Dixit

iTrader: (1)

So Im creating this thread for anyone else who has had problems with the Mototron injectors and trying to get them to act like stock.

This was the original thread.
https://ls1tech.com/forums/pcm-diagnostics-tuning/450727-installed-60-mototrons-fuel-trims-way-off.html#post4241545

Now trying to find out how one can go about finding the correct injector offset so I can get this table inline and get it accurate and act like stock again. Right now still having hesitation/bucking when I get off the gas and get back on it.

For now Ive reduced the minimum pulse width table by 50% and the default pulse width by 50% and reduced the short pulse adder by 20% and still getting a bit of hesitation and bucking during decel and accel transitions.

Now the only info I could find anywhere on the net for these injectors is this:

Static flow 10.8g/sec @ 600kpa
Gain=0.110ms/mg
Offset=0.055ms
Turn on Time=1.14ms @ 14VDC
Turn off time=0.85ms @ 600KPa

I dont know how to calibrate this offset table and from all the threads Ive read on LS1tech, HPTuners, EFILive, LS1Edit forums no one really talks about how to do it unless the manfacturer has a full spitout on offsets at different voltages and kpa.

I was thinking of just scaling it higher percentage wise, but a few of the forums and threads show its not as simple as that, some injectors require it, some dont based on how they are manufactured.

Dixit

Bink

EFILive/ Flashscan?

Set up a map of LTFTs as data.
Copy the PCM Inj. Offset table but with LTFT as Data - instead of pw adjustment.
Column of GM.Volts and Row of GM.MAP in kPa.
Should give you % offset adjustment.

Dixit

iTrader: (1)

Actually using HPTuners. I can setup custom maps but dont understand how Im going to set one up using LTFTs with the Injector Offset table. That table is MAP and Volts, LTFT is RPM and MAP. Sorry you lost me there. Ive read so much on this injector offset that my brain is mushed with info that Im trying to process.

I tried talking to someone at Mototron but they just went "Huh?" when I asked them if they had specs on their 60lb injector as far as offset goes via battery voltage and map. He might as well have said "whadyou talkin' 'bout willis?"

Now heres something else to throw into the mix that seems to have caused more problems in trying to find the offset using the method you are talking about. When I dropped the min pulse width almost 50% and default pulse width the same, my STFTs went negative, went from +15s to almost -7. But not in all cells, most of them. The 1200rpm column still is positive around +5 or so. Right now Im sitting on STFT only since I disabled LTFT to get a grip on this mess.

Dixit

Bink

With EFILive you can record LTFT/STFT and MAP and Volts pids. Then set up a map where the reported data (LTFT/STFT %) is referenced to the associated MAP/kPa and Volts. Just like the offset table.

Then you multiply the injector offset table by the map (%) you've created.

I would guess the stfts swing you've seen is due to the refinement of pw by reducing the min pw.

Dixit

iTrader: (1)

Im going to have to see if HPtuners will allow me to map the STFT against say the injector offset table. If not, Im going to have to just scan those PIDs and then somehow setup a chart in excel and try to figure it out from there.

Man, hahaha what the hell did I get myself into in getting these bad boys? I just cant leave my car alone can I, gotta keep fuking with it hahah

Dixit

EC_Tune

Since: Turn on Time=1.14ms @ 14VDC your minimum injector pulsewidth should be the same or -slightly- higher.

The injector offset table compensates for pintel opening speed (mSec's) based on differential pressure across the injector (hi vacuum = slower pintel) and Voltage applied (hi voltage = faster pintel).

I checked a 98 F-body's injector offset at 14 Volts & 04 Z06 and they are nearly identical at that voltage. The trucks have a significantly different offset table for some reason (probably Multec-II's ???) and ~ 50% shorter Minimum Pulse Width.

Bink

Yes, but you are contributing to the knowledge and experience of all (sounds Yoda-like, LOL) - as long as you post your findings.

Dixit

iTrader: (1)

EC_Tune - 1.14ms @ 14VDC is my minimum pulse width then? Cause thats a problem.

Bink - Havent been able to get some conclusive data, because my decel pulse width is causing major issues and throwing bad data into the table. For example, Ive dropped my min.pulse width table by 50%, default pulse width by 50%, short pulse adder by 20%. However Im still seeing 1.3msec pulse width on decels. I was at 1.6msec before with the stock Z06 injectors, 1.3msec is still way too much for a 60lb. And my STFT goes to -30% during decel, this throws the numbers off on my custom map to try to figure out the injector offset.

I cant seem to figure out how to get it to commmand less than 1.0msec of pulse width. If I cant get it below that my hesitation issues will not go away and no way I can get accurate data for my custom injector offset map I created to figure out what I need to do to scale that table.

From my math I should be able to command a 1.0msec pulse width since my minimum table is showing .630 and adder shows .288 for that value, so thats .920 msec I should be able to command. However th decel scan still shows 1.3msec. Before it was 1.6msec when I had the stock min.pulse width, default pulse width, and short pulse adder tables. So I took off 0.3msec. Still got more to go but cant seem to get it to drop.

Dixit

Zombie

iTrader: (2)

Sounds like the problem is in the Decel fuel cut off, not the offsets. Change the entry and exit points. Try bumping them 5kpa higher. They are based on map pressure. That should solve your issue.

Dixit

iTrader: (1)

Zombie, pardon my ignorance, but I dont know much about this table. Never really messed with it. I know tons of others.

If I bump both the entry and exit by 5kpa on the MAP vs Baro, how does this fix the problem or help fix it? What is it doing? I dont quite understand how this table works. I see decel for RPM, MAP, Spark, man there is alot for simple decel aint it?

I noticed the lowest my MAP readings show on the decel is between 35-25.

Dixit

Zombie

iTrader: (2)

You are probably not seeing enough vacuum on decel to trigger entry into DFCO. Bumping it 5kpa just moves the threshold closer to atmosphere. You don't really need to change the exit, but that might not be the best spot for a smooth transition now.

I've played with this table when my car was 6spd and got the transitions pretty smooth. With the stock values it was only going into DFCO on VERY hard decel.

Dixit

iTrader: (1)

Got it, Im slightly lost on this MAP entry and exit. I thought the entry was at what point DFCO above that map is enabled and anything above the Exit number is where DFCO disabled. So I ended up raising the Exit to 31 and saw it did nothing on my drive home from work. The help on it dont seem to really explain how it works, from the reading the both seem the same, made me more confused after reading it.

Heres what they state.
From reading that it seems that the anything below the MAP Entry enables the DFCO, but then anything below Exit is where it turns off, why would they just say anything above the entry is disabled, I dont understand why the exit is setup that way.

So after reading this again I somewhat answered my own question, So instead of making the Exit at 31, I should make the Entry 31, but that I assume I will have to bump up Exit to about 40. Correct?

Dixit

Dixit

iTrader: (1)

So I modified the entry point and it didnt seem to work, but during my drive to work I saw few times where it did work. It seems like the decel doesnt kick in anything below 2500rpm, most of my driving is in that range when grandma'ing to work. But one incident I was above it and saw the decel kick in and my injectors were running 0.3msec. Heres the chart


Now shouldnt it still work for decels from say 2000rpm to 1000rpm or is there a reason for it not to work, because in those ranges my STITs go way down to -30 at time. Here is an example of what happens when I get off the throttle on a decel below 2000. As you can see the STIT just keeps dropping when I get off the throttle.


I need to resivit the decel area in the tune to see what I can maybe do about this.

Dixit

Zombie

iTrader: (2)

Dixit, you can play with the DFCO exit rpm point, but if you make it too low it will affect low speed drivability if DFCO keeps kicking in.

As for you STFTs, it looks like they keep going negative because your O2 sensors are railing high. I've never gotten mine perfect with my mototron 60's, but I never cared too much since the car ran good and my LTFT's stayed where they were supposed to. You can play with your O2 switch points to get them a little better, thats what I did.

When I get my car back with the 370 I'll be playing with them some more.

The 60lb injectors i've tuned on the stock cammed cars were very easy to dial in. Adding a cam really affects low rpm fueling and makes them much more difficult to get right. I'm getting rid of my 224 cam and going to a z06 cam in the new motor, drivability kicks butt!

RedWS6 00

I only modified one table when I change my fuel injectors, although mine are not as huge as yours, but perhaps the same method may work.

I used an Excel file, fuel injector scaling, someone posted it either on here or on Hptuners site. I modified it abit to create lb/hr as well as g/sec. In HP tuners I went into Engine/ Fuel Control/General Fuel/Flow Rate vs. KPA

The excel file can be downloaded from
www.solent-renegades.co.uk/hptuners/injectorscale.xls

Hope this helps

Dixit

iTrader: (1)

Yea thats the same spreadsheet I used and the values are identical, the problem is trying to get this large of an injector working on a stock 346 displacement. I cant get it to command a low enough pulse width on the decel where it doesnt go into DFCO.

Dixit

GrannySShifting

iTrader: (10)

Ive got some 60s idling pretty good, 346 cammed cars, but the min pulsewidth I ever seee is 1.6 ms. Do you think the pulsewidth is the hesitation problem or something esle?

Dixit

iTrader: (1)

At this point I dont know what to think if that is or is not the problem, but I can say this much. When Im watching my scanning tool by HPtuners and watching the STFTs, on the decel it starts going straight from 0 to about -30 and if I get on the gas right around there it hesitates slightly, if I get on the gas from a decel when the STFTs are around 0 or + values theres almost no hesitation.

So did you end up just changing the flowrate table and thats it? Man these 60lbers are killing me, may have to pull them out if I cant figure this out. I wish I can get a nail on whats causing these hesitations on decel and accel transitions.

Dixit

BTW I used to live in SilverSpring before I moved to ATL, still have lots of friends in Glen Burnie.

GrannySShifting

iTrader: (10)

It may be a difference in how the corvettes do DFCO. There are a ton of guys around GB

Have a wideband acessible to see if there is a lean spike there?

EC_Tune

The other issue could be your DFCO Entry RPM as you have to be above the entry RPM to enable DFCO. You may want to try lowering this value to say ~1600-1700 RPM

EC