a Load plummet issue
 

Recently I found an issue that Load plummeted while pulling my car. Currently I'm working on this problem.

Today, fortunately I was able to pull my car in Osaka ( no snow!! ).

Attached is the graph when I pulled my car. VirtualDyno result is overlayed on the graph created in Excel.

I drew two green circles on the graph. It seems that AFR goes leaner around the area where Load plummeting.

What do you think caused this? Glad to any comments. Thanks.

this is likely your issue, I wrote a tech article for our site about this:

http://www.mellonracing.com/index.ph...roducts_id=805

Hello,

Thanks! Ummm... It looks very similar to mine. :cool:

okay, I have a spare MAF. I'll try to compare both new and old MAF.

BTW, with cleaning the MAF can we reuse it?

yes, i simply wiped the dirt away from the airflow sensor with a clean q-tip.

>yes, i simply wiped the dirt away from the airflow sensor with a clean q-tip.
Thanks to the info, Mellon Racing.

After Installing new MAF sensor bought from my dealership, I tried what happens to Load.
Look at the pic, surprisingly, the cause of the Load plummet was not MAF!

I tried to log again but unfortunately Load plummeted again.

Attached is the log and the pic.

It seems that Load, MassAirFlow, and MAF_Hz were plummeted. The other stuffs, such as MAFVolts, and MAP were not plummeted.

Ummm!! I don't understand this phenomenon.:confused:
Is there anyone who can figure out what the cause is? Also, welcome to any advices for figuring it out. Thank you very much.

whats your mivec maps look like?

what BOV do you have?

tephra,

mivec intake looks like an agressive version of the stock map. especially 2000-3500 rpm. On the contrary, exhaust map is milder version of the stock map. values ​​in the area of 160+ Load of the map is set to 0.0.

I have a stock BOV.

have you changed your 3xMAP tables?

where did you get the MAP_Calcs and MAF_Calcs from?

emailed...

Ah, I've been forgot about 3xMAP MAF tables!
Load may have hit the lower of either MAP Load or MAF Load.

I'll try to check it. Thanks a lot!:)

After getting advice from tephra, I increased values of 3x MAP MAF tables enough where Load plummeting. (Attached pic.)

As a result, no improvements were found.

1. MAF sensor is new and clean.
2. 3xMAP MAF tables have no effect.

Oh, My God...As the cause of this issue, what is left? I really have no idea what the cause is at all.:helpme:

Append:
After submitting this article, I've re-examined about the 3xMAP tables.

When Load plummeting, (MAP - Baro) is like below. It takes around 20.xx-22.xx. Columns of 19.60 and 21.53 in 3xMAP tables are most close when the ECU processing the interpolation. Values of both columns probably might be too small.

I have a last chance tomorrow before leaving Osaka. I'll try it. I can't give it up.;)

Notice your load curve is x20
Take your boost and x200 n plot a curve, you will see the exact same pattern.

clck,

I have to leave Osaka now, I'll log on my way to the ferry port.
After getting a log, I'll try to plot it as you advised. Thanks! http://images.ibsrv.net/ibsrv/res/sr...ilies/wink.gif

#I can't post for several days because on the ferry, then over the snow mountains. :cool:

You can log the Load that comes from the MAF and MAP separately to see what's going on with your tune.