Need help, light throttle/ decel pulls fuel

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EECBandit
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Need help, light throttle/ decel pulls fuel

Post by EECBandit » Fri Jun 29, 2018 9:48 pm

I have a problem where under extremely light throttle to coasting, the ecu pulls a lot of fuel. As soon as I give it some gas the KAMRF's bounce up to within 1-2% of 1.

I have tried cleaning up the MAF below the Idle MAFv, but decel still pulls almost all KAMRF 11%.

Is there a way to cut some decel fuel so that the ECU doesn't try to pull as much fuel?


Running a 331 with a A9P EEC.

Thanks.

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skunk
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Re: Need help, light throttle/ decel pulls fuel

Post by skunk » Sat Jun 30, 2018 6:27 am

Have you logged Throttle Status to see if your "light throttle* is registered as a closed throttle position? Also look at ISCDC .....it's likely in daspot mode. You could experiment with pre-position or bump FKARCH up a hair but that would also fatten up everything down low and require minor adjustments to your MAF curve. You could also reduce the lean HEGO Bias down low by moving the numbers toward negative (rich)

You have to consider that at low loads your Kamrf is learning from what supposed to be your idle cells. If your idle is increased above stock you may need to alter the adaptive learning table to reflect the idle cell.

Personally I wouldn't worry a whole lot about a lean decel. It actually is easier for the engine to recover on tip-in. I can't remember stock characteristics since I've enable DFSO based on the X3Z.

John
1987 Turbocoupe.
A3M1/A9L, BE/EA, Tweecer RT.
306,Single Turbo, Ported E7's, Ported Stock Intake, 42lb Matched Green Tops, PMAS 3" Blow-Thru Protube (42# supercharger calibrated),T5z, 3.73 gears
..... Nothin Fancy.......Just something to keep me from the honey-do list.........

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EECBandit
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Re: Need help, light throttle/ decel pulls fuel

Post by EECBandit » Sat Jun 30, 2018 3:48 pm

Thank John,

I like the idea of not worrying about it. The car runs fine, just trying to see if I can tweak it a bit. I was looking at MEFTRD and might give that a decrease and see how it responds.

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skunk
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Re: Need help, light throttle/ decel pulls fuel

Post by skunk » Sat Jun 30, 2018 5:24 pm

Just remember that is part of the Transient Fuel system and isn't in the mix for long.

The more I think about it.....the more I think you need to take a look at the adaptive learning table to reflect properly. I am basing my opinion on you comment about KAMRF variance. This is the only place that governs learned fuel.

I don't know what your Idle RPM is but its highly doubtful it's stock. Look at FN1325 loads below 20 all reference cell-80 which is 625 RPM . If your closer to 900 RPM change all the -80 to -82. That should force decel trims to reflect closed throttle idle trims.

It won't effect anything else so if you don't like the outcome, just flip it back to how you had it.

John
1987 Turbocoupe.
A3M1/A9L, BE/EA, Tweecer RT.
306,Single Turbo, Ported E7's, Ported Stock Intake, 42lb Matched Green Tops, PMAS 3" Blow-Thru Protube (42# supercharger calibrated),T5z, 3.73 gears
..... Nothin Fancy.......Just something to keep me from the honey-do list.........

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EECBandit
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Re: Need help, light throttle/ decel pulls fuel

Post by EECBandit » Sun Jul 01, 2018 7:07 am

Thanks John, that's a great suggestion. I have 4 throughout the table right now but never changed RPM scale. I have my idle set at 824 so I am going to try and reference another cell for below idle and low load.

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skunk
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Re: Need help, light throttle/ decel pulls fuel

Post by skunk » Sun Jul 01, 2018 10:31 am

Well there's the answer. Setting closed throttle and decel to learn is going to bounce KAMRF around alot. You don't have to re-scale rpm to correct the issue but its nice to have it reflect the range your using.

If you employ that strategy of fast learning leave all -80 alone or set to reference your idle RPM. If your at 824 you could go with either -81 or -82. Then go-to Z_LTMT880 thru 883 and set that as desired.

John
1987 Turbocoupe.
A3M1/A9L, BE/EA, Tweecer RT.
306,Single Turbo, Ported E7's, Ported Stock Intake, 42lb Matched Green Tops, PMAS 3" Blow-Thru Protube (42# supercharger calibrated),T5z, 3.73 gears
..... Nothin Fancy.......Just something to keep me from the honey-do list.........

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EECBandit
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Re: Need help, light throttle/ decel pulls fuel

Post by EECBandit » Sun Jul 01, 2018 7:17 pm

I'll definitely give it a try and report back. won't be able to do it for a few days because of work and other commitments.

Wish I could try it sooner :)

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EDS50
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Re: Need help, light throttle/ decel pulls fuel

Post by EDS50 » Fri Jul 06, 2018 3:49 pm

Is DFSO or MFA enabled?
1992 LX - 25.1c Chassis, Vortech Blown Dart 332, Lentech Trans, TRZ Backhalf, A9L, Moates QH/SL v1.9, BE, EA, TunerView

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