Mallory Ignition 676M User Manual

FORM 1554M (REV . A) 10/02

OPERA TING INSTRUCTIONS

HYFIRE® 7C CONTROL UNIT

PART NO. 676M

RPM Switch:

NOTE: This feature is not available on the HYFIRE® 667S. The built-in RPM switch can either turn an electrical load off or on at a selected RPM. See below for more detail.

NC This is the RPM switch (mode 7) relay contact that is

normally closed. In other words, as long as you haven’t reached the point where the RPM switch is active, this contact remains connected to the “common” or “C” terminal. You would use this connection if, for example, you wanted to turn something OFF (such as a nitrous system) when you reached the RPM switch point. See Example 1.

C This is the common terminal for the RPM switch (mode

7) relay in the main unit. It is connected to the RPM switch, where it will switch the accessory connected to the “NC” terminal OFF, and the accessory connected to the “NO” terminal ON when the RPM switch value is reached. The “C” terminal can be used to switch either to power or ground.

NO This is the RPM switch (mode 7) relay contact that is

normally open. In other words, as long as you haven’t reached the point where the RPM switch is active, this contact isn’t connected to the “C” contact. You would use this contact to turn something ON (such as a shift light or an air shifter) at a specific RPM. See Example 2 and Example 3.

RPM Limiters:

The HYFIRE one has a range of 1000 to 12,800 RPM in 50 RPM steps. On the main display, there is a decimal point on the mode digit. When that decimal point is lit up, the RPM limit is increased by 50 RPM.

RPM1 (Mode 1)This is the RPM limit that is always active if you

RPM2 (Mode 2) This is an auxiliary RPM limiter that is acti-

RPM3 (Mode 3) This is the other auxiliary RPM limiter. It also

High Speed Timing Retards:

RET1, RET2, RET3 (Modes 4, 5, 6) These are all high-speed timing retard functions that are activated by 12 volts on the appropriate top-side connector terminal. Each higher stage overrides the lower stages, which means that you set each stage for exactly the amount of retard you want, rather than adding up each stage to get the actual retard. See Example 6.

NOTE: When you apply 12 volts to RPM2, RPM3, RET1, RET2, or RET3 the display will switch to show that function. If you have both an auxiliary RPM limit AND a retard selected, the display will show the retard value.

676M Control has three built-in RPM limiters. Each

haven’t selected any other RPM limit.

vated when you apply 12 volts to the “RPM2” terminal on the top-side connector. This could be a burnout limiter. When selected, it overrides RPM 1 (the main engine protection RPM limiter). See Example 4.

is activated by 12 volts on the “RPM3” terminal on the top-side connector, and overrides both RPM2 and RPM1. Use this limit as a staging (starting line) RPM limiter. See Example 5.

See the accompanying illustrations for some examples of how to use the RPM limiters, the RPM switch, and the timing retard functions.

Push this button to change the mode.

FIGURE 1

MODE

1 - RPML 1

2 - RPML 2

3 - RPML 3

4 - RETARD 1

5 - RETARD 2

6 - RETARD 3 7 - RPM SWITCH

P/N

50 RPM

STEPS

676M

VALUE

8 - HSA SLOPE

9 - HSA CUT-IN

A - HSA MAX

B - TRIGGER

C - CYLINDER

D - DEG / PSI E - MAP SELECT

BTR

MODE

+50 RPM

CONTROL CENTER

Additional Functions:

The HYFIRE® 676M has two more modes that can make the ignition installation and setup work better. One of these is the high speed advance function. This lets you put small amounts of timing in the engine after the torque peak to pick up a bit of horsepower. There are three things that need to be set up for this: the cut-in RPM (Mode 9), the maximum advance (Mode A), and the slope (Mode 8). The cutin RPM is the RPM where you want the curve to start working. The slope is how much the timing will advance every 1000 RPM after the cut-in RPM. The maximum advance is the highest amount of advance you want the system to reach.

For example, say that your engine has the torque peak at 6500 RPM, and you want to add some timing after this. You might want to start adding timing after 7000 RPM, so this becomes your cut-in speed. If you then want 2 degrees additional timing at 8000 RPM, then the slope would be set for 2 degrees per 1000 RPM. However, let’s say that you don’t want more than 2 degrees of advance, so you would set the maximum advance at 2 degrees. See Example 7 for more detail.

The other similar mode available is trigger compensation, which is set when the mode indicator is “b”. This lets you compensate for the various delays in ignition timing caused by both electronic and mechanical changes. To set the trigger compensation, set mode 9 to 5000 RPM, and mode 8 to zero. What this does is tell the system to start the high-speed advance at 5000 RPM, but with a slope of zero, there should be no advance. Once the system is set up this way, watch the timing as the engine revs past 5000 RPM. If the timing does not stay at a steady value (once the 5000 RPM point is reached) then adjust the compensation value until it is as flat as possible. For example, if the timing retards slightly as the RPM goes up, increase the compensation value. If the timing advances slightly as the RPM goes up, decrease the compensation value.

NOTE: This function is only valid for RPM above the highspeed advance cut-in RPM. If you have the high-speed advance cut-in set above the normal operational range of the motor, the compensation function does nothing.

Push either of these buttons to change

DOWN

the value of the mode.

NOTE: If any button is held down for more than 1/2 second, the displayed value will change automatically.

Once the compensation is set, then the high speed advance settings will be accurate. The factory setting should be correct for most types of flying magnet type crank trigger systems, and should not normally need to be adjusted unless you are using a different trigger type.

Number of cylinders selectionNumber of cylinders selection

Number of cylinders selection

Number of cylinders selectionNumber of cylinders selection

The next mode that can be set is mode “C”. This allows you to select 4 through 12 cylinder operation. This ensures that the RPML and the timing are proper for the engine. Mode 6F is special—this is for odd-fire V6 engines ONLY! The cylinder firing spacing should be 45/75 (at the distributor) or 90/150 at the crank.

MAP Sensor Functions:

The 676M has two modes for use with a MAP (manifold absolute pressure) sensor. Mode “d” lets you select the number of degrees of retard per pound of boost, from .1 to 4 degrees. Mode “E” lets you select the type of MAP device. Typical MAP sensors used in turbo/ supercharged engines are either 2 or 3 bar range, and these correspond to “2” and “3” in mode “E”. Selection “1” is different. This is not made for a 1 bar MAP sensor . Instead, selection 1 lets you use an external 0-5 volt signal to control a 0-20 degree retard. This signal could be from an external dash-mount control, such as the Mallory 29784, or from an external proportional nitrous controller.

MAP sensor and extension harness are not supplied with 676M. Part numbers are:

716 2 bar MAP Sensor 717 3 bar MAP Sensor 29785 Extension Harness

NOTE: The 3 bar MAP Sensor (PN 717) and Extension Harness (PN 29785) are included when a complete Mallory 667BTR Ignition System is purchased.

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