Fast compatable with MSD DIS-4

[LarryG]

Got an issue. Finally got the car running- been another 2-1/2 years. I still use the Fast Classic box- the grey one. Two years ago I bought off this site an MSD DIS-4 plus HO ( high output ). I bought it primarilly for the two step to control the launch boost. Got it all together and onto the Dyno to break the motor in. Car ran great until we plugged the MSD into the sys. At that point at 5,200 RPM its like the motor hits a rev limiter - breaks up. From the shop I called a tech at MSD. I was told I needed to reprogram the FAST, changing the Coil Charge to constant 2.0-2.5 MIC. I find that my FAST has no option to change such a thing. I then called FAST- the tech never called me back..
This MSD is the one with dials - not the dip switches.. It was in the box and new when I bought it - but Im thinking the guy who sold it to me possibly knew it was not compatiable - Im not sure about that. Anyway - I would like to use it - its all wired in with the coil interface etc..Does any one know IF I can modify my FAST box to accomodate this particular MSD unit ????????? Thanks Larry

 

[antiquettype]

I ran the same set up with no issues. I know many people have had problems with the dis-4 but I have not. I don't want to be too simple, but did you realize it has the staging rev limiter and the top end rev limiter? Make sure it is not doing what you are telling it to do. Of course I have the dip switch one so it isn't so obvious. Other than that just make sure you have it wired to the battery. I've never had an issue so I can't help any more than that.

 

[LarryG]

As I understand it - the MSD with the Dip Switches will work - its the newer dial ones - like the one I bought - just my luck...Thanks anyway...Larry

 

[protracracing]

If you are just looking for a two -step Bob's new 2 step should work with your
fast system.I have used the old dis-4 (With dip switches)with classic fast systems with no problems.

Dennis

 

[HighPSI]

I ran the rotary dial box without any initial problems. It ended up failing after one season I now sell the Bailey 2-step because of all the MSD failures

 

[MSDGN]

I run an MSD DIS-4 with XFI and it's fine...I got the same stuff about Coil Charge from MSD when I first hooked up the MSD and anything over idle the motor was breaking up...that wasn't it...I had all the RPM dials set to zero...you HAVE to set the RPM MAX dials...which I didn't know and doesn't state in the instructions...I thought because I have a rev limit set in XFI that I didn't need to set those dials..Wrong!...I would check your RPM MAX dials settings...maybe you have it set at 5200

 

[LarryG]

I run an MSD DIS-4 with XFI and it's fine...I got the same stuff about Coil Charge from MSD when I first hooked up the MSD and anything over idle the motor was breaking up...that wasn't it...I had all the RPM dials set to zero...you HAVE to set the RPM MAX dials...which I didn't know and doesn't state in the instructions...I thought because I have a rev limit set in XFI that I didn't need to set those dials..Wrong!...I would check your RPM MAX dials settings...maybe you have it set at 5200

Just checked it...High limiter was set at 9,000 and the 2 step at 7,000...The pink wire ( retard ) is not hooked up nor is the brown anti theft wire. The blue wire ( 2 step is wired to the transbrake.. The only setting that was set alittle odd was the wayspark - that was at setting 3- I moved it to number 1- I will try it tommorrow, but- I doubt that will have any affect. I ran the pwr and ground directly to the battery - I had to add like 2 feet to make it reach - I wouldn't think that should be a problem.
I talked to a Fast rep today - guy named Robin. He said the classic box and the newer style should NOT be an issue. He said basically the difference with the units is the speed of the processor. I just want to chase this out before I remove the MSD unit - hate going backwards on stuff. Thanks for your input - please advise if you have any other thoughts..Larry
PS: I do have a MSD shift light set up in the car also - the wire comes off the stk coil pak - I THINK #3 .. That goes to a select dial - which I have set at 6,000 RPM - the minimum setting for now..Could that be an issue?

 

[CKBuick]

Larry
I have used the MSD-DIS4 HO box on my car for several years. I had one failure. The car would not start. I would take a very close look at the dial settings. To make sure the problem is with the MSD box install the jumper and run the car.

 

[Craig Smith]

The MSD guys are idiots. The DIS-4 was/is the cause of this problem. They, in their ultimate wisdom, put a filter circuit on the input that testing showed would vary as much as 50% in the minimum pulsewidth it would trigger on. The original DIS-4 units had a filter that set a minimum input dwell time of 750 microseconds. Don't remember the exact value but that comes out around 9000 RPM on a V6 IIRC. The new filter circuit they put in required a much longer dwell time, and the minimum time varied wildly from one box to another. You just didn't know what you were going to get, and the techs will tell you it's the fault of the device controlling the DIS-4.

Throw that piece of junk away and call Cal for something that WILL work.

</rant>

 

[protracracing]

Where is the rev limiter set on fast system ?


Dennis