NefMoto

I am trying to understand why my "Engine Load Specified" (rlmx_w) remains so high even when there is only partial throttle input from the driver.  The pattern that I've noticed is that as soon as I press the throttle for light acceleration, the Engine Load Specified jumps right up to 220.125%.  Only when the throttle has been completely released (no input) for at least 1-2 seconds, then the specified load begins to fall back to it's resting point of 124.

To me this says that my specified load is following LDRXN (max spec load) all the time.  Why would this happen?  Why isn't control returned back to KFMIRL during part-throttle input?

Normally, I would think the answer to this question would be that rlsol_w via KFMIRL is meeting or exceeding the limits defined in LDRXN, but they do not, as you will see by the screenshot I've provided below.  My part throttle tests show that 30-50% throttle should have a specified load no more than 95% and no less than 61%.  However, you will find in the attached log file that in these cases, the specified load is pegged at the max LDRXN value of 220%.

I am providing:
- A log file with part throttle data.
- WinOLS file containing Original and Modified bin
- Screenshot of KFMIRL and LDRXN

I appreciate any thoughts/feedback.

(http://i.imgur.com/8E7qY.png)

My main concern is that I'm occasionally hitting limp mode and what I discovered in my logs above is my most likely explanation for this.

Here is the code that is thrown when I experience limp mode (<5 PSI boost allowed).

17705 - Pressure Drop between Turbo and Throttle Valve (check D.V.!)
        P1297 - 35-00 - -

My thoughts are that the specified load is so high that the ECU eventually sees this as not being met, and assumes that the charge is being lost somewhere.  Does this make sense?

I think I'm learning on my own that "Engine Load Specified" is tied pretty closely to rpm.  Actually this is mentioned in the S4Wiki:


Looking at my Requested vs. Actual loads, it looks pretty normal.  So this may not be the cause of my limp mode.

Is it only on a cold start that you get DTC 17705?

"Engine Load Specified" is a misnomer. It is a maximum, not the load request. You are looking for "rlsol" (EngineLoadRequested).

http://nefariousmotorsports.com/forum/index.php/topic,970.msg8653.html#msg8653

Thank you.  This makes a lot more sense.  Now I can stop pulling my hair out as to why I thought I was seeing a request for 220% at 20% pedal position.  Not a request at all.  This is the LDRXN mapping.

I've had it happen at various engine temperatures, but it occurs most often when the engine has been running and is hot.  Last night I changed around my KFMIRL so it's not requesting too much load too soon.  I am testing today to see if the DTC comes back.

Would DTC 17705 indicate positive deviation?  It's possible I wasn't meeting requested load.

As far as i know, there is no load based positive deviation code... you are looking at a kind of boost deviation code, but not one related to the PID (plsol - pvdkds), but rather related to the pressure drop model (possibly pvdkds-pvdk).

Stupid question: are your BPVs ok?

If so, start with KFMIRL/IOP interactions (as you already started to). Post up logs of req/actual boost too. If you get a positive deviation code, you'll know it, because it says "positive deviation" :)

I suppose I should mention what hardware I'm working with.  It's an '03 GTI 1.8T. So a single BPV... it's a Forge 007.  I'll double check that it's operating correctly but those things are pretty bullet-proof as far as I know.

I've read a lot of mixed statements regarding KFMIOP and its relationship with KFMIRL.  Of course, the funktionsrahmen states that IOP should be the inverse if IRL. Although I've seen many people state that this is not necessary.  Still a little unlcear on how this map should look.

I'll see if I can get some logs up soon.

Posted logs for the limp problem in the following new thread.  My concern about "EngineLoadSpecified" was answered.

http://nefariousmotorsports.com/forum/index.php/topic,1138.0title,.html