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Megasquirt queries
omega 24 v6 - 13/8/08 at 10:34 PM

Finally I have the engine running. It starts from cold no problem and it warms up and goes onto the ve table and idles roughly. The setup is alpha N and on the "tuning-ve table screen" That is the map with the dot and cross hair I can play with the settings.
Here's the rub. The car seems "smells and sounds" to be running far far to rich. If I alter the table then the car will run much better and the revs go up etc as you'd expect to hear as things get better. But when it "falls off" of the grid"map" then the engine stalls and it won't start again untill either
I set the ve table back to higher figures
Or wait till it cools down enough to go back onto the warm up wizard.
Also even after callibrating the tps a couple of times the ve table during tuning shows an idle tps on the third row of the ve table ?? IMHO that means that the lower 3 rows are being wasted because the tps will never be lower than at idle. Map is around 59 to 63 and the setup is
MS1 V2.2
VR conditioner
gsxr1000 tbs
wasted spark v/hall coil
alphaN setup
no air idle valve (but is set in msq as bosch pwm as can't work out how to set as none"
2 litre xe redtop.
I'll post a copy of my MSQ tommorrow if it'll help anyone make a judgement.

[Edited on 13/8/08 by omega 24 v6]


BenTyreman - 13/8/08 at 10:59 PM

You can alter the TPS ADC bins on the y axis to move the closed ADC to be on the bottom row and the WOT ADC to be on the top row.

Try re-calibrating the wideband sensor in free air if you suspect inaccurate reading.

If it won't start when hot, try altering the relevant points on the cranking curve to increase cranking pulse width. If it tries to start, then alter the afterstart enrichment amount and duration.

If it smells too rich, increasing the VE values only makes it richer. Sounds a bit contradictory.


clairetoo - 13/8/08 at 11:03 PM

The map needs to be altered so that , at tickover , it will use all the map (my maps are scaled from 24 to 215 , the full range of the TPS).
If it wont start after altering the fueling , it sounds like `after start enrichment` needs increasing - I had the same problem .


omega 24 v6 - 13/8/08 at 11:05 PM

quote:

You can alter the TPS ADC bins on the y axis to move the closed ADC to be on the bottom row and the WOT ADC to be on the top row.



Just by hand i.e. manually on the ve table itself??
When I say it's rich I mean my gut instinct and experience are telling me this i.e smell and black smoke when the throttle is blipped plus lots of soot on the plugs.
There seems to be a few ways to make it richer for starting then?? cranking pulse widths I've not changed at all.


clairetoo - 13/8/08 at 11:07 PM

Just type in the numbers you want - but be sure to set the spark map to the same numbers


omega 24 v6 - 13/8/08 at 11:12 PM

quote:

it sounds like `after start enrichment` needs increasing



Indeed but I thought the ASE only kicked in when the coolant temps was below the set amount in my case 80 degreesC. So IIRC altering that should only be done when first starting the engine from cold.


clairetoo - 13/8/08 at 11:19 PM

quote:

Map is around 59 to 63


I thought you are running alpha-n ?


BenTyreman - 13/8/08 at 11:21 PM

Cranking pulse width is the ONLY way to increase the cranking fueling.

After the engine goes above a certain rev number (usually 300rpm), the fueling comes from a combination of afterstart enrichment and warmup enrichment, applied as a multiplier of the VE table.

If the engine is trying to go, then its a problem with the ASE. If it isn't even trying, then it's a cranking problem. Try datalogging the cranking. MegaLogViewer will tell you the engine status (i.e. is it flagged as cranking).

Under the table view of the VE table, you can alter the y axis values. I recommend significantly more bins low down. I have 6 of the 16 bins available on MS2 covering 0% to 11%. Only 4 cover 45% to 100%, as I have found the changes above 50% to be fairly linear.

The spark table is very important to the idle of the engine, and the ability to recover from low revs. I have found the best response from idle is to choke the engine by using too low an advance.

I set the advance to a static 10 degrees. I set the throttle stop to get the engine to idle at 1000rpm. I then created the following table:
Description
Description


As soon as the revs drop too low, the correct advance kicks in and the engine gains more torque, so brings the revs up.

If you put 105% in the 71 degree ASE box, then 105% will be used for any temperature above 71 degrees.

[Edited on 13/8/08 by BenTyreman]


omega 24 v6 - 13/8/08 at 11:21 PM

I am running alphaN but i have the MAP gauge on the main page as a gauge. and in realtime it shows up as a bar graph as well.


omega 24 v6 - 13/8/08 at 11:27 PM

quote:

If the engine is trying to go, then its a problem with the ASE. If it isn't even trying, then it's a cranking problem



I should emphasise that the engine starts runs and gets to idle with full operating temperature and fan cutting in. Then when I "live tune the idle" and I make a wrong adjustment it falls off of the ve table and will not restart. Looks like I may have to look at the cranking pulse widths in order to acheive a restart. How much should I increase them by do you reckon?


clairetoo - 13/8/08 at 11:28 PM

quote:
Originally posted by omega 24 v6
I am running alphaN but i have the MAP gauge on the main page as a gauge. and in realtime it shows up as a bar graph as well.

Which means you have missed a setting somewhere when going from MAP to alpha n - it should show TPS on the `guage` and maps .


omega 24 v6 - 13/8/08 at 11:32 PM

quote:

Which means you have missed a setting somewhere when going from MAP to alpha n - it should show TPS on the `guage` and maps .



On the main page of megatune you can select a wide variety of gauges to be displayed/changed to suit your needs. I have both tps and MAP gauges showing but I do not think that there is a problem. Although I have noted that some of the ve tables I have looked at have tps as a % and some are "ADC"???


omega 24 v6 - 13/8/08 at 11:34 PM

I think discussing topics like this could be benificial on Say a Friday or Sunday night in the chat room with all interested parties participating. I've got more response from 2 of you in 1/2 an hour than 2 weeks on the MS forum.


matt_claydon - 13/8/08 at 11:38 PM

It'll always show a gauge for MAP even if you use A-N, at least mine did.

Can't agree more about having lots of bins close together at low throttle - with ITBs a lot happens in those first couple of percent throttle movement so that's where you need the most resolution in the table.

Definitely make sure you rejig your VE and spark tables so the bottom row corresponds to closed throttle and top to open, otherwise you're wasting rows.


matt_claydon - 13/8/08 at 11:41 PM

Oh yeah, don't confuse afterstart enrichment with warmup enrichment. Warmup is exactly as it says, but ASE can operate under any conditions. I found I didn't need it, certainly not for more that a few engine cycles!


BenTyreman - 13/8/08 at 11:41 PM

I've found the cranking pulse width to be fairly forgiving. 50% in either direction doesn't make a bit of difference on mine.

Same with the fuel table. I can make 10% changes richer or leaner on the VE table and it has very little change on the engine. It should be able to idle from around 10:1 to over 16:1.

Any tables that have a % are wrong. MS1 does not use throttle% anywhere, only ADC (at least it didn't when I last used it last year). I have since fitted the MS2 chip. Well worth the £30-odd I payed to upgrade. Many more features, more room for expansion, faster and most importantly 10 bit ADC instead of 8 bit ADC (0.1% thottle precision rather than 0.5% precision).


omega 24 v6 - 13/8/08 at 11:41 PM

OK now I've got something to look at. Time for bed said zebedee. thanks to all for now.


MkIndy7 - 14/8/08 at 12:11 AM

I've never messed with the cranking settings on mine, purely the after start enritchment and the vet low Ve values and the ignition advance or mechanical throttle stop to alter the ide speed.

If there is anybody thats quite sure of there settings maybe they could upload a picture of their Ve table or Graph so people have an idea of the pattern they should or could be following.

I know mine is a very shallow graph with fuel being added gradually until very high throttle, I'm sure i've seen somewhere that you can half the required fuel and increase the Ve values to effectively get a better map resoloution.

Actual pictures of what your likely to be aiming for could either be very helpful or send you completely the other way... just remember you can change lots electrically to get an engine to work in a fasion.. but if there's something Mechanically wrong your never going to get to the bottom of the problem.


clairetoo - 14/8/08 at 07:26 AM

quote:
Originally posted by omega 24 v6
I think discussing topics like this could be benificial on Say a Friday or Sunday night in the chat room with all interested parties participating. I've got more response from 2 of you in 1/2 an hour than 2 weeks on the MS forum.

That could work - as long as I get time to respond (I'm not the worlds best with a keyboard )
Or how about a dedicated megasquirt forum ? I dont think there's any one on here with one who hasnt been stuck at some point , and that way a database of usual problem's and their solutions would very quickly be built up , and could be used by any one.
I am on a few megasquirt forums , but unlike here the response time can be measured with a calender................