Speeduino is now on Github Sponsors (Rather than Patreon): https://github.com/sponsors/noisymime
Any questions you have before you begin buying, building and installing.
I have a 87 Pontiac Fiero. Basically all original and I want to keep it that way. But the engine management is, well, crap.

We have been talking about using one of the other stand alone units and just rebuilding the whole thing. But then I came across this. So far everything screams "HELL YES". I am looking for anyone familiar with hooking this up to older (1987) GM fuel injected engines to help with some guidance. This would be my first foray into something like this. All help and advice is greatly appreciated.

This car is a daily driver and a car we show routinely. We also run one of the largest Fiero only car clubs in the world with several thousand members world wide.

Thank you in advance.

First step should be for you to read the wiki.

The come back with questions. Specific questions.

Your type of post will get no useful responses.

Note that Speeduino is very DIY. It is expected that you put in a lot of effort in understanding how it all works.
theonewithin wrote:First step should be for you to read the wiki.

The come back with questions. Specific questions.

Your type of post will get no useful responses.

Note that Speeduino is very DIY. It is expected that you put in a lot of effort in understanding how it all works.
My intent was to garner information as to types of changes or additions (sensors and the like) that may have to be made to an older motor like this. I did not think that looking for general information on usage to older FI engines would be a problem. I wanted to do this before I invested the tremendous amount of time needed to scan all the small details only to find out that this is not a usable alternate unit for my need and I should look toward the Holley system or one of the others. All of which are very DIY, as you put it.
There is no indication a Speeduino should not fit your engine. The biggest mechanical challenge will be the crank trigger wheel. As far as I know, the Distributor of your engine is problematic. Good point to eliminate it or at least reduce it to a cam trigger. Then have a look at the TPS, which could be a simple switch on older fuel injection systems.
The rest is adapting to the engine loom and maybe make some modifications to it, like pairing injectors for semi sequential operation. Then maybe replace air and water sensors and choose an ignition system, in your case a 3x2 wasted spark coil with integrated drivers would match.
This is work you have to do with any after market injection system. In many cases you can have a look at the MegaSquirt, the installation is in no way different. I´m sure there is someone who offers a solution for a crank trigger wheel if you can not DIYS.
Tuning the engine is the same procedure as with any other system, get the full version of TunerStudio software for 100$ and you are ready to go. TS is one of the best solutions around and not limited to one injection system.

Yes, and read the WIKI. It will answer you some specific questions and also give you basics for any after market engine management system.
You can look at the MS instructions too, but don´t get confused with some details, especially the outdated EDIS ignition stuff.
The final (small) problems are usually polarity of trigger sensors (VR or Hall type) and how to connect the ignition drivers.

Good luck!
Note Chris has an error in his post.

For Speeduino you don't pair injectors for semi-sequential. You connect them as if they were sequentially driven and the ECU fires the outputs in pairs.

Putting injectors in pairs is exactly that. Paired injection.
I just thought of the "usual" Speeduino, which has only 4 injector outputs. So with 6 cylinders, I would take those two that are in top dead center and connect the injectors to one driver. If the ECU times the one squirt per revolution to crank angle for each of the used drivers, this seemed semi-sequential to me. Different from all drivers injecting at the same time.
What is wrong with that? Please explain, I´m a little confused.
The effect seems similar, but the control and limitations are different. Semi requires a cycle signal, and paired does not. This is important, as without the cycle signal, the paired injectors could fire on either TDC (it doesn't know which of the two crank rev's it's on in this cycle), where Semi will only fire on a specific TDC (it knows).

That said, paired may be configured to squirt on every TDC, ensuring identical fueling to every cylinder, every time. However, there are other effects to adding squirts-per-cycle that must be considered or possibly dealt-with. All of this makes knowing the differences important to choosing which scheme is best (or which to test) for a specific application.
OK, so I was not that wrong, but did not mention that semi-sequential includes the timed injection in any case. Batch and paired are the two systems I usually replace, as turbo engines respond very well to timed injection.

Thank you for correcting me.
Thank you

I am not aware of a Fiero problem with the distributors. I just replaced my original one 2 years ago at 140,000 miles. Now the ignition modules are a different story. Please tell me what you have heard.
If I understand you a cam sensor based system would be better than one using an hall effect switch inside the distributor. Putting a cam sensor on the 2.8 V6 would be an interesting idea. I would have to think about how to do that cleanly. All the other sensors are just old school GM sensors so upgrading them to better, newer ones is not out of the question.

I would prefer to have all injectors driven independently. Doubling them up is basically going back to the old Bosch Jetronic injection system in the early 70's I feel. But I could be missing something.


I am not trying to garner more HP I am trying to have a system that has more parts that are more easily available and the ECU can be more reliable than a 35 year old ECU in the car now. We are not having problems but buying one is getting harder and harder because they are unique to the Fiero. Not to mention that this should be more efficient when done.

Will this require cats of some kind? I can get rid of the EGR system. I'm wanting a more solid system for my daily driver.
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