MSD 6A ignition

[FastWoman]

Hi all,

So I bit the bullet and bought an MSD 6A ignition module to iron out the last of my weak ignition problems. I did a really nice installation, both electrically, and structurally. I tested it. It sparked when I jumped across the magnetic pickup leads -- a HARD spark that went ZZZIT. All good.

Then I tried starting the engine. I got an initial fire, as I often do, and then nothing -- crank, crank, crank.

Anyway, I'll be brief, 'cuz I know y'all must hate my long posts:

MSD tech support was unable to tell me what polarity to hook up the magnetic pickup, other than to say to try both ways, and go with the one that gives the more retarded timing. I initially tried Nissan red to MSD violet (positive) and Nissan green to MSD green (negative). Apparently this didn't work, and I flooded my engine.

I then tried to determine which configuration gives me a correctly timed spark. Problem is that the multiple sparks seem to freak out my timing light. It's only good for one or two flashes before it stops flashing. It's a nice timing light (Sun), but it's also a bit fussy. Of course with more testing, more flooding. I can smell the gas! I did confirm, BTW, that I'm getting a continuous series of sparks, by unplugging one of the wires and putting it near ground.

Anyway, I'm sort of stuck for the moment. Can anyone tell me the correct polarity of magnetic pickup wiring to make this thing work?

Also how do I start a flooded fuel injected engine? This has never happened to me. Do I disconnect the fuel pump and crank to clear the cylinders?

Thanks!

Peace,

Sarah

Edited November 4, 2009 by FastWoman

[YawnTee]

Don't crank the cylinders without removing the plugs! If it's REALLY flooded at worst it will look like a water fountain at Vegas instead of trying to compress fluid ha. Had to do that to my first 510 when the rear end was on jack stands all night and the little Hitachi had a bad check valve.

Who's the MSD guru, my car is not here at work with me.....?

[FastWoman]

Basically pull the plugs and let all the fuel blow out the plug holes while I crank? I can crank by jumping to the starter solenoid, so that I don't engage the fuel pump or ignition. I imagine it would be a good idea to run two wires away from the engine compartment, so that I don't create any sparks near raw fuel.

[jmortensen]

If you're using the distributor to trigger the MSD without using the module, memory of my own install tells me it shouldn't matter which wire goes to which side of the magnetic trigger pigtail. Both wires go to the pickup which gets triggered when the reluctor wheel passes by it. There shouldn't be any timing change in looking at the impulse with the wires reversed. The 280Z distributor is different than the 280ZX, but it's the same basic idea in use.

The fact that you're getting spark is the important thing. If you're getting a nice hot spark and the thing flooded I'd be inclined to believe that you have something else messed up, plug wire sequence or something.

[FastWoman]

Well, the engine was running OK (not well, but OK) before I swapped ignition modules. None of my plug wires have swapped positions. I did pull the plugs one by one to regap to .060", but the wires went right back on after each one was pulled. It would be REALLY hard to screw up the wire order. I smell gas, so the injectors are working. I didn't work on anything but the ignition module, so I wouldn't expect that to change. All that's different is the ignition module, which sparks, but which may not be triggering on the right part of the waveform. It makes sense to me that inversion of the waveform would alter the timing, and the MSD tech support person pretty much said the same thing, although he seemed to think the engine could be started with either polarity.

Anyway, I can repeat the trial and error approach, this time trying the opposite polarity of wiring, but it's a lot harder to air out a FI engine than a carbureted one. I've read elsewhere that my proposed approach of de-energizing the fuel pump is a good way to work past the flooding.

If my engine runs, I'll just have to assume its properly timed, because the multiple sparks trick out my timing light. I suppose I'll need to buy another timing light. Dunno.

Anyway, thanks, everyone. Wish me luck.

[rxsleeper]

I was trying to understand why your MSD is not working and noticed this in the instructions:

NO-RUN ON FOREIGN VEHICLES

Some foreign vehicles with fuel injection systems may require an MSD Tach/Fuel Injection

Adapter to run with an MSD 6 Series Ignition. This is because many of these systems use

the same trigger source to operate the MSD, the tachometer and the fuel injection. This

results in a voltage signal that is too low to accurately trigger the fuel injection. To fix this, an

MSD Tach Adapter, PN 8910, will remedy the problem on the majority of vehicles. If the PN

8910 does not fix the problem, the PN 8910-EIS will be required.

Note: Toyotas and Ford Probes will require the PN 8910-EIS Adapter."

I use a Pertronix/MSD (in the 240) and I am assuming that you need to use the mag triggers with the 280 distributor and I am wondering if the Injector system uses the mag pickup as described above? I used the standard point triggers.

I was trying to learn a little more about the injection system since I have a ZX in the wings. Trying to help and learn at the same time.......

Paul

[rxsleeper]

Didn't want to try and edit the previous post so I went and looked at the FI manual. Sarah, hopefully this helps:

I have attached an image and here is the text:

[jmortensen]

That sounds like a winner to me.

[FastWoman]

Paul! Yes! That's it! THANKYOUTHANKYOUTHANKYOU!!

Yeah, I had checked fuel pressure -- OK

Ignition -- OK (runs off of starter fluid)

Mildly flooded from the cold start valve, but not what I expected.

Continuity with the injectors -- OK

Could actuate the injectors by grounding them individually

Pumped up the system by running the fuel pump, juiced the intake with a healthy shot of starter fluid, and started the engine. It ran for maybe 5 sec. Fuel pressure dropped a bit, making me think (again), "AHA! It's squirting fuel." Then I remembered the fuel pressure regulator just doing its job. So I juiced the intake again, started again, and the fuel pressure held steady. No injection because...

(and here's where you filled in the missing piece)

... Nothing was triggering the fuel injection computer! :stupid:

Given that, do you think I can simply hook Nissans's negative coil wire back up to the neg side of the coil for the trigger? Is that safe for the fuel injection computer?

Thanks again, guys!

Peace,

Sarah

[FastWoman]

OK, back on the phone with MSD tech support. I asked what signals could be used to trigger the EFI from the MSD 6A. They said it can't be done. The configuration I'm supposed to use is to have the old OEM IM read the signal from the reluctor and pull the (-) coil wire to GND with every trigger. That signal is fed to the MSD6A through the white wire to trigger it. The signal also triggers the EFI. The only problem is that my OEM IM is a bit weak. I suppose I could use it to trigger the MSD6A, but instead...

Couldn't I trigger the EFI off of the tachometer output, which is a 12V square wave?

BTW, Paul, the tach/EFI adapter you mentioned doesn't do what we're thinking it does, at least according to MSD tech support. They say I can't get from point A to point B without a working OEM ignition module.... but I don't entirely believe it.

[70 Cam Guy]

If you think your ignition module is weak, is this something that can work for you?

The article is really meant for a 240z retrofit but you seem pretty savvy with electrical so maybe it will give you some ideas or another direction to try.

http://www.zhome.com/ZCMnL/tech/gmhei.html

[FastWoman]

Nice install. Thanks for the link! Hopefully I won't need to go the Rube Goldberg route, but in case I do, it's nice to know I can do it with something so cheap and ubiquitous.

After sleeping on it, I think I'm just going to try the 12V square wave tach output to drive the EFI. I figure I'm not going to hurt anything. After all, the EFI computer has seen MUCH, MUCH higher voltages from the (-) side of the ignition coil. What's an itsy bitsy 12V square wave by comparison? Either it will work, or it won't. If it works, then good. If not, then I'll probably look for an HEI IM to trigger the MSD unit, the tach, and the EFI.

This really seems like a dumb way for MSD to have designed their system. Did it not occur to them that some people might buy the unit to replace/upgrade a dead/dying OEM electonic ignition module? Then again, maybe they already have this capability,m and their tech support doesn't know it. I really don't have much confidence in the kids with MSD's tech support. They sound very much like the ubiquitous neighborhood kids who drive lowered Hondas with loud mufflers and primer paint jobs -- the type that usually wires a bunch of stuff together and twists the distributor around until the engine runs and makes lots of noise. (I actually hear one of them outside right now!)