RedLanEVO

iTrader: (16)

Ok. Everything was working fine and I didn't touch the map at all after I switched the stocker to the Buschur pipe. Accel enrichment tables should be factory as I never touched them. Latencies and scaling weren't touched either.

My accel table looks like this.

%
1.625
1.5
1.125
1
1
1.20312
1.32812
1.42969
1.42969
1.42969
1.42969
1.42969
1.42969
1.42969
1.42969

RPM
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
5500
6000
6500
7000
7500


How should we adjust the enrichment tables if they are in fact controlling the decay time? I guess we can try it and see if anything changes.

l2r99gst

iTrader: (2)

OK, I can explain this a little better with this picture of your stumble log:


The red line at the bottom is your Hz reading from the MAF. The next green line above that is your RPM. The next brown flat line is LTFT Mid. The fluctuatiing green line above that is STFT. The flat blue line is LTFT Lo.

You can see that in both instances where you blipped the throttle, right after this the STFT starts climbing, the car stumbles (goes below your target idle), then the STFT tries to rapidly decrease to bring the idle back up. The higher your blip was, the higher the STFT reacted.

There is one of two things happening here that I can logically think of right now:

1. The MAF is showing the airflow returning to normal pretty quickly after the throttle blips. If this is accurate, then it isn't a maf reading issue. But, since your stock pipe didn't act like this, it lends me to believe it is a maf reading issue. I'm guessing that the reading of the Hz returning to normal may not be the case, as evident by the STFT jumping around so much, first very high, then compensating low to bring idle back. The pipe may be causing a misreading of the actual airflow and reporting a nice steady Hz when that actually isn't the case.

2. The MAF and pipe are functioning and reading correctly and something else is controlling the STFT and causing these huge positive swings. Something like the accel enrichment table. The only reason why I don't think it is anything like this (although it may be partly) is because this doesn't happen with your stock pipe.

This is why I asked if you changed anything else at all after using the Buschur pipe...anything mechanically or in the ECU.

l2r99gst

iTrader: (2)

Since I double posted on accident, I will use this space for my next questions:

Do you have any log of blipping the throttle on your stock pipe? We can use that to compare to the log above to see what has changed and see how the MAF actually reads during this. This may help us determine whether or not the Buschur pipe is misreading during the throttle blipping.


Eric

RedLanEVO

iTrader: (16)

Oh yeah, I can see it in Logworks too. I converted the file.

Well then what to do? I know there are no leaks. Everything is tight, clamps, hoses, etc...
I haven't messed with anything on the intake manifold. It was working fine with the stock tube w/cone filter.
What would cause it to act differently and have something else control the decay time (if something really is) by just switching out the hardpipe?

l2r99gst

iTrader: (2)

Well, that's why I really just think it is the pipe causing the MAF to misread the airflow. Possibly the way the DV is dumping back in, etc.

We can try tweaking the maf scaling some more, but I don't know if we can completely resolve it. This is because the MAF scaling are adjustments at a particular Hz level. If the maf is telling the ECU that the Hz are 50 Hz, for example, and it really isn't, then altering the MAF scaling won't help us. Let me decide on the next changes for you to try.


Eric

RedLanEVO

iTrader: (16)

I actually don't. I fixed my trims back then with the latencies and injector scaling then did WOT tuning so I don't have any logs of the airflow w/fuel trims.

If it really comes down to it, I can put back in the stocker and reset the ecu and let it relearn then log the blipping of the throttle.

l2r99gst

iTrader: (2)

Don't worry about it. I can easily log it on my car with the stock intake pipe for comparison.

I'm really thinking it is the way the pipe is allowing the MAF to read the airflow after the throttle is lifted. The shape of the pipe and the way the DV comes back in, may be hindering it's ability to monitor true Hz values in this situation.

l2r99gst

iTrader: (2)

One other thing on why I asked about the accel enrichment and other tables.

You have to remember that our MAF also contains the baro and intake temp sensors in it. So, the new pipe can be altering the baro reading as well. Since mrfred disassembled the accel enrichment table routine and found that it is an RPM dependent baro compensation, we may be able to use that table to fix the stumble.

Can you do a log of the stumble again log all of the same items and add baro, intake temp, front o2, wideband (if you have it), and throttle? I can compare it to a log of my own to see if anything jumps out that is drastically different.


Thanks,
Eric

RedLanEVO

iTrader: (16)

Hmmm...ok. Well I do have the Buschur mini batt kit with the shorter uicp and am using the ETS hard-pipe recirc. That makes the DV sit by the uicp instead of, like a stocker, sit by the intake pipe..but that didn't make a difference on the stock tube.
Maybe it is the intake. If we can't get it to work, I'll have to try something else.

I'll log it.

l2r99gst

iTrader: (2)

Yeah, well since you didn't change anything from stock to the Buschur pipe, I think it's safe to say it is the pipe causing the issue. It's just a matter of whether we can make it work with your particular setup. If not, a new pipe it is.

RedLanEVO

iTrader: (16)

Here is it with all you requested.

l2r99gst

iTrader: (2)

OK, I'll take a closer look at this later tonight. On first glance, though, why is your idle AFR not stoich? Is your wideband reading correctly?

RoadSpike

iTrader: (5)

If the stumble is where i think it is where it suddenly goes a little lean then drops to 500rpm for little bit then I may have an answer for you. With my own buschur pipe i ran into that very same issue where it was beginning to stumble just a bit on my car. I found out that it was going slightly lean after letting go of the throttle.

So what i did was went into the MAF smoothing table and increased the first three values for my evo 8.

The old values where:
144.2
144.2
154.2

I increased those to around 165 dropping to slowly to 162. The smoothing table appears to control the amount of fuel being dumped into the engine at this super low airflows high numbers appear to mean more fuel. This fixed my lean stall maybe a similar exercise will help you.

RedLanEVO

iTrader: (16)

Yeah I don't know. I smell fuel from the exhaust so I think it is reading correctly. At cruising, the AFR's are stoich...not at idle obviously. I really don't know why.

RedLanEVO

iTrader: (16)

Thanks RoadSpike, I will try that too.