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powertoweight

lotus accel problem

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Hello

First post.

I am working on a 199x Lotus Elise S1with the original Rover K-series that has been turbocharged and  controlled by G4+ Storm. 

I have previously adjusted my fuel cells for a decent run but had a very minor tip in hesitation. I then discovered that the Accel Load  Axis was set to MAP and changed it to the recommended TPS. Now it does not tip in very well at all and has a huge bog that sometimes the engine cannot recover from until I lift off the throttle.

After switching to TPS I have increased Accel Clamp from <20 to 85 and decreased decay from 30% to 5%. Now when warm my log shows an Accel Fuel addition of 85% @ 2700 rpm. Is there a suggested maximum value for Accel Clamp or Accel Fuel?

Hopefully my log and map successfully uploaded.(This map does not show a really bad bog where it would not recover until lifting throttle)

Thank you for the help

base.map.pclr Log 2019-11-27 10;13;50 am.accel.llg

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There are a handful of things fundamentally wrong with your fuel setup. I suspect your previous config leaned really heavily on accel enrichment to fix things up, but now with a "normal" enrichment that drops off after a second or 2 its exposing other issues.

Quite simply, your fuelling settings are causing it to run very lean under pretty much any load over ~25% TPS.

Specific issues I can see (probably not all of them):

your fuel system type is configured as "no pressure correction" - ie its a fixed fuel pressure regardless of manifold pressure (aka you have no vacuum/boost ref to your fuel regulator). If this is true, you probably need to change it now you have boost going through the engine. If its not true, your config need to be modified to match the real world

your fuel density coefficient is set to that of methanol, but your AFR is set to that of petrol. 1 of these is wrong and will throw off modelled mode calculations

your fuel charge cooling coeffient number is 53C. Unless you somehow measured this or know that this is correct for your fuel, set it back to 10 like it typically is for petrol engines.

the values in your fuel table seem a bit suspect. 135% VE @ -80kpa MGP, then 65% VE @ -20kpa MGP, both at 2000rpm. Then there is a massive jump of ~40% between the 0 & +20kpa lines. In general your VE table should roughly match the shape of your torque curve. Your fuel table needs some serious work.

You have closed loop lambda enabled - which isnt bad in itself, but you shouldnt be trying to tune it with this enabled as it will mean the ECU is busy correcting things in the background, so your changes may not do what you think they should. Only turn this on once you have a good tune, and this just smooths out environmental issues. It shouldnt be used to "make" the fuel tune.

 

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I changed the fuel density temperature coeff.  to petrol and fuel charge cooling coeff. to 10. But as soon as I change the fuel system type from "none"   to "MAP" the engine falls on it's face dead. I had previously tuned the fuel so that it ran reasonably well but obviously I had some base parameters incorrect. 

Here is a log of when I switched from "None-no FP correction" to "MAP referenced". Do I just need to shift all my fuel numbers substantially to get it to start or am I missing something?

Log 2019-11-28 1;37;04 pm.llg

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Did you also set the base fuel pressure to 300/350/whatever you are running? This will show up and default to 0 as soon as you set "Map referenced". Because it just dies its a little tricky to be certain, but it looks like it goes crazy rich (~53ms injector pulse), so I suspect one of the other fuel system parameters is wrong/missing. The fuel table1 values arent perfect but it should still start & probably idle with what you have in there.

Are your injector parameters correct? 725cc @ 310kpa with the dead times & spw's as defined?

can you post the current pclr and a log of it trying to start after your changes?

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Looking at the pulse widths of it running, 725cc looks like a believable number. It also seems to run ok for now so probably not worth ripping them out to check. Maybe if there are other issues later.

Next thing I notice is that you are running off the bottom edge of the ignition idle map and so sitting at minus 6.5* timing at idle, and you are still 5-600 over target. You are also running quite rich at points.

First thing would be to tweak the fuel cells around idle so there is not so much of a jump between them (eg aim for around 5% difference in neighboring cells as a starting point), and anywhere it runs rich, drop the cell and those near it by 3 or 4 points. 

Once your idle fuelling is ok, then you probably need to bump up quite a few cells in the base idle table by 5 or 10 points (maybe 20) until your idle gets more under control. Low timing at idle may be why it always felt a bit flat taking off - espeically when its negative. In fact your ignition idle table could probably have say 5 points added to every cell at 0 error and below. Dropping this sharply to negative ignition numbers will make it drop rpm really quickly once you have the idle valve operating more normally.

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Thanks to your help I got this thing running acceptably. 

Now that I have turned the CLL back on my hot starts have a heavily surging idle(at start up) and possible stall. Any suggestions there?

Thanks again

base.map.4.pclr Log 2019-11-29 2;13;35 pm.restart.surge.stall.llg

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8 hours ago, powertoweight said:

back on my hot starts have a heavily surging idle(at start up) and possible stall. Any suggestions there?

 

This is because you didnt do this:

On 11/29/2019 at 1:55 PM, cj said:

Once your idle fuelling is ok, then you probably need to bump up quite a few cells in the base idle table by 5 or 10 points (maybe 20) until your idle gets more under control.


I have attached a new version of your tune with the idle ign table fixed up and a few changes to the main idle table around the idle area.  You can use the compare function if you want to see what I changed.  Your fuel map still looks like quite a mess around idle area and really needs to be fixed.

VqYLy5B.png

 

base_map.5.pclr

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Thank you for your help. I will try that ignition correction on Monday. 

The fuel map is set super high around -80  -100 due to it measuring very lean at that point. I have not tried to address that yet.

 

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3 hours ago, powertoweight said:

The fuel map is set super high around -80  -100 due to it measuring very lean at that point. I have not tried to address that yet.

Of course it will go lean on overrun, this is overrun fuel cut.  Dont worry about what the lambda does when there is no combustion.

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On 11/30/2019 at 11:41 AM, Adamw said:

Of course it will go lean on overrun, this is overrun fuel cut.  Dont worry about what the lambda does when there is no combustion.

So I should just set these fuel numbers similar to  -60kpa  values?

 

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I would try something like my changes in red below, this gets rid of most of the odd cells that dont seem to fit in with the rest of the general fuel map shape.

 

Rpfwlq4.png

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I have made the suggested changes. It goes down the road great! Many thanks. 

The hot start is still leaving much to be desired. It starts a bit fast then idles up and down for some time, it may stall.

I tried switching back to closed loop idle, it stalls easily. I recently turned off Ignition Idle  Control, not any better. played around with idle mixture(it idles smoothest at 13.8:1 AFR) and Idle Stepper motor counts.

The included log shows a stall and a restart without an ignition key cycle.

Any suggestions?

Log 2019-12-2 12;03;55 pm.hot.start.surge.stall.llg base.map.6.pclr

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I'm not convinced your idle stepper motor is resetting correctly. This will make your idle really inconsistent. You have an output configured as ECU Hold power, but the settings menu for this is not present, and the f12 status screen shows it as disabled. This, combined with your idle settings of "reset @ key off" suggests to me that the stepper reset isnt completing. 

Your firmware is also really old, so bumping that up will likely help as there have been a fair few idle related fixes in the last couple firmwares. I'd do this first, but read all the revision notes and back up your config first!

If you are still seeing "hold power disabled" in the f12 aux functions screen (correct value would be enabled/active), then try changing the idle stepper reset to "key-on". This will delay startup but work around apparent bug you have - assuming firmware doesnt fix it.

Also, this cell in your fuel map should be more like 54

image.png.21e86771a0072450e64244d61a75fcb4.png

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The ignition idle table in v5 looks pretty normal. The one in v6 looks to have been forgotten then ignition idle was disabled, and then picked up junk values.

I'd suggest you turn ignition idle back on and use the v5 table.

However, leave throttle idle control in open loop for now, and disable closed loop lambda. Both of these can be enabled later on, but get the tune right first.

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Thanks to your help, I finally have it starting and running quite well.

I have decided at this time that I am not going to update the firmware(I'm just doing this to try to help out a friend and don't want to get buried in this if I have to start from scratch). I know, I know...

What are "normal" post start enrichment numbers? Mine range from 38-28%  from 30-60*C. Seems high to me.

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Those are pretty normal numbers. Remember the post start enrichment only applies for 3-5 seconds before it switches over to the warm up table with typically much lower values. This means it's really only to provide a bit of extra petrol to wet the port walls etc and deal with unstable air flows from cranking. Once running for 5+ seconds this setting has no impact on anything

See the "hold time table" for how long exactly this table is in effect for.

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