Hello everyone,

My name is Vincent and even though I don't post much I have been a member for a long time. I am a newb when it comes to MS, but not electronics or how fuel injection systems work. I have an 87 N/A RX7(with S5 upper and lower intake) that I am attempting to squirt. I just built my 3.0 PSB MS3 according to Aaron Cake's website(using MS2 instructions). I am using a JimStim that is setup for a Nippon Denso 24-2 wheel and have 12 volt pullup resistor's on the primary and secondary.

I had the RPM's working on the bench, but as I was setting everything up in TunerStudio, now it doesn't seem to work(I didn't know about having to power cycle the unit during the configuration process for certain changes). I have tried switching the spark output to JS10, which is where it think it's wired-but when I do I get a conflict. For now I have it set for LEDs spark and all three LED's stay lit up on the box(which have pullup resistors per Aaron's instructions).

Is there a way to test it on the bench before I put it in the car? I am about to start modding the harness today in preparations for installation, and I just want to make sure it's gonna work now before putting it in the car, which is why I bought the JimStim in the first place. I am considering getting an old CAS and playing around with it on the bench as well, but from what I've read I shouldn't have to do that.

Please let me know how to proceed. It would be greatly appreciated.

-Vincent

 

Here is what I've come up with on my .msq file so far. Any suggestions or comments would be greatly appreciated.

 

• LEDs for spark is correct.
• Firing order should be 1234. I don't know if it makes a difference.
• You're configured for mainboard injectors and spark, so you must not be using a MS3X.
• You can use semi-sequential fuel injection, which then makes the injection timing consistent. With sequential off the timing is somewhat random and can change from one start to the next. If you add a MS3X you can do full sequential (and also run your ignitors from the 3X).
• PWM current limiting should be off unless you have low impedence injectors without resistors.
• If you are premixing, you probably want to turn off overrun fuel cut.
• I suggest table-based staging.
• Change your VE and spark tables so your top row is 100 kpa.
• Trigger angle/offset should be 0.
• Your cranking and dwell settings might be high. Mine are 3 and 3.
• Suggest using the idle advance and idle VE settings, but you might want to delay turning them on until you've got your idle tune close with the main tables.
• Your last warmup enrichment value should be 100%.
• Raise your accel enrichment mapdot threshold to 1000kpa/s. It has an effect even with enrichment set to 100% TPS.
• I use a MAT correction value of 50%.
• Your AFR/EGO control authority might be a little aggressive. Keep an eye on whether it causes problems. Mine is turned off (0%).

 

I will make the adjustments. Is there any wiring differences when running full sequential? Reason why I ask is because I haven't altered my harness yet. I was trying to avoid spending 90 bucks on the MS3X card(hence the reason why I built a second VR circuit in the prototype area). But, if it means only having to do my wiring once in order to run full sequential then it would make sense, right?

Can I use your initial settings for semi-sequential that you posted in the MS forums?

Is full sequential really worth it on a rotary?

Plus, I still need help with bench testing this thing....Ken?

Thanks again for the incite. It would be awesome if I had your tables so I would be closer come dyno time! I just hope I'm doing everything right.

Thanks!

 

Also, I cannot even get semi sequential to work right with 1 or 2 squirts per cycle, alternating or simultaneous, without TS telling me it's invalid. So I changed it back for now.

 

How do I use table based staging?

I'm also having a hard time adjusting the VE table with the 110 percent you provided. Why do the % load values go to 250?

Can't find the accel enrichment that your talking about.

Everything else makes sense.

 

Yes, with full sequential you wire each of the four injectors individually back to the MS3X. With batch or semi-sequential you wire two injectors to each injector output on the main board.

I don't know. All I know is that my engine runs better than it ever did with MS1 or MS2 batch. I have not optimized my injector timing. Maybe you can experiment with it on the dyno.

My msq is attached (MS3 1.0.2).

 

Dude you are awesome! Us SCCA ITS guys have got to stick together! My car is still a little ways from being road race ready, but in the mean time I will hopefully be doing TT and hill climbs next year. I really appreciate it, this should get me going.

Since I have to wire it up a special way to get what I ultimately want, I am thinking about biting the bullet and going with the MS3X. Sucks though because building that second VR circuit in the prototype area was a PITA!

Did you notice any overall power increase with sequential? Or just overall driveability? So to run sequential, all you need to do is run individual wiring to the injectors and that's it?

 

Sequential can give you much better response and slightly better fuel economy if tuned properly.

Ken

 

Here is a copy of a conversation me and a friend were having...if this would work, this would be the same things as sequential injection, except you would fire both injectors at once.

Matt(who is currently building an MS2 setup and does EFI tunning as a hobby):

"With my MS2, I have 2 option ... simultaneous and alternating. With simultaneous, all injectors squirt at once. With alternating, they alternate "banks". Sequential on a piston engine would be squirting individual injectors in the firing order of each cylinder.

Ideally, for a rotary, I'd guess that you would need parallel alternating injector setups. Basically, the mains would alternate per rotor up to X RPM, then the secondaries would alternate in parallel with the primaries as conditions are met. I would guess RPM.

This could be done with standard alternating injection as well, but you'd have the secondaries firing at all RPMs. With tuning, I don't see that it would be a huge issue. But, it would take some effort to figure out timing and sizing for both injectors firing together.

So, I suggest hook up the primary and secondary for rotor 1 as one bank and do the same for rotor 2 on bank 2, and run it like a 4 cylinder. You will spray the primary and secondary together every revolution. Essentially, this should be no different from the standard 4 cylinder tune as when you alternate there you get 2 squirts for each cylinder each cycle, which is exactly what you're doing with 2 sets of injectors on each rotor.

Without seeing how the CPS functions for the multiple compression chambers on the rotary, I will just guess and say that you would just need to run it as stated above, but maybe fudge the "Squirts per rotation" variable to 3 (rather than the assumed 2). This will basically run it like an alternating injection setup on a 6-cylinder (2 rotors x 3 combustion events per rotation). This should get the injectors in time with the rotors and squirt fuel for each cycle properly.

If the CAS isn't timed with the rotor rotation (one rotation is 3 combustion events) then you would need a different setting. For instance, if it runs 3x faster than the rotors turn, you'd need to run it like a 2 cylinder, not a 6, so you'd need 1 squirt per rotation (x2 rotors alternating).

If you run the banks as suggested, and set it up like a 6-cylinder, you would need to scale the injector size down to compensate for the setup.

On a 6 cylinder, you squirt fuel 3 times for a single combustion event. With what I'm suggestion, you are basically squirting 1, but with 2 injectors ... or 2/3 of the fuel it expects. Scaling the injectors smaller artificially makes the pulse widths larger, keeping you within the usable range of your fuel map settings.

So ... Injector scaling should be something like:

Primary size + Secondary size * 0.66

That will compensate for spraying both injectors at once and for the difference in fuel expected for the extra squirt.

this is all theory ... =)"

If this works, all we really need to do is figure out how much the CAS turns for every rotor turn or combustion cycle. Then we can get the math right to size the injectors correctly. Make sense?

-V

 

My recommendation:

If you're running ms2, just run simultaneous with the primaries on 1 channel and the secondaries on the other. That is supported by the code with staged injection, and will give you good drivability.

If you want sequential on the rotary, get an MS3. It can do full sequential without any hacks like you were suggesting in the last post, and will run better even than the ms2 can.

Ken

 

I have an MS3...just not the expander card. I guess I will be ordering one today. That is the only way I can run sequential fuel, correct?

 

On an MS3 that's the best way to do it, and then you don't have to modify the main board at all to do ignition either... the ms3x will do it.

Ken

 

Something else I just thought about, how many of the grounds on the MS3X card need to be hooked up? I thought about stealing a few grounds off of the MS3 harness I bought from DIYAutotune. Will that work? I am going to "build" my own harness using unused wires in the DIY harness, and I need to know whether or not I need to buy some extra wire...

Thanks

 

I would hook them all up if you can. If you can't then at least 3 of them.

Ken

 

I will be hooking up all of the grounds.

Update, I have got the RPM's working with an extra factory CAS I had from my spare engine! Took the gear off of the end of the CAS and chucked my cordless drill to it! Drill is rated at 1,400 RPM's and I am getting 1,440 with MS3!

Now all I need is a few more wiring supplies and I can get started putting it in the car since everything is tested as far as I can go.

Thanks for everyone's help and I will keep everyone informed...

-Vincent

 

Ok well here's another update.

Everything is done and tried cranking the car today just a little while ago with no success. I'm working night shift right now so I had to stop and come to work(bummer).

Nevermind, that is for an FD...lol

Would this cause no RPM? In analog mode the inner yellow pointer would move up when cranking but the number would stay ZERO. As I stated in my previous post, I tested the RPM's before I put the MS on the car with nothing else connected and it worked great.

One question, what do I do with the shield wire? It seems like I remember seeing somewhere where it said to hook it up to a ground pin on the MS side but NOT to hook it up on the CAS side. Is this correct?

That's all I can think of right now. Everything else works, coolant temp, IAT, TPS, Fuel pump, o2 sensor, hell I even get cranking fuel showing up so I know the injectors are firing.

Still waiting on tubing and filter so I can build my intake and I don't have the vacuum line tied into the MS yet either...

Let me know!
-Vincent

 

Started a thread on the MS3 Forums:

http://www.msextra.com/forums/viewto...?f=131&t=42532

Thanks