MSefi.com read only forum (Jan.15,2018)

Hello everyone.

I'm running MS2 v.3 main board
Firmware 2.8x I believe
Innovate LC-1 wideband controller
Tuning with Tuner Studio MS & Mega Log Viewer

My Honda originally came equipped with a vacuum advance/retard distributor. I have a 36:1 trigger wheel with the VR sensor mounted to point @ the 9th tooth (90 deg) when the motor is @ TDC. The Honda service manual for my car says that timing for the motor should be 15 degrees BTDC. And, advance from the vacuum advance module @ 20 inHg should be +4 degrees. 20 inHg is the same as 67.7 kPa. My engine idles @ about 60 kPa. It also says that my timing should be a 4 degrees BTDC with both vacuum lines to the advance module clamped off. I don't quite know what to make of that last part. Maybe it is @ 4 degrees BTDC during cranking?

1. Do I need to set a trigger offset sense the VR sensor is set @ TDC not 15 deg BTDC?

2. Should I have my advance map @ idle kPa/RPM set @ 19 degrees advance?

3. What should my max advance be? I read in the mega manual that common max advance is 24 to 36 degrees, and should be reached by about 3k RPM

Also, I started using the auto tune VE feature in MLV, it has tuned the VE table to be more efficient. The car was running really rich before. I was getting a lean spike, and hoped that auto tune could fix it, but it is still there. I'm pretty sure my ignition table is not correct, so here I am.

I am attaching my .msq as well as a datalog. The datalog is only a couple minutes long, and only goes up to about 4k RPM. It doesn't ping or anything, I'm just not comfortable enough with the tune that is on it to risk redline yet. Even though redline is only 6200 RPM.

Thanks in advance for any guidance you may have to offer.

Just set the offset so the spark advance you see in TunerStudio agrees with your timing light.

Hondas don't need a lot of advance, but unless this is identical to an engine we've tuned before, it's not likely I can give you specifics. (And most of the Hondas we've tuned were E85 powered autocross cars, so the maps we have probably won't help).

Matt Cramer wrote: ......Hondas don't need a lot of advance, but unless this is identical to an engine we've tuned before, it's not likely I can give you specifics....

Ok... so I've smoothed out the lean spikes a lot, runs smooth now. The only problem I have now is when I go to rev it over 4k RPM it looses power and makes a bit of a clatter. Should I take off some advance? I thought that as RPM goes up, timing should advance more. I'm at 24.5 degrees advance at 3100 RPM, and 25 degrees at 4k RPM to redline. Is that too much for a gas Honda? Anybody know where I can find out stock maximum advance at redline for a Honda A20A3 motor? I think that is the only stock ignition speck I don't have.

Loss of power under 4k RPM turned out to be low fuel pressure. At least partly. I was running @ 35 psi, I turned it up to 50 psi and it quit clattering @ high RPM. It still doesn't pull much once it gets to 4k, but normal driving I shift @ about 3k anyway so... It doesn't have any problem free revving to the rev limiter @ 6200. I'm not quite sure what the deal is.

Could you post a data log of this and a copy of your MSQ?

Matt Cramer wrote:Could you post a data log of this and a copy of your MSQ?

Here you go.

If you need me to check for it not running well above 4000 RPM, I will need a data log that goes over 4000.

But it looks a bit backwards to have the timing retard at low MAP readings instead of advancing.

Matt Cramer wrote:If you need me to check for it not running well above 4000 RPM, I will need a data log that goes over 4000.

But it looks a bit backwards to have the timing retard at low MAP readings instead of advancing.

Thanks for the input. If you are referring to the 600 RPM column, my thinking was to help it fire up on cranking. It helped some, but it did have some adverse effects on low RPM acceleration. If I rev the motor a little and slip the clutch a little on take-off there is no problem. I was considering changing the first three columns from 600, 1100, 1600 to 500, 800, 1000. That way I could use the whole 500 RPM column as basically just a cranking column, and the 800, and 1000 as idle/off idle acceleration.
I have a data log that goes over 4k, but it was too large to upload. I haven't driven it for the past couple days because the starter went out. I expect to get the new starter tomorrow. After I put it on I will make a shorter data log that goes into the higher RPM range. At least as high as it will go under load.
Thanks again for your help. I will get the new data log uploaded ASAP.

I didn't mean the 600 RPM column; idle timing has its own rules. But when the RPM comes up, you're running less timing at low MAP than at WOT; it's like putting a vacuum advance on a distributor only modifying it to move in the reverse direction from what it should.

I didn't mean the 600 RPM column; idle timing has its own rules.

I *think* Matt meant "cranking timing has it's own rules" - i.e. it has it's own settings: http://www.megamanual.com/mt29.htm#rn.

Idle timing is a bit different from normal timing tuning too, though (and maybe this is what Matt meant). The transition from cranking to idle advance shouldn't be too huge, and there are other considerations too (like idle stability, emissions, etc.).

But of course Matt is correct as always in saying that advance should decrease as load (MAP in kPa) increases: http://www.megamanual.com/begintuning.htm#spark

Lance.

I meant the latter - the rules of thumb for tuning timing at idle are a little different from tuning it in other parts of the map.

Thanks again for the help fellas. I will review the links after I make this post.
The attached .msq has an altered advance map. I flipped the map/advance relationship, and added a little more advance. The attached data log was made using this current .msq.
I only got it up to about 5k RPM, it just doesn't feel right. I don't want to mess anything up. It's a freshly built motor with about 2k miles on it. I broke it in with a vacuum advance distributor.

Well.. So much for that. My motor threw a rod this morning. What I've learned from this experience. If you don't like the way your car is from the factory, buy a different car.
Thanks again for your time, and guidance.