Dual Sync Issue

[sr1032]

Took the kids for a drive today and on the way home she started acting funny. A ton of hesitation and bogging and was really only happy above 2500 RPM. I checked the handheld and it was running rich, so I knew it was missing cylinders or there was something wrong with the ignition system. It got super bad at the tail end and fired off a backfire that sounded like a shotgun blast and died in my driveway, won’t start. Checked the fuel pressure, a little low but still there. Checked the MSD 6A and the light is steady red, could still be the culprit, but doesn’t seem likely and of course MSD documentation says the solid light indicates a functioning unit. No way to check my coil that I know easily (SS Blaster) and of course I recently tossed my spare coil canister, figures. Up next was to check for spark but I have fuel pressure so I know there is no spark or the sensors in the distributor aren’t correct, I mean it won’t even remotely start. So I pulled all the plugs and checked compression. I had another reason, but that was to use the starter to help me get the car in them garage, don’t judge too harsh, had to be done, LOL. Good compression all around, 180-190 psi each cylinder. So I pulled the distributor cap and found this, this is a Holley Dual Sync that is on a garage kept car and has been in the vehicle for about three years. The cap is just as bad. I would’ve never added this to my list to check given she is garage kept and has spent maybe five days outside in the seven years I’ve owned it. I checked with a buddy who has pretty much the identical setup and he said his was getting this way as well. I doubt Holley will stand behind it given how old it is but c'mon, this is unsatisfactory. I’m not positive this is my problem yet, but I feel it has to be addressed. To me it’s either this or the coil. Thoughts/have any of you experienced this on your distributor? I’d expect so much more for the money and I’m basically stuck getting another one given how I set the car up.

[Danny Cabral]

I assume this is a Generation 1 Dual Sync Distributor: https://forums.holley.com/showthread...nc-Distributor (Related Forum Thread)

Originally Posted by Danny Cabral If your crank or cam sync unit isn't transmitting a signal, troubleshoot the sensors, wiring, reference voltage & ground, reluctor, alignment, air gap (LINK), radial run-out problems (LINK), etc. If a regular datalog indicates an "RPM Error" when scrolling through the problem area, then it's time for a System Log to confirm which sensor flatlines. FYI: Crank & Cam A/D means Analog To Digital. It's not the +5V reference supply voltage. Troubleshooting 3-wire Hall-Effect sensors: https://www.yumpu.com/en/document/re...le-electronics (Understanding/Troubleshooting Hall-Effect Sensors - "Troubleshooting", Page 2) https://www.team-bhp.com/forum/attac...e-beatbook.pdf (Fluke Multimeter Testing - "Hall-Effect Sensors", Page 17) Record a System Log to verify crank & cam sensor signals. Check mark the "RPM", "Crank" & "Cam" channels. Look for a uniform, uninterrupted crank or cam sensor signal pattern. The crank or cam sensor signal should never flatline (no pulse) or indicate an RPM "Error" anywhere. Also, fully charge the battery and ensure the engine is cranking fast enough, at least 100+ RPM. Another common issue, is trying to analyze a compressed view of a long System Log. Zoom In for detail - click & hold at one point of the datalog, and drag & release to another point nearby. It's best to record short System Logs/Datalogs that capture the problem. http://forums.holley.com/showthread....s-amp-Datalogs (Datalog & System Log Information)

[sr1032]

It sure is. I’ll give them a call tomorrow and see what they say. Not positive that’s my issue, but it clearly needs to be fixed.

[madmax2]

All MSD distributors have the same rust.

[Danny Cabral]

The 2nd generation Holley Dual Sync Distributor internal rust issue is supposed to be resolved.

[Bill C]

Yes, the 2nd generation Dual Sync Distributor I bought appears to have a glaze type sealer on the circuit board, and the rotor/reluctor is black, it almost looks like a powder coat. I doubt it will ever show oxidation like the 1st generation units I've seen. Many times companies will show a revised model and not make many changes. On these distributors that's not the case; they're clearly improved and better sealed. Also the distributor body to cap fit is much firmer, positively slips into place before you, even put screws in it.

[ilikeike]

I had the same issue with garaged California car. I maybe had 2000 miles on it, it wouldn't fire one day. I started troubleshooting, opened the cap and WOW! Looked like it came off the Titanic or something, I couldn't believe the corrosion on my pampered car. I had to purchase a new distributor, I wasn't happy.

[knightrider]

Nice to know, mine's only around a year old no idea if it's Gen 1 or 2, but had the cap off the other day and it's rusting. Nothing like yours yet, but thought to myself that's not good.

[smalliehunter]

Dual Sync Gen2 Rust Issues

Guys, I have the Gen 2 Dual Sync distributor for my SBC and have the same rust issue with it! I had a Gen 1 and Holley replaced it with a Gen 2 at no cost which was great, but I'm still having the same rust issue now! My car is in a heated garage and never driven in the rain, and I never wash the engine compartment and only detail it with detail spray and a rag. I contacted Holley and their tech told me that ALL distributors get rust in them and it's the natural process of the ignition inside the cap which causes condensation. I asked him what was the solution and he told me to remove the cap if the car is sitting for any longer than a couple weeks, or "drill a couple holes in the cap", what! Before I installed my Holley HP and Dual Sync distributor with 6AL, I had zero rust in my old distributor and I've owned a few hodrods and have never had to deal with this ongoing rust issue. The Gen 2 Dual Sync distributor has been installed for about a year and a half and I have maybe driven 2000 kms in the summer months only. I just finished replacing the Gen 2 with another one now and I'm ready to fire it up today, but don't want to run into the same rust issue that I just barely made it home with. Please, if anyone has any suggestion and or solutions, I would very much appreciate hearing them. I've attached pics of the rust in the Gen 2 Dual Sync distributor & engine compartment, so you can see it doesn't see any moisture. Thanks guys, Smalliehunter.

[madmax2]

Went to Coil-Near-Plug, no more internal rust issue.

[smalliehunter]

Madmax2, thanks for the input. I don't want to go that route as I'm trying to keep the engine super clean and I've hidden all the wiring in a SS conduit for the injectors. In all your research, have you discovered why these Dual Sync distributors rust? I was shocked when the Holley tech guy said they all rust and to drill a couple holes in the cap or remove it. Very poor design if that's what's required to prevent rust.

[Bill C]

Haven't had any trouble out of my Dual Sync distributor so far. In hindsight a junkyard Vortec 350 distributor, timing chain set and crank reluctor would've cost half as much, last for 200,000 miles. And be just as easy to convert to Coil-Near-Plug setup down the road.

For a $365.00 distributor it does seem ridiculous for how many have trouble with them. Wonder how much ionization inside the cap contributes to the oxidation? In other words, if used as cam/crank signal only and no spark whirling around in it do they still look like that after a while?

[smalliehunter]

Hi Bill. If there was any other option to not go with the Dual Sync distributor, believe me, I would take in a heartbeat. Unfortunately, I don’t have the room for another distributor as the Hilborn ITB intake limits room at the firewall, etc. The Dual Sync distributor is awesome when it's first installed, but after a while it starts showing signs of rust and the car starts acting up and eventually won't run. I guess I know now from all the info I've recently found online, and what MSD tech told me (remove the cap), that I'm dealing with a very poor design and there's not much that can be done other than removing the cap every once in a while.

You're bang on about the cost being a bit ridiculous for how much trouble these things cause and how unreliable they are, almost $700.00 CAN with shipping, duties & taxes.

If there's anyone out there that has an MSD Dual Sync distributor Gen2 that's not having the same rust issues that the rest of us out there are, please chime in and let us know your setup and how you are preventing the rust. Danny, if you have any ideas and a solution, I'd love to hear about it and it'd be very much appreciated.

[Danny Cabral]

Danny, if you have any ideas and a solution, I'd love to hear about it and it'd be very much appreciated.

Sorry, I don’t use distributors. I use Holley distributorless ignition systems (cam sync unit & DIS/CNP).

[madmax2]

Cheap ferrous materials, I have a rusty MSD billet distributor too.
My old OEM distributos never do rust for ionization (Chevy & Mopar). I buy a Dual Sync for CNP use.