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[schim187]

Yoooo guys,

So, I've been on here awhile, have read a shit ton on Crome, have had pro license for 2 years and recently started dicking with Gold roms.

I slapped some Precision 880's(2.3ohm) and a resistor box on my B18C, added a 3 bar GM map, and still have my same setup with egay T3/T4 .57 trim turbo, LC-1, and a few different Ecu's i've chipped/converted for Vtack.

I've been bugging JD way too much about this and thought I'd reach out to the community:

So, in CROME PRO, I change injector offset (stock) to something close to 880's, then start messing with Injector Offset under fuel multiplier till car runs.  Did that, had to use auto tune to drive around and get afr's close, then logged and slowly crept into boost up to about 14lbs, making changes every couple of minutes.  Car is driving ok, and pulling decent under boost (have some breaking up issues, but need to further look at my plugs/gap).  At idle tho, I came to an offset of 57.0 with a .274 multiplier, and car idles like shit still.  I know that these bigger injectors like mid to hi 13's to idle on, but idk.

I figured I'd try tuning on a gold bin since I am considering getting dealer license, so today I sat in my school p/l with my loud ass car trying to get it to idle.  I went through almost every injector offset under options in Gold, played with the offset tab under the injector selection and cannot for the life of me get the car to idle w/o 1%TPS.  If i let off, it dies.  I tried changing IAC to -50% so i could get the map close, but no matter what I try, car will *almost* idle at 7.5~8 afr, which I don't know how it still runs.  Otherwise, if i slowly change the offset, it goes swinging to lean.

I read through the Crome 1.6.5 pdf manual thats floating around and cannot see what i am missing.  I think Mark (lilpooh) and a few other of you guys were having similar problems in the past.  Most threads I found were not resolved, and if they were, solution was not posted.

I tuned an LX w/a 1.5 on 10lbs and home made water meth setup (btw i need to post that up here, uses windshield washer fluid, neat setup which allows a lot of additional timing up top) today and it took about 2 hours (1 hr of which caused by a TPS sensor randomly going out).  The kid is super happy with it and never thought a 1.5 had the capacity to pull some of the hills here in MT like it does.

Lemme know what you guys think, besides Crome sucks, and that I suck, because I am well aware.

* WB is mounted just in front of stock location, and exhaust is sealed all the way to the back

[Joseph Davis]

Peniswhistle.


Have you done the free air calibration??

[HiProfile]

Are you 100% sure they're 880cc? If not you're properly fucked.

Otherwise throw the stock 1.75bar back on and start from there. Then clean & check the plugs to see if one cylinder is way lean or rich. If not, continue to find the injector offset with that MAP. If you get it to work, make note of cold and warm idle vacuum readings. Swap on the 3bar, check what vac readings you get. If not try an older version of crome.

My feelings are you have: the injector size wrong, a bad injector, or crappy 3bar. If it's a bad injector, I will give you a nog price on my 800cc injectorators and you can kiss the resistor box and your idle issues goodbye.

[92CXyD]

My precision 780/Delphi 75lb run on my setup as 930cc, 32offset, and battery offset of 3ms to 1.5ms. Fuel pressure at 45psig with engine @ idle and fpr  vac disconnected. 

[schim187]

Peniswhistle.


Have you done the free air calibration??

Yes twice plus bought a new sensor at work...ill prob return the old one as new since I work at the Walmart of auto parts stores

[schim187]

Are you 100% sure they're 880cc? If not you're properly fucked.

Otherwise throw the stock 1.75bar back on and start from there. Then clean & check the plugs to see if one cylinder is way lean or rich. If not, continue to find the injector offset with that MAP. If you get it to work, make note of cold and warm idle vacuum readings. Swap on the 3bar, check what vac readings you get. If not try an older version of crome.

My feelings are you have: the injector size wrong, a bad injector, or crappy 3bar. If it's a bad injector, I will give you a nog price on my 800cc injectorators and you can kiss the resistor box and your idle issues goodbye.

Yea 880's I bought from lilpooh when I used ta be East Coast before I lived in the middle of nowhere away from everyone (part # PFU 042-0880)...

the 3 Bar map may be an issue, i pulled it off the twincharge B18C i was working on a year ago, but it looks like the kid broke it, then glued it (one of the mounting tabs)...i'll throw the stock on and troubleshoot one at a time, but atm press. seems consistent when i'm driving...if i wasn't a broke ass college kid i would buy some supa injectorators up quickly from some nogs--give me till June when I have a real job.  Injectors all checked out for resistance (2.3ohm), also have consistent voltage to each one.

I still need to check/gap the plugs and i'm sure that would help me find a good idle.  Seems like everyone else has an easy time tuning something this simple, but i run into retarded shit all the time and spend way too much time troubleshooting.

So opening Crome Pro on a base map w/stock 240's, what order do you guys go in to set the new injectors?

I change stock offset first to the closest to 880 2ohm injector (to closest injector<880 so i can reduce multiplier), then change fuel multiplier, then adjust offset in increments of 100 until it starts, then narrow down from there.  I found the Fuel Injector Lag Time (latency values), but where do I enter these in CP?  Under fuel injector offset, crome is programmed for each injector, so I generally just use the values found under the stock injector offset tab for whichever injector i selected.  Under a gold bin, i try to use standard offset under fuel injector selection to get it started, then deal with advanced fuel corrections under latency to get it running, but when i raise regular offset i have to lower latency to get it to barely idle, and still sitting at 7.5 afr (matching logworks to crome to o-meter wtf).

My precision 780/Delphi 75lb run on my setup as 930cc, 32offset, and battery offset of 3ms to 1.5ms. Fuel pressure at 45psig with engine @ idle and fpr  vac disconnected. 

Gold or pro?  I'll try these #'s...car runs on anything from 800 to 2000 mS.  Shit is frustrating and I suck at life.

That is all.

[schim187]

Gold or pro?  I'll try these #'s...car runs on anything from 800 to 2000 mS. 

*Except for when it will not idle

[HiProfile]

I hope you mean .80 to 2.00 mS.

The correct procedure is to create the working basemap, set the fuel multiplier for 880cc, then set the offsets to whatever is closest. 14v is the cell that is most important while it's running, 13v and 12v are mostly for startup. 13v will also be for high electrical load if you idle really low and have a crappy alternator.

Next you start the car and adjust battery offsets for your CURRENT voltage cell so it warms up. Once warmed up, readjust the current battery offset cell so you get a ~14.5:1 AFR. If you target a "good idle" at 13:1 AFR, you're telling the ecu the wrong offsets. Offsets tell the ecu how the injectors work, the fuel table is for enriching idle. You use offsets to target the same AFR's as the stock injectors, THEN you adjust the fuel/ign tables around idle to get a smoother idle.

Lastly you can swap to the 3bar and make adjustments for that. Ideally you would make a few pulls with the stock MAP to iron out any irregularities from the injector change.

[schim187]

I hope you mean .80 to 2.00 mS.

Microseconds tried to enter 'mu'....anyways ill try this order thanks hiprofile!

[Speed Phreak]

Large injectors are real lazy at super low duty cycles, treat them like much smaller injectors around the idle fueling area and you'll be a lot happier with the results. Before Crome and OBD-1 conversions came along, this is the trick I was using to idle the 1100cc injectors on my Zdyne setup...

[92CXyD]

Large injectors are real lazy at super low duty cycles, treat them like much smaller injectors around the idle fueling area and you'll be a lot happier with the results.

Esplain this in depth 

[Speed Phreak]

Esplain this in depth 

Poor/cheap mans way of accounting for the offset problem of larger injectors having poor response and dwell time issues at the very low duty cycle needed to maintain a proper AFR on a 1.5~2.0L engine. I found it easier to just "overdrive" injectors around the idle area to account for the offset issues and get to a proper AFR instead of fiddling with offset times. Then again i'm a little lazy and that works for me since I used it previously on OBD-0 EMU setups without much issue.

[schim187]

I don't understand so your saying take a stock baseman, for instance, and mess with the fuel maps only?  Treating them like stock injectors would mean not changing my fuel multiplier or any injector offsets-

[Speed Phreak]

I don't understand so your saying take a stock baseman, for instance, and mess with the fuel maps only?  Treating them like stock injectors would mean not changing my fuel multiplier or any injector offsets-

Seem like you do understand, since that's some what the gist of it. You can still adjust the multipliers for your larger injectors but you have to remember that adjusts the multiplier for the entire fuel map... Around the idle area try treating the map as if you're running 450cc injectors and see what that nets you... (copy and paste the idle area from a 450cc calibrated map if you need too).

I've have Crome Pro and use it on my 2.0L LS/VTEC, 85# Accel injectors @ 50psi, Base rom or Gold rom no idle issues...

A couple more tips:

Adjust your target idle up to 900~1000rpm to help combat low duty cycle fueling inaccuracy.

Also try changing the vacuum and rpm rows around idle to provide yourself more resolution. IE adding finer increments so the ECU doesn't have to bounce between 750~1000rpm to find a fuel value(same for vacuum columns)

Also this article will help you out a tad with understanding what I mean about low duty cycle(pulse width) fuel issues.

http://www.injectordynamics.com/LowPulseTech.html

Cheers

[schim187]

What he's ultimately saying in the article using the 850's in that graph of multiple injectors, is set offset to ~2 msec so that they are opening all the way, then adjust multiplier and fuel tables from there, so you're not in the partially open region?

Makes sense.  I have offset set to 65.0 in pro and its idling, not as good as I like, but ill try this. Tried stuff in gold again for shits n giggles and still couldn't get it to idle.
Thanks speed ill let ya know results-