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Thread: Sniper With Pertronix

  1. #11


    My experience with the Pertronix Ignitor:
    I fried the ~10 year old Ignitor I unit by leaving the ignition on while I played with the new Sniper EFI (key-on/engine-off). There's a possibility that the Ignitor was already going bad from starting problems before my Sniper EFI. A new Pertronix Ignitor II (which has over voltage protection) & matching coil solved the problem. The Sniper EFI does NOT control the distributor. Engine is 1977 International 345 V8, distributor is OEM IHC "gold box" (early electronic ignition). Running great for six weeks now.

    Coil +
    Pertronix red wire
    Switched power

    Coil -
    Pertronix black wire
    Sniper yellow (coil sense)
    Signal wire to tachometer

  2. #12


    Quote Originally Posted by 493Duster View Post
    Supertruck, I ended up sending the Sniper back to Holley twice and they replaced the ECU each time. When I got it back the last time, I eliminated the Pertronix altogether and went with a regular Mopar electronic distributor and added a MSD box. I left the yellow wire disconnected, hooked purple wire to MSD tach output on box. To be honest with you, after about a month the car stated running weird, having hard starting issues, etc. Took Sniper off and went back to a carburetor. Hope you have better luck than I did.
    Well, I received my THIRD unit. First one I bought, second one the parts store replaced, third one Holley sent me. Between the second & third, I bought an MSD 6A box and wired it according to the instructions for an Ready-To-Run distributor. While Holley was replacing my unit, I replaced my fan control relay, and hooked my aftermarket tach up to the tach feed (brown) wire from the accessory connector. I removed all the unused wires from the accessory connector and one unused wire (yellow) from the main connector.

    I connected the unit, ran the Wizard, hit "send" (or "start") the screen went blank, the fuel pump engaged and ran for about two minutes. I shut it off. When I switched the unit back on, it was "Searching For ECU".

    Frustrating! I'm just baffled. The only thing left to change is the harness. I can't see why/how that would be a problem, but you never know I guess. It may be that the harness has just cost another ECU though.

    Back to the drawing board. It's virtually impossible for Holley to have sent me three duds. I can't see it. I can't figure what's going on. Good thing I'm not driving this truck this winter.

    By the way, it's a '71 F250 4x4 with a 410 FE, Summit 850309-1 distributor, Taylor 718222 coil, MSD 6A (to eliminate the possibility of the distributor frying the ECU by way of coil negative wire), nothing weird electronically (no HID or LED lights, no crazy stereo) fully restored. I have the pink wire running off the brake warning light circuit (which is on at run & start, and off with the key). I have electric fans powered through a relay. I wired that according to the wiring diagram Holley suggested, blue wire to relay ground. I have an auto meter 2897 tach connected to the brown wire on the accessory connector. Using the green/purple ignition wires hooked to the single purple wire 'adapter' for the tach signal from the 6A. I'm just baffled. HELP!
    Last edited by supertruck; 12-11-2017 at 03:20 PM.

  3. #13


    With the THIRD unit giving in on first start, TRIPLE check all connectors. This sounds a lot like something in your setup fries ECUs.

  4. #14


    I have done so. Again. I've been extra thorough with everything - solder & heat shrink, wire wrap everywhere. Nothing seems to be working. Something, somewhere, seems to be giving the Sniper EFI what it doesn't want. Very difficult to figure out.

  5. #15


    Check the pin-outs on every plug in the system, and make sure something isn't wrong. Make sure each wire color connects to the correct pin.
    Last edited by 351C Sniper; 12-12-2017 at 03:56 PM.

  6. #16


    Quote Originally Posted by 351C Sniper View Post
    Check the pin-outs on every plug in the system, and make sure something isn't wrong. Make sure each wire color connects to the correct pin.
    Good point. Will do.

  7. #17


    From, which Danny posted 5 years ago. Hope it helps:
    "This is an excerpt from Hella concerning diode protected relays:
    Eliminating voltage spikes: Voltage spikes from 300V to 500V can occur momentarily when a relay is switched off. Sensitive electronic equipment can be damaged or malfunctions can occur if these spikes reach the vehicle electrical network without suppression. A relay with a resistor reduces these voltage spikes to less than 100 Volts. A relay with a diode eliminates them completely. The correct polarity of the connections is marked on the diode protected relay."

  8. #18

    Default Possible cause!

    Okay, I think I may have found something. On a '67 Ford (the body of my truck is from a '67), there's no such thing as a "clean switched power source on at run & start". The Holley installation video shows the guy connecting the pink wire to the fuse box. No available circuit in my truck. In fact, only two things have power in start & run: ignition and the brake proportioning valve warning circuit. Not wanting to connect off ignition, I went off the other circuit for the pink wire.

    Turns out that circuit provides a path to ground, and once you finish the Wizard and hit send, the Sniper sucks a bunch of power from the red wire, and backfeeds the pink wire through the brake warning lamp circuit to ground and therefore fries the ECU. Seems pink wire and main power aren't isolated from each other inside the Sniper.

    The remedy I'm told is to run the pink wire off a relay which takes battery power for the pink wire (tap into the red in the Sniper harness) and actuated by the ignition circuit. Oh and send unit back for repair. Hope this works! Thoughts?

  9. #19


    How about using the correct terminal on the ignition switch?

  10. #20


    Quote Originally Posted by 351C Sniper View Post
    How about using the correct terminal on the ignition switch?
    There really isn't one. This is '67 wiring. The screw terminal on the back of the ignition switch doesn't provide power when cranking. The rest of the wires are molded in. One can go either to the red/green ignition wire, or to the light green brake warning circuit. Either way it's a tap off a circuit and I really don't want to go off the ignition circuit. We know what happens when I use the other. I don't mind using a relay. I'm a little surprised the supplied harness with the Sniper EFI only has a relay for the fuel pump, not the whole works.

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