DIY inexpensive engine management

[BeRad]

Edited : turns out i should read the whole thread before posting

Excellent write up, great detail, and is more than thinking outside the box.

+rep

[oldcorollas]

how do you think this compares to the Megasquirt series, or the Delco GM stuff, i terms of cost, effort and end result?

[MWP]

Well done with the instructions!

Im wondering what the pros & cons are compared with a Megasquirt2 as well.

What is the tuning software like?
Exactly how much tuneability do you have? Map sizes, etc?

[grue0038]

these are merely my opinions on the pros/cons vs other EMS:

pros:
- hardware reliability. OEM ECUs have millions of dollars of R&D into their design.
- 'other than WOT' tuning. they have also usually spent hours and hours on engine dynos to tweak the small stuff- cranking/startup, ECT compensation, throttle tip in, cold running/starting, part throttle transitions, transitioning from DFCO to on-throttle (the point where the injectors turn back on as you touch the throttle), stuff like that. i was surprised how close the 3GSTE was to the hybrid honda/toyota base map i started with. it actually behaved better driving cold/off boost the first time i started the car up on the new ECU than it ever did on the factory toyota stuff.
- tuning software can be had for free. i'm using CROME free, it has all the functionality of almost any EMS minus onboard datalogging. for that, i use freelog. it's probably worth the $175-199 to just get eCtune and start with something that's hands-down better than most engine management out there.
- almost all the software available is very easy to use and intuitive. i know folks complain about the UI for systems like hydra and AEM, and sometimes even megasquirt.
- there are so many people not only running these ECUs, but developing new stuff for them as well. same goes for the EVO ECU crowd- there is more evolution/development going on with those ECUs than AEM could ever hope to see simply because there's a bigger workforce. this applies to megasquirt as well- there are a TON of people helping to develop stuff for MS.
- most stuff is configurable. for instance, i use a cheap 3bar MAP sensor mounted in the toyota housing and the software works with it. many jap cars use the same thermistors in the IAT and ECT sensors, so you can get away with using your stock sensors just like most aftermarket EMS.


cons:

- as of writing this, you pretty much need to install a honda distributor on whatever engine you're running. for the 3SGTE, it's not a huge deal, since the ignition system is inside the distributor on hondas, and honda ignition is superior to toyota ignition from a spark energy standpoint.
- the toyota TPS scale is a little too low for the honda ECU. i fixed this with a simple opamp amplifier for the voltage signal.
- cold start on the honda is controlled by the FITV (fast idle thermo valve). cold idle on the 3S is controlled by the ECU. i just installed a honda FITV under my intake manifold to fix the issue.
- technically speaking, this conversion may be beyond the scope of a lot of people if they aren't willing to put some work into it to learn how all this stuff works. when working out stuff like this, it isn't enough to know that you have to connect 'this wire to that wire,' you need to know WHY those wires go together, otherwise troubleshooting becomes impossible. there really is no user manual to refer to, and no customer support line to call. for a lot of people, this is one of the biggest cons.

as far as features:
- add up to 10 boost columns to the tables (10x20 for NA, up to 20x20 with interpolation for boost)
- fully sequential injection with individual cylinder fuel trims (i think ignition trims are on the way as well)
- boost, fuel and ignition trims by gear
- some of the tuning software has extra outputs for thigns like nitrous and H20 injection
- full throttle launch/shift (this one is really fun. i laugh like a little kid every time i use it)
- antilag to build boost on the line
- support for ITBs (alpha-N)
- real-time tuning
- depending on the software/hardware you use, some stuff (hondata does) has onboard datalogging that can be activated by an aux input (like an A/C switch) for logging on track.
- failsafes like overboost, overheat, anti-theft, etc.
- secondary maps for things like staged fuel injection (use VTEC solenoid output)
- with crome, you can make up to 16 different tunes and load them all into a single chip (with appropriate hardware) and use a switch to change the map you're running. i currently have a double map in my car- one for petrol and another for ethanol. i only run petrol when i can't find ethanol, but all i need to do is flip a switch.


if you want to check out some of the software, go to:

www.hondata.com
www.tunewithcrome.com
www.ectune.com
www.hrtuning.com (neptune)

most will let you DL the software for free. the ones like hondata and neptune have proprietary hardware that gets installed in the ECU case to interface with the software.

[trdee]

absolutely ingenious +rep!

[wagonist]

Awesome info!

How would this go with a Gen 4 3SGTE, with the coil on plug system? (no distributor)

Gen IV 3S-GTE has crank sensor already (whether it has the same number of teeth as Honda though), plus Cam sensor (1 signal/revolution) off the end of inlet camshaft.

The Gen IV ECU controls the spark timing, so how the Honda ECU could control that would be something to sort out.

[grue0038]

yeah. i'd be willing to bet that the crank reluctor is a multiple of 12 though, so one could just grind off the requisite number of teeth (preferably from a spare wheel, but i suppose you have to tear the timing belt off to get to that wheel anyway) to get the correct signal. where the cam sync is phased is another question. honda needs it between 3 & 4. if that wouldn't work out, a single notch wheel on the cam pulley would also work.

demultiplexing the ignition signal is another issue, but i drew up a circuit a while back that should be able to do it. i never got around to testing it, but i posted it on the ectune forum and another member's dad over there is a hardware engineer so he said he'd take a look at it. hopefully he can get that tested, as it's not a particularly complex piece of hardware- 3 ICs really. a counter IC syncs up to the engine rotation and counts off each IGT signal, enabling each successive cylinder's coil each time a new igt comes through. that output is sent to an AND gate (output only goes high when both inputs are high) along with the IGT signal, so the signal is sent to the gate for all 4 cylinders, but only one is enabled at a time.

alternately, grind 7 notches in the crank pulley, mount a sensor and run a GM DIS pack.

[wagonist]

The Gen IV 3S's "mark" for the cam angle sensor is bolted onto the end of the camshaft (I suspect where the distributor wheel normally screws into), so most likely, if this signal is in the wrong spot, it could be moved such that it corresponds.

[Sam_Q]

old thread dig up time

can you explain more about how to work and hook up this "GM DIS pack" ?