Rb25 neo runs lean in 4th and 5th gear light load

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godzilla_753
 

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Joined: Thu Dec 13, 2012 7:07 pm

Rb25 neo runs lean in 4th and 5th gear light load

Post by godzilla_753 »

Hello,

I have the car running fairly well at idle and I'm trying to adjust K constant enough to drive it to the dyno after upgrading the turbo and injectors. I am only slowly driving it down the road not going above 2500rpms and it drives fine from 1st to 3rd gear but as soon as in to 4th i start seeing afr close to 16-17 and in 5th gear goes all the way 20.2 and above. Car bogs when it runs this lean. According to the map I'm in the close loop zone. I have disconnected the o2 sensor and set the feedback temp to 200 degrees aswell.

I have changed the fuel filter and played with k and latency but I get the same results in 4th and 5th gear. I have checked base fuel pressure and its solid I have an aem regulator. I've done a boost leak test and it is solid no vacuum leaks.

I am noting that battery voltage fluctuates from 13.5 to 12.9v, I am not sure if this might be causing this?

I've also attached a log file for reference.

Thanks
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NIStune_2014-07-28_1811_56.csv
(310.79 KiB) Downloaded 106 times
godzilla_753
 

Posts: 28
Joined: Thu Dec 13, 2012 7:07 pm

Re: Rb25 neo runs lean in 4th and 5th gear light load

Post by godzilla_753 »

Here's my bin file aswell.
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WC34_0V800_Z32_680CC_LS2_coils.bin
(64 KiB) Downloaded 105 times
Matt
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Re: Rb25 neo runs lean in 4th and 5th gear light load

Post by Matt »

Something definately wrong here, your TP (load) never makes the trace cursor go past the first column

Your K constant is a little off (using auto calculated values with Z32/680CC I get 334 instead of the 361 K value)

Maximum MAF voltage is 1.7 volts at 1400rpm. Seems a little low. Where did you get your MAF from?
godzilla_753
 

Posts: 28
Joined: Thu Dec 13, 2012 7:07 pm

Re: Rb25 neo runs lean in 4th and 5th gear light load

Post by godzilla_753 »

Hi Matt,

I have the car running pretty well in light load and cruise. I think I have the K constant at the ball park where I need to be 385. I redid the k constant and injector resize and found the ttmin and max values were off at first and after corrected the car ran better. Also I fixed a leaking vband at downpipe not sure if this was related.

I did a partial run today, with ignition backed off, at 10psi of boost and i noticed the ecu accessing the middle of the fuel map. I have attached a log and bin file for this run. Can you check if everything looks good before I take it to dyno?

I bought the oem used z32 maff off ebay and cleaned it before installing

Thanks
Attachments
NIStune_2014-08-05_1054_54.csv
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ecu tune 8-5.bin
(64 KiB) Downloaded 97 times
Matt
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Re: Rb25 neo runs lean in 4th and 5th gear light load

Post by Matt »

Read this post regarding Z32 AFMs
viewtopic.php?f=12&t=1431

Make your TTPmin table:
132 132 132 132 132 132 132 132 132 132 132 150 162 170 176 200

There is an offset with WC34 which I have fixed (128 + min TP) in the test releases

Looks better now that it is accessing the map properly
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