Engine Hacks: Adding fuel injection to a riding lawnmower

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Are you tired of fiddling with the engines on your lawn equipment every spring, trying to get them to run again? [jhark] was and decided to do something about it by converting his riding lawnmower over to fuel injection. After stealing a fuel injector from his van and bolting it onto the mower’s carburetor, he sprinkled in a dash of Arduino magic. With a small amount of code tweaking he was ready to roll mow. You can find a schematic and his code if you follow the forum link to the second page.

For more fuel injection goodness, check out this project where [Steve] upgrades his Austin Healey to use the fuel injection system from a General Motors vehicle. This build log is pretty comprehensive and shows each element in the system, describes what it does, and shows where it should go. If you are a car nut, this is definitely one to check out.

Finally, if you are looking to really dig into the nuts and bolts of automotive fuel injection, take a look at the Megasquirt fuel injection computer system that allows you to finely tune things to your specific car and model.

Comments

  1. NATO says:

    FYI, you don’t need an MCU to do this. I graduated from an automotive engineering college, and in our fuel injection class, several students chose exactly this as their final project. Most of them used discrete components to fire the injector, if you know how inefficient these little flat headed engines are then you know why precise fuel control is not at all necessary :)

  2. mowtown says:

    That’s cool. But how does he measure the fuel mixture? How does he know it isn’t running lean, and will burn down the spark plug or a piston? Especially on really hot days.

    How does he handle cold starts, where a choke is important? We also use our tractor for blowing the drive way in winter, so fuel mapping would be much more tricky. And it’s a more expensive 2 cylinder engine (on a Gravely) that we wouldn’t risk.

    I’ve been interested in putting some data acquisition on the Gravely tractor. They don’t make’em like that anymore.

    As for starting in the Spring.. I had a push mower I left out every winter in Michigan. I’d cover it with a plastic trash can lid. In the Spring, I’d drain the carb float bowl and tank. After adding fresh gas, it’d start right up. We’re talking first pull (after priming). It was a really old mower, with a rusted through deck that I’d reinforced with angle steel.

  3. Mike says:

    Horray for the new theme. :)

  4. fartface says:

    Not hard at all when you get past the “oogy boogies” of dealing with an engine. I in fact added a turbo to a engine like that before. +25hp for more cutting power! plus the turbo whine makes it cool.

    the “problem” that is alluded to is not a real problem. “getting it to start in the spring” is simply because the mower or other engine was not stored correctly for winter. and even with FI you need to do this.

    IF people were not lazy and topped off the gas with some stabilizer and ran it for 10 minutes before storing it will start with the first pull 6 months later.

    • nes says:

      I in fact added a turbo to a engine like that before. +25hp for more cutting power!

      Pictures or it didn’t happen! +25 hp on a mower? What, were you running 30psi of boost and methanol? What did the conrod embed itself into after it launched through the side of the case? lol :-)

    • Anonymous says:

      I’ve got an even easier, cheaper, more redneck way to store power equipment: drain the tank and run the carb dry. Works for my generator, motorcycle, lawn mowers, snowblower, and weedeater.

      I’d like to see this idea applied to an old inline-6 truck engine.

  5. fartface says:

    Oh and megasquirt sucks. Been there done that. it needs a major redesign to update it. MAP sensor on the board? how amateur.

    Buy a GM 7730 ECM and tune it or hack it to your pleasure. It’s the most hacked GM ECM out there.

    • Elias says:

      What would be wrong with a MAP on the board? Don’t think the delay would make too much difference even if you have a bit longer pneumatic hose in between. You can always of course just solder wires to the board and relocate the pressure sensor itself. Does the GM ECU run a dual wide band lambda if required? Does it have launch control possibility? Electrical fan control?

  6. Red Five says:

    After stealing a fuel injector from his van and bolting it onto the mower’s carburetor
    Isn’t that what’s known as throttle-body injection? It sucked on my ’86 Chevy Celebrity; why would I want it on my riding mower?

    Oh, and judging by that mower seat, the van wasn’t in usable condition anyway, so I guess pulling the injector wasn’t that big a deal.

  7. Steve-O-Rama says:

    Same as Mr. NATO said (I’m someone with an automotive & electrical engineering background, too): it’s not terribly hard to get a running engine, seeing as this type of engine will run on such a wide range of air/fuel ratio (and let’s not forget the fixed ignition timing), but it is interesting, nonetheless. On the one hand it’s unnecessary (no points deduction, I’m in that camp often); on the other he’s got a working fuel injection system for (I’m estimating) about $50 and some programming, so way to go!

    I’ve already ‘hacked’ the Ford EEC-IV PCM for my full-size Bronco, by reading & deciphering the assembly code contained therein to find data & registers of interest. Mass air, electronically-controlled transmission, sequential injection, complete control, does my evil bidding…. If only I’d stuck with the factory engine parts, I *might* have obtained ‘decent’ fuel economy. LoL

    And +1 for Mega-squirt being not all that great. MAP sensors are sooooo 1980s. ;) And before anyone bitches about it, yes I know the multi-thousand horsepower engines may (or may not) use MAP sensors, but a) you don’t drive it every day, and b) those guys don’t have to pass emissions tests, get decent fuel economy, OR have an engine & control system last 200,000+ miles.

    Then again, many late-model Hondas still employ these sensors. Maybe their engine manufacturing process is more uniform…? They’re cheaper to implement, to be sure. However, I still prefer a vehicle with mass-air. It’s just smoother, not so “ON/OFF” Cracky McCrackHead like speed-density, IME.

    Ah well, enough ranting. Props to the guy for getting the idea and just running with it!

    • nes says:

      MAP sensors are sooooo 1980s. ;) And before anyone bitches about it, yes I know the multi-thousand horsepower engines may (or may not) use MAP sensors, but a) you don’t drive it every day, and b) those guys don’t have to pass emissions tests, get decent fuel economy, OR have an engine & control system last 200,000+ miles.

      Then again, many late-model Hondas still employ these sensors.

      Pretty much most modern stuff fitted with a turbo has a MAP sensor. Unlike Megasquirt, the sensor usually goes on the manifold and they often incorporate an inlet temperature sensor. They may have appeared in the 80s but they’re still current and less fragile than MAF and TPS IMHO.

      Also Megasquirt 3 doesn’t have a built in MAP sensor. Just saying…

  8. Tim the Toolman Taylor says:

    Everytime I’ve tried this, something goes horribly wrong. Luckily my neighbor is always around to offer advice. Nice guy, but I’ve never seen his face.

  9. Ned says:

    On top of megasquirt, theres also FreeEMS (http://freeems.org/)

  10. Jason says:

    I am so doing this when I get the time

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