MSD Install: Confirm My Diodic Reasoning!!!

[BobBarry]

Both my MSD6A and my RS9000's showed up today; of course, my wife had the truck out and we were going out tonight, so I didn't get to do the install. Well, it gave me time to raid all the local Pep-Boys of their Weatherpack connectors; it looks like the install would take less than an hour, but I'm rather neurotic about hatchet-jobs, so I'm making up little harnesses for a true waterproof plug-n-play setup (also so I can hook everything back to stock in a minute if anything goes bad).

I got the adapter harness to plug into the Duraspark distributor connector. I didn't know that there were two ways to hook the system up; with this harness, the factory Duraspark box is completely bypassed, but there's also a way to hook it up through its white wire to run through the factory spark box.

Now to the questions:

* The first one is really a general electronics question. I made up a little harness out of a shortened HELP! alternator cable extender harness, into which I soldered in the diode supplied by MSD (since everybody has said that they had to do this to allow the truck to shut off). The markings on the diode were minimal, at best. There was one white band toward one end; in the installation diagram, it seems that this white band is installed toward the alternator. Is that the right way to install it? What is the standard designation for the direction a diode prevents the flow of electricity?

Anyway, I got a chance to put it in tonight, and the truck runs fine with it in that way; I imagine that if I installed it backwards, that brown wire wouldn't get any juice in the proper direction.

* A second question concerns the resistor wire to the coil. That becomes the new feed for the MSD box. I'm assuming that the voltage of that wire doesn't matter much, as the box gets its juice from a separate 12V(+) feed, so there's no need to remove the factory resistor wire.

* I also got the timing adjustment, which I'm trying to find a place for in the dash. The easy choice is between the surface just to the left of the steering-column, between it and the left vent control. The more involved way is to replace the ashtray with an aluminum faceplate, and mount the knob there.

I'll post the results, hopefully tomorrow.

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Bob Barry<UL TYPE=SQUARE>* '78 Cherokee 4-door
* '88 Grand Wagoneer[/list]http://studentweb.providence.edu/~rbarry/wheels/

[Slippery]

Read this: http://www.netcentral.co.uk/satcure/design/diodwork.htm

If I've interpreted it properly (4:30am, brain's not working http://www.ifsja.org/ubb/wink.gif), the current flows through the diode toward the stripe; the stripe should be on the "outlet" end. According to them, you have it right. (I should note that I don't know the first bloody thing about electronics, and you should feel free to dismiss my opinion.)

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Jason K.
http://us.f1.yahoofs.com/users/e46e6dee/bc/My+Photos/Festiva.jpg?bcw0GX7Ax3rIxilV
'88 Ford Festiva
40mpg work car
Cost $150, paid for itself already
-----------------------------
'90 Chevy Lumina
Biggest POS in the 115-year history of the automobile
4 cylinders, less than adequate for a car half its size
Crappy rear disc brakes, $19M class-action lawsuit settled
------------------------------
Some other junk not worth mentioning

[This message has been edited by Slippery (edited June 28, 2001).]

[wagdriver]

Diodes are 2 terminal divices, having an Anode and Cathode(the striped end) in order for current to flow the anode must be positive with respect to the cathode. The Anode must be at .7 volts higher in voltage than the Cathode in order for the device to conduct. Anode----|&gt;|----Cathode(alternator)
|white stripe

On a schematic the first vertical and greater than symbol would be a triangle with the second vertical bar represents the cathode, the white stripe is the cathode end.

Not having seen the schematic I will assume this is a blocking diode for some reason. I hope I have not added to your confusion. If you really want to know go to Radio Shack and ask the sales person for a Mini-Engineers book by Forest Mims they have several of them about simple circuits and are written for new enthusiasts. Hope this helps http://www.ifsja.org/ubb/wink.gif



[This message has been edited by wagdriver (edited June 28, 2001).]

[BobBarry]

Thanks, Guys! I think I've got it right, then.

The purpose of the Diode is to prevent (+) voltage from trickling back into the system through the brown wire, which hooks into the (+) switched ignition circuit. The brown wire is a resistor wire (in most cars, the GEN light provides the resistance, but in a gauge setup, the wire has to provide the resistance itself), but apparently enough electicity will leak through in the FSJ setup to power the MSD, which draws 12V(+) directly from the battery through a 10ga cable.

So, electricity should only flow to, and not away, from the alternator through that brown wire. If the stripe is installed toward the alternator, then the one-way gate in the diode only lets the current flow toward the alternator.

Good- I'm off to Pep-Boys, then, to pick up some more Weatherpack connectors (this is the only groups I know that I feel comfortable sharing the intimate detail that they are my favorite kind of connectors... http://www.ifsja.org/ubb/smile.gif )



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Bob Barry<UL TYPE=SQUARE>* '78 Cherokee 4-door
* '88 Grand Wagoneer[/list]http://studentweb.providence.edu/~rbarry/wheels/

[Langdon]

Bob, I removed the resistor wire in my setup, mainly because it was in poor shape. I called MSD and the tech told me that this was OK, as the 6A could handle battery voltage. I have not had any probs so far...

[ChrisCollege]

Bob,

I just did the same install with huge head aches. You can see the thread went on for 3 weeks. My problem turned out to be a MSD wired harness was backwards. I was using the magnetic pick method and they had the two pick up wires switched in the factory MSD harness. When I switched to the white wire pick up every thing worked great. It sounds like you have everything correct including the diode. If you run into question send me a email. After three weeks of screwing it up I have become fairly familar with the two install methods and the MSD tech line.


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Chris
88 GW
Stock except for:
TFI with a MSD6

93 YJ
2.5 suspension lift and 33" BFG MTs
RS9000 in cab remote
Ramsey REP8000
Custom storage and bumbers plumbed for air
Lot-o-lights and Optima
K&N

[ChrisCollege]

Bob,

I also have the RS9000 on my YJ with the in cab air adjustments. So email if you have questions.

Chris

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Chris
88 GW
Stock except for:
TFI with a MSD6

93 YJ
2.5 suspension lift and 33" BFG MTs
RS9000 in cab remote
Ramsey REP8000
Custom storage and bumbers plumbed for air
Lot-o-lights and Optima
K&N

[Puvong]

Hello Dr. Bob,

I think you have got it right?. The Diode is simply the device that allows the current flow in one direction and also used for voltage "spike" protection as you're already mentioning.
I had thought the same way that to wake up this old American iron will needed to spend some $$$. Then I also purchased MSD's Ignition package about three weeks ago and nerver have the time to install them. Anyway, the package include: MSDA6, Timing control, 8.5mm Univ-fit wire, MSD for Ford's CAP, base CAP, and rotor, MSD TFI Coil, and some misc wiring...Whooping empty my pocket over $500, but I think it'll certainly worth the money that spent in the long run I guess.

[YJason]

FYI-The MSD-6 series ignition boxes aren't waterproof. The only ignition boxes that MSD makes that are waterproof are the MSD Offroad and the Marine models. I have heard of several that failed due to even mild water introduction, such as sitting parked in the rain and condensation building up. Only the Offroad and Marine models are incased in an epoxy resign(sp?).

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Jason
------
1988 Grand Waggoner & 1990 YJ

[nograin]

I think the 6 T is epoxy encased as well. T was the circle track model.

My understanding as well is that the factory unit isn't needed, nor is the resistor to the coil. I believe my instructions specifically were to remove the resistor (on a Chysler set up). I would do that, and leave the duraspark & resistor sitting there, ready to plug in if needed. Very cool to hyave the retard hooked in. That will make the switch back even easier if it ever becomes neccessarry. You may be able to reduce advance 2-4 degrees with the MSD 6. In fact, you may have to.

If you ever find you are switching timing alot, the control knob is just a reohstat, so you can install an equivalent resistor and switches if you wish.

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360 727auto-trany, NP229
body by beer (PO) :(
carries wood inside
no "wood" outside
http://users.erols.com/mathewg/85gwsmll.jpg
My other car is a fish

[BobBarry]

Well, the MSD install went well today; I've screwed up enough installations to make sure I did it right the first time, and it fired right up with the first turn of the key.

As I mentioned, I used weatherpack connectors for all wires, crimped and soldered them securely, sheathed them in factory-style ribbed flexible conduit, and tie-wrapped everything where it won't melt, short or interfere with anything else. Switch two plugs, and I'm running back on the factory Duraspark box, if need be.

The timing advance/retard is pretty neat. To bad the control knob can't be flush-mounted. I fabbed up a panel to replace the ashtray; It's a flat aluminum piece that surrounds the factory lighter outlet, and it leaves space for a couple more switches or indicator lights (hmmm, maybe I could build that LED tach and mount it in the plate). The only thing I have to do to that is paint it satin-black to match the rest of the dash. Too bad I couldn't carry over the woodgrain. http://www.ifsja.org/ubb/frown.gif

I've got the timing adjusted to match the degrees on the knob; so when the knob says 10º BTDC, it is actually 10º advanced. Testing it out, it pings on full-throttle acceleration if I dial in more than the factory-specified 12º.

It's hard to tell whether there is much improvement. The truck ran pretty well before, but I think it's got more torque; I didn't need to give it much gas to cruise up a hill that usually slows the GW down a bit. I've got this big trip to Cincinnati on Sunday, so we'll see how the mileage turns out.

I also got the RS9000's on tonight, just before darkness set in. This was my first time doing shocks with an air-gun, which made it a cinch; it took longer to jack up and remove the front wheel than to actually change the shock. I didn't have to remove the wheels in back, or even jack it up, so I was able to swap the right-rear shock in under five minutes. Rancho also includes a neat decal to lay on the shock once it's installed. I'd love to put in the remote adjustment system for these shocks, but that's just a pure gadget; it takes all of seven seconds to reach under and adjust the knob. I've got them on 1 (the softest), and they seem smoother than my former Gabriels (which are going on the Cherokee, as they're relatively new).

It's just cool to be able to adjust things.

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Bob Barry<UL TYPE=SQUARE>* '78 Cherokee 4-door
* '88 Grand Wagoneer[/list]http://studentweb.providence.edu/~rbarry/wheels/

[Dutch]

Bob,

Hope you post the results of the new shocks and MSD unit following your trip. Ralph and I did a short comparison between his new Edlebrock's and my Rancho 5000's. Long story short... night and day difference! Rancho's very firm while the Edlebrock's were remarkably compliant. Although Ralph may disagree smile.gif I think they both serve a different function well.

My MSD unit did not enhance "power" noticably but I was happy to report that "punch" was significantly improved. By that I mean off-throttle response and a big reduction in lag. If any power/torque gains were made it was in the upper RPM range but that may be a result of the Performer Cam.

Dutch