User-configurable outputs - advance data possible?

General Megajolt Questions and Answers

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nickj
Posts: 32
Joined: Sat Feb 17, 2007 7:52 pm
Location: Norway

User-configurable outputs - advance data possible?

Post by nickj »

Hi,

I've just installed Megajolt on my 4.2 Jaguar straight-six. I'm also running an Innovate data logger
(DL-32) and three LC-1 wideband sensors (one for each SU carb). With the data logger I'm currently
logging 3 air-fuel ratios, manifold pressure and RPM. I'd like to add ignition advance to this as well.

Is it possible to use one of the user-configurable outputs to achieve this? The DL-32 is happy to log
signals between 0 and 5 volts, so maybe a voltage can be output to cover the possible ignition range?

I'm also looking for an additional source for RPM, to avoid splitting the RPM signal from the MJ-unit
(I move the Innovate gear between cars, so the less fussy the install the better). My Smiths tach
has been converted for modern ignition, so theres no old-Smiths-tach issues.

Any insights?

Nick

brentp
Site Admin
Posts: 6293
Joined: Wed Jan 24, 2007 6:36 am

Post by brentp »

Hi Nick,

The user defined outputs are simple switches- they do not provide a variable voltage output, so unfortunately they cannot be used to log advance.

However, if you can log RPM and Load you should be able to infer your ignition advance based on your current table. I'm sure we'd agree this is a sub-optimal solution, but perhaps workable.

For the RPM output- there are a variety of sources for this signal:

MJLJ TACH_OUT - there should be enough current source for multiple devices
EDIS PIP - This has shown to provide enough current drive for the MJLJ and a tachometer
EDIS IDM signal - clean 12v output- although it emits a diagnostic pulse when the engine is not running
Flyback diode circuit - see installation guide

Hope this helps,
Brent Picasso
CEO and Founder, Autosport Labs
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