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10.0AFR decel 941701715 v7

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Old Sep 25, 2016, 03:32 PM
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10.0AFR decel 941701715 v7

Ive been fighting a problem with rich decel. At Thunderhill yesterday every single time i would lift off the throttle and onto the brakes for the braking zone the AFR would stick at 10.0AFR. The previous track day is when it all seemed to start. Confirmed by the excessive black smoke behind the car. Aha. Ive tried the "rapid fuel cut control" patch with zero luck. Is that a Speed density only thing? Im at a loss for daignoses.



1. Car is stock turbo/block/injector/maf but with revolver cams.
2. Leak down test confirms health of engine, highest leak down of 4%.
3. Injectors just cleaned and balanced 300 miles ago.
4. TPS shows 13.3 at idle, 100 at WOT.
5. Would converting to SD help?
Old Sep 28, 2016, 06:22 PM
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Can you post up a log with this happening?
Old Oct 2, 2016, 07:38 AM
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I'll get a log today. Oil analysis came back showing 3% fuel dilution.
Old Oct 2, 2016, 10:42 AM
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I added the fuel cut decel delay timer to my XML. And found this when opening table. Set to 63,000MS(63 seconds). Reduced to 250ms. See what happens.

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Old Oct 10, 2016, 12:41 AM
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Originally Posted by ReidFletcher
I added the fuel cut decel delay timer to my XML. And found this when opening table. Set to 63,000MS(63 seconds). Reduced to 250ms. See what happens.

any update on this ?
Old Oct 10, 2016, 08:10 AM
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Originally Posted by mines5
any update on this ?
Just drove the car yesterday finally. Didn't really seem to make a difference. The car on the street will cut off injectors within 300rpms. But on the track is where is impressively bad. I'm starting to wonder if there is some sort of iat temp compensation.
Old Oct 10, 2016, 11:44 AM
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Originally Posted by ReidFletcher
Just drove the car yesterday finally. Didn't really seem to make a difference. The car on the street will cut off injectors within 300rpms. But on the track is where is impressively bad. I'm starting to wonder if there is some sort of iat temp compensation.
Can you check your BOV ? is it VTA ?

Also your TPS % ..
Old Oct 11, 2016, 09:05 AM
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Originally Posted by mines5
Can you check your BOV ? is it VTA ?

Also your TPS % ..
Bov is a Forge recirculated.

Idle % - 13.3%
WOT % - 100%

Local Subaru/Evo tuner adjusted the closed loop load threshold, he thinks that the car may be sticking in open loop on decel.

The toughest part is recreating this issue on the street
Old Nov 6, 2016, 03:37 PM
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FInally was able to go drive the car. Been fighting getting my new ETS 3.5" intercooler fit behind stock crash beam and building a catch can.

Anyhow i noticed something weird. The injectors will shut off as long as the TPS voltage is between 13.3 and 13.7. Coming down a canyon road i was able to replicate the problem. The Tps would stick at 14.1 and AFR would remain rich. Once we got back into town and the oil temp cooled off and the TPS would then drop to 13.7. WTF makes the tps voltage change from time to time. i adjusted the TPS to 11.3 at 0rpm. Idle is at 12.5,(iac must be helping?) and lufting of the throttle the AFR stick at 13.x. Log included.

BAD TPS?
BAD IAC settings?
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Old Nov 6, 2016, 04:04 PM
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Looking over some logs my tps is 14.9 volts idle
Old Nov 6, 2016, 04:05 PM
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Maybe its caused by the agressive revolvers, valve overlap.
Old Nov 6, 2016, 05:36 PM
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Zero out these two tables:
1. ISCV Demand RPM Adder [rpm > 4500, load > 170, speed > 12 mph] (sub_1EFC0)
2. ISCV Demand RPM Adder (Moderated by Baro, IATS) (FFFF6EA8) (sub_204B6) [sub_1EFC0]

Old Nov 6, 2016, 10:06 PM
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Ok i will try it. I also zerod out some of table i thought relevant. Screenshot below. But I will try the process of elimination to figure out whats the exact issue.

I also have been loaned another known good TPS sensor to try first. I question my sensors health because of the random changes in TPS static %.
Old Nov 8, 2016, 08:17 PM
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Went and drove the car tonight. Did my best to replicate the same coniditions from Sunday^. I could not replicate the rich decel. I did notice that it does take a good 2 seconds for the injectors to close via wideband. Im happy that i havent ran into the issue again. Any way of getting the injectors to snap shut. It sure does make it tough to slow the car in the braking zone when the engine is still technically running. aha
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Old Nov 13, 2016, 07:10 PM
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Went to the track this weekend. Problem is still unresolved. Every single corner/braking zone/throttle lift on track the car would just stand at 10.0AFR with LOTS of black smoke. wtf. ahah

The lamest part of this is that its so hard to replicate this issue.

Is there some issue with elevation change? Thunderhill road course is ~138ft. Reno is ~4500ft



I was recommended by Bainstuning who was at the track to change to 96530706. I've done it and car runs. Anyone comment on effectiveness of this?


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