MegaSquirt Your 280ZX Turbo
10-26-2008, 01:23 PM
#1
MegaSquirter
Thread Starter
Join Date: Jul 2007
Location: Capital of Texas
Posts: 58
MegaSquirt Your 280ZX Turbo
Like many upgrades for the 83 Turbo, this one came out of frustration with the 25 year old wiring and technology. Search after search for alternative ignition and fuel driving computers for this vehicle only made me more frustrated. That is, until I ran across a little do it yourself (DIY) aftermarket fuel and ignition management system, the MegaSquirt system.
I found a website that had the MegaSquirt kits at a very affordable price. That site is; http://www.diyautotune.com. I emailed the staff with what I was looking for and within one day had a complete price quote for my particular setup.
MS130-K $187 Megasquirt-I kit with V3.0 PCB
MSStim22-K $45 Stimulator kit
MSHarness $65 12' wiring harness
IATwPiggy $22.25 IAT Sensor
38NPT-Bung_S $8 Steel Bung for mounting IAT sensor (Aluminum or stainless also available for $9)
TuneCable $5.50 6' DB9 tuning cable
USB-2920 $20 (Only needed if your laptop doesn’t have a true DB9 port)
Subtotal without wideband-- $352.75
Read!
The first and most important thing is to read the MegaSquirt mega manual. It can be found here; http://www.megamanual.com/mtabcon.htm. This will either scare the crap out of you, or encourage you to proceed. Truthfully, I got scared, but I have a different outlook on things. This is the assembled result:
Here is a list of websites that will answer any and all questions that you might have about assembly, applications and purchasing of the MegaSquirt system. I borrowed this from another post.
MegaSquirt Main Website
MegaSquirt/Relay/Stim board order site
Car Craft MegaSquirt Article
MegaSquirt Consolidated Forum
MegaSquirt Extra Forum
Read through the websites and become familiar with the MS system as well as the computer software required to run the 83, MSnS (MegaSquirt and spark). I went with the upgraded software which is MSnS-Extra. It has more features and is also compatible with a wide-band 02 sensor. With this system, fuel and ignition are fully programmable and since ignition is based on manifold pressure, you can retard timing with boost, and you get rid of the flapper AFM, that has to be good!
To run MSnS-extra code on MS hardware you have to give something up for ignition control. You give up Fast Idle (FIDLE). FIDLE now becomes the ignition output trigger with MSnS-extra. With the downloadable program called MegaTune, fuel and spark setting can be controlled at the same time with a simple connection to your lap-top computer, and in some instances a Palm computer.
Assembly
When your box arrives the fun begins. If you are experienced at soldering, then it should take you about 4+ hours to assemble. Yes, you have to solder the components together, hence “do it yourself”. If you’ve never attempted to solder, then this might not be the project for you, or go to your local radio shack and get a small kit to practice. Once you have it mastered, the inexperienced assembler will take 8 to 14 hours to put this together. Believe me, there are a lot of little parts. I also recommend purchasing the MSStim. This is a great way to practice your soldering technique and it serves as a testing platform for the assembly stages of the project. The key here is to TAKE YOUR TIME, don’t rush this stage or you will never see the end of the project.
Programing
The MegaSquirtnspark (MSnS) software can be found here. Download the most current listed code. There are other posts that recommend adding a 2 pin header at the H1 location on the PC board. I did not do this. I just used a cutoff of one of the resistors to make a jumper, which worked well for me.
To download new code put the jumper at H1 when MS is powered OFF. Power MS on, have it connected to your laptop and MegaTune running and follow the directions with the software. Once the MSnS code is downloaded you can re-test your hardware with the MSStim. Also, the center LED on the MS box use to be the warm-up indicator, but now this is connected to ignition output as well. So, you have an indicator that your ignition is firing, at least at the computer side.
Now you have MSnS tested and ready to install in the car. At this point, it is suggested that you use the MegaTune software to set the system up with your basic car settings. Set MSnS to use time based cranking. Also Very Important Step, in the Spark Settings tab in MegaTune it is vitally important that the “Spark Output Inverted” tab be changed to show “yes”. Don’t forget this step.
Install
Once the ECU is assembled, tested and checked ok, then it is time to put the system in the car. I used the wiring harness from DIY and rewired the engine bay. This helped immensely. This process took me about a day to complete.
Time to remove that outdated AFM and old wiring harness. Due to my lack of funds, I left the boot connecting the AFM to the turbo. I took a small piece of 3-inch PVC pipe and connected the boot to the intake air filter. $5 and the job was done.
With the 83 distributor on the turbo, this swap is much easier. I have read other posts where the EDIS system had been adapted but to me seemed like entirely too much work. The vehicle has a solid ignition, so in my mind, why not use it. For a complete guide on adapting the stock ignition go to this site; That’s all there is to making the stock ignition work.
240sx TPS wiring
The TPS on the stock 83 has to be removed and a TPS from a 240sx used. On the 240sx TPS there is a built in connection as well as a three wire pig-tail. The wires in the pig tail connect to the harness as:
Red to Vref
White to TPS
Black to TPS ret
The problem I had was the 240sx mounting wings were different than stock . It took me a little while to figure out a mod for this, but I ended up using a small piece of plumbers strap and soldered it to the back of the new TPS, so far, it has worked very well.
MS recommends using a GM air-temp sensor as well as a GM water temp sensor. The air temp sensor can be mounted to the z-pipe going from the turbo to the intake. The water temp sensor is a direct screw in replacement. If you order these parts from your supplier, they will also come with the correct bung and connector pig-tail. I drilled out the correct sized hole in the intake pipe, and soldered the bung to the pipe. A little black paint and it looks good as new.
Setting the Timing for MegaSquirt
Set the engine to top dead center (TDC) on the number 1 cylinder. It has to be on the compression stroke and not the exhaust. Once TDC is achieved turn the crankshaft back by hand to what you think is 50 or 60 degrees BTDC. For MS to function the ignition trigger from the distributor needs to be at least 5 degrees before the maximum advance that will be used. For the stock setup, 45 degrees is the most I would need so I set it at 50 degrees BTDC. The marks on the crankshaft pulley only go to 30 BTDC so you will have to guesstimate the rest. I later found that this was not an exact science as the software can make up for most errors, so just get it close.
Loosen the distributor and give it a turn by hand with the MSnS powered up. Turn the distributor until you see the middle LED come on. When this lights up stop and tighten the distributor back down. A timing light comes in very handy from this point on, so if you don’t have one get one with the adjustable advance setting. Have someone crank the engine and check the settings with the timing light. If your timing settings in MSnS are set to 5 BTDC for cranking, then adjust the settings on the back of the timing light. When the engine cranking with the timing light activated, it should show 0 on the crankshaft damper. Any adjustments can be set in MegaTune using the spark trigger angle and cranking settings tab. I used these settings to get mine started;
Constants:
Enrichment Settings
Spark:
VE Table
NOTE: Very Important Step, in the Spark Settings tab in MegaTune it is vitally important that the “Spark Output Inverted” tab be changed to show “yes”. Don’t forget this step. If you do it will fry the chip inside the computer that controls the spark.
Fire up the Engine:
With these settings I had mine running on the second or third crank. Go slow and make your adjustments in very small increments. As of the time of this writing, my 280zx has gone from 16 MPG to 21MPG with MegaSquirt, and I haven’t really tuned it for mileage. Good Luck and hope this helps someone.
I found a website that had the MegaSquirt kits at a very affordable price. That site is; http://www.diyautotune.com. I emailed the staff with what I was looking for and within one day had a complete price quote for my particular setup.
MS130-K $187 Megasquirt-I kit with V3.0 PCB
MSStim22-K $45 Stimulator kit
MSHarness $65 12' wiring harness
IATwPiggy $22.25 IAT Sensor
38NPT-Bung_S $8 Steel Bung for mounting IAT sensor (Aluminum or stainless also available for $9)
TuneCable $5.50 6' DB9 tuning cable
USB-2920 $20 (Only needed if your laptop doesn’t have a true DB9 port)
Subtotal without wideband-- $352.75
Read!
The first and most important thing is to read the MegaSquirt mega manual. It can be found here; http://www.megamanual.com/mtabcon.htm. This will either scare the crap out of you, or encourage you to proceed. Truthfully, I got scared, but I have a different outlook on things. This is the assembled result:
Here is a list of websites that will answer any and all questions that you might have about assembly, applications and purchasing of the MegaSquirt system. I borrowed this from another post.
MegaSquirt Main Website
MegaSquirt/Relay/Stim board order site
Car Craft MegaSquirt Article
MegaSquirt Consolidated Forum
MegaSquirt Extra Forum
Read through the websites and become familiar with the MS system as well as the computer software required to run the 83, MSnS (MegaSquirt and spark). I went with the upgraded software which is MSnS-Extra. It has more features and is also compatible with a wide-band 02 sensor. With this system, fuel and ignition are fully programmable and since ignition is based on manifold pressure, you can retard timing with boost, and you get rid of the flapper AFM, that has to be good!
To run MSnS-extra code on MS hardware you have to give something up for ignition control. You give up Fast Idle (FIDLE). FIDLE now becomes the ignition output trigger with MSnS-extra. With the downloadable program called MegaTune, fuel and spark setting can be controlled at the same time with a simple connection to your lap-top computer, and in some instances a Palm computer.
Assembly
When your box arrives the fun begins. If you are experienced at soldering, then it should take you about 4+ hours to assemble. Yes, you have to solder the components together, hence “do it yourself”. If you’ve never attempted to solder, then this might not be the project for you, or go to your local radio shack and get a small kit to practice. Once you have it mastered, the inexperienced assembler will take 8 to 14 hours to put this together. Believe me, there are a lot of little parts. I also recommend purchasing the MSStim. This is a great way to practice your soldering technique and it serves as a testing platform for the assembly stages of the project. The key here is to TAKE YOUR TIME, don’t rush this stage or you will never see the end of the project.
Programing
The MegaSquirtnspark (MSnS) software can be found here. Download the most current listed code. There are other posts that recommend adding a 2 pin header at the H1 location on the PC board. I did not do this. I just used a cutoff of one of the resistors to make a jumper, which worked well for me.
To download new code put the jumper at H1 when MS is powered OFF. Power MS on, have it connected to your laptop and MegaTune running and follow the directions with the software. Once the MSnS code is downloaded you can re-test your hardware with the MSStim. Also, the center LED on the MS box use to be the warm-up indicator, but now this is connected to ignition output as well. So, you have an indicator that your ignition is firing, at least at the computer side.
Now you have MSnS tested and ready to install in the car. At this point, it is suggested that you use the MegaTune software to set the system up with your basic car settings. Set MSnS to use time based cranking. Also Very Important Step, in the Spark Settings tab in MegaTune it is vitally important that the “Spark Output Inverted” tab be changed to show “yes”. Don’t forget this step.
Install
Once the ECU is assembled, tested and checked ok, then it is time to put the system in the car. I used the wiring harness from DIY and rewired the engine bay. This helped immensely. This process took me about a day to complete.
Time to remove that outdated AFM and old wiring harness. Due to my lack of funds, I left the boot connecting the AFM to the turbo. I took a small piece of 3-inch PVC pipe and connected the boot to the intake air filter. $5 and the job was done.
With the 83 distributor on the turbo, this swap is much easier. I have read other posts where the EDIS system had been adapted but to me seemed like entirely too much work. The vehicle has a solid ignition, so in my mind, why not use it. For a complete guide on adapting the stock ignition go to this site; That’s all there is to making the stock ignition work.
240sx TPS wiring
The TPS on the stock 83 has to be removed and a TPS from a 240sx used. On the 240sx TPS there is a built in connection as well as a three wire pig-tail. The wires in the pig tail connect to the harness as:
Red to Vref
White to TPS
Black to TPS ret
The problem I had was the 240sx mounting wings were different than stock . It took me a little while to figure out a mod for this, but I ended up using a small piece of plumbers strap and soldered it to the back of the new TPS, so far, it has worked very well.
MS recommends using a GM air-temp sensor as well as a GM water temp sensor. The air temp sensor can be mounted to the z-pipe going from the turbo to the intake. The water temp sensor is a direct screw in replacement. If you order these parts from your supplier, they will also come with the correct bung and connector pig-tail. I drilled out the correct sized hole in the intake pipe, and soldered the bung to the pipe. A little black paint and it looks good as new.
Setting the Timing for MegaSquirt
Set the engine to top dead center (TDC) on the number 1 cylinder. It has to be on the compression stroke and not the exhaust. Once TDC is achieved turn the crankshaft back by hand to what you think is 50 or 60 degrees BTDC. For MS to function the ignition trigger from the distributor needs to be at least 5 degrees before the maximum advance that will be used. For the stock setup, 45 degrees is the most I would need so I set it at 50 degrees BTDC. The marks on the crankshaft pulley only go to 30 BTDC so you will have to guesstimate the rest. I later found that this was not an exact science as the software can make up for most errors, so just get it close.
Loosen the distributor and give it a turn by hand with the MSnS powered up. Turn the distributor until you see the middle LED come on. When this lights up stop and tighten the distributor back down. A timing light comes in very handy from this point on, so if you don’t have one get one with the adjustable advance setting. Have someone crank the engine and check the settings with the timing light. If your timing settings in MSnS are set to 5 BTDC for cranking, then adjust the settings on the back of the timing light. When the engine cranking with the timing light activated, it should show 0 on the crankshaft damper. Any adjustments can be set in MegaTune using the spark trigger angle and cranking settings tab. I used these settings to get mine started;
Constants:
Enrichment Settings
Spark:
VE Table
NOTE: Very Important Step, in the Spark Settings tab in MegaTune it is vitally important that the “Spark Output Inverted” tab be changed to show “yes”. Don’t forget this step. If you do it will fry the chip inside the computer that controls the spark.
Fire up the Engine:
With these settings I had mine running on the second or third crank. Go slow and make your adjustments in very small increments. As of the time of this writing, my 280zx has gone from 16 MPG to 21MPG with MegaSquirt, and I haven’t really tuned it for mileage. Good Luck and hope this helps someone.
10-26-2008, 09:51 PM
#2
Pr0n Addict
Join Date: Sep 2007
Location: virginia
Posts: 4,617
great write up. it makes me wish i had a car worth doing it with. i'm sure it's quite helpful to many though.
10-26-2008, 10:39 PM
#3
Big Poppa
Join Date: Jan 2005
Location: Mission, British Columbia
Posts: 4,499
good write-up thanks for doing it and having it posted here. i have always been thinking of doing it, but i dont like all the variables in tuning since dynos arent exactly all that common around here with an operator who cares. the wiring is no biggie, just the tuning.
10-26-2008, 11:23 PM
#4
NisTuner
Join Date: Sep 2005
Location: Cleveland, Ohio
Posts: 2,800
In my opinion that's one of the best things about having a Wideband O2. The fact that you can log all your AFRs. Not a true dyno, but a good way to see what you're running under real life conditions and then you can generally tune for the best A/F ratio.
10-26-2008, 11:41 PM
#5
Über User
Join Date: Sep 2005
Location: lemont, Illinois
Posts: 9,532
decent write up... the wiring isnt to bad i was however hoping to hear much more indepth with how you personally soldered the actual board together and what specifics you were using and then any modifications you had to do in order to compensate for the mods and the Z specific stuff. but still good info
11-28-2008, 01:41 AM
#6
Registered User
Join Date: Aug 2004
Location: Bay Area, CA
Posts: 1,075
I'll be selling my Megasquirt setup if anyone's interested. ^^
11-28-2008, 12:43 PM
#7
NisTuner
Join Date: Sep 2005
Location: Cleveland, Ohio
Posts: 2,800
If it's anything like I did with NIStune I just took my old 84' ECU that I wasn't using anymore and just practiced with a desoldering iron as far as taking the om and processor chips out. So if I ruined the ECU and the trace pads it wouldn't matter just for practice. Then practiced soldering them back in. Really another good way is to go on youtube and watch videos of people showing how to solder and then practice on boards you have. If anything I bet the MegaSquirt soldering is easier simply because you're just soldering it together vs. having to desolder stuff.
Heat Rave R, what are you going to use instead. Actually I might be interested in your MS setup. I was thinking about either getting another NIStune board, or going MS on my 280ZX and using my NIStune board in my Z31.
Heat Rave R, what are you going to use instead. Actually I might be interested in your MS setup. I was thinking about either getting another NIStune board, or going MS on my 280ZX and using my NIStune board in my Z31.
11-30-2008, 02:48 AM
#8
Registered User
Join Date: Aug 2004
Location: Bay Area, CA
Posts: 1,075
Originally Posted by duowing
Heat Rave R, what are you going to use instead. Actually I might be interested in your MS setup. I was thinking about either getting another NIStune board, or going MS on my 280ZX and using my NIStune board in my Z31.
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