On-demand timing/ECU control with OBD2

#1

New to the forum- hi all. Have been browsing a lot of information on woodgas lately and I am curious how people do woodgas setups with modern engines that have EFI and individual coil (non-distributor) ignition systems.

How is timing advance usually handled on these? Will the computer automatically advance the timing far enough based on the knock sensors, or is it necessary to do modification to the ECU?

If modification is necessary, is there anyone out there who has made a switch that can turn the extra advance on or off through connection with the OBD2 interface? (Basically like a custom multi-position tuner like what people put on diesels, but with parameters based on woodgas in gasoline engines)

Just general curiosity, I’m not doing a project right now, but have been thinking about it. My main interest would probably be in GM engines, either a LS-based 5.3 or 6.0 or an older 454 TBI

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#2

To adjust timing I think you could just mod the MAP sensor signal. Maybe add a potentiometer to the signal wire. Just my two cents I have never attempted it but If I were that would be the first place I would go to tune timing.

May just use a second sensor set for different parameters and use a switch to flip between the two.

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#3

Hello Mike and welcome to the DOW ( drive on wood )

I don’t have any experience with the OBD2 vehicles but have a lot of miles from vehicles 96 and older .

I have a V-10 Ram that advances the time about 35 degrees when wood gas is put to it . Also I have dodge dakotas 96 and older that I rotate the distributor enough to make the fire jump to the next peg.

The timing issue can get very complicated !!

Here is a tread in the general discussion that might help.

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#4

Hey, the man himself! Thanks for the response.

I’d figure based on your comments and some others that it may advance the timing automatically. I know it does that for gas, but I just asked originally thinking it might cause an error code since gas doesn’t usually need that much advance.

I don’t have the workspace (or really, the time) to do a build right now, but I’ve been reading a lot lately. I’ve seen people on here talking about the “Keith style” gasifier- is that just your specific dimensions for a common gasifier type (open top/stratified downdraft, Imbert, etc.), or have you developed a significantly different concept? I saw that you have a book available, so I’m not asking you to give away too much detail, I’m just interested in the general concept

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#5

Hello Mike . I think some will advance but I know from a build on this site that the 4.7 dodge will not advance enough for the woodgas.

The gasifiers I build are a down draft with a huge amount of heat recovery .

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#6

Hmm, that sounds like a clever idea to simulate certain inputs. Seems like it may be more useful for remapping fuel than timing to me though. Do you have any links to more info about this?

#7

Yes it controls both, but when in a wood gas mode, we dont care about the fuel mapping only the timing.

The harder the vacuum the more advanced.

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#8

If you go with an LS based engine you can get the MSD ignition system. They supply you with a number crystals to tune the timing curve. This is all based on the MAP sensor and CPS

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#9

https://www.aa1car.com/library/map_sensors.htm

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#10

check my link getting obd2 legal gm you can do almost anything.

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#12

I looked at your thread, and it looks like you did what I was asking about- you said that when you turn off the fuel, it would automatically switch to wood timing. I did not see why that happens though. Is the answer to that in your screenshots of the tables, or what exactly causes the timing to advance with wood?

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#13

I have it hooked up so when I turn the fuel off the intake air temp disconnects and reads -40 degrees that part of the timing map I advanced I wont be out driving if its that cold out so when I flip back it reads the real temp and the timing runs stock.

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#14

Nice, that’s the kind of simple solution I was interested in. Glad I joined this forum

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#15

Paul, was just thinking about this again the other day. What software/tuning device did you use to remap the timing based on the air temp sensor?

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#16

Hello Mike.
This may be a lot more involved than you want, but Here’s an Arduino-based open source system for engine management that can do everything:
https://speeduino.com/home/
Buy some or all of the components from him, or build it yourself.

Pete Stanaitis

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#17

Thanks, that’s a cool system. Not quite what I was looking for right now though- I mainly just want to know what kind of PC software and connector people are using to modify existing ECUs. Particularly interested in ones that are good with the GM LS-based engines for trucks. Not sure if people here are using HP Tuners, EFI Live, or what. I’ve seen those get good reviews, but was curious if there was something cheaper or better that can be used for this purpose (modifying intake air temp vs spark advance table)

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#18

Here this is more information on a single page then I have ever seen for tuning, and actually focuses on LS engines. They mention some cheaper alternatives “Low-end tuning software packages such as Tuner Cat OBD-II Tuner and JET Performance Dynamic Spectrum Tuner only offer tuning software and require additional tools for monitoring data logging.”

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#19

hp tuners is what i am useing mike a little pricey for a one time use but if you have other uses its worth it.

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