timing off (pops, etc) - ideas on this map? (pics)

General Topics for configuring, operating and tuning the Megajolt. Also see the <a href="http://www.autosportlabs.net/MJLJ_V4_Operation_Guide">Operation Guide</a>

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paulc
Posts: 66
Joined: Thu May 01, 2008 10:49 pm

Post by paulc »

right now - i am getting some hesitation / backfiring with the above map.

ok - so one more clarification point on your comment Danny :oops:

less load = lower KPa = less aggressive advance curve = advance10

more load = higher KPa = more aggressive advance curve = advance0

is that right?

PS - it does go a lot lower. it's on full airbag suspension. 8) :lol: it also goes a lot higher :shock:

brentp
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Post by brentp »

Actually, more aggressive advance is a higher number. It's in degrees before Top Dead Center, meaning the higher the number, the earlier it sparks before the cylinder reaches TDC. Earlier = more aggressive. Got it? :)
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DannyP
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Post by DannyP »

Paul, I have updated my map several times, and just uploaded version 18. You may want to try it, but remember, it is TPS sensor, not vacuum.
Attachments
Mjconfig18.mjlj
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paulc
Posts: 66
Joined: Thu May 01, 2008 10:49 pm

Post by paulc »

thanks Danny - your map works quite well in my car. a few adjustments to the outputs and shiftlight and i took it for a long hard drive last night with the laptop and A/F gauge hooked up.

tuned it some more and found some interesting things.

i have to do some digging into this because i was expecting idle to be at the low end of the KPa - but idle is somewhere around 65KPa. I'm at sea level, so that may effect the numbers more (this is where i have to learn more). Can anyone enlighten me on this?


reving the motor with no load gives a counter clockwise movement through the map like below.

4th gear up a hill at 40mph pegs to 105KPa and ~23degrees (based on the map shown)
Image


I tried, but wasn't able to get the KPa to go below 45. I might play with the map some more.

adjusted the carbs and was very impressed with the T4 2L power WOT on the highway makes a beautiful sound. :D :D

oh - and the popping was as a result of mostly incorrect jetting on the carbs and a little incorrect timing.

DannyP
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Post by DannyP »

Paul, just keep playing with it. That's why I am at 18, actually 19 now, had another little tweak. Others on here can give you some info on MAP sensors, I know zero about that, TPS only!

Glad to hear you took a ride and enjoyed it, and that my map helped you out. Keep playing around, and driving.

One of these days I'll get a buddy to go with me in the car with my laptop, and fine tune it some more. The key is to let someone else drive, and then I can watch the gauges on my dash(AFR and CHT) and on the 'puter.

NITROPIXIE
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Location: Fareham, GB

Post by NITROPIXIE »

paulc are you running twin carbs or just a single?? If twins then test by just connecting it to one carb and see if it goes any lower. It could be that your getting an average between 2 carbs reducing the amount of manifold pressure.

If this is the case then try using smaller diameter vacuum tube.
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paulc
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Joined: Thu May 01, 2008 10:49 pm

Post by paulc »

it's dual carbs, and i spent a lot of time getting them sync'd.

I totally agree Danny. I have tried to get my wife at the helm of the laptop / tune, but she isn't too interested. :lol:

Cheeze
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Joined: Fri Jul 18, 2008 6:47 pm

vauxhall coolant temp sensor cts

Post by Cheeze »

evening folk, just a quick one, i have been having a look at my cts on my engine to use it with the megajolt jr, now im having a few problems woring out how to get the settings to use it with the program,

I know that the resistance decreases as the temp increases, but it putting it in a figures into the tables

Anyone help?

NITROPIXIE
Posts: 704
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Post by NITROPIXIE »

Cheeze i think your best bet is to connect up the sensor to megajolt and then put it in a glass of hot water with a thermometer and take note of the temperatures every 5 or 10 degrees or so.

You can setup the megajolt as http://www.autosportlabs.net/MJLJ_V4_ve ... iary_Input
1310 A-series Mini, lightened and built myself. V4 board and loving it

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TwoSheds
Posts: 64
Joined: Sat Jan 12, 2008 9:44 am
Location: UK, near Leeds

Post by TwoSheds »

paulc wrote: i have to do some digging into this because i was expecting idle to be at the low end of the KPa - but idle is somewhere around 65KPa. I'm at sea level, so that may effect the numbers more (this is where i have to learn more). Can anyone enlighten me on this?[/color]
Hi Paul,
I had similar symptoms on my hotwire RV8 - 70KPa at idle - it turned out to be a leak in one of the vacuum operated ancillary systems - the heater controls if I recall correctly - having fixed this I returned to 20 (ish) at idle. Different engine I know but I think that in principle they should be similar. An air leak on a carbed engine might also explain some of the other probs you have been experiencing. On my engine the ECU compensated manfully for the extra air and there were hardly any 'running' problems - just a reduction in power.

Cheeze
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Joined: Fri Jul 18, 2008 6:47 pm

Post by Cheeze »

Im sorry guys about my post, i dont know why its appeared in your thread

paulc
Posts: 66
Joined: Thu May 01, 2008 10:49 pm

Post by paulc »

TwoSheds wrote:
paulc wrote: i have to do some digging into this because i was expecting idle to be at the low end of the KPa - but idle is somewhere around 65KPa. I'm at sea level, so that may effect the numbers more (this is where i have to learn more). Can anyone enlighten me on this?[/color]
Hi Paul,
I had similar symptoms on my hotwire RV8 - 70KPa at idle - it turned out to be a leak in one of the vacuum operated ancillary systems - the heater controls if I recall correctly - having fixed this I returned to 20 (ish) at idle. Different engine I know but I think that in principle they should be similar. An air leak on a carbed engine might also explain some of the other probs you have been experiencing. On my engine the ECU compensated manfully for the extra air and there were hardly any 'running' problems - just a reduction in power.
Thanks for the suggestion. I'll give this a try. it runs very well now, but i'd like the piece of mind knowing it was 100%.

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