First proper drive

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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spandit
Posts: 129
Joined: Wed Dec 22, 2010 10:43 pm
Location: East Sussex, UK

First proper drive

Post by spandit »

Ventured out onto the open highway today. MAP readings are still very noisy, despite having a mig tip and a filter inline (although the filter is quite coarse - it's not a paper one). However, you can just about see that the load readings go up with RPM on the road so that's OK. I've tried filtering the data a bit but it's still too noisy.

I also found that I couldn't change the ignition advance when the engine was running (it changed automatically with load and RPM but even when it said it had committed to flash, it hadn't). As someone hinted in another thread, this might be because of interference from the spark plugs so I'll change to resistive ones when I get a chance (I thought having resistive leads would be enough). I didn't try using the alternative map as couldn't be bothered wiring another switch in!
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Data from my first drive out - these are all averages from 10 time readings
Data from my first drive out - these are all averages from 10 time readings
rewc04.png (60.72 KiB) Viewed 4681 times

brentp
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Post by brentp »

subjectively, how well does it run compared to before?
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spandit
Posts: 129
Joined: Wed Dec 22, 2010 10:43 pm
Location: East Sussex, UK

Post by spandit »

I think it starts better but I'm comparing it to the winter - it's hot here at the moment

I don't really know what I'm looking for regarding timing - unless it misfires how can I tell if I've got the right setting or not?

The table I had loaded used the distributor centrifugal settings from the manual coupled to a generic load curve that was already in the spreadsheet I downloaded from here (and subsequently edited to make it easier for others to load the data into MJ Configurator!)

I suppose if the engine load is never falling below about 40 then I can look into dropping the lower values from the table and giving a smoother curve for the rest, if that makes sense. It's a pity I couldn't change the data as the engine was running but I'm sure it's an interference problem as suggested

spandit
Posts: 129
Joined: Wed Dec 22, 2010 10:43 pm
Location: East Sussex, UK

Post by spandit »

Just logged a couple of minutes at idle with the laptop as far away from the engine as possible - made no difference to the stability of the readings and still couldn't flash the MJLJ with engine running. However, switching to the alternate map let me update/flash at will with the engine going - exactly the same symptoms as the other fellow. His problem was solved with resistive plugs, though, so I'll invest in a set - hoping it might smooth out some of my graphs too

cng1
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Post by cng1 »

Please do fit resistive plugs. Running without them is a recipie for problems.

I'd be interested to see a zoomed in graph again as the time period on that one loses the important detail.
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spandit
Posts: 129
Joined: Wed Dec 22, 2010 10:43 pm
Location: East Sussex, UK

Post by spandit »

Here's a 15 second burst - RPM fairly smooth but load still all over the place
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15 second chunk of my first drive
15 second chunk of my first drive
rewc05.png (46.58 KiB) Viewed 4650 times

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