428 with MSD or Other Problem.

[mj_duell]

Hello Everyone,
Well, I just got my 428 ready to fire this morning and I've had trouble ever since. I have gone though and checked the usual suspects. I have plenty of fuel, the firing order is correct, I've checked the timimg about six times and I still can't get this thing to run. The firing order is correct and I've verified that as well. The motor tries to fire like a few plugs are missing every time I try to start it. I checked the cap and rotor, coil and my Motorsport Distributor and they seem fine. The only thing I can think of is the MSD 6AL Box. It is wired as follows:

Big red wire to Positive power on Solenoid.
Small red wire to keyed power switch.
Black to ground.
Purple and Green wires to Purple and Orange from distributor.
White is not used.

I have checked the ground and its good. It comes very close to firing but doesn't. When I checked the plugs, some were wet with fuel some were carboned from ignition. I have never used a MSD ignition before and any help would be great. If there are any good testing procedures for this set-up, please let me know as well.

Thanks,

Mike

[KobraKarl]

Mike ,

Have you checked to make sure that your distributor is not 180* out of phase.?...or to put it another way...are you sure that when you are at #1 TDC that you are not on the exhaust stroke....you would get these symptoms...

good luck , KK

[mj_duell]

Hi Karl,
I set the TDC on #1 and I am sure it is on the compression stroke. I checked it with my finger (I know, great gauge), but it did get pushed out of the spark hole. I will check again.
Thanks for the quick response.

--Mike

[deadwood1584]

Mike,
make sure purple distributor wire to green harness and orange dist wire to purple and white wrapped so it does not ground out. or call msd at 915-855-7123 as they are awesome for helping out.
Good luck,
Eric

[Rick Parker]

We seem to go through MSD issues quite often and rarely is it actually the unit, so hang in there. To be certain the box is not at fault, start with the basics. IE:
Be sure the heavy red wire from the MSD box it attached to the battery side of the starter solenoid, and the small red wire is attached to a switched 12 volt source that is hot when the key is in the "ON/RUN" position AS WELL as the "START" position.
To actually test the box itself, set the parking brake, put trans mission in neutral, remove the coil wire from the top of the distributor and place it near the block or a good ground source, (not the carburetor). Disconnect the wire from the MSD box at the distributor. It has a 2 wire connector were it joins the distributor. While holding the long wire from the MSD box take a short piece (2"-4") of regular 16-18 gage wire forming a "U bend/jumper wire" in the small piece of wire and touch both conductors of the long wire at the same time. Each time you break the circuit as described a spark should be created at the coil/distributor wire near the ground souce. If you have spark each time then the MSD box is OK.

Rick

[mj_duell]

Wow!,
Thanks for all the help. I started this post only a few hours ago and members have jumped right in to help (as usual).

Rick,
I will run the test you laid out tonight. I don't thnik it is the box, but it may be a wiring or ground problem. I'll keep you informed.

deadwood1584,
I have checked the wires to the distributor. They match the colors you specified. I will be calling MSD today and try to see what they think.

I am really stumped. It almost fires everytime. It's like it only fires 4 of the 8 cylinders while cranking. I am sure the timing is correct and I was on the compression stroke. I have checked the wires many times and they match suggestions here and in the instructions. I have a solid ground to the motor and frame. The coil is firing. Should I check anything in the distributor? Not to sound crazy, but the firing order is 1-5-4-2-6-3-7-8 for a 68' 428FE right?

--Mike

[CSCHWER]

Reroute the purple and green wires, especially if you routed them inside the dist. I had the same problem and all it took was to change the routing/clamping of these wires in the dist.

Chet

[mj_duell]

CSCHWER,
Can you explain a little more? The connections of the green and purple are good. When you say re-route what do you mean? Oh, I have a stock type Ford Motorsport distributor just for your info. I don't know if I mentioned that to anyone before. It has orange, purple and black wires running from it.

Thanks.

--Mike

[CSCHWER]

I have a Protronic (GM) type dist. so I removed the module (4pin) and hooked the MSD supplied wires and connector to the connector on the end of the magnetic pickup in the dist.

The plastic clamps MSD supplied would not allow me to mount the connector using the bolts and mounting holes where the ign. module was mounted so I mounted the wires with 2 aluminium clips. I had the same problem you are describing so I just mounted the wires with 1 plastic clamp in the hole closest the exit. I'm thinking about just cutting off the connector on the mag. pickup and soldering the wires together.

Chet

[mj_duell]

I think I will try the same. The connection does look a little questionable. It would be easy to make a direct soldered connection and redroute the wires. I will give that a try. I'm starting to think that maybe the issue. I'll try it tonight and write back tomorrow. Ho can I tell if the stock Magnetic Pickup is any good or needs to be replaced? I just talked to MSD and they think it maybe a cranking voltage problem. I'll check that as well.

--Mike

[CSCHWER]

Mike,

I've never checked a magnetic pickup. My guess is.... spin the distributer with a voltmeter attached. It is probably polarized... ie +/-

Chet

[Rick Parker]

To check the pickup coil in the distributor requires an ohm meter. It should read between 400-1300 Ohms. Disconnect the distributor from the MSD box. Insert the test probes into the connector at the distributor. If you are in that range you should be ok.
With that said go back and be sure that the distributor is pointing to #1 when #1 is at TDC on compression stroke (line up timing marks) after finger is "ejected". If all this is correct and functioning AND you have fuel, it will run.

Rick


Rick

[mj_duell]

Thanks Rick,
I am sure of TDC of #1 and that I am pointing to #1. The more I think about this, the more I think it is a wiring problem. I will run your test as well as the others tonight. A freind of mine just said that it is possible that the gasket for the Holley is in the wrong position. That would cause the same type of symptoms. I don't think that is the case, but worth a check as well.

Thank you to all who are helping me with this problem. Without this forum, my knowledge of the history, building techniques and engineering of Cobras would be greatly limited.




--Mike

[CSCHWER]

If you have a electric choke make sure you have voltage to it. Don't ask me how I know.

Chet

[mj_duell]

"How do you know?" Ha, Ha, Just kidding. No it's manual. I'm going to dump this 750cfm Holley for a Demon soon. I hear that they are more dependable and take less tuning. Have to get the engine to fire first.

--Mike

[Chaplin]

Before you go any futher, have you pulled your plugs and looked at them? I'd make sure that they are wet with gas before I'd condemn the ignition system and chase wiring issues all day.

[mj_duell]

Hey Chaplin ,
Yup. I have fuel on the plugs. A few plugs!. the rest have carbon like they've fired. The engine was broken in (first run) with that Holley and Dyno'ed as well. I purchased the harness and MSD seperately. After a lot of checkeing and rechecking I figure it has too be the wiring. A few members have givin me diagnostic tests to run. If they check out I'll start working over the carb. Speaking of carbs, do you have any recommendations for Speed Demon carb CFM. The motor is a 428 bored .30 over, Cam: 292/.560 (244@.50)) , Intake is a Edelbrock performer.



--Mike

[CSCHWER]

Mike,

Dumb trick # 3. Forget to put the RPM module in? I have no idea what the RPM be without it.
Chet

[Chaplin]

Mike-

From your question regarding CFM, I'm guessing you're thinking about getting a new carb? If so, you might want to look at the Mighty Demon as opposed to the Speed Demon. I have the same motor you do (same cam too) and I am switching to a Mighty Demon 750 with mech. secondaries. I called up the techs at Barry Grant and gave them specs for my motor and they said that the Mighty Demon would be better than the Speed Demon for my application. It might be worth calling them before you buy the carb.

[mj_duell]

Chaplin,
Thanks for the feedback. Same motor. Cool! Now I have someone too answer all of my questions (lol). How do you like your cam? .560 lift is a lot for the street don't you think. I haven't gotten to the point of driving this beast and I was worried about the cam specs. What kind of motor problems have you had running this set-up? I am going to look into the Mighty Demon as you have suggested. I checked out your gallery. Nice Cobra! I wanted an ERA, but a little out of my range. Next one maybe. I keep trying to sell the wife on the wonders of aluminium.



--Mike