Hello--FI conversion MegaSquirt on an '80 spider 2000

[opamp]

Hi everyone!

This serves as my hello to everyone and also, the beginning of a hunt for info.

TLDR version: looking for advice from anyone who has done a MegaSquirt conversion to FI. I've browsed the forums and I'm compiling data--but if anyone has done an MS conversion and found a great resource for fiat conversions--I'd very appreciative!

Long story:
Still getting oriented here--my dad and I restored an '80 FI turbo spider that was converted to carb by the previous owner...who loved the car, but did not know what he was doing...

We are finally converting it back to FI--and eventually, we may also throw a small turbo on it...but for now--we are taking the first step back.

Because the ultimate plan is to turbo this thing, we have opted for a MegaSquirt II (V3.0 board) as a controller, running simple tach off the negative side of the coil (I know, eventually we will go VR or Hall and control ignition too...) just to get things started. Got all of the parts and sensors to do the conversion using MAP and stock injectors (may upgrade later)--luckily the previous owner left the exhaust with the lambda sensor--so just gotta get a fresh sensor!

Anyone who is in the same boat, feel free to ping me, make suggestions or follow along, I'm planning to create some videos and perhaps tutorials as well...time shall tell.

Cheers!

[RRoller123]

Welcome aboard! You will find lots of friendly and helpful people here.

[joelittel]

I'll be very interested in following your project.

Have you checked out the MegaSquirt forum? I believe you can find it through DIY Autotune

[PhillySpider]

I can understand the desire to go back to FI. Dunno I'd throw a turbo on my spider. Even if all goes to plan, simple physics dictates a reduced lifespan on a motor outfitted with a turbo. Good luck, curious to follow your progress.

[MattVAS]

Programmable Fuel Injection is do-able. From scratch on a Fiat it can be pretty annoying.
Our test car here at the shop have our PFI kit with ITBs and a NOS Bottle, so pretty much all of it is do-able.

As for the Turbo you'd really be wise to keep it well undertuned as much more that 150HP you'll start to see quick failures of the transmission and rear end.

[opamp]

Thanks everyone for the warm welcome and thoughtful suggestions!

Current status:
MS2 board complete and electrically tested using the MegaStim board (not JimStim). Thoughts: if you're running a similar setup, in order to test using MegaStim, you'll need to jump one of the flyback/protection diodes (outlined in MS assembly guide) and you'll also need to make sure that TunerStudio is setup to run using "Basic Trigger" (Ignition Options/Spark Mode).

Things I'd wish I'd known before I started:

• 1. FI on the Fiats (and most vehicles) is non-sequetial or banked--meaning an entire row of injectors fires simultaneously and multiple times per engine cycle. *this should tell everyone something about how much I knew when I got myself into this project...LOL*
  
  2. The flow rate of the injectors can be a real pain to figure out or find if you're using stock injectors. Here are the P/Ns:
  -- Main injectors are: Bosch 280150121 (EV1 body style, Low impedance, 178.1 cc/min)
  -- Cold-start injector: Bosch 280170041 (EV1 body style...haven't found remaining info yet...)
  
  3. A useful webpage about injectors is: http://users.erols.com/srweiss/tableifc.htm
  
  4. The idle air control (IAC) on the fiats is also a somewhat poorly documented component, and on the components that were sent to me, there was no IAC...know that there are other options (such as this one: https://www.diyautotune.com/product/cus ... iac-valve/ combined with an off-the-shelf IAC from a local parts store) that can be used with the MS and Fiat to control idle.
  
  5. For the MS, there are multiple ways to monitor the engine speed (tachometer): 1. Coil negative, 2. Variable Reluctor (VR) and 3. Toothed wheel. There are combinations of these, but know that #2 and #3 require modifying the engine, but often (from what I've read) provide a more reliable/less noisy signal.
  
  6. You cannot control spark timing if your tach signal comes from the negative side of the coil. This should follow from the setup, but I am providing this because I had to think long and hard if I wanted to worry about spark timing when I started this project...
  
  7. Hunt around for several useful manuals: Wiring Diagrams (Fiat Spider 2000 type CSO), Fiat 124 Service Manual, Bradley Artigue's "Fiat 124 Spider Engine Maintenance and Modification", and Bradley Artigue's Bosch L-Jetronic Fuel Injection Guide.

I'll update this list as I get further...

Useful Webpages:

• 1. MS assembly info, etc.: http://www.megamanual.com/mtabcon.htm
  2. MS extra webpage: http://www.msextra.com/
  3. If you're in North America a good place for parts and MS kits: https://www.diyautotune.com/
  4. TunerStudio can be found here: http://www.tunerstudio.com/index.php/tuner-studio
  5. If you have a calico engine, like mine, finding engine ID info can be found here: https://www.mirafiori.com/id/

Re: Turbocharging/programming--Thanks for the thoughts @MattVAS and @PhillySpider, I agree: I definitely want to be intelligent about forced induction...We will cross that bridge when we get there. I'm not looking for huge amounts of power, in fact, I'm really more interested in learning about how to do it than anything. My present thoughts (not very well thought-out): I would be putting a tiny turbo and setting waste gate pressure way below 10 PSI (I think I read that the original turbo ran around 6?). Either way, I really appreciate the suggestion to keep it under 150 HP because I have been pondering what sort of safe limits there might be. I haven't even started researching turbo setups, but if we decide to go that way, I'll probably be looking for suggestions/comments!

Thanks to everyone for the warm welcome--I'll try my best to keep everyone up to date!

The next steps for us are:

• 1. Attach and wire all sensors
  2. Wire up the harness (without injectors) and just get baseline readings off of the carbureted setup (mostly for tach stability testing, etc.)
  3. Bolt on the FI manifold, plenum, etc.
  4. Try first start with MS setup!

[joelittel]

Fantastic write up, looking forward to the next.

Post pictures if you're able. Everyone loves pictures.

I think Brad Artigue recently posted an updated CSO wiring diagram on the Facebook and Mirafiori sites.

[opamp]

Whew,

Crazy few months--first off: thanks again for the comments--I've taken boatloads of photos and videos. Here is a photo of the car we are working on (Right click and open in new tab):

https://drive.google.com/file/d/1w0ZWPi ... sp=sharing

The quick update since last we left off:

• 1. Wired MS to car to test tach input (left carbs on so we could drive): success
  2. Replaced O2 sensor and did road test to ensure readings.
  3. Replaced Coolant "T" with updated one.
  4. Installed Coolant Temp sensor
  5. Done a quick road test on carburetor to get a quick feel for sensor readings, etc.
  6. Taken some photos and videos

Wiring the MS to car to test tach input
This step, for me, was shockingly simple...as a reminder, I'm using a build-it-yourself version of the MS2 on a v3.0 mainboard and a wire-it-yourself harness (both from diyautotune). My biggest concern from reading over forum posts and a lot of MS documentation was that the signal from the tach might be exceptionally noisy. Here were the steps I took to make sure my MS would work:

• 1. Check that the MS worked with the MegaStim board (done previously)
  2. Disconnect the jumper wire I had installed to go around the flyback diode in the tach input circuit (required to use the MegaStim)
  3. Power the megasquirt from the car to ensure the board came online (connected to laptop).
  4. Connect the white wire from the shielded pair to the coil negative (DO NOT connect to coil positive!!!)
  5. Start car and check readout on laptop.

Good news: the tach signal was stable--I did not check it with an o-scope, but did verify with an automotive multimeter and the car's tach that things looked correct...and I did not lose synchronization the entire time (hooray!).

Here is a reference photo for what comes next:
https://drive.google.com/file/d/1w_xNx3 ... sp=sharing

Installed Coolant T, Coolant Temp Sensor

• 1. Safely drained enough coolant from system to remove the T-fitting
  2. Removed and replaced the coolant T (original shown below)
  https://drive.google.com/file/d/1xcBZ4P ... sp=sharing
  3. Installed coolant temp sensor
  4. Topped Up coolant.

O2 Sensor Replacement
Luckily for me, the exhaust on my car is from the original fuel injected car--which means it already has a spot for an O2 sensor...if you don't have FI exhaust/header--I think the official recommendation would be to get replace it with the FI version.

*WARNING: Objectionable comment below*
If I were stuck with carb exhaust...I'd probably just find a spot in the exhaust to weld in a narrow or wide-band sensor (someone is bound to get upset about this idea...and you're right, it's probably not the best recommendation)...keep in mind that the stock Fiat O2 sensor is a 1-wire sensor--which means it is 1. grounded to the block/chassis and 2. it is heated by the exhaust gasses--which means you probably want it relatively close to the exhaust ports...
*End objectionable comment*

All sarcasm aside--the sensor is pretty straight forward, here is what I did:

• 1. Make sure the engine is cool
  2. (optional) Remove the heat shield from the exhaust header
  3. Remove old O2 sensor (can't recall what size socket this requires)
  4. Install new O2 sensor and torque to spec (30-36 ft-lbs)

After installing a new O2 sensor, installing the coolant T and temp sensor, we took the car for a quick drive to make sure the sensors were reading correctly...and the tach and O2 sensors worked wonderfully...the Temp sensor is still causing problems: more to come on that.

Immediate Next Steps:

• 1. Solder and test wired connections
  2. Track down coolant temp sensor issue
  3. Remove carburetor parts
  4. Dry fit FI manifold and plenum
  5. Upgrade fuel system (hoses and pumps)
  6. Test injectors
  7. Install FI components

Apologies for the long and spaced-out posts...the build is still moving--but I've only had about 4 hours total time to work on this in the past 2 months...

[ORFORD2004]

Did it on mine turbo with megasquirt II v3.0
You should run EDIS4 for your ignition to be able to play with the timing. (more boost= less timing)
Put a trigger wheel on your crank.
Put a wideband sensor. I recommend 14point7.com
No more need of the cold start injector.

[opamp]

Did it on mine turbo with megasquirt II v3.0
You should run EDIS4 for your ignition to be able to play with the timing. (more boost= less timing)
Put a trigger wheel on your crank.
Put a wideband sensor. I recommend 14point7.com
No more need of the cold start injector.

Awesome--I'm glad to hear you were successful. Curious to know which trigger wheel you used for your crank/what mods if any where required to fit it. Thanks for the rec on the wideband--definitely gonna need it when a turbo goes on. What turbo setup were you running?

Re: Cold start--I have actually had several people tell me the same thing on other vehicles (non-Fiat), so it's reassuring to hear someone with a FI spider who has experience with this--which is just one less thing to worry about!

[ORFORD2004]

36-1 tooth from Miller Mule
Lancia Delta Integrale intake, throttle plate and fuel rail. https://www.ebay.com/itm/Ansaugbrücke-A ... 1438.l2649
Allison exhaust turbo manifold.
https://www.ebay.com/itm/Custom-Race-T3 ... 55?vxp=mtr
Also forged connecting rod from GM350, original piston with Total seal rings.

[philipjrj]

Hello Opamp, did you make any more progress with your Megasquirt install ?

I have a 1981 with the Legend Turbo. It runs beautifully but the fuel control is very basic and a programmable system might be a big improvement.

[toplessexpat]

I converted a 80 spider to Microsquirt. Used the coil negative for rpm. Changed the TPS for an Alfa one so you’ve got a variable signal, used the charcoal canister T for the MAF signal. Gutted an old ECU box and fitted much of the gubbins in there... although you can still buy the Ecu connector new which would make for a nice install in a right sized case. Also switched to wide band O2

One long day installation, a day to tune - I cheated and used the auto tune application on the laptop, then fine tuned. Great improvement over stock.

Worked out the same setup for a friends Turbo. Will remove all the enrichment valves etc, as the MS will take care of all of that. Overboost valve will stay - just incase - but you can replace with a Honeywell valve that is setable.

[philipjrj]

Hello Toplessexpat, did you do the install on your friends Turbo ? I have a 1981 Legend Turbo and thinking about converting to MS.