Search found 95 matches

by BRUCEROE
Tue Jun 15, 2010 3:15 am
Forum: Installation
Topic: How does MJ know which time around?
Replies: 2
Views: 1976

The crank trigger systems use "waste fire", which means they fire every revolution. Like lawn mowers. The unneeded spark at the end of the exhaust stroke does no harm. To make the system a lot more efficient, the 2 ends of an ignition coil secondary are connected to 2 cylinders that reach top dead c...
by BRUCEROE
Mon Jun 07, 2010 4:37 am
Forum: Future Upgrades
Topic: Ignition system with repetitive sparks
Replies: 26
Views: 34755

According to this, an open ignition coil will send a diagnostic signal on the IDM lead. Guess that doesn't keep it from working, because I've been running an EDIS8 with only 2 coils for a while. Bruce Roe
by BRUCEROE
Fri Jun 04, 2010 8:29 pm
Forum: Operation
Topic: plug wire cylinder# question
Replies: 3
Views: 2933

Is the shielded wire working out? Bruce Roe
by BRUCEROE
Thu Jun 03, 2010 2:24 pm
Forum: Operation
Topic: Aux input (voltage to input) Megajolt v4 jr
Replies: 14
Views: 10598

Voltage Divider

That will work. But then there is still the problem of generating a calibration chart for the original gauge-sensor combination, how do you do that? Also, 12V to the gauge varies a lot from say, idle with lights on, to full speed no load. That voltage variation will cause the MJLJ gauge to change ev...
by BRUCEROE
Fri May 28, 2010 8:14 pm
Forum: Q&A
Topic: 3 cylinder application
Replies: 2
Views: 2355

More Detail

An even fire 3 is like a 6 with half the cylinders missing. It takes 2 turns, 720 degrees to hit everything. At zero degrees, 1st coil fires your first cylinder in the firing order. At 120 degrees, 2nd coil waste fires the 3rd cylinder in your firing order. At 240 degrees, the 3rd coil fires the 2nd...
by BRUCEROE
Fri May 28, 2010 6:49 pm
Forum: Q&A
Topic: 3 cylinder application
Replies: 2
Views: 2355

3 cylinders

Basically think of it as a 6 cylinder engine with the even cylinders missing. You have cylinders 1,3, & 5, so 2, 4, & 6 are missing. Wire it up with an EDIS 6 coil pack (3 coils). The second wire on each coil output is grounded to complete that circuit. Bruce Roe
by BRUCEROE
Tue May 25, 2010 2:58 am
Forum: Operation
Topic: Understanding Advance Correction?
Replies: 5
Views: 4659

It can also be used as a tuning aid. I connected a 2K variable resistor. With the internal 2.2K pullup, voltage varies from 0 to nearly 2.5V. That in turn is translated to -12 degrees at 0 ohms, 0 degrees at 1K ohms, and +12 degrees at 2K ohms. Voltage isn't linear, but the translation table fixes t...
by BRUCEROE
Thu May 20, 2010 2:13 am
Forum: Operation
Topic: Aux input (voltage to input) Megajolt v4 jr
Replies: 14
Views: 10598

If I had your email, I could send the conversion table as a .txt file. For some reason, my APPLE doesn't like to deal with .txt files. Or brentp can make it available. Here is my translation from temperature degrees F to voltage into MJLJ, with a 2200 ohm pullup resistor to 5.00V. This circuit is sh...
by BRUCEROE
Wed May 19, 2010 10:39 pm
Forum: Operation
Topic: Aux input (voltage to input) Megajolt v4 jr
Replies: 14
Views: 10598

Here is the generic temp sensor with resistance every 5 deg C; thats every 9 deg F. I figured the voltage with a 5V source through the MJLJ 2200 ohm series resistor every 9 deg F, extrapolated between. Below is MJLJ conversion table. Bruce Roe http://www.pe-ltd.com/Downloads%5Ccoolant_temp.pdf 255 2...
by BRUCEROE
Wed May 19, 2010 3:02 am
Forum: Operation
Topic: Aux input (voltage to input) Megajolt v4 jr
Replies: 14
Views: 10598

If you use your present sensor (which NEVER exceeds 5V), you will have to measure the voltage and temperature (trust your original gauge?) over the operating range. Then make a conversion table for the MJLJ. Without a conversion chart the MJLJ gauge will apparently be reading backward. And disconnec...
by BRUCEROE
Tue May 18, 2010 6:25 pm
Forum: Operation
Topic: Aux input (voltage to input) Megajolt v4 jr
Replies: 14
Views: 10598

Temp Sensor

That would NOT be OK, for a couple of reasons. The 2.2K resistor in the MKLJ would throw off your present circuit. Even if the 2.2K were disconnected, it is likely your present circuit sometimes exceeds 5 volts at the sensor. The MJLJ can't be calibrated outside of 0 to 5 volts. But connecting a sec...
by BRUCEROE
Tue May 18, 2010 3:48 am
Forum: Operation
Topic: Aux input (voltage to input) Megajolt v4 jr
Replies: 14
Views: 10598

Temp Sensor

The MJLJ has an internal 2.2K pullup resistor to internal 5V. It can be calibrated to use a standard EFI temperature sensor. Is your present sensor already in use in the car; sensors don't have an internal voltage? Adding another might be the easiest. Bruce Roe
by BRUCEROE
Sun May 16, 2010 7:08 pm
Forum: Q&A
Topic: Jumping timing
Replies: 8
Views: 4605

TIMING JUMP

It sounds to me, as though its jumping between programmed spark and (10 degree) limp mode. I doubt it is the VR, because losing sync there would put your timing all over. I'd suspect the MJLJ or its wiring; at this age, a loose or tarnished connection could do it. Cleaning or wiggling the chips that...
by BRUCEROE
Sun May 16, 2010 3:48 am
Forum: Installation
Topic: No spark, shielded cable?
Replies: 4
Views: 3451

NO SPARK

The wire gauge of the shielded cable is unimportant. You need 2 wires inside each shield, esp for the VR, and the polarity is critical. I found that communication from the PC to the MJLJ didn't really work, unless the engine was running. You can use a pretty log cable to the PC, though. Good wiring ...
by BRUCEROE
Fri May 14, 2010 3:03 pm
Forum: Powered by Megajolt Gallery
Topic: VW 1500 Squareback with Megajolt
Replies: 10
Views: 20998

VW

Very impressive work. I suppose you have some sort of fuel injection? Bruce Roe