Self tune mefi burn, am I crazy?
 

After talking with few well known guys about selling me a proven flash for my upgraded 575scis I was told by all 3 of them to install 02 bungs and get AFR readings AFTER the burn and send back for adjustments, mainly because of my cam choice.

So I started thinking- I still need to buy a scan tool, invest in the AFR, weld the bungs, and then I need to pay any shipping to send a LOCKED ecm back and forth to fine tune, if needed. Or fly a guy out to sit on my boat and tune, which is the only way to get the most accurate tune

OR.....purchase mefiburn software, and sit down to do my own tune? How hard can it be? I decided to go with this option, which also doubles as a scan tool and leaves my ecu open for adjustments and diag.

Bob at mefiburn seemed very friendly and helpful, the support at this point appears to be above average.

As much as I love this site, it seems to lack knowledge in two key areas, hydrodynamics and efi self tuning. Not knocking the guys on here, cause the site is extremely strong in most boating areas of discussion, in fact the best. Some of th smartest engine, glass, prop, drive, diag, and electrical DIY'rs on the planet hang here, wonder why they hide from these areas?

I am going to document my tuning journey, win lose or fail, for two reasons. One is for guidance from anyone on this site that has experience, and two is to help others that are considering doing the same.

I am not looking to spend the rest of the summer tuning my boat, in fact I am hoping to get a tune relatively quickly.

Key areas that need to be addressed

-cold start way too rich
-rev limit raised to 6000 rpm and custom table for fuel cutoff
-calibrate to run on 120 degree stat
-calibrate to compensate for increased boost and cam change


Wish me luck! The fun should start next month

A friend of mine runs HP tuners, http://www.hptuners.com... I have no idea why this is not more common on boats.. I use to tune my 99LS1 back early 2000... go out record or monitor a run , then change what I needed to. I have no doubt you`re gonna love having the ability to tune your own stuff.

This was the main reason I went to a carb setup because I don't want to send out ECM for tunes while I sit, wait and hope for the best.

I tune motorcycles on my dyno all the time and its not bad once you understand what the motor is needing. With the afr installed you should be good to go.

Good luck.

I did basically what you are going to be doing. I'd be happy to share my experiences with you. Just PM me.

What MEFI unit? I presume a MEFI 4.

What ignition system?

If at all possible get a copy or download the baseline tune off your ECM and save it. Make multiple copies. If the tune is locked and you can't get the password then your job is harder.

You would need to do extensive data logging to gather all the fuel and timing parameters and reconstruct the data on a new unlocked base tune. You can't have too much data logging in this case! Log from a cold start idle through warm up. Log everything at steady state rpms through out the rpm band. Log slow and heavy acceleration from idle to WOT and everything in between. Log decel both heavy and slow (monitors what ignition and fuel does under heavy vacuum).

Once you modify the tune save it as a new file. When another change is made save it again as another new file. This way you have sequential copies of changes and can go back should you need to.

Make small changes and limit your changes to one variable at a time!

The rich cold start you wish to address is fairly easy to fix. There is a specific table labelled "Coolant Temp vs BPW". In essence and electronic version of a choke. Cool motor gets more fuel, warm motor needs less fuel.

Hey thanks for the tips.

I have a stock mefi3 system, and stock merc HEI ignition....no plans to change.

The ECU is stock, and I will save the files as you noted. Finding someone to provide a "close" tune to adjust is near impossible, mainly because they will lock it so that their hard work can not be pirated.

The hardest part that I see ahead of me is aligning the ARF readings with the ecu data log. From what I can tell with the stuff I planned to purchase so far it would be manual, I need to do more research because I would like the two to work in the same log.

Thank you! Good luck with all your winter improvements as well

If it were me would can all the merc crap, run a laptop programable on your boat and be done with all this sending back and forth B/S...its a short in the dark and usually not very close to where it should be....I run megasquirt with my own EFI setup with a procharger....

Ok, you have a MEFI 3 with a stock tune but a modified 575 correct?

I believe, but am not sure but the MEFI 3 ECMs were locked by Merc with a password. I can't confirm this but you will know when and if you try to download the file using MEFIBURN. I have a MEFI 1 and it was not locked. I was able to download and save the stock tune and go from there. Made my job much easier.

It is true that the AFR readings would be logged separately from what Scanner Pro logs. However you can wire and set up Scanner Pro to log AFRs as well. It takes a little extra wiring and some tweaks on ScannerPro. Not insurmountable but extra work. To date I've simply logged them separately and taken time hacks on the recording to along with a series of throttle inputs to align the playback. I also do some steady state simple paper/pen notes and that has worked well.

Much of the idle and warm up can be done on the trailer with a hose attached. This is good for cold start to warm idle no load tuning.

Do you know the stock motor cam specs and boost?

What modifications did you do to the motor? Cam? Heads? Both? Injector mods?


PM me for more details. I wish you the best of luck.

Here are a couple links to add a gauge. There's another I remember seeing that details the process fairly well but I can't seem to find it.

http://tunerpro.net/forum/viewtopic.php?t=518

http://www.carols62.com/ramjet/cruise_control.html

This might be the other link.http://www.carols62.com/ramjet/wideband.html

I've wanted to wire it up but have been too lazy.

Yes, you are crazy. Our season is way too short to go down the path you are headed.

Those motors don't need much to run real good. Go with a reputable shop that has a proven cam/tune recipe that is known to perform and be reliable.

Keep it simple and go boating !

I get what you are saying about the path, however the same could be said about spending the summer sending expensive ecu's cross country to be tweaked all summer long cause my boat runs like crap. The fact that they lock the ecu's is what bothers me, I would not be able to even collect data after a few of them lock them up, I don't like that.

Wish I could have kept it simple, a scared lobe caused me to have to upgrade from flat tappet to hyd roller.

The reputable shops I have talked to do not have enough confidence to say the tune will be right for this area based on my cam choice. Further tweaking will be mandatory. As I read it doesn't look to be rocket science, however a dyno would make this much much easier.

The bottom line is if can not get it right I can always try one of the "canned tunes" later, First week of May is my deadline. And if that doesn't work I will bring the boat to Lake George for a prop shaft dyno tune. :D

How hard can it be? :lolhit:

mefiburn.com supplies the unlock passwords

Thanks for the tip on the cold start tune

I do know the stock motor cam specs and boost, they are off the shelf merc 575sci.

Engine mods are just hydr roller conversion, 120 degree stat from 150, boost upgrade from 4.5 stock to 6 psi, and cp performance adjustable fuel regulators. 7.5:1 stock comp, and a lower end that will support huge HP are stock and untouched.

Many will tell you this engine came in need of a tune more than any other efi engine from merc. It is beyond rich, has chronic IAC issues, throttle blade issues, and the cold start table will kill a manatee.

It uses 4 large injectors in a tbi setup that works much like a 4 barrel carb set up. I have been told this set up make it easier to get close, but difficult to fine tune.

Save yourself the mailing option and have them remote in live for the extra $50! :)

----
Remote tuning

We can tune your controller remotely, anywhere in the world, if you have purchased our MEFIburnTM software and you have a high speed internet connection while connected to the vehicle you want tuned. You will be able to watch your laptop's screen as the MEFI calibration parameters are changed and saved. Clear descriptions of what is being done will be explained as it is happening. Our price for remote tuning is $250

That is actually a very good way to go. Remeber anytime you want to you can tweak the tune and you always have a reference file to go back to.

That won't work with my mefi3 computer which doesn't accept live changes. Decent idea however.

Honestly I don't know why so many make such a big deal out of fuel air metering when it comes to efi vs carb. Sooner or later we have to learn this stuff, no time better than now!

I purchased the MEFI Burn program a few years ago. It works very well, and works exactly as advertised. However, I found it needing more tuning time and expertise than I had to give.
I recently purchased the Holley HP EFI system.
Why?
"Self-tune"
You just set the basics, such as engine size, max timing, desired AFR etc. The 02 sensor is connected directly to the ecu (closed loop) enabling the ecu to learn the settings needed to achieve the desired afrs. After the base maps have been built by the ecu during closed loop operation, the 02 sensor can be removed and the system will operate strictly from the base maps (open loop) that it has learned. No more manually changing fuel curves or spark advance cell by cell. I'm not saying that tuning the MEFI systems is wrong, or not worth it, it just wasn't for me.
I have it installed, and both engines are running but have not had it out on the water yet. I will be glad to report back as soon as I have some real data to share.

Steve

What makes you say that...just another eprom. You may wantto call Mefi and have a talk with them...All you need is laptop with wifi and a cell sevice of course.

The best way to start is on the dyno set the brake at given rpms say 2000,2200,2400 on up to your rev limit,sweep the throttle at those rpm from zero to full watch your afr adjust as neccessary,make full throttle runs on dyno and also check your cruise speed on dyno ,when you think you got it right install engine in boat and check your afr at all speeds adjust as needed,we have done several efi projects using mefi burn and it works real well never done a 575 sci,it does require alot of time and patience

If Bob can get your MEFI unlocked that would be huge! Download and save the original .bin file.

You can still data log even on a locked ECM. You just can't save or change the .bin file without zeroing out the controller. You don't want to do that. Building a tune from scratch would be a PITA.

From my limited experience extremely rich idle conditions will cause the IAC to surge. I nearly doubled my injector size and prior to trimming out fuel the IAC was surging full tilt from open to closed trying to keep the idle under control. Motor sounded cool but it was completely impractical. Trimming your idle and cold start fuel values "may" help the IAC issues.

This AFR meter logs data. Not sure if it logs it over rpm or not but if so that would be the ticket IMO.

i own the innovate dual sensor handheld wideband. it logs RPM and also logs map w/ external module.

you should move this thread over to the baja section. Lots of EFI experts over there. :poopoo:

Bam! Lol

I agree. Id put the money towards a aftermarket Holley EFI setup. Talk to Haxby or Eddie young.

I had gone the FAST efi setup. I got the starting tune from another member. I set it up where the efi could richen the AFR by 25% if the O2 thought it was too lean and only lean out by 2%. In the beginning I had a friend drive the boat while I made changes to get close. Once I was close I would just run a log and then go back to and update. I had lots of help from other OSO members as I was trying to get the idle perfect.

I was having a problem one time and was able to talk to a fast engineer. He was great help and got me past my problem.

Would I do it over again? Hell yea!

LOL, I sit in the back of JimV's Fountain with a laptop and an Innovate LM1. Pulling fuel and throwing fuel at his Haltec FI system. Never realizing we are running almost 100mph in a little 27' Fountain.

I say go for it 4bus. I don't know how much the Mefiburn is but I would look at what the cost difference to go with a different ECU system. Holley, Big Stuff, FAST or Megasquirt. Then you can always tune your new upgrades.

Mega squirt just sounds so inappropriate

4bus stay with it,there is definitely satisfaction to doing it yourself,no doubt in my mind that you will master it soon.

Has anyone tried the kits from dynojet research on the mefi stuff?

fixx
 

i make my own!!!...DIY.....

Are you taking about the cmd units?

I thought about it, but two possible problems with the system for my application

1. Requires a permanent O2 sensor, because it constantly monitors. O2s do not like water, and are not exactly cheap to replace.

2. If the system fails it will revert back to what ever you have, stock tune, which may not be safe for my new mods

FYI. The mefi burn software for mefi 1-4 is only $595, and the software also serves as a data logging scan tool that allows you to see many sensors and parameters at once. The rinda scan tool alone is 395, and really isn't any good for an over all picture.

I'm still goin for it!

You don't need to leave the sensor in. It's a much more user friendly tuning platform then Mefi burn. I don't know if they have a system that will work with the TBI though. Might be worth a call to Keith @Dynojet. If they have a system that will work it would save you a lot of time. Tuning a Mefi 3 with mefi burn is very tedious.

Running an O2 sensor all the time is not a problem if mounted correctly. I'm going on three seasons plus a tuning session and its not an issue.

I tossed around the idea of using the CMD system but it only tackles fuel issues. With MEFIBurn I can tweak all the parameters, timing, coolant temp vs bpw etc.

The most difficult part to tune with MEFI are the transients (heavy accel/heavy decel).

4bus, not sure how I missed this thread. I kinda thought you would have to go a different route after a cam change. What route did you go to select your new cams? My motor is being pulled down for rings and inspection...I am afraid I will end up with a different cam like you.

I was going to go with a "Canned tune" but I didn't go with a "canned cam" :D

Knowing so much about automotive diagnostics, but have little experience in custom ECU tuning has been eating away at me for years....now is the time. I can always try a canned tune afterwards. The guy you sent me to was great and very supportive, and honest! But, he wanted me to have an afr meter, I needed a scan tool, and he said I will prob have a trouble around the docks with my cam choice but keep sending it back with new readings until we get it right.....um, or just tune myself?

These are my came specs

612/637 lift, 242/248 duration on 114 CL +2 advance

I can't imagine trying to solve a hard acceleration issue, or dock stall issue by sending an ecu back and forth through the mail.

the mega squirt is the cheapest deal I think...but you need to come up with your own wiring harness...not a huge deal...building mine right now...will post some pics as soon as I get it back together...you only need the MSII box which will run the EFI and the ignition/timing curve..less than $500

I've spoke with him, they could work my connector but he told me wide band o2 using auto tune is the only way to go, which means live 02 sensors all the time

Cheapest? Not really worried about cheapest, however I think the MEFIburn price is hard to beat, and I won't be making harnesses...and it will still scan with a merc tool when I am done, which is valuable come resale time....I think. Not to mention I am tweaking my stock file. Als keep in mind that I have twins, which doubles the cost for your application...mine stays the same

You guys really hate the merc computers huh? We have a few locals that have failed at tuning that also seem to hate the merc computers. I will either be joining you all for a drink about why computers suck, or I will be the new resident expert

Here is the cost break down for you

Innovate wideband AFR $155.00
SS bungs and plugs $40
Welding to tails $100
MEFIburn, tunerpro, scanner pro $595.00