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Can't get a smooth idle with homemade ITBs


Metro

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Your PW is sub 2ms. That is in the non-linear range of the injectors. You have no precise control over how much fuel is being injected. Try changing "number of squirts" to 1. (I'm running sequential and can't remember if this doubles the pulse width - I think it does.) You may want to turn on "sequenced batch fire" so you can have consistent injector timing every time you start.

 

Just to be clear, your target AFR table has a different load range than the VE table. You should make them the same and adjust the values accordingly.

 

I only suggest turning off "include AFR" for testing purposes. Your current settings bounce between 12.5 and 13.8 target AFR. This is included in the fueling calculations when "include AFR" is on. (Once you figure out the fluctuation problem, turn it back on.)

 

I think this combined with the small pulse widths (due to large injectors) causing you to lose control of fueling is causing the fluctuations. 

 

To get the PW down, you can try any combination of the following: bump the idle up, pull some timing at idle (try 10 deg), switch to 1 squirt per cycle, bump up your AFR target.

 

With large injectors far back in the manifold it will be more difficult to tune idle, cruise, and transient conditions. See my MS3 build thread: http://forums.hybridz.org/topic/102280-ms3-w-ms3x-install-l6-turbo-sequential-injection-boost-control/

I'll second this - just because your injectors still "work" at these pulsewidths doesn't mean that they should be expected to be repeatable.  Changing to sequential should indeed double your pulsewidth and get you well into the linear region and if nothing else you will know if that was the issue or not.  Also - doesn't MS have a "minimum injector on-time" setting that will allow you to set a "floor" that the injector PWs can't fall below?  You could also experiment with that setting to see if low PWs are your issue.

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Yeah, just because something worked in the past, doesn't mean it's working now. I think I need to throw out what I thought I knew and start over. It seems like it was working alright at one point, so I need to debug it until I find where it went wrong.

 

I'm not sure if MS2 has that feature, but I'll look for it.

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The "Minimum injector on time" equivalent in MS is the injector deadtime. You can bump that up but it will limit the control precision because all adjustments to the PW are performed before the dead time is added. Only do it as a test. This can let you know if it will run evenly and steadily with a richer mixture.

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So what are you using for rpm ? Have you set your timing to a fixed number to see if it smooths out anything?

Has your rpm source changed when going from MS1- MS2.

Timing light has verified nothing wonky with your spark?

 

I ask all these things because it's the road I'm heading down now. My coils did funny things while testing . I'm back revisiting everything including the possibility of a pull up resistor for my Hall effect sensor.

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The "Minimum injector on time" equivalent in MS is the injector deadtime. You can bump that up but it will limit the control precision because all adjustments to the PW are performed before the dead time is added. Only do it as a test. This can let you know if it will run evenly and steadily with a richer mixture.

Agreed. I was suggesting this as a debugging step. The better solution would be to run sequential and double the PWs.

 

I'm assuming that I haven't seen anything more on this because you don't have a cam postion sensor? Sorry my experience is with Electromotive stuff, but with the TEC3 if you set it up for sequential and no cam position sensor is present it will just guess and "get it wrong" half the time. With waste spark this turns out to be pretty much imperceptible, and you still get the benefit of increased PWs. Anybody know how MS reacts in this scenario?

Edited by TimZ
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Agreed. I was suggesting this as a debugging step. The better solution would be to run sequential and double the PWs.

 

I'm assuming that I haven't seen anything more on this because you don't have a cam postion sensor? Sorry my experience is with Electromotive stuff, but with the TEC3 if you set it up for sequential and no cam position sensor is present it will just guess and "get it wrong" half the time. With waste spark this turns out to be pretty much imperceptible, and you still get the benefit of increased PWs. Anybody know how MS reacts in this scenario?

 

The MS2 software supports sequential injection, at this point it has nearly the same code as MS3. The problem is with the hardware. MS2 only supports 4 injector channels (which probably conflict with other outputs I'm using). Not to mention to get that, I would need to add extra injector drivers and another VR input circuit for a cam sensor. I haven't looked into it too much right now, so I'm not exactly sure.

 

The MS3 hardware has many programmable inputs and outputs so it doesn't require any modification. 

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After spending a lot of time trying to tweak the fuel injector settings to no avail on Friday, today I dug out my original MS unit. It has nothing done to it, aside from a few things I did to butcher it years ago, but last time I put it away it was in perfect working order. So I modded it for wasted spark, loaded my December 2013 settings and plugged it in. 

 

On the first attempt, it started and died two seconds later, but it was sounding nice. The second attempt I gave it some throttle and it roared to life. It's running extremely rich, but it was buzzing steadily at whatever rpm I held it at. And damn, it revs up quick! I was holding it around 1100rpm with a 3.5ms PW and around 11:1. I reflashed  MS with with EasyTherm to fix my IAT sensor. I used the values listed in TunerStudio's MS2 config. Either it didn't work or I reflashed the ECU with the wrong file because it's reading negative temperatures in the log file.

post-563-0-26652100-1404018420_thumb.png

 

So with that, I tried plugging my MS2 chip into the old board and it was back to missing and shaking. So there has to be something wrong with my MS2 settings (injectors?) or that chip is bad, which seems extremely unlikely. The settings I'm using for my 450cc DSM injectors came from the injector thread on this forum and from forum posts on the MS Extra site. Now I know my injector settings for MS1 are spot on, but the settings completely changed between versions.

 

 

I suppose I should datalog the MS2 chip on the old board and compare. I noticed there's almost no noise on the MS1 log, but nothing has changed in regards to the grounding with the harness.

2014-06-28_21.30.28_MS1.zip

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Sorry for the basic sounding advice, but did you just simply plug in the MS2 daughter card? 

Reason that I ask is sometimes it is the simple things that I forget, as in, did you run the 12 supply for the daughter card?

http://www.msextra.com/doc/ms2extra/MS2-Extra_Conversion.htm

 

Edit: that was useless help, I just remembered that only effects your outputs for MS2

Edited by AkRev
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I had exactly the same results, Metro, when I converted from MS1Extra to MS2Extra. Every single MS forum post I made, I was the one to blame, it was grounding, can't be the MS2, Can't be this, can't be that.

 

Pull the MS2 chip out and reload my old MS1 tune...smooth as anything. Plug in the MS2....back to the rough idle.

 

I never figured it out, I just tuned around it and went on.

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I had exactly the same results, Metro, when I converted from MS1Extra to MS2Extra. Every single MS forum post I made, I was the one to blame, it was grounding, can't be the MS2, Can't be this, can't be that.

 

Pull the MS2 chip out and reload my old MS1 tune...smooth as anything. Plug in the MS2....back to the rough idle.

 

I never figured it out, I just tuned around it and went on.

 

Wonderful, there's no way I can tune around this on MS2. It would be simpler to try and use the MS1 with blended tables.

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Which version PCB are you using for your MS2? For your MS1?

 

Can you strap some resistors in line with the injectors and set it up without PWM control?

 

I've read up on the settings and think this may be contributing to you problems. You may not be holding the injectors open appropriately.

http://www.msextra.com/doc/ms2extra/MS2-Extra_Tuning_Manual.html#pwm

http://www.msextra.com/doc/ms2extra/MS2-Extra_Conversion.htm#injchar

 

the MS2 section is weak on detail, but the MS1 seems to spell it out.

http://www.msextra.com/doc/ms1extra/MS_Extra_Tuning_Manual.htm#pwm

 

I have no experience with low Z injectors - but it appears that these settings can definitely affect the running, especially with large injectors. 

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Which version PCB are you using for your MS2? For your MS1?

 

Can you strap some resistors in line with the injectors and set it up without PWM control?

 

I've read up on the settings and think this may be contributing to you problems. You may not be holding the injectors open appropriately.

I have no experience with low Z injectors - but it appears that these settings can definitely affect the running, especially with large injectors. 

 

I'm using a V3 board.

 

While I have an '81 280zx's resistor pack to play with if I wanted. The thing is, I've tried using high impedance injectors with PWM disabled (240cc GSXR injectors), with no luck either. When I said I was messing with the injectors the other night, I basically was changing every parameter on the injector page on at a time.

 

There's always the chance it's spark related, but those settings seemed to copy over fairly well. Also if it were off, I would think the car wouldn't run and the timing is spot on every single time I check it.

Edited by Metro
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I thought that when you used the high impedance injectors that the AFR table was still being used. The way you had it configured it would have similar effect.

 

I think it is fuel. Not spark.

Edited by Sam280Z
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I started a thread on the MS forums, maybe they can help.

 

One of the other things I did was to fix the EasyTherm values for the Ford IAT. I accidentally grabbed the Celsius values instead of the Fahrenheit. With that fixed I was able to get the PW in the same range as MS2. MS1 would cutout and die at 1.3ms, which makes sense to me with a 1.2ms opening time.

 

I'm seriously beginning to question why I'm bothering with MS2, but I don't want to admit defeat yet. At least with MS1, I can move the car out of the driveway, if necessary.

 

Also it sounds pretty cool, which was kind of the whole point of this venture. 

Edited by Metro
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"I'm seriously beginning to question why I'm bothering with MS2, but I don't want to admit defeat yet."

 

After being in on Group Buy #2 in 2002, and running MS-n-Se from Magnus since....I've yet been given a cogent reason to fight the MS2 battle until my chip (and the three spares I have) have given up the ghost and totally died. By then, old Motecs will likely be on eBay for $300 all day long and I'll just use them...

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There's always the chance it's spark related, but those settings seemed to copy over fairly well. Also if it were off, I would think the car wouldn't run and the timing is spot on every single time I check it.

 

 

My timing was right on the mark too, but the longer I watched the light, the more I saw problems. Not doubting you, but make sure you don't discount anything! I feel your pain dude.

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Don't give up. Many many people are running MS2 - feature bloat and all. The fact that we are having trouble doesn't mean that there is something wrong with the product, just that there is something wrong our understanding of what it is doing. 

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