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ignition trouble

blue bronc

Full Member
Joined
Apr 11, 2006
Messages
309
Loc.
Fort worth
Earlier in the week I posted that I was having trouble with bronco and I was so sure that it was a fuel issue. I checked the fuel pressure, filters all of it.
I checked the spark and it was firing so I thought it had to be fuel related.
I had driven for 4 days with not a single problem it cranked this morning with out any trouble I got to work no trouble.
When I was leaving work it would not start so I tried for a while then it cranked for about 10 seconds then it died.
It was getting fuel so I thought to check the ignition again. This time it was not firing.
So sometimes it fires and I have no problem and sometimes it won’t and I get stranded. I got it to start and I got it home but I need to get it fixed.
I have a MSD6 Off-road Ignition Controller
A MSD Blaster coil

What is my next step I am not real good with the electronic side of things.
How do I get my ride going again?
 

Skuzzlebutt

PhD, Dr. of Broncology
Joined
May 26, 2001
Messages
4,393
Loc.
Honeymoon Bay
The one big down side of electronic ignitions is that there aren't any simple tests. To find out if a componant is defective, you need to replace it with a known good one. Off hand I would guess your controller is the most likely part to go bad.
First thing tho, is to make sure every connection is perfectly clean & tight.
 

Skuzzlebutt

PhD, Dr. of Broncology
Joined
May 26, 2001
Messages
4,393
Loc.
Honeymoon Bay
For the coil, run 12v to the + post and loose wire to the - post. Tap the loose end of the - wire against a good ground. This will simulate the opening and closing of points. You should be getting spark at the HT coil lead every time you break ground. This'll work on most coils. I'm not sure if the MSD is a special case.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,355
You can do the same thing with some of the MSD boxes. Which distributor setup are you using? Points? Electronic?
Before you use the jumpers, try this.
If your Off-Road box uses the same wire color scheme as a standard 6 series, then you can disconnect the White wire from the MSD box (at the distributor end of course), turn the key on and tap the end of the wire to a good known ground. Each time you tap and release the wire, you should get a nice healthy spark from the coil. If you don't, chances are that either you're not getting good power to the MSD controller, or it's gone bye-bye.

Then use the jumper method like Skuzzlebutt says, and that will tell you if it's in the wiring somewhere. That's a common problem. Hidden wiring issues.

I just went through all that in case your wire colors are the same, but I seem to remeber that the Off-Road version uses special plugs (Weather-Pack I think?) instead of just bare wires. So they might even use different colors too, but basically you want to find the trigger wire and touch it to ground to see if you get a spark.
Hopefully you can still use that info. At least to start tracking down your gremlin.

Paul
 

t.lay

Bronco Guru
Joined
Mar 17, 2005
Messages
1,261
Loc.
Grayslake, IL
I'm dealing with some of the same stuff on an initial start up after a rebuild. No spark at the coil that I can tell. I suspect I cooked my duraspark box before I sorted out some grounding issues.Here's some photos of how my wiring went together with a centech harness, duraspark and a junkyard ford duraspark harness - maybe it will help - if anybody sees anything obvious, let me know what I've messed up on.

The centech troubleshooting guide (which IMO reads like japanese appliance instructions from the 60s - but I like the harness) talks about checking resistance between the orange and violet wires going into the coil (400-800 ohms at a 2000 setting and 70k between the orange and black and between the violet and black). Basically telling you if the wires to the dist are ok - so it keeps narrowing down what could be going wrong.
 

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Hazegray

Sr. Member
Joined
Aug 10, 2004
Messages
795
t.lay: Why are you running a resistor in the system? Go out & buy a 12V coil & be done with it.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,355
I would agree with that. Resistance is not good except to give older coils and components a longer life. If your coil is rated for 12v without a resistor, and your particular Duraspark box is too (what color Duraspark are you running?) then the resistor is just weakening your spark and adding a lot of heat in that local area.

Other than that, I can't really see where each of the wires goes, so I'm not sure if it's right or not. I'll keep looking at the pictures though. Just to see if anything jumps out.

Paul
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,355
In the picture of the resistor, I think I see two white wires and one blue one at the opposite end. But it looks like there's a second connector on that end too. Is there another wire, and where do each of the wires go to, and come from?
Is one of those white wires going to the MSD box? If so, is that the full-voltage side of the resistor, or the reduced voltage? I forget what color wires come from the Centech harness (my bad) but if it's the blue one, then it looks like you've got lowered voltage to the MSD and that's not correct.
All connections to an MSD box (and pretty much any other high-end aftermarket ignition too) is going to need the full system voltage to run properly.
The big Red wire obviously goes straight to the battery, so that's not usually a problem, but the smaller, keyed ignition source, which is also red on my MSD, gets the full 12+ volts.
That make sense? Or am I reading the photo wrong?
Let me know.

Paul
 

t.lay

Bronco Guru
Joined
Mar 17, 2005
Messages
1,261
Loc.
Grayslake, IL
Duraspark has the blue connector. As for the why on the resistor - it's my first time at wiring and the instructions said ...

The blue wire comes out of the harness and says ign pwr - connects to red wire out of the duraspark box and on the the starter solenoid. White wire from the duraspark connects to a violet wire labelled start - goes back to harness - then out to solenoid.

p.s. sorry blue bronc - didn't mean to hijack the thread.
 
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DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,355
t.lay said:
Duraspark has the blue connector. As for the why on the resistor - it's my first time at wiring and the instructions said ...

Yep, sounds familiar. Most instructions were written with either old knowledge, or lawyers setting the tone and not wanting anyone to fry anything. Naturally. But of course, you might have a coil that requires it too, so...No problem. With your setup it might be correct. Depends now on the coil. Is yours stock? Or an aftermarket one that's supposed to have a resistor? If so, then leave it in there or change out the coil to one that can handle 12 volts to give you, more power. As Tim Allen would say...


t.lay said:
The blue wire comes out of the harness and says ign pwr - connects to red wire out of the duraspark box and on the the starter solenoid.

Hmm, the part about it hooking to the red wire is possibly OK, but where on the starter relay is it hooked? That doesn't sound right.
And someone refresh my memory. On a blue-grommet Duraspark module isn't the white wire supposed to be keyed power, while the red wire gets the juice only while the starter is cranking?
Maybe I'm wrong. I don't have a diagram in front of me.
But I'm still curious what the wire on the starter relay is. Let me know.


t.lay said:
White wire from the duraspark connects to a violet wire labelled start - goes back to harness - then out to solenoid.

Yep, that's your starter relay energizer (GM color codes of course!) that would also send a full 12 volt jolt to the ignition module and coil (theoreticaly) to help the coil deliver more spark and to tell some modules to retard the timing to help with the starting.
Of course that goes back to my previous question about whether red or white is the starting-only power wire to the Duraspark.
Do you have a diagram that mentions that?

Anyway, we'll get to the bottom of it. Hang in there.

Paul
 
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