req_fuel with ms3 and ev14 injectors
 

Hello all. I've been installing/tunning megasquirt over the last few weeks and i've run into some issues i can't debug for some reason. First heres some info about my car:
* 92 Na
* 94-97 engine swap retaining 92 wiring.
* MS3 built by following the trubokitty guide
* 94-97 intake crossover pipe
* MAF delete
* 01-05 throttle body
* sequential injection mod
* ev14 550 injectors with the flow force byoi kit
* coolant reroute, mishimoto radiator, fans etc

Hopefully that is enough info to help out.

Now my problem is that i can't get the car to run without either A) setting `req_fuel` to something like 17 or B) highlighting the entire fuel ve table and bumping it up like 50. Both of those will get the car started, but as soon as i give it gas it gets WAY to rich (obviously). I recently had rx8 yellow injectors and i drove the car quite a bit on those, but that had the same issues of needing the fuel table to be bumped up quite a bit.

Another probably related issue is that once the car is warmed up, to start it i have to turn the key on like 5 times to get enough fuel into the cylinders to start. I've attached my tune hopefully that helps. I'm assuming i just missed something when converting the 94-97 base map to work on my 92.

Where did you get your injector deadtime information? 0.490ms is likely way to low.

Update:
I took the 94-97 basemap from trubokitty and restarted all my changes. I've attached the new map i built. This one seems to act more reasonable in that the req_fuel number is not super high. I have to tidy up some wiring for my knock sensor, flex fuel and sequential injection mod, but once i do that i'll take it for a longer drive and report back with a log.

It's better because the injector deadtime is now 1.2ms which is probably closer to what it should be. You really should try to find the actual deadtime for you injectors though.

Ah yes i must have forgot to set that the first time around. I wanted to start fresh anyway since i've learned quite a bit in the last couple weeks. My injectors are ev14 550CC. I took the 640CC table from the flowforce website. I'll hunt around for data about my injectors specifically. I got a piece of paper with some data, but i couldn't make much sense of it for Megasquirt.https://cimg1.ibsrv.net/gimg/www.mia...54a0ba154d.jpg

That paper is all you need. The top row is likely fuel pressure. You'll use the 43 column.

The problem with that table is that it is in time and ms3 uses percentage. Any idea how to convert it?

Maths

It’s still wrong though, shouldn’t be .45 at 14 volts. That tables most likely opening time, where as dead time includes opening and closing. Double the taxable and use 14volts as 100%. So like 10volts, 2.5/.9=2.77*100=277%

I'm sure it says ms in tunerstudio?

oh ok, you mean the curve is in %, the base value is in ms..


I thought dead time was the DIFFERENCE between opening delay and closing delay, not the SUM (you definitely cannot just double the opening time)

Here's a photo of the table. I give TunerStudio what 100% is in milliseconds (which i guess is at 0.45 at 14v?)
https://cimg7.ibsrv.net/gimg/www.mia...173a797abf.png

0.45 is about half of what it is currently operating at if i understand correctly. I have a suspicion it won't run very well at that low. I'll try converting the table to percentage and report back.

You’re going to run out of VE if you continue with .45, double it and retune.

Sorry for the very late response, but i've been too busy to play with the car. I finally spent some time learning what injector-dead time actually is among other things. I made a spreadsheet to do all the math for my injector dead times and came up with this:https://cimg6.ibsrv.net/gimg/www.mia...312df3669f.png

i inputted those values and it was like night and day to how the car runs. I also had some incorrect settings in my tune in that i was using "semi sequential" instead of "fully sequential". I also have installed my iacv (this was previously not working/unplugged) so now i have a proper, stable idle.
Thanks for the help fellas!

Big difference, huh?

You said earlier that you got those dead times off the FlowForce website, but I do t recognize them. I've got the % listed out for easy inputting into MS.

To my knowledge, those 117 injectors have the same valve as the 298 injectors that go into our 640 kit, so you can use the same dead time numbers. https://goflowforce.com/instructions

Thanks for the information. I'll try it out. I'm using the dead times as provided on a sheet of paper that came with my injectors. I'll try the 640 times

Thanks for the tip. I just used said dead times from the 640s and it seems to run smoother at idle. I did have a slightly hard time starting, but that can probably be attributed to my battery or alternator dying.

You may need to adjust your Cranking Pulse or ASE if you're having a hard time starting it.

I actually figured this one out too. My cranking was set to 200 rpm for some reason so it would crank, and Ms would think the car was started. Also my alternator is dying, so night time driving causes the next start to be a little rough as the battery isn't quite charged enough.

Sorry I misposted.