420A Anyone have experience piggybacking a ECU?

[Mitsubi-doo]

My 1999 Eclipse is a automatic transmission, and I decided to keep it automatic for now. But I am committing to my t25 turbo set up this winter. And I'll need a proper tuning solution, that allows my auto to play nice.

Wanting to try piggy backing megasquirt
What are the best options?
And anyone care to share experiences with mega for the 420a? Especially piggybacking.
The ampd microsquirt peaked my interests.
The ms2 always had.
Do certain widebands play nicer with mega?

 

[BLACK'98DSM]

If you're wanting to run a single O2 sensor, most modern wideband kits have an extra harness to hook up to the ECU. When I first installed my GlowShift wideband setup, I still had the stock ECU and welded an additional bung in the downpipe to run it as a separate system.

When I swapped to MegaSquirt, I installed that additional harness and tied the wires into MS3. Any setup with that feed will function just fine, and you don't have to use it now. It's up to you but get something with ECU compatability. I never did piggyback the MS but it's possible. Just separate the engine sensors and run the rest like stock. I don't get why not to run it as a standalone though. You don't need the stock ECU to run that transmission. There is also a TCU for essential transmission functions.

 

[Mitsubi-doo]

If you're wanting to run a single O2 sensor, most modern wideband kits have an extra harness to hook up to the ECU. When I first installed my GlowShift wideband setup, I still had the stock ECU and welded an additional bung in the downpipe to run it as a separate system.

When I swapped to MegaSquirt, I installed that additional harness and tied the wires into MS3. Any setup with that feed will function just fine, and you don't have to use it now. It's up to you but get something with ECU compatability. I never did piggyback the MS but it's possible. Just separate the engine sensors and run the rest like stock. I don't get why not to run it as a standalone though. You don't need the stock ECU to run that transmission. There is also a TCU for essential transmission functions.

Thanks for your reply!
I had planned to run a dedicated wideband and weld in a bung on my down pipe.
Does the glowshift setup talk well to mega? I like there gauges and was wanting to run them.
I'm running dedicated sensors for most of mega inputs, but the mega guides point at ways to share TPS / cam / crank signals

I would go completely stand alone but the particular transmission in a auto 420a is a 41te/a604 it does have a separate TCM, but I'm 99% sure uses CAN network to reference TPS/MAP for shift quality since it dosen't have a physical connections like a vacuum line and a cable. Most of my Chrysler diag reference seem to point to this. Otherwise I'd completely stand alone.

 

[jesse12345]

I've honestly been thinking about a piggyback system whether that be ms3 or I've even been looking into the apexi fuel controller. That's a discontinued product but it would be cool to try to see what works and what doesn't with these cars. It runs off of a map sensor but I don't know how good it would be. I just feel like the old fmu trick just isn't a great option anymore. It's cheap and does work but to me it's not great. I hate that the 420a cars have virtually zero support now days.

 

[Mitsubi-doo]

So I was emailing diyautotune about my set up and goals, and further research I decided to go budget and play with some of the newer tech from megasquirt. I ordered a AMPD microsquirt set up. Technically its called running a ecu in parallel according to them.

My factory ecu will be able to handle idle control, alternator, and relay functions, while giving data to my transmission. Neon guys have the same iac and similar set ups done this with old megasquirts.
But if you have big goals for your project for later, you might want ms2/ms3 or some of the newer full on tech. Im doing a smaller budget turbo build, and been wanting to experiment, im committed now

I've honestly been thinking about a piggyback system whether that be ms3 or I've even been looking into the apexi fuel controller. That's a discontinued product but it would be cool to try to see what works and what doesn't with these cars. It runs off of a map sensor but I don't know how good it would be. I just feel like the old fmu trick just isn't a great option anymore. It's cheap and does work but to me it's not great. I hate that the 420a cars have virtually zero support now days.

I was originally gonna do a 8:1 or a 12:1 fmu set up
And try to play with it and make it work. But really want to be in control of the timing and fueling to get it right. Theres too many variables.
The apexi i thought about and almost ordered a ebay one, but its only really modifying signals to "fool" the ecu, this may not be predictable all the time and is limited to what the factory ecu limits were set to as stock. Megasquirt has been used on many neon's and 420a, theres alot of info if you gather the 1st gen neon's in the mix.

Theres this place that sells something on tindie thats called Chrysler Scanner, that has the ability to modify and code the SBEC3 Mopar ecm thats used in the eclipse, with an adapter to tap into the auxiliary obd port of course. simular to a skyed ecu, but this company did it themselves and made it open source. I gave up on them because every time I tried to order it was out of stock and they stopped taking orders from the u.s this time when it was in stock.

I wish the 420a was much more supported lots of potential.
Whatever you do, research and ask the right questions to get what you are willing to settle for. My settle is a piggyback/ parallel megasquirt.

 

[jesse12345]

Well since I'm not trying to make big power I was trying to keep this piggyback setup a little cheaper. Definitely let me know how that microsquirt plays out I would for sure try that if it works pretty good.
Mine is a 95 and it doesn't care if it sees 10 pounds of boost or 20 as long as I have the fuel. That's sort of why I was looking into the newer apexi to have a little more control. I've just been looking and seeing what's out there. I'm not anywhere near picking out a tuning solution yet.

 

[BLACK'98DSM]

I've seen a few others ask about the microsquirt over the years. But no definitive info has been shared. Make sure to share pictures and results with us.

 

[Mitsubi-doo]

I've seen a few others ask about the microsquirt over the years. But no definitive info has been shared. Make sure to share pictures and results with us.

I've seen those posts too. Im excited and will definitely post pictures and all the knowledge I can doing the microsquirt parallel ecu.

 

[Mitsubi-doo]

The start of my microsquirt set up came in. I got all the basics. Ecu, harness, tune cable

im looking at a spartan 3 wideband, and a CAN gauge to be able to monitor boost / AFR primarily, while being able to see all microsquirt sensors. Still doing some research so I get what I want.

im also trying to decide on a GM 3 bar map sensor that I can utilize as they seem easy to integrate to. Idealy remote mounting and connecting with a vacuum tube.

Any tips appreciated megasquirting a 420a. Also good write-ups so I can compare my microsquirt.
Still researching the forums and reading up on all things mega.

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