Mustang5L5’s progress thread - Rear window fun

Trogdor · Jun 4, 2025

Mustang5L5 said:
Sure i've attached it.

This is really just the base tube from DIY autotune, set up for Ford coolant/iat sensors, 302 with 19# injectors and my wideband. I haven't changed anything regarding fueling or stuff like that

Thank you for posting that.

Mustang5L5 · Jun 8, 2025

Played around with it a bit today.

Warmed it up and set the timing. Was off 2 degrees so I made the adjustment in the software. Easy.

Played with the fan programming for my PWM controller. Works as intended which is pretty sweet.

What doesn’t work is AC ON for the fan. I put the AC and the fan doesn’t ramp to full as is should. The ECU is controlling the fan clearly, but either ist not getting the AC on input on the pin, or it’s just not doing anything about it for some reason. Need to dig into this.

Was about to go for a drive and let autotune do its thing…but forgot I never torqued the lug nuts and put them on hand tight. Had to run off to other errands so will need to wait.

Need to play with the idle startup a bit. Takes an extended crank to start it. Runs fine after that but would like it to start up quicker.

Mustang5L5 · Jun 8, 2025

Digging through the manual. Pin 10 on the 60 pin is the AC status pin. Looks like it corresponds to a Jumper 2

Problem is this is not mentioned in the install instructions so i likelly didn't touch it. Will need to dig around a bit more because I don't want to pull the ECU out again. I just buttoned it all up.

Mustang5L5 · Jun 8, 2025

More digging. FOund the input, and I can see it's getting a signal. 5V when no AC demand. Drops to 0V when i call for AC.

Means a setting is not right somewhere.....gotta find it

FastDriver · Jun 8, 2025

I have no idea how good autotune is. I once coded my own in Python, customized for my BS3s. Shouldn't completely trust it, IMO.

Anyways, what data does your system call for with regard to the injectors? If it's already a base tune for a stock fox, and you have 19s you might be good, already, but let's verify. Then, you're not wasting time tuning.

Let's also make sure we know your wideband is reporting correctly. Are you reading straight from Lambda, or does it report based on your assumed stoich? i.e. does it assume 14.64:1 because it thinks you're running pure gasoline, or 14.08:1 for E10, or 13.8 for E15?

We can tune no matter what it is, but we need to know in order to select target AFRs. This is probably in a setting you can adjust.

Mustang5L5 · Aug 4, 2025

Took the car out and went for a drive. Used the autotune feature and it was definitely driving a lot better after 10 mins, but I still have a long way to go. Stumbles a little at low rpm. Runs good up top but doesn’t want to push it yet.

Still working the fan out. It’s not working the way it should be, so something in my settings is off. It does come on with the ac so that’s good, but the fan also randomly comes on/off even below my min coolant temp, and doesn’t ramp to full, so I got hot while driving.

Gonna figure this out… it in terms of tuning I think I’m gonna have to pay someone for some remote tuning. Given I drove the car 5 miles so far this year, just not a lot of seat time to really dial this in. Rather just get it up and running and enjoy it.

Because the few WOT in 2nd blasts I did, this thing really does pull hard. Definitely would smoke my ST.

I think I should put my Accufab 70mm on first, and swap the 19s out for my 30# injectors. Then tune. Maybe I’ll send them out for cleaning and flow testing first.

Getting the urge to sell the SN95. We will see

FastDriver · Aug 4, 2025

If you do send em out & notice any problems with your 30s, let me know. I have some spares on the shelf.

The low RPM stumble, assuming you've got your timing and fuel in the ballpark is often transient fuel. It will lean out if you dont have the tip-in and accel fuel right. It's better to be a bit on the rich side, there. Best practice, after setting injector data correctly, and roughly mapping timing to stock or slightly more aggressive, is to dial in AFRs (VE & Tgt AFR), then start working transient stuff, finally after fuel is dialed in, come back to spark and either dyno it, or go to the track and datalog.

hoopty5.0 · Aug 5, 2025

This has always been my rub with MS, but I assume it would be with any platform. You really gotta know what youre looking for in there. Autotune is ok for some fine adjustments here and there but all of the issues youre dealing with are ones that someone who deals with it daily are going to know how to fix quickly.
Not sure if Steve is still messing with tuning since assuming the honcho role at DIY. If you need someone, the guy who did my bronco tuning REALLY impressed me with his knowledge and was working on a HCI fox with a microsquirt when I showed up yesterday.

Mustang5L5 · Aug 5, 2025

I think i know a guy that can do it. I really want to iron out the fan issue first because it's not doing what it should be doing. It's supposed to turn on at min speed at 180 degrees, and ramp to full speed at 195. Instead it turned on at 140 degrees at min speed and stayed there. I have the datalog and can't see why it went on at 141 degrees, vs 180.

AC on and WOT cutout work fine though.

I think i know what I should be doing, but at the same time I'm a little apprehensive to start making changes yet. So like i said, i'll likely swap the TB over, send the injectors out and swap those in, and then see who I can work with on this just to get the brunt of the work done fast so I can drive the car.

It was fun as hell for the 10 mins or so i was driving around. Just tons of torque and it pulls hard. It did stumble a bit at lower RPM so I can't wait to get this sorted.

AeroCoupe · Aug 5, 2025

So do you think that due to just the newer processor that the motor is actually making more hp or maybe a fatter curve? I keep telling myself that the MS will unlock some hidden power in my combo just due to the new processors etc and how much more tuning capability it has over the A9L and SCT chip.

TuFun · Aug 5, 2025

Fascinating stuff! And here I am messing with two screws on my 2-barrel.

hoopty5.0 · Aug 5, 2025

AeroCoupe said:
So do you think that due to just the newer processor that the motor is actually making more hp or maybe a fatter curve? I keep telling myself that the MS will unlock some hidden power in my combo just due to the new processors etc and how much more tuning capability it has over the A9L and SCT chip.

I think it gives you more resolution to use across a broader spectrum of inputs. The factory computers knew how to adjust within a given narrow set of parameters that could not vary too widely or it would fail to compensate. That and it allows you to create your own parameters (ie when to turn accessories on/off).
That reads like a word salad so I hope it makes sense. I'd bet you could tune a few extra HP into a stock car vs the A9x

AeroCoupe · Aug 5, 2025

Basically like a short sweep vs long sweep gauge...better resolution = better results.

Noobz347 · Aug 5, 2025

Not to mention that modern processors can refer to sensor inputs many, many more times in the time span that our 30 year old ECUs do and respond quicker.

FastDriver · Aug 5, 2025

IMO, that's just not how it works, fellas. Spark timing, and fuel. Unless you can make one different with a system vs the other, there's no performance advantage.

Noobz347 · Aug 5, 2025

I guess we should just stop making better cars then.

WhiteCobra95 · Aug 6, 2025

FastDriver said:
IMO, that's just not how it works, fellas. Spark, timing, and fuel. Unless you can make one different with a system vs the other, there's no performance advantage.

Amen! Perfect summary.

There are two parts to base engine control: 1) the base parameters like spark, fueling, injection parameters, and cam positions (modern engines). and 2) The controls / models that determine the base parameters and set the actuators. The base parameters are system independent and absolutes - two different controls systems can deliver the same base parameters by different means (e.g. MAF vs. MAP vs. alpha/n load sensing). If two different controls systems replicate identical base parameters, there is nothing gained. However, if one engine management system can control fueling better than another or provide a more favorable spark setting (steady state or during transients), then the base parameters are NOT the same and you can achieve better performance.

Bullitt347 · Aug 6, 2025

Faster processing speeds can lead to better performance.
The ECU has to calculate when to inject fuel into the engine.
It has to start the process before the fuel is injected.
Injector coil time, the time it takes the electrical solenoid to open/close has to be precisely calculated to get the fuel in the cylinder/runner on time.
This is usually called "injector offset" and can be used as a tuning tool. I can change this parameter on my Holley Dominator ECU and I am sure other systems allow for this as well. You have to really know what you are doing though. Plus you can change individual cylinder air/fuel parameters. One cylinder running a bit rich or lean? Add/subtract however much fuel to just that cylinder to make it happy while leaving the other cylinders alone.
Spark timing is another tuning tool. This can also be adjusted per cylinder with the right ECU system.
The major hurdle for a modern EFI engine to spin over 8K rpm was initially the ECU. The processing power required to calculate accurately the fuel injector lead time went up exponentially as the engine neared and eclipsed 8K rpm.

Mustang5L5 · Aug 6, 2025

I just meant it felt much more powerful compared to a stock SN95.

hoopty5.0 · Aug 6, 2025

FastDriver said:
IMO, that's just not how it works, fellas. Spark, timing, and fuel. Unless you can make one different with a system vs the other, there's no performance advantage.

Stock for stock, no, probably not. Hence my statement of "you MIGHT be able to find a few extra hp." The whole reason we switch to aftermarket ECMs is because with mods, the input parameters mentioned above surpass the limits of what the factory parts can handle.
Now that we have better computing, the aftermarket ECMs are not needed as much due to the robustness of the OE hard/software.

Oh, and you CAN make spark better by going to a trigger wheel and individual coils. I think we can agree that there's a lot of improvement to be made on TFI.

Mustang5L5’s progress thread - Rear window fun

Trogdor

Mustang5L5

That is…until I whipped out my Bissell

Mustang5L5

That is…until I whipped out my Bissell

Mustang5L5

That is…until I whipped out my Bissell

FastDriver

I was uncomfortably high & wearing a helmet

Mustang5L5

That is…until I whipped out my Bissell

FastDriver

I was uncomfortably high & wearing a helmet

hoopty5.0

mechanicus terribilis

Mustang5L5

That is…until I whipped out my Bissell

AeroCoupe

lube between the nut and the face. I know my lubes

TuFun

Females affect them in a very negative way O_o

hoopty5.0

mechanicus terribilis

AeroCoupe

lube between the nut and the face. I know my lubes

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor

FastDriver

I was uncomfortably high & wearing a helmet

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor

WhiteCobra95

Bullitt347

I have been doing it wrong this whole time

Mustang5L5

That is…until I whipped out my Bissell

hoopty5.0

mechanicus terribilis

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Stangnet Facilities Maint Tech... Er... Janitor

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