The great big Electronic Fuel Injection thread!


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On a side note, around Monday I'll post some photos of the EFI stuff I have. This afternoon I'm leaving foe the weekend and probably won't have time.
Better late than never, right? :ph34r: This is something to give an idea of the hardware used for an EFI engine. Not all of this is mandatory; obviously I have multiple versions of many parts and some are completely unnecessary.

1. Toyota volume airflow meter(VAM).
2. Innovate wideband oxygen sensor, driver, and logging software.
3. Nissan mass airflow meter(MAF).
4. Ford boost control solenoid(BCS).
5. One of two Suzuki SV650 throttle bodies with a modified Ford 35lb/hr injector and fuel rail.
6. GM engine coolant temperature(ECT) sensor.
7. GM 8-pin HEI module for timing control.
8. MegaSquirt-I with pcb V2.2
9. "Gillis valve" ball-and-spring boost controller.
10. Nissan intake air temperature(IAT) sensor.
11. Ford ECT sensor.
12. Ford variable reluctor(VR) crank wheel sensor.
13. Bosch 3-wire narrowband O2 sensor.
14. Nissan 270cc/min fuel injector.
15. Ford E8(1998) 14lb/hr injector.
16. Ford E4(1984) 35lb/hr injector.
17. GP Sorensen aftermarket 35lb/hr injector.
18. Nissan JECS throttle position sensor(TPS).
19. Suzuki SV650 TPS for the electronically controlled secondary butterflies.
20. Megasquirt stimulator(engine simulator) for MS assembly & troubleshooting.
XX. There is also a standard SV650 injector and Bosch injector pigtail that aren't labeled. The SV650 injector is about half the size of a standard Bosch, but it still flows ~19lb/hr.

Some things I am missing are the open-element Ford and GM IAT sensors, fuel pumps, the DIYAutoTune MAPDaddy 4-bar upgrade sensor, and the 7bar sensors I am playing with.
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Better late than never, right? :ph34r: This is something to give an idea of the hardware used for an EFI engine. Not all of this is mandatory; obviously I have multiple versions of many parts and some are completely unnecessary..
WHOA! little over kill hey? I member when I squirted my E30 bmw with a garret turbo, its safe say ill never go back using megajunk! , and like someone stated before it is way over priced for 50 bucks in eletronic parts.

I have no idea how big my injectors are, and I just thought they probably are little bit on the heavy side of flow sense those street bikes go fast? I wanted to note that when I EFI'ed my motors using the ford escort 14/lb injectors, I ran fuel pump at less pressure (20~30psi) that helped it a lot, yah the spray might not be all that great but oh well...

I never stated this either, the hole point back when I did EFI my motors was because fact I was going run force induction, I heard people do that with carb's but seemed like a lot more work (hehe) and I never had any luck with carbrators anyhow.... so,, keep work up! my site is almost done, I will be doing weekly live shows soon....


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I just present what I do for informational purposes, not to promote any one system over another. There are many commercial options that are better than MegaSquirt, but it is still the cheapest option for people who can't print their own boards or develop their fueling strategies and firmware. I intend to try at least printing my own boards eventually.

As for prepping a blow-through carb, the things I have read show it as being fairly simple, especially with motorcycle carbs.
Bump! Any thoughts on using a PerfectPower SMT6 to do this? I got my hands on one and it looked "doable". Interfacing with the engine is the hard part. The ECU needs a square wave pattern as a tach signal and some kind of steady 12v power supply. It's wired with a secondary injector plug. Just controlling the secondary injector and leaving the ignition alone sounded like a good start.

I think an injector w/tps + map signals is all it needs. Keep it as simple as possible. Lambda feedback would be an upgrade and the ECU can handle it. There is a MAP sensor with it already, as well.

I think it can be done for about $500-$750. Cost is the issue, but I think it would make returns on efficiency and pay itself off over time. I have a good lead on the units and will be using them as secondary injector controllers in other applications. I like their flexibility and compact functionality. Making one as simple as possible for the small engine crowd would be a huge market for it.

What would you do for fuel pressure?

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It sounds like it's possible to use it as a standalone because they do make passing mention. I think it's too expensive for what it can do, but if you try it, let us know how it turns out.


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Some of the parts would be good like the pump, small injector, TB, and sensors, but it's not jackpot unless the ECU is programmable. Unfortunately, many do not. A good example of that is the scads of EFI street bikes and crotch rockets that have to have a piggback like the Power Commander to do tuning.

The '09+ Honda CRF450R, '08+ TRX700XX, newer Suzuki LT450R, and newer Yamaha WR250R/X all have EFI in some form or another as well as numerous Euro and Asian scooters. Might look into some of those. Honda Racing Components(HRC) offers a tuner for the CRF450.

The problem, IMO, is that it's just as big a PITA to adapt an OEM system as it is to start from scratch.
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Your right Stang it is expensive, there was another guy MiniMs Website that made a smaller board for the Meagsquirt the circuit board was 3.4" x 5.2".
I've got a copy of the board design if anyone wants a copy (you were able to download it from the website)
I actually had a few of these boards made last year. A company called advanced circuits ( will do a 3 for $33 dollars a piece. If I can find my order number you could just use that. Just make sure its the lastest revision of the gerber files because a few of the trace widths were too close. We currently have one of these running our 240sx with no issues. Theres also another verison...someone called blue smurf or something? has it. They modified it to take the v2.2 software and daughter card. I've only seen images of it. I would highly recommend this kit. Nice to see your still working on this.

As far as crank sensors go, we've gotten away from the 36 tooth wheel, even though measquirt sells them now haha...figures....I picked up the MSD small engine ignition kit. Took forever to get the bastards to send me the coil that belongs to it. Anyway it uses a hall effect sensor, much cleaner signal than the VR sensor. Doesnt require the EDIS system. The 36tooth wheel we designed could sustain high rpm, but really wasn't very practical. This setup allows for a small magnet in the flywheel.

Other than that it's all fuel map tunning after that.
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Do you (or anyone) still have the Gerber files of the MiniMS? I'd like to make one or two myself, but the whole project seemed to have died years ago, even before this thread did. :wink:

Earlier this year I got most of this whole mess (except the green MS upper left) and a pile of discrete components for the cost of one new system:

But they're still on the large side for use on a bike. I'd like to use parts from that board on the top left to build a MiniMS...even though I already reassembled and got it working. :doah: