Dodge Dakota 1992
3.9L V6
multi port fuel injection
single coil with distributor
megasquirt MS3X
DIYAutotune 36-1 Crank sensor
Stock Injectors
Stock Sensors (Except MAP- MS3X on-board)
MS3X controls; AC, Fan, Overdrive, Torque Converter
Raspberry PI3 Running Tuner studio in dash. (Will be radio and tuning when finished)
I'm having trouble with Injector dead time and VE tuning. I think once I get all the other settings down the VE will fall into place. It seams there are large changes from day to day in the VE table and the temperature makes big differences as well. I'm thinking that there may be an issue with MAT temperature compensation. All sensors show correct values as far as i can tell.
Any pointers are welcome.
***** Updated Tune file *******
Updated tune file because I was unsure witch tune the log is from. They are correct now.
Working on logfile, Must make it smaller file size too large
Tuning Help
Moderators: jsmcortina, muythaibxr
Tuning Help
Last edited by AlanJ on Mon Apr 24, 2017 5:15 pm, edited 4 times in total.
92 Dakota Work in progress (ms3x)
-
E4ODnut
- Master MS/Extra'er
- Posts: 406
- Joined: Sun May 02, 2004 9:13 pm
- Location: Gibsons, BC, Canada
Re: Tuning Help
First of all, study the set up manual. There is a lot of very good basic tuning information there. Everyone has his or her own style of tuning, but for what it’s worth, this is what I prefer to do.
The default tables will generally get you in the ballpark. I don’t use O2 correction at all and run open loop at all times. It has served me well. I don’t use accel enrichment at first. Only after I am happy with my VE table I will bring it in if necessary.
I had a look at your MSQ and a few things did jump out at me, in particular both your VE table and Spark table look a bit weird, same with the prime pulse. Go with the default values to start with. Your dead time is 2.8 ms? Again, go with the default of 0.9ms. Flood clear is 50%? Try the default, ~90% or so, if I recall. Are your idle homing steps really only 120? Again, go with default, or better yet, don’t use idle control at all at first if you can adjust the throttle stop. Are you really using a narrow band? A wide band is essential equipment in my opinion.
Get your VE table dialled in as close as you can, as soon as you can. This means getting the engine to start and run reasonably well in the driveway. Get it warmed up and set as many no load values as you can so that the engine runs with the AFR values you want at each particular load and speed point. Then, and only then are you ready to go out on the road to start tuning the rest of the table.
With the engine at operating temperature, start a data log file and go for a short drive. Come home, stop the log file and shut things down. Take your laptop in to some nice quiet place and do a VE analyze on the VE table. Save the changes to a new MSQ file and go for another drive. This time log a longer drive with more driving conditions. Go home and analyze the file, make the changes and repeat the process as many times as you have to. I find that VE analyze is a great tool, but it is not perfect. I usually have to kind of look at the trends and fine tune the values by hand a bit to have them where I want them to be. It takes time and patience, but when it’s done, unless something drastically changes in your engine, the tune will be solid for years.
Once you are happy with your VE table then you can work on Spark and all the other lesser tables. You may have to go back and tweak your VE table, depending on what changes you made in other areas, but, that’s half the fun of it all, don’t you think?
The default tables will generally get you in the ballpark. I don’t use O2 correction at all and run open loop at all times. It has served me well. I don’t use accel enrichment at first. Only after I am happy with my VE table I will bring it in if necessary.
I had a look at your MSQ and a few things did jump out at me, in particular both your VE table and Spark table look a bit weird, same with the prime pulse. Go with the default values to start with. Your dead time is 2.8 ms? Again, go with the default of 0.9ms. Flood clear is 50%? Try the default, ~90% or so, if I recall. Are your idle homing steps really only 120? Again, go with default, or better yet, don’t use idle control at all at first if you can adjust the throttle stop. Are you really using a narrow band? A wide band is essential equipment in my opinion.
Get your VE table dialled in as close as you can, as soon as you can. This means getting the engine to start and run reasonably well in the driveway. Get it warmed up and set as many no load values as you can so that the engine runs with the AFR values you want at each particular load and speed point. Then, and only then are you ready to go out on the road to start tuning the rest of the table.
With the engine at operating temperature, start a data log file and go for a short drive. Come home, stop the log file and shut things down. Take your laptop in to some nice quiet place and do a VE analyze on the VE table. Save the changes to a new MSQ file and go for another drive. This time log a longer drive with more driving conditions. Go home and analyze the file, make the changes and repeat the process as many times as you have to. I find that VE analyze is a great tool, but it is not perfect. I usually have to kind of look at the trends and fine tune the values by hand a bit to have them where I want them to be. It takes time and patience, but when it’s done, unless something drastically changes in your engine, the tune will be solid for years.
Once you are happy with your VE table then you can work on Spark and all the other lesser tables. You may have to go back and tweak your VE table, depending on what changes you made in other areas, but, that’s half the fun of it all, don’t you think?
Robert
'53 VW Beetle Street Baja dual port 1641 MSnS-Extra
'53 VW Beetle Street Baja dual port 1641 MSnS-Extra
Re: Tuning Help
The manual has a lot of info to be sure. But its difficult to find and apply the info needed.
I have to use the truck as a daily driver and those auto adjustments get me through at the expense of gas (that stuff is cheap right?). I would prefer not to use them but.....
The spark table is weird. It is a hodge podg from the recommended table. I had to pull a bunch of timing to keep detonation down. So i took a bunch of timing from the bad areas. it is on the list of things to do after it gets close to finished. I used the table generator with information i could find on the internet, All the VE values were way too low to start, I was having a serious lean issue. I added dead time to compensate because otherwise all the VE values would be over 100 and 150. I can not find out how big my injectors are. Auto-zone doesn't know and i researched as much as I can, the consensuses is 19 LB. Idle homing steps of 120 is actually a lot more then i need. 25 Steps is roughly equal to 1/8 inch. the max travel is less than a half an inch. these seam to work great. The idle only hunts when the VE table is off....
Would a wide-band make my life easier? ill get one this week if it would. I just figured that it was my inability to understand the tuning concepts....
The engine runs great at idle and when the throttle is blipped. Much better than the stock computer. In edition the throttle response is excellent below 2500 RPM. Its the higher areas that are giving me a problem. The narrowband shows I'm running too lean and eventually get to 255, and it still shows lean. I'm working on trying to learn from the logs how to tell if its actually lean or flooding out....
That is the best part! but i need more I/O for the Megasquirt so i can keep up my ideas......
I have to use the truck as a daily driver and those auto adjustments get me through at the expense of gas (that stuff is cheap right?). I would prefer not to use them but.....
The spark table is weird. It is a hodge podg from the recommended table. I had to pull a bunch of timing to keep detonation down. So i took a bunch of timing from the bad areas. it is on the list of things to do after it gets close to finished. I used the table generator with information i could find on the internet, All the VE values were way too low to start, I was having a serious lean issue. I added dead time to compensate because otherwise all the VE values would be over 100 and 150. I can not find out how big my injectors are. Auto-zone doesn't know and i researched as much as I can, the consensuses is 19 LB. Idle homing steps of 120 is actually a lot more then i need. 25 Steps is roughly equal to 1/8 inch. the max travel is less than a half an inch. these seam to work great. The idle only hunts when the VE table is off....
Would a wide-band make my life easier? ill get one this week if it would. I just figured that it was my inability to understand the tuning concepts....
The engine runs great at idle and when the throttle is blipped. Much better than the stock computer. In edition the throttle response is excellent below 2500 RPM. Its the higher areas that are giving me a problem. The narrowband shows I'm running too lean and eventually get to 255, and it still shows lean. I'm working on trying to learn from the logs how to tell if its actually lean or flooding out....
That is the best part! but i need more I/O for the Megasquirt so i can keep up my ideas......
92 Dakota Work in progress (ms3x)