you idle at.

I still can't see your datalogs however. Not sure if that's a me problem so if someone else on the forum can check.

marxpreston11 · Jun 23, 2026

Mustang5L5 said:
Try this. Made some adjustments to your AFR table and VE table based on what kpa you idle at.

I still can't see your datalogs however. Not sure if that's a me problem so if someone else on the forum can check.

Ill put that in and let you know, yea not sure why it's not showing afr. I have it selected in the log parameters.

Any suggestions to get more hits on this for more help?

marxpreston11 · Jun 23, 2026

Mustang5L5 said:
Try this. Made some adjustments to your AFR table and VE table based on what kpa you idle at.

I still can't see your datalogs however. Not sure if that's a me problem so if someone else on the forum can check.

Ok, so i found out why you couldnt view it, The project was set to narrow band and not wide band.... see if you can view this one?

It idles alot better. It still has random surges at times, not sure whats happening there.

Mustang5L5 · Jun 23, 2026

I see it now.

Looks like your idle surges in time with some instances when you go a little rich. Your average AFR is 13.4 but commanding 13.5/13/6 which isn't bad. But you might have to experiment with either adding fuel to lower it down to 13.0-13.2 or taking fuel away to come up to 13.8ish and see if it idles a little better. I think this is still a VE table adjustment here.

Next time you send a log, send the tune along with it. Because if you make any changes I can't use the version I have and can;t load it into the log file. Then i can watch the cursor over the VE table to see what the values are and what the tune is making the AFR do. I wasn't able to see it on the log

WHen you start to drive it and use autotune, make sure you lock those idle cells. you don't want auto tune making adjustments to those and messing things up. Right click on the cells in the autotune menu and hit lock selected cells

(this is my VE table. I idle down at 45kpa between two cells)

marxpreston11 · Jun 23, 2026

Mustang5L5 said:
I see it now.

Looks like your idle surges in time with some instances when you go a little rich. Your average AFR is 13.4 but commanding 13.5/13/6 which isn't bad. But you might have to experiment with either adding fuel to lower it down to 13.0-13.2 or taking fuel away to come up to 13.8ish and see if it idles a little better. I think this is still a VE table adjustment here.

Next time you send a log, send the tune along with it. Because if you make any changes I can't use the version I have and can;t load it into the log file. Then i can watch the cursor over the VE table to see what the values are and what the tune is making the AFR do. I wasn't able to see it on the log

WHen you start to drive it and use autotune, make sure you lock those idle cells. you don't want auto tune making adjustments to those and messing things up. Right click on the cells in the autotune menu and hit lock selected cells

(this is my VE table. I idle down at 45kpa between two cells)

Wow, yea I'm no where near that. I checked for a vacuum leak i don't have one. Maybe I have a valve slightly open and need to adjust rockers?

But again if i put in the factory ecu it runs amazing. I quit for the night was pissing me off too much lol.

The cam is whatever came with the stage 3 trick flow. I want to say it's a mild cam.

X-cam34 · Jun 24, 2026

[EGO / idle]

egoRPM: 500 → 1100
egoTemp: 170 → 150
egoLimit: 10 → 5
egoKP: 45 → 60
egoKI: 15 → 5
egoKD: 5 → 0
idleadvance_rpm: 800 → 1000
idleadvance_clt: 120 → 140

[VE table ]
9. Whole table smoothed
10. Off-idle cliff removed (e.g. 65 kPa, 1000→1200 rpm was 42→68, now a ramp)
11. 25 kPa high-rpm dead corner cleaned (was dropping to 35, now ~45)
12. Idle cells came up slightly from the smoothing fill (65 kPa idle ~39→47)

[AFR table ]
13. WOT: 11.6 → 12.5–12.7 (rpm-tapered)
14. Idle: 13.8 → 13.5
15. Cruise: capped at 14.7

[Spark table ]
16. Whole table smoothed, knock-safe (no cell gained timing under load)
17. WOT peak: 34 → 33.5
18. Low-rpm jitter cleaned (44 cells, max move 1.5°)

93 5.0 Microsquirt with Stage 3 trickflow tuning issues

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