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ECUflash Fuel Cut - Verified Injector Pulse hits 0 in log

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rough

Proven Member
800
74
Nov 12, 2012
Indianapolis, Indiana
Problem -- Hitting fuel cut around 5k rpm --


Mod Break down
E3 16g
660cc Injectors
255 fuel pump
FMIC w/ Hard piping
HKS SSQ BOV
bpr7es plugs and NGK wires.
Aeromotive FPR
3" Exhaust
Shimmed Wastegate


Small boost leak at throttle body shaft - drop's 1 psi about every 3 seconds, system holds 30psi.
This can't be my fuel cut issue.


I'm hitting fuel cut all over the place!! My logs are showing injector pulse width hitting 0 around 5500 rpms.

Doesn't matter if i'm on waste gate pressure or have it turned up to 20psi.

I've set my tune back to stock, had no effect on the fuel cut.

I've attached a log.

Here is a video of the violence.
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I feel I've searched the internet for a good 10 hours looking at anything named boost leak, fuel cut, ect, and nothing has altered my situation.

What I'm looking for is any help, advice, solutions to this problem if you had it before!

Thanks!
 

Attachments

  • fuelcut2.csv
    13.7 KB · Views: 84
I"m working on my big maps rom from scratch, going to do a pull on lunch, grab a log and video, and see how it goes.

I'm really leaning toward something like the fuel pump or injectors as those are the last few things I replaced, the car ran fine, boosted like heck, then one day it just happened.
 
Same here. Using a multimeter will help, is easy enough to check injectors, mine read at 2.4ohms clinics 750cc. And link will assist, since you can shut off each injector to test them. And pump well if you have the right pressure at your AFPR and it holds that pressure even after the car is shut off, there no need to open up the pump.
 
The AFR is bogus, I can't get it to match my wideband. I'm been messing with the formula forever, so you have to take the Rear o2 voltage "wideband" and convert it.

When the injectors hit 0 the wide band is reading
0.976 volts which equates to 10.9 afr which I can see on my wideband.

I just flashed my black box ecu with the modified big maps, wide band started off lean then leveled off at stoich "14.7"
Lunch time, I'll take her for a spin and log, video it.

I have my stock injectors I could put back in, as I never fuel cutted with them at 15psi. I might do that this weekend if this tune doesn't help. If I take them out, I will flow test them, and if there not close to the 660's I was sold "lot's of injector fraud out there" I'll sell them and purchase some 1600's.
 
Some pictures for attention.

BLT @ 25psi
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and The injectors being installed.

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I take a lot of pictures so I can look at them and see if I can see a problem.

Will post back here soon with a video and log.
 
Have you verified your global fuel settings?
Let the car warm up, and lock it in openloop. Are you on ecmlink or ecuflash?

If ecmlink: check the "lock in openloop" checkbox in misc tab
if Ecuflash: set your openloop threshold tables all to 10

Adjust your globals until your wideband matches your logged value.
i.e.: Afrest = LC1WB (or whatever your WB value is)
 
I use Ecuflash,

I currently have the injectors at stock scale of 450.

I'm really thinking I got sold some injectors that are around 450's instead of 660's because my fuel trim's are best around stockish, I tried 500-660 and the car would run incredibly bad, no matter what I did with the latency's, fuel trims went through the roof, but on the stock tune she runs alright, till this :D

So with the bigmaps flashed over I NO longer get fuel cut, just feels like my motor swells up, and quit's producing power. On one of my logs I hit over 100% on IDC's "Injector duty cycle" and had a load over 260.

I couldn't get a good pull or video as traffic was horrible here, I'll try again after work :(
 
Here is a new log of cruising and a pull @ 15psi, it held there, didn't creep or drop! But had massive power loss around 4500ish
 

Attachments

  • newlog.csv
    47.6 KB · Views: 98
Alright, here's my theory. :) I can't verify this because you're posting a log and I've got no way of looking at your tune (not that I know how to tune ECUFlash) but I've got a feeling your fuel cut issue is being caused by what your ECU "thinks" you're getting for airflow at the MAS. Your logged "g/s" right when you hit fuel cut is 345.29 @ 5.5k in the first log you posted, converted that's 45.68lbs/m. The mass limit on a 2g MAS is 675g/s (50lbs/m) assuming it's working properly and your tune isn't inflating airflow numbers, which is pretty close to the airflow numbers you're logging.

That being said, I don't know how ECUFlash works exactly but in ECMLink it's possible to have completely wrong injector globals and compensate for the +/- fuel using the MAFComp sliders and have really inflated/deflated airflow numbers, which seems to be your case. My reason for thinking this is that the 16g you're running is rated for 42lbs/m max and you're logging 45lbs/m @ low boost. People that run 30psi through a 16g and are fully mod'd on E85 are lucky to see those airflow numbers at 7.5k let alone 5.5k.

I'd suspect the inflated airflow readings are tricking the ECU into thinking there's a lot more air moving thru that MAS and it's hitting fuel cut because of it. That, or if ECUFlash has a rev limiter make sure you don't have it set for 5.5k because that will cut fuel at whatever RPM you set it to.
 
Your on to something here gofer! My log is in excel format, here is a screen shot of my new log.
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I'm hitting 74.4 pounds per minute!! How!!!??
I know I did some pretty good port work but damn LOL, something is wrong!

Could this be a wastegate issue, I shimmed it recently due to it staying open, maybe I shimmed it too much and it's sticking closed, it's hard to move by hand... About to go out and test it :/
 
Are you sure your ecuflsh rom has the settings in it for the maf your using? Almost seems like the settings are for an EVO maf and your using a 2g maf. Or maybe the maf comp settings got changed by accident?
 
I'm on the 2g maf, I have a spare I can try out this afternoon. I'll be putting the stock tune back on, and pull another log.

So if I put the stock rom back on, the car runs great besides the fuel cut, trims are good, which leads me to believe the injectors I have are not 660cc... Best fuel trims I get are around 450 injector scaling. IDC's sometimes exceed 80...

Which in turn leaves me confused... Why am I running super rich, but hitting fuel cut with only a tiny boost leak in the TB shaft seal "got new O ring, just need the weekend!"


Only thing I changed to the maf was the intake and filter.
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I've changed nothing in the MAF settings in ECUFlash, all my roms are virgins in that area.

I live for this troubleshooting stuff but sometimes it drives me nuts!!
Any help is appreciated, and thanks so far for all who have helped!
 
Last edited:
Sure do have a multi, the maf seems to be working correctly, I can test it, but in my current logs, Gofer was correct, the tune was causing inflated numbers.

Here is a another pull, my injectors are hitting 98%, and are scaled as 450's!!!
I'm almost 100% certain now, but will verify with a flow test, that I got had on these 660's!
No way I should be running out of injector, nor scale them stock for decent trims...

But i'm still confused as to why i'm dipping into the 9's on the wideband if I'm running out of fuel, I should be lean...

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Attachments

  • newrun.csv
    8.2 KB · Views: 69
I have a file but you would need ecuflash, here is a screen shot of what I have to work with.
Stock Maf settings are currently flashed on the last log.

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Does there happen to be a BoostLimit table under the Limits header? I believe the right column of that table are load values that the ECU will enable fuel cut. It looks like when your car's "cutting" you're hitting a load value of 159.375.

Not sure what that means, wish I had experience tuning ECUFlash, but maybe try tricking the ECU and CAREFULLY removing the metal honeycombs inside the MAS. Try doing another pull and see what happens (logging of course) and if you get the same result re-install the honeycombs. :idontknow:

In the mean time, I'm moving this to the log file advice forum since that's where you'll get the best help.
 
Thanks Gofer!

Here is what I have for boost options.


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I'm learning as much as I can about ECUflash and it's been fun so far, hopefully I can figure this out, resolve this, so everyone else encountering this problem will have a solution!
Thanks for all the help so far!
 
I have that printed out and is bathroom reading material :D Thanks for the help thus far!
Going to keep reading and plugging away at it!
 
Those don't look like the proper maf values for a 2g maf to me. However I also don't have much experience using ECUflash. But these are the values for a 2g maf to the best of my knowledge, in decimal not hex. You could give them a try, should help deflate the airflow hopefully back into a more "normal" range. Try to use the deadtime adjustment to get idle and cruise afr's dialed in, and use the global injector scaling to get wot AFR dialed in.

MAF Adder: 64

MAF Compensation/Maf Scaling Table:
133.00
133.00
168.00
182.00
190.00
195.00
200.00
204.00
208.00
212.00
215.00
218.00
220.00
227.00
230.00
232.00
235.00
234.00
234.00
232.00
231.00
 
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