03whitegsr

iTrader: (8)

I've seen this problem on other systems. The manifold has pretty major pressure pulses in it. Not only do you have first order pulses from the actual air movement, but you have secondary pressure waves from valve events, pulse flow dynamics, engine vibration, etc. Depending on how often the sensor is sampled and then how much it is filtered can really make a difference on drivability.

The JDM MAP may have a heavier diaphragm that provides a slower reacting system. It may even have built in electrical filtering.

There is another option though. A passive electrical filter using capacitors and resistors may provide adequate filtering to the electrical signal. Going with an electrical solution will also make it quite a bit easier to quantitatively monitor the changes and control the bandwidth you are letting in.

Where's an EE guy?

tephra

iTrader: (6)

yeah my GM was jumpy too (especially 5500rpm)

I think its pressure pulses thou, not the sensor..

mine was mounted on the FPR line...

tom04841

I have the most current instructions and it is patched correctly i think...lol. Here is one thing I have noticed compared to the video that Mr. Banks posted. I have both ECU flash and live map open, when I make a change in ecu flash to the alt maps, it doesn't say image written (to the right side of ecuflash) like in the in the video. Another thing I have noticed, is if I have ecuflash open, my openport cable is listed in the lower right corner, but as soon as I open live map, it goes away.

I hope this gives someone some insight to my issue.

l2r99gst

iTrader: (2)

If you are making changes to an alt map that isn't in the livemap app, then you use ECUFlash to make the change, save the rom (this is where the image written comes from), then hit write in the LiveMap app.

However, if you are just changing the fuel, timing, or the VE maps, then you don't use ECUFlash at all. You do it all in the the LiveMap app.

tom04841

When I make changes in the live map app, then hit write to ram, nothing happens. If I hit the write button on the data page, it verifies, but then when I hit read from ram, i get the same values as before i changed it.

Am I missing something?

l2r99gst

iTrader: (2)

You don't use both write buttons.

OK, let's say you want to write some new timing values, you do the following:

1. Click Read RAM ign
2. Edit the cell(s) you want to change timing in
3. Click Write RAM ign

That's it. You can click on Read RAM ign again to verify the changes held. If they didn't then make sure you fixed the DMA patch with logic's instructions. The initial release had an error in it that didn't allow RAM writing to work.

l2r99gst

iTrader: (2)

The map signal is jittery, but very little (or at least what is logged)...maybe a 2kpa jitter. Nothing that I would assume would cause this IPW jitter. I think logic is getting close to testing SD and he will be using the JDM 3-bar, so I will wait for his results to see if the JDM 3-bar has more dampening of the signal is this range.

On a side note, I did flatten the maf scaling and smoothing in the suspect area and it didn't do anything to rectify or lessen the problem.

Besides the map sensor theory, one other thought I had was the various solenoids/valves that are connected to the IM, such as the EGR, FPR, etc. I'm wondering if perhaps one of them are opening/closing just in the map/RPM range and causing the fluctations. Even though 96530006 has EGR turned off by default, I may try capping off the vacuum lines to the throttle body to be sure nothing is going on there. I may test the other solenoids as well.

In speaking with logic, he told me that he removed most of those solenoids, so his test should give great data, since he is using the JDM sensor and removed solenoids. That should give a definitive answer on whether this is related either to the sensor or the emissions solenoids.

There was an error with the intial DMA instructions that prevented writing to RAM from working. If you double check your settings now, it should work.

Also, btw, what map sensor are you using? Since your log seemed to have the same issue as mine, I am curious. Also, do you have all of your emissions related solenoids still connected to the IM?


Eric

mrfred

iTrader: (50)

The hole in that theory is that the emissions solenoids will affect the IM vacuum which will be picked up by the MAP sensor. Can't hurt to try it out to verify though.

l2r99gst

iTrader: (2)

Yeah, I completely agree, but nothing seems to be correlating with the jittery IPW. Map does jitter a bit, but not by much. But, maybe it's enough and gets multiplied through the calcs (map ve, rpm ve, maf scaling, maf smoothing, etc, etc) to actually make a difference? Or maybe my logs just aren't picking up the true jitter in map?

I don't know...that's why I need more data and more tests from others. Since the SD patch is just replacing maf volume with MAP, it would lend me to believe that the map sensor is the cause, yet my logs don't indicate that.

mrfred

iTrader: (50)

I wanted to wait until I had reviewed my disassem a little more, but I'll say now that "MAF Hz" is calculated by dividing master load (as I call it) by another RAM variable (and multiplying by a few scaling constants). If load is not jittery, then the cause is going to be that other RAM variable. I need to look at how that other RAM variable is calculated. I've been trying to find the time, but I've been too busy with some personal things.

l2r99gst

iTrader: (2)

I appreciate the effort. Load is jittery as well, but again, not as much as the IPW. You can see the various screenshots that I have posted within the last few pages (starts on page 4).

The following are 'jittery' during the issue:
-load (I am just logging tephra's 1byte load right now)
-map
-Hz
-RPM (sometimes...this is what I can feel and I think is an effect of the IPW)
-IPW (seems to occur in the 2ms-4.5ms area)

It seems to happens only between 65-85 kpa and 1800-2400 RPM. Both have to be true for the problem to arise. Once outside either of those ranges, the IPW smooths out and no hesitation can be felt.

Of all of those, IPW has the biggest jumps, maybe a change of up to 80% (in some cases it appears to be a rapid drop down...say from 3.6ms to 1.99ms). The rest are miniscule in comparison. The curve that seems to follow the jittery IPW the closest is Hz, if zoomed in sufficiently for proper resolution. but, this is maybe a 10Hz swing in the 125-225 Hz range, so in the 5% range.


Eric

roger smith

iTrader: (4)

Will 2-3 psi jumps cause the IPW to get jumpy too?
IPW is calculated from the thermodynamics(?) equation PV = nRT right?
It seems to me large variations in pressure will cause variations in IPW.
It's like constantly going sea level to 10000ft elevation, back and forth.

There's like a 100 dollar different between a GM and OEM 3-bar sensor. That difference might be what smoothens the signal (compensates for valve events). Maybe the OEM sensor was tailor made for the pressure variations the evo produces?

edit: I checked out one of my recent logs and my MAP (oem 3-bar) signal's biggest variation is 0.4 psi. Mostly 0.2 differences. This is in the area you mention, 1800-2400 rpm, 80-100 load. I'm not running SD yet though.

gear head

iTrader: (3)

I'm going to go out in a few to try the updated settings.

I'm on the JDM 3-bar. Yes the solenoids are connected, but they are all disabled

l2r99gst

iTrader: (2)

Sounds about the range I see too with the OMNI 4-bar. And gear head above just stated he is using the JDM 3-bar. So, it may not be a sensor issue at all.

roger smith

iTrader: (4)

Sorry if this is of no help, but I tried out some example values from the PV = nRT equation.
What I found...

A 3 psi difference makes a 60% difference in fuel injected
2 psi - 40%
0.4 psi - 8%

Big differences.