PDA

View Full Version : DIS-4 Questions/problems?


silversid
08-07-2003, 06:34 PM
Hi,
I was curious to find out if the DIS-4 MSD igntion should be buzzing or humming it goes with rpm speed. I'm not sure if this is correct behavior or not. Also i wanted to know how i can fix the top end speed it had dropped approx 15mph since i installed the unit.

msdtech1
08-07-2003, 09:31 PM
The laminations of the transformer inside the unit can emit a certain amount of noise from the unit. This is normal on all CD style ignition systems. Generally, the noise is not offending and if the unit is securely mounted the noise will be dampened. Most units are mounted in the engine compartment and therefore the noise is not an issue. Check to make sure you do not have a large amount of timing retard programmed into the unit at high rpm.

MSD Tech1

silversid
08-08-2003, 08:05 AM
Thats the problem i have absolutly no timing retard at high rpm it's at 0 degrees i've also tried other settings but all they do is lower the acceleration rate to what the new top speed is. Any other suggestions... But the two step rev staging doesnt work either could this indicate a bad msd ignition?

msdtech1
08-08-2003, 10:10 AM
How are you actuating the two step function?

MSD Tech1

silversid
08-09-2003, 12:14 PM
By push button press it for a moment and it should step up the rev correct? then let go. It's connect to a ground the other side.

msdtech1
08-09-2003, 07:06 PM
The ground connection on the other side of your momentary push button switch is correct. As a test, place an ohm meter from ground to the blue wire on the MSD and then push button to see if you have ground when the button is pressed. You can also remove the blue wire from the switch and touch it against ground to see if the rev limiter kicks in. Set the low RPM limit to its lowest setting - Switch 2 Positions S1, S2, S3, S4 should all be in the OFF position for a 3000 RPM test. Also check to make sure you have Switch 1, Position S1 in the OFF position as well. If that is in the ON position then you have added 4000 rpm to the settings on the max and staging rev limits.

MSD Tech1

silversid
08-15-2003, 04:38 PM
Hey that works but shouldnt it bring up the rpms as well when you have this depressed or not? you must press on the gas pedel for to get the rpm rev limiter to stay that high if i can get it that high w/ foot on brake. I seem to be having some type of low end problem w/ the device i think.

msdtech1
08-15-2003, 05:41 PM
This is how the Two Step Function is suppose to be used at the drag strip.

1. On the low side limit (blue wire activated), set the rpm limit where you want the engine rpm to be held at when you are going to launch the car.
2. On the high side limit (blue wire not touching ground), set the rpm limit approximately 300-500 rpm above the engines maximum rpm. Example: if max engine rpm is 7000 then set the high side limit between 7300-7500 rpm. The high side limit is for protection against over-rev.
3. Stage the car in the starting lights and apply ground to the blue wire. Push the throttle to the WOT (wide open throttle) position. The engine rpm will be held at the low side limit setting.
4. When the starting light turns green or slightly before, remove the blue wire from ground. Engine rpm will increase and the car will launch. If everything is set propperly, you should not hit the high side limit that you set.

MSD Tech1