Major Issues After Install

[UR50SLO]

Just had a '63 Chevy II in for Sniper EFI and HyperSpark Distributor & coil. Once running it would cut off, back fire, black smoke, etc. Tried putting the power to the units off a relay so a clean battery source, no change. Had some bad spots in the wires (we knew this) had new wires to replace (MSD 8.5). Replaced the wires and the problem is instantly gone. If you have a ignition miss anywhere in your system it will cause the Sniper to freak out. Hope this helps you guys. Scott

[MrSinister55]

Went to a party on the 4th and was talking to a guy who went with the MSD Atomic EFI. He had been running his with zero issues for a couple years, until this summer. His is now just cutting off at random. I don't need that. Even if I did get this thing sorted, I'd never trust it to take it any real distance.

[rschid]

Yeah, mine didn't act up until I was 30 miles from home. I didn't know if I was going to make it home. Not to say RFI can't be an issue, but I think they led you down the wrong path.

[MrSinister55]

Thanks. My particular issues only happen after everything is heat soaked under the hood, so it could be any of the electronics. I did replace the alternator and coil, and I was using the Holley coil driver instead of the CDI box I had been running with the carb. It's odd to me that I never had any issues with interference with the two CDI boxes I had in this car (killed one by forgetting to disconnect the battery when welding on the frame), nor do I get any noise through the radio. The only real bummer is the hit to my wallet, the rest is just hot rodding.

[rschid]

Sorry it didn't work out for you, I understand your frustration. I bought my distributor from Chris at EFISystemPro. He seems very sharp and very willing to help. But he recommends repeatedly to do it one step at a time. His theory is that if you change the fuel system and ignition at the same time and you have a problem, it doubles potential causes. I didn't know that when I started, Just so happened I did the EFI first and then decided to try timing control and ordered the distributor from him and started reading on his website. Anyways, I didn't have issues until I went to timing control and when I switch back the problem goes away, so I know it's the distributor in my case. I'm using the coil driver module that came with my Sniper and an old school canister coil, trying to decide if I want to throw another $250 at the coil & CDI box that are designed for this system to see if that is the issue or just run it like it is. Anyways, sorry it didn't work out for you. Enjoy your hot rod!!!

[MrSinister55]

I didn't. I went this route to simplify install and avoid potential issues. Didn't work! :D Nobody here or at Holley Tech mentioned the distributor as being a potential issue, so I never touched it.

[rschid]

Just wondering if you tried just swapping the distributor. I'm still fighting the HyperSpark with timing control. Runs great with the MSD Street Fire.

[MrSinister55]

Sure am, carburetor is back on and the car is running great again. I do not have the time or inclination to keep fighting this thing. Short of rewiring my whole car, I'm out of ideas and I'm not wasting more time or money trying to make this thing work. So I'll make somebody a good deal on a basic Sniper unit (I'm retaining the electric fuel pump setup) and Dual Sync distributor for SBC with maybe 30 miles on them.

[Twisted Z]

Glad to see you're getting somewhere!

[BITE_ME]

The rear of the alternator is the input for cooling air.

[MrSinister55]

Well, I didn't even have to try the belt test. I hooked my multimeter up at the battery after symptoms appeared and it was showing loads of AC in the system. I swapped out my cheap alternator for a known good alternator from a buddy's shop. The symptoms have improved and the AC readings on the meter are less, but are still there once it's good & hot. Took an AC reading with it cold and was showing a trace amount of AC in the line. Took one after it showed the first symptoms on the new alternator, and this is what my meter shows: https://www.youtube.com/watch?v=asGAJa8BBIw

It is hotter than the fires of hell under the hood now. It never got this hot before. Maybe I'm baking alternators, I don't know. The back of the alternator is only a couple inches away from the front primary tube, so maybe it's just too much heat. I get no AC in the system when cold, but a ton when hot. I also swapped out my coil for the almost new spare I had as well, as another tech with Holley thinks the coil was to blame, which it doesn't appear to be.

BUT the handheld is not freaking out anymore, nor are all the sensors reading NO DATA when the symptoms start. So something has improved at least. It's got a horrible miss now due to what I think is a burned plug boot, because the resistor plugs are a hair longer than my old non-resistor plugs, and the boot is just touching the primary on the back cylinder on the driver's side. I'm going to have to go back to the old plugs, since they were clearly not the culprit, and throw some more money at this thing to get a new set of plug wires to replace the set that's a year old. I can't win. Thanks to everybody who offered advice, help, or just well wishes.

[Firebob]

6 weeks! Dude you're nowhere near the record. I haven't been able to drive my car since January. If unhooking the charge wire (or the plug), or pulling the belt off from your alternator doesn't make a difference, you have an issue different from mine. It sounds similar, but mine is a drastic difference when in hooking the alternator. I've been through four alternators. Now running a CS130. No change. Good luck.

[MrSinister55]

Fair enough. Thanks again.

EDIT: I've been reading and researching AC Ripple and its effects on automotive charging systems. The symptoms look an awful lot like mine as reflected in the Sniper & tach. Gonna try the no-belt alternator test, and also the headlight on test with the alternator belt on once symptoms start. If they flicker, that makes three unrelated systems showing the same symptoms. At that point, it almost has to be a bad diode in the alternator. Also, look at my voltage readout on the handheld in the videos, it's NEVER steady, it's always moving around by up to .3 of a volt. I understand it will fluctuate, but it's always all over the place within that .3 of a volt or so. I noticed it was more stable with the cable unhooked from the alternator. If it's a bad diode, I bet that fluctuation will increase over time. My voltmeter gauge is steady at idle & cruise, but will dip in time with the turn signals, when I turn on the headlights, etc. I'm thinking the voltage readout on the Sniper is much more accurate than an analog SunPro gauge.

[Danny Cabral]

So given my symptoms displayed in the videos I posted, do you think AC noise in the charging system could be the culprit?

I can't answer that question.

I'm going to try your test by removing the belt anyway, I'm just looking to confirm my suspicions are plausible.

Yes, many people are surprised when doing this.

If AC noise is indeed the culprit, is there a chance that it's damaged the Sniper ECU?

No.

[MrSinister55]

Yes, that's a much better design alternator.

Thank you. So given my symptoms displayed in the videos I posted, do you think AC noise in the charging system could be the culprit? I'm going to try your test by removing the belt anyway, I'm just looking to confirm my suspicions are plausible. If AC noise is indeed the culprit, is there a chance that it's damaged the Sniper ECU?