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gnxtc2

Well-Known Member
Staff member
Joined
May 28, 2001
Messages
4,203
Here goes, just got off the phone with MSD Tech for an unrelated issue but asked the tech guy if the MSD DIS-4 vs FAST conflict issue was re-solved and said "YES" He said it had something to do with dwell.:confused:

MSD found the problem to be with FAST. :eek: MSD said you have two options to get it fixed.

1st option:
Wait until late summer for a new MSD box to be available. The new MSD box supposed to have some type of dial that can control "something" The guy was putting me hold every so often and was talking in a hurry and couldn't get what the dial was for. I just remember it had something to do with FAST. You know long that could be.

2nd option: He told me to send back the FAST ECM to have the "Bounce circuit modified to between 2.5-4 milliseconds" He further stated that FAST should know what should modified also.

MSD will not modify the current boxes for this conflict nor would he take returns.

Hope Craig will chime in on this for further information to re-solve this issue. Also what cost, if any will be passed on to us.

Hope this helps.

Billy T.
gnxtc2@aol.com
 
This information is not correct. This problem is not our fault OR their fault, but simply a compatability issue. Their stuff works as per their specs and so does ours. We have already determined what we need to do so that our specs leave a wider "middle ground" as we have many mutual customers. Also, the debounce time referred to in your conversation with the MSD tech definitely isn't 2.5 to 4 milliseconds. You wouldn't make it 100 feet from a stop light if it was. This time actually refers to the minimum dwell time that the input channels of a DIS-4 will consider a valid trigger signal. The specification they have given us is from 1.2 to 1.7 milliseconds.

Control systems such as ours with a single ignition control output must generate a "chain" of output pulses that each fit within the available time between TDC events on a running engine. The faster the engine goes, the less time you have for this pulse to occur. At some engine speed, the pulse we generate will simply be too short to pass through the input filter on the DIS-4, and you will feel something quite like a rev limiter. These minimum dwell times would never be a concern with a device that had 4 ignition control output channels (assuming V8 for discussion's sake). On a V8 with a waste-spark ignition system much like that on the Buick V6, each channel has only 1/4 of the work to do that a control system such as the FAST has to do. While the one output we have has to provide a pulse every 90 degrees of engine rotation, each channel on a system such as the GM Northstar or Ford EDIS-8 ignition module only needs to provide a pulse every 360 degrees of engine rotation. The DIS-4 seems to have been designed more with this concept in mind.

As this situation applies to Buick V6 customers, both the factory computer and the FAST computer use a single control line to the ignition module (the EST signal), and the module simply steers that signal to the appropriate coil. So to some degree, you are up against the same issue. Due to a slight difference in the EST signal we generate as compared to the EST signal from the factory Buick computer, it is possible that you will experience an ignition breakup due to the problem described above about 400 to 500 RPM sooner with a FAST system than with the factory computer on DIS-4 equipped cars.

The firmware in your FAST ECU can be modified to exactly duplicate the factory EST signal for $40 plus shipping costs. However, depending on how high you need to spin your engine vs. where your problem is occuring, this change may not completely fix your problem. Due to the way that each unit is intended to operate, the wound may be bigger than the only bandage we can provide right now.

Both of us are undergoing major product changes and we will be taking advantage of this opportunity to provide more complimentary products. Until then, I hope this sheds some light on the nature of the problem.
 
Originally posted by Craig Smith
This information is not correct. This problem is not our fault OR their fault, but simply a compatability issue. Their stuff works as per their specs and so does ours. We have already determined what we need to do so that our specs leave a wider "middle ground" as we have many mutual customers. Also, the debounce time referred to in your conversation with the MSD tech definitely isn't 2.5 to 4 milliseconds. You wouldn't make it 100 feet from a stop light if it was. This time actually refers to the minimum dwell time that the input channels of a DIS-4 will consider a valid trigger signal. The specification they have given us is from 1.2 to 1.7 milliseconds.

Control systems such as ours with a single ignition control output must generate a "chain" of output pulses that each fit within the available time between TDC events on a running engine. The faster the engine goes, the less time you have for this pulse to occur. At some engine speed, the pulse we generate will simply be too short to pass through the input filter on the DIS-4, and you will feel something quite like a rev limiter. These minimum dwell times would never be a concern with a device that had 4 ignition control output channels (assuming V8 for discussion's sake). On a V8 with a waste-spark ignition system much like that on the Buick V6, each channel has only 1/4 of the work to do that a control system such as the FAST has to do. While the one output we have has to provide a pulse every 90 degrees of engine rotation, each channel on a system such as the GM Northstar or Ford EDIS-8 ignition module only needs to provide a pulse every 360 degrees of engine rotation. The DIS-4 seems to have been designed more with this concept in mind.

As this situation applies to Buick V6 customers, both the factory computer and the FAST computer use a single control line to the ignition module (the EST signal), and the module simply steers that signal to the appropriate coil. So to some degree, you are up against the same issue. Due to a slight difference in the EST signal we generate as compared to the EST signal from the factory Buick computer, it is possible that you will experience an ignition breakup due to the problem described above about 400 to 500 RPM sooner with a FAST system than with the factory computer on DIS-4 equipped cars.

The firmware in your FAST ECU can be modified to exactly duplicate the factory EST signal for $40 plus shipping costs. However, depending on how high you need to spin your engine vs. where your problem is occuring, this change may not completely fix your problem. Due to the way that each unit is intended to operate, the wound may be bigger than the only bandage we can provide right now.

Both of us are undergoing major product changes and we will be taking advantage of this opportunity to provide more complimentary products. Until then, I hope this sheds some light on the nature of the problem.

Craig

I have nothing against FAST or MSD.

Obviously there is a problem here and both companies admit there is. But neither company wants to take responsibility. The user, us Turbo Buick racers, are caught in the middle. All we want is how to remedy this problem.

Your last statement says it all.

Just looking for a fix.

Billy T.
gnxtc2@aol.com
 
Originally posted by Craig Smith

As this situation applies to Buick V6 customers, both the factory computer and the FAST computer use a single control line to the ignition module (the EST signal), and the module simply steers that signal to the appropriate coil. So to some degree, you are up against the same issue. Due to a slight difference in the EST signal we generate as compared to the EST signal from the factory Buick computer, it is possible that you will experience an ignition breakup due to the problem described above about 400 to 500 RPM sooner with a FAST system than with the factory computer on DIS-4 equipped cars.

The firmware in your FAST ECU can be modified to exactly duplicate the factory EST signal for $40 plus shipping costs. However, depending on how high you need to spin your engine vs. where your problem is occuring, this change may not completely fix your problem. Due to the way that each unit is intended to operate, the wound may be bigger than the only bandage we can provide right now.

Craig,

Would the fix allow my combo to be stable to 7500-7750RPM???
 
I fixed mine and found some power at the same time. Put a crank trigger on it. You want believe how much better the motor sounds and runs.
 
Off topic

Hi Richie,
Good pic's of your car on the other site. Definately getting it to the ground.

Steve:D
 
If I was to send my FAST ECU back and have the firmware updated to work with my 2 older MSD DIS-4's (coil on plug setup for modular ford) would I have to have the firmware updated again if I eventually updated the DIS-4's to the new ones?

Any help on this subject would be greatly appreciated. It's an ongoing problem I would really like to get resolved.....Thanks

David
 
Craig Smith said:
This information is not correct. This problem is not our fault OR their fault, but simply a compatability issue. Their stuff works as per their specs and so does ours. We have already determined what we need to do so that our specs leave a wider "middle ground" as we have many mutual customers. Also, the debounce time referred to in your conversation with the MSD tech definitely isn't 2.5 to 4 milliseconds. You wouldn't make it 100 feet from a stop light if it was. This time actually refers to the minimum dwell time that the input channels of a DIS-4 will consider a valid trigger signal. The specification they have given us is from 1.2 to 1.7 milliseconds.

Control systems such as ours with a single ignition control output must generate a "chain" of output pulses that each fit within the available time between TDC events on a running engine. The faster the engine goes, the less time you have for this pulse to occur. At some engine speed, the pulse we generate will simply be too short to pass through the input filter on the DIS-4, and you will feel something quite like a rev limiter. These minimum dwell times would never be a concern with a device that had 4 ignition control output channels (assuming V8 for discussion's sake). On a V8 with a waste-spark ignition system much like that on the Buick V6, each channel has only 1/4 of the work to do that a control system such as the FAST has to do. While the one output we have has to provide a pulse every 90 degrees of engine rotation, each channel on a system such as the GM Northstar or Ford EDIS-8 ignition module only needs to provide a pulse every 360 degrees of engine rotation. The DIS-4 seems to have been designed more with this concept in mind.

As this situation applies to Buick V6 customers, both the factory computer and the FAST computer use a single control line to the ignition module (the EST signal), and the module simply steers that signal to the appropriate coil. So to some degree, you are up against the same issue. Due to a slight difference in the EST signal we generate as compared to the EST signal from the factory Buick computer, it is possible that you will experience an ignition breakup due to the problem described above about 400 to 500 RPM sooner with a FAST system than with the factory computer on DIS-4 equipped cars.

The firmware in your FAST ECU can be modified to exactly duplicate the factory EST signal for $40 plus shipping costs. However, depending on how high you need to spin your engine vs. where your problem is occuring, this change may not completely fix your problem. Due to the way that each unit is intended to operate, the wound may be bigger than the only bandage we can provide right now.

Both of us are undergoing major product changes and we will be taking advantage of this opportunity to provide more complimentary products. Until then, I hope this sheds some light on the nature of the problem.


Does anyone know if this incompatability issue between F.A.S.T. and MSD has been resolved yet ? I've done lotsa reading but haven't found the answer. :confused:

George
 
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