Page 1 of 3 123 LastLast
Results 1 to 10 of 24

Thread: Sniper with MSD CD box & points distributor.

  1. #1

    Default Sniper with MSD CD box & points distributor.

    This installation is for a 1970 Chevrolet big block with OEM points distributor using the Sniper QuadraJet throttle body. I'm trying to upgrade from a basic Sniper installation to one with an MSD 6AL CD box. I have contacted the Holley Sniper tech line as well as the MSD tech line with no success. I've followed the installation diagrams for both the Sniper and MSD and find that there is no one source for the configuration that I am trying to use. The Sniper CD box installation diagram only shows connection of the tach out signal wire to the purple tach input wire into the Sniper unit. Sniper techs advise me I must use the gray tach signal wire on the CD box to connect to the purple tach wire on the Sniper. I then connect the CD box as directed for a points distributor installation. This configuration results in a condition where the car runs a very short time and dies. I'm advised by Sniper techs that I'm burning the residual fuel in the throttle body. With this configuration the CD box starts normally with one long and five short LED indications. The CD box does not indicate with the LED during cranking as advised by MSD. Sniper techs advised The white signal wire from the CD box is not used. Yes, I configured Sniper to run with a CD box and yes the fuel pump is engaged. Power to the CD box and Sniper come from the same source, the ignition accessory on the fuse panel.

    I contacted the MSD techs and described the problem. They advised that I needed to connect the white signal wire from the CD box to the negative points wire from the distributor. This configuration results in proper operation indication from the CD box showing signal cranking indication. Unfortunately, the result is the same and the car will not start.

    With the exception of the Sniper all my components are new. In diagnosing the situation and trying to resolve I replaced the distributor condenser as well as replaced the Blaster 2 coil and new MSD Super Conductor plug wires.

    I again contacted Sniper techs, but there's confusion with the white signal wire issue. There is a white signal wire on the 10-pin connector on the Sniper. I have no accessories installed and therefore I’m not using the 10-pin connector at all. The Sniper diagram does not show what the white wire on the 10-pin connector connects to. There is no connection diagram that shows installation of Sniper with MSD 6AL.

    Question: Am I supposed to connect the white signal wire from the Sniper 10-pin connector to the white signal wire from the MSD 6AL CD box?

    Having no success I disconnected the CD box and reconfigured the Sniper for points distributor operation. The car started immediately and I drove it back into the garage.

    My experience with this is that Sniper techs understand Sniper and MSD techs understand MSD, but there's no credible bridge of understanding with the two devices. Again there's no diagram that shows the complete connection of Holley Sniper with MSD 6AL.
    Last edited by Monkeywrench; 11-13-2019 at 04:34 AM.

  2. #2

    Default

    You didn't explain what you're trying to accomplish, so I'll have to guess at a few things. I assume you don't want to control timing. Is that correct? You just want to run the Sniper for fuel only and use your existing distributor and CD box?

    If you aren't controlling timing, then the Sniper just needs an RPM signal so it knows what to do. It should be getting that from the tach out on the CD box. The white wire wouldn't be used in this situation. If you are controlling timing, then the distributor signal needs to be fed to the Sniper and then the white wire sends the controlled timing signal to the CD box, which then controls the coil. Controlling timing with a points setup would be a real trick. I think you would need to build a custom cam with only one lobe and then jump through some hoops to condition the signal. I'm sure a sharp electronics guy could figure it out, but the average shadetree mechanic probably isn't going to have much luck.

    (You really should just buy a HyperSpark distributor, since you'll be much happier in the long run.)

    You didn't say anything in your post about datalogs or what the handheld screen shows. Maybe you aren't aware of those things? If not, you should be using them when trying to debug a problem. The datalog will show you pretty clearly if you're getting an RPM signal or not.

  3. #3

    Default

    Did you watch this video? Seems fairly simple. https://www.youtube.com/watch?v=1EFiTBQ9DvI

  4. #4

    Default

    It would be interesting to see timing control accomplished with points. It wouldn't be hugely different from converting a magnetic distributor. RFI is likely to be an issue. Points make a lot of RFI.

  5. #5
    Join Date
    Jan 2010
    Location
    Brisbane, Australia
    Posts
    1,592

    Default

    Points distributor with EFI. I can't see why. You have spent some money, so just get an electronic trigger distributor. Gary
    Regards, Gary

  6. #6

    Default

    Thank you for the detailed notes. I've been running the Sniper throttle body for about six months now. The original installation notes advised the user to work incrementally to minimize problems. This is and was good advice because I found many problems that needed to be addressed to make the Sniper run properly. Once I got the Sniper working well I decided to go to the next step and connect a CD box. I chose to install the CD box to try and achieve a hotter spark. In my testing I found a very minor but slight backfire under high rpm high load conditions such as entering passing gear. At this point I am running about 85 to 90 miles an hour. I have no intention of controlling the timing at this time. The literature from Holley and MSD tell me that it is possible to run the MSD 6AL CD box with the Sniper QuadraJet EFI and a points driven distributor. My problem here is that there is no published diagram nor bridge of understanding to describe how to set the system up. The tach out from the CD box to the Sniper (Gray signal wire out to purple signal wire in) is exactly how the system was wired except with that configuration there is no trigger to the CD box. That signal trigger should come from the distributor to the white wire on the MSD CD box. That configuration is recommended by MSD but not by Holley Sniper.

    I have a brand new MSD tach drive distributor on the bench waiting, but I'm trying to test and understand the systems prior to moving forward. Yes, I understand how to take and read data logs. Data logs do not seem relevant at this point since I can’t get the system to operate as configured. The signal indication on the CD box tells the story. With the Holley Sniper recommended configuration there is no signal trigger when cranking the engine. With the MSD recommended configuration a signal trigger is generated, but there seems to be no fuel released to the throttle body. If no one is able to assist in this matter, I will likely give up and continue with the MSD Tach Drive distributor installation. That would be an opportunity lost to increase our understanding.

    Thank you for the comment. Yes I have watched this video. I'm using the OEM distributor from Chevrolet for this engine. Since the sniper runs well with this distributor I'm assuming the signal trigger is adequate for the CD box. I went through the process of finding TDC during the original sniper installation procedure. Again installation of the CD box with the wiring configurations as recommended by Holley Sniper and MSD resulted in a no run condition. Returning to the original Sniper configuration without the CD box resulted in perfect operation. No changes were made to the distributor.

  7. #7

    Default

    If you enjoy the challenge then go ahead and figure it out. Shouldn't be too tough, the Points Output triggers the CD box (white wire) and then the CD box tells the Sniper what the RPM is (tach out).

    If you just want to quickly move on to a running combination then buy a HyperSpark distributor and use the Sniper to control timing. Don't bother with the MSD distributor. Sell it new in the box and use the money to buy a HyperSpark. Your EFI setup will work a lot better once you are controlling timing anyway, so frankly, I don't see much point in messing around with either points distributor or a non-timing controlled setup. You'll find that using your time to tweak the new digital timing table will be more rewarding that trying to figure out a points fired CD install.

  8. #8

    Default

    I apologize, I'm having a bit of trouble posting to the forum via my iPad. I'm trying to keep the look & feel of a 1970 vintage automobile. This particular car uses a mechanical tachometer. The MSD tach drive distributor is the only distributor I have found that works with the MSD six series CD box. Thank you for the tip on HyperSpark. I did check out the HyperSpark distributors on the website, but did not find a distributor that utilizes a mechanical tack drive.

    Yes, as to your statement that it shouldn’t be too tough, and I think I'm very close. I've been working with the MSD CD box with billet distributor combination for just under 20 years now. In that time, I have fried a CD box by just putting wires together, and so I'm a little gun shy. At this point I think I have connected the two devices in the combinations as suggested by both Holley, MSD and this forum. In discussion with one of the techs it was suggested that I send the box back to have it tested. I don’t think there’s anything wrong with either of the devices and is more likely my inability to explain the situation in a way that the tech could understand. Really all I'm asking for is a diagram that shows a complete Sniper plus MSD plus OEM points distributor installation. This stated on the assumption that Holley has completely tested this combination in their laboratories.

    As to timing control, MSD suggests that there's a reconfiguration of the Tach drive distributor that will allow this to happen. Anyway thanks again for your time.
    Last edited by Monkeywrench; 11-14-2019 at 03:09 AM.

  9. #9

    Default

    Okay, you should've told us what you were trying to do at the beginning since that would've saved some time. If you want a period correct looking install then what you need to do is to take your original distributor and have it converted to a Hall-Effect sensor. Then you'll have a period correct looking distributor that works with the Sniper and CD box and provides you with a tach drive. Don't bother with with the MSD distributor. It won't look correct and it has the wrong type of trigger system for the Sniper. Converting a factory distributor over to a Hall-Effect setup is not difficult. It isn't something you can do by yourself, but it is fairly easy for technician who has the correct tools. With a Hall-Effect crank sensor in your factory distributor you'll have full timing control of the CD box.

  10. #10
    Join Date
    Jan 2010
    Location
    Brisbane, Australia
    Posts
    1,592

    Default

    Absolutely perfect response, completely agree. Gary
    Regards, Gary

Page 1 of 3 123 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
About us
Holley has been the undisputed leader in fuel systems for over 100 years. Holley carburetors have powered every NASCAR® Sprint® Cup team and nearly every NHRA® Pro–Stock champion for four decades. Now, Holley EFI is dominating the performance world as well as our products for GM's LS engine. Holley's products also include performance fuel pumps, intake manifolds & engine dress–up products for street performance, race and marine applications. As a single solution, or partnered with products from other Holley companies - Hooker Headers, Flowtech Headers, NOS Nitrous, Weiand, Earl's Performance Plumbing, or Diablosport - Holley products can give you the edge you need over the competition.
Join us