Cool!! I've been noticing if I change that value to anything below 1.0 I hit what seems like a wall with my 83lb'ers... pretty much on decel once the pcm starts calcuating pulswidth below 1.0ms it seems like it just shuts the injectors off completely since AFR's start increasing beyond 40-50+, must be the PCM minimum limiit huh?

 

I read somewhere (I think the megasquirt website) that it takes injectors 1 ms to open. So, with a commanded PW of <1 ms, they are getting the signal to close before they even reach full open. I'm not sure what the result would be, but it could explain that.

Mike

 

DST is Jet's version of Tuner Cats called Dynamic Spectrum Tuner. Yup it was set at 3600 and dropping it to 500 rpm fixed my problem. I worked a bit more on it yesterday and it seems to be working perfectly. I'm working with E85 in Open Loop and 5lbs of boost so far and while the tune is still not great (lack of time to actually work on it) it's pretty darn good and seems to be pretty responsive to my changes. Only problem I'm having is with my data logger which is called MXScan and it really sucks because it doesnt have a graph function so I have to put my .csv files in Excel and try to graph that way....it's ugly. Oh well, still works and I will get this thing dialed in soon so I can up the boost.

 

Mike - makes sense since I guess at some point this would have to happen. So is it safe to say basically any ECU or programming that goes below 1.0ms using this size injector may have the same result? I just keep it at 1.0ms and everythings fine I wonder if that's what everybody does.

 

Got it running/driving on the two bar last night. Car idles at 22-23 kpa.

Took the values from where the car previously idled (35 kpa), stuck them in the 25 kpa cells. Then took all the other values and divided by/2 (70kpa into the 35 kpa cells etc etc).

Car started up smoothly on the first try. Little rich at idle but after a few minor tweeks it was completly driveable and smoother then my 1 bar tune.

Im gonna run my ve's and timing tables through an excel sheet to smooth out the transitions and start logging my wideband. After that!!!! BOOOST!!!!

You guys rock!!!! Thank you for all the help until now.

 

What tunercat heading is this under? I'm looking at the available "Tables" and I don't see a heading of "Min Injector Pulsewidth". Is it a sub table under another heading?
THanks!

 

Im having a slight issue with surge while in park. What should i be looking at to resolve this?


dave, min injector pw is under ecm constants.

 

Constants>Fuel Parameters... If you have the latest version which is X for Tunercat for OBD2

 

When I was running H/C I found setting the idle spark advance to 30 degrees seemed to fix that surging.

 

I had the surging problem when I lowered below 1.0 or 0.9ms... I think what was happening was the fuel injectors were totally shutting down with any Pulsewidth below about 1.0ms, so it would basically die out any time the PCM calculated less than 1.0ms... I raised it slightly to 1.0 and the problem is totally gone.
EngineerMike explained the injectors may not be able to open or squirt fuel with less than 1.0ms.. makes sense to me since any time I see pusle width's under 1.0 the box turns yellow and the AFR goes WAY up (20-30:1 AFR), the 1.0 setting keeps the injectors firing at 1.0 even if the PCM says 0.8.

 

I just cant seem to get this thing to idle correctly in park. When in drive it tries to achieve 600 rpm idle. But when i put the car in park it does not try to achieve the 700 rpm that is commanded. But i should be able to get this thing to idle at 600 rpm. I DONT GET IT!!!!

You can drive around all day with no issues, timing seems good, wb02 readings seem on the money. Place it in park and it WILL idle for maybe 15 seconds without issue. Then you start noticing the surge, it keeps getting worse until the car finally stalls out.

min pw is set to 1.1
closed tps advance 28 deg

Could someone look at my file? Just let me know which emails to include.

Thanks guys.

P.S. havent hit boost yet but after tuning the around town stuff by hand i can say that it shouldnt be a problem.

 

I had the idle surging problem after I changed a few things.... those things were:

1) Messed around with the MAF tables.. I returned to stock and it went away, now I run SD mode
2) Messed with the min pulse width and set too low
3) Your Idle AFR may be off causing strange problems

At what point did the thing start to have this problem? Whatever you changed is probably what needs to be adjusted.

 

When I originally loaded the 2 bar file it was doing it. What should my idle afr be? Right now it hovers right around 14.7

 

Could someone please PM me the latest 2-bar file? Im working on this and would like something to compare to.
Gary

 

Anybody? hope this thread wasnt given up on. Im having a few problems with my VE table, someone post a file?