No Spark

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bobscuda67

bobscuda67

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So I'm driving along Thursday about 10 miles from home and the car just dies, no sputtering, just like the key was turned off. On the side of the road I tried replacing the EUC with a known good Mopar orange unit and the ballast resister. Didn't work. Tried wiggling some wires,no go. Checked the ground too. Disconnected my tach wire and that didn't help.
Called AAA and had it brought home.
Got to looking at it Friday and have some test numbers
The pickup coil in the distributor was .320 ohmns.
The coil measures at 12,370 and it is .9 pole to pole. I also have 10.57 volts at the coil's + pole with the key on run. That is with the FBO ECU which does not use a ballast resister. The coil is an FBO unit too. The coil wire tested ok.
I checked the bulkhead connector at the firewall, all ok. The ignition switch is 20 years old but has not been used that much. It seems ok.
Where should I look next? All of the ignition parts are only couple years old and hardly used, they maybe have 600 miles on them. :banghead:
 
So it still doesn't start?

Do you by chance have a different coil you can try?
 
Whoops, forgot to mention that I did replace it with a known good coil that I carry with me.
Still no fire. I did recheck the voltage at the + coil pole and it was 12.57 volts.
About ready to go under the dash, ugh.
 
Grab your digital volt meter... set it to 2K ohms.. disconnect the 2 wire plug at the distributor, you should have around 800 ohms, give or take.. anywhere between 600 and 1,500 ohms is usually OK.

Before you disconnect the volt meter, flip the setting to 2 volts AC or 20 volts AC range... crank the engine if the distributor is in.. spin the shaft if it is out... for the system to work, you need to see over 1 volt AC.
 
Where are you checking the spark? From the coil or a plug? Have you manually grounded the negative coil post like a set of points to see if you can create a spark? Rotor arcing to the shaft perhaps?
 
I have a spark plug removed to check the spark. I have .321 ohms on the distributor leads and my multi doesn't have a AC setting but when I set it for tone it clicks when I spin the shaft.
A couple pics of what I have. The ballast is a dummy And the coil is from an earlier version of the FBO ignition. When I bought the new ECU Don said that I should be able to run the older coil and not the Pertronics 40011 they recommend now.
I have it mounted on it's side with no resistor, I wonder if got to hot?
 

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Oh, and I did replace the rotor, the one that was in it looked ok. Still no fire though.
 
Are you sure it's .320 ohms or .3K ohms, big difference. The resistance varies on these, somewhere between 200 and 400 ohms. If it's actually .3 something ohms, that's a fraction of one ohm. If it's .320K that is 320 ohms and is OK

Make sure the box is grounded. Disconnect everything from the coil such as tach and radio condenser. Make SURE the box is grounded.
 
I just like to check at the coil so that I can eliminate component by component....
If you can make a strong spark by momentarily grounding the coil you know right then the coil and power to it are not an issue.
 
Yea, on the 2k setting it was .321.
I checked the ground between the box and the negative battery terminal and it's grounded.
 
Ok Bruce, I get .9 AC volts spinning it as fast as I can by hand. It might have hit 1 volt a couple times.
 
bobscuda67 said:
Ok Bruce, I get .9 AC volts spinning it as fast as I can by hand. It might have hit 1 volt a couple times.
Click to expand...

Should be good. Lot's of times the pickup coil goes bad in these which causes the symptom you have.

What was the air gap set at on the reluctor? It should be .008 with a BRASS feeler gauge.

Once you have eliminated coil, pickup coil etc, then you can move along.

I had a Dodge van that gave me fits until I finally figured out it was the pickup coil. lol. I would be driving down the road and it was like I reached up and just turned the key off.
 
I just checked a good known distributor I have for the OHM's reading, one was around .321, and the other was .581.

I'm not sure why they vary so much, but your readings appear to be in the "good" range.
 
I just re-read the one post above about the ballast being a dummy. I assume it's acting as a jumper between the two wires.

Did you by chance check continuity between the two posts?
 
Well I checked the gap on the reluctor and pickup, it was between .018 to .020. Don't know why it was that wide. Reset the gap to .008 and retested. I get 1 to 1.2 volts AC out of it now spinning it by hand.
The ballast is a dummy with a wire instead of a winding in it. I didn't like the jumper that came with the FBO ignition. The continuity is good. I also did reinstall my entire Mopar orange box system, coil and ballast and it still didn't run.
 
I know Trailbeast had an issue with the actual connector on the distributor...
 
I don't remember "if this works" because you have an aftermarket ECU

Leave the key in "run." Pull the coil wire to look for spark. Take the harness side of the distributor connector and touch the bare end repeatedly to ground. ON A MOPAR box you'll get a spark each time.

If you do, I'd think you have a distributor problem. If you don't it might mean something else or might mean "this box doesn't do that."

Check coil voltage "key on." What do you get?

============================

If you have a tach connected, unhook it. You only want one wire to each coil terminal, the ones going to the box. No radio cap and no tach

THE PROBLEM is this is not a Mopar "look alike" box and I don't know if "normal" diagnostics apply.

Example........on a Mopar box, "key on" coil NEG voltage is quite low, 1/2--1 volt because the coil is drawing current. I don't know if this one does so.

Sorry.......edit.........see you subbed an orange box.

I would put the orange box in until you fix this.

Suspect a harness/ connector problem.
 
Ok after resetting the reluctor and polishing it up a little it started instantly with my orange ECU backup ignition. So I reinstalled my FBO ECU and coil, no start. Replaced my FBO coil with my Mopar coil, didn't start. Went back to the orange box and it started.
Looks like I need another ECU.
I have been testing the harness and connectors, but they all seam good.
I liked the FBO box as it made the car idled better over the Mopar orange box but I think I'll change ECU's.
I want to thank everyone for helping me out.
 
When you said "ground is good" in post #11, how did you verify that? You can't just look at it. You need <1 ohm to BATT-. I see just a sheet-metal screw in the photo, which causes endless problems for people. Try grounding the case of the FBO ECU with an alligator jumper before you condemn it. If that works, run a dedicated ground wire (everyone should).

Unless you have a "ballasted coil" (>2 ohm), you will need a ballast to run that coil. Otherwise, it will get real hot after 5 min and start melting the paint on it, like one did when I jumpered 12 V straight to drive a new purchase home. Also, the orange ECU probably won't live long without a series ballast to the coil.
 
BillGrissom said:
When you said "ground is good" in post #11, how did you verify that? You can't just look at it. You need <1 ohm to BATT-. I see just a sheet-metal screw in the photo, which causes endless problems for people. Try grounding the case of the FBO ECU with an alligator jumper before you condemn it. If that works, run a dedicated ground wire (everyone should).

Unless you have a "ballasted coil" (>2 ohm), you will need a ballast to run that coil. Otherwise, it will get real hot after 5 min and start melting the paint on it, like one did when I jumpered 12 V straight to drive a new purchase home. Also, the orange ECU probably won't live long without a series ballast to the coil.
Click to expand...

I tested the ground with a multimeter but I will make a ground strap as you suggest before I order a new ECU. The FBO box does not require a ballast. I have an older version FBO coil I was using with the new FBO box. When I ordered the new ECU from Don he told me I didn't need a new coil.
Yes, I have a 1.8 ohm ballast resistor I use with the Mopar orange box and Mopar coil.
I think I bought the ECU in 2013 sometime, I'll have to look for my paperwork.
 
I installed a ground strap to the FBO ECU and it still no go. Put the Mopar box on and it started.
In testing for the ground I did notice that the Mopar box has the distributor's dark brown with white tracer wire pole grounded to the case. And the FBO box has the other wire grounded to the case. Does that make any difference?
Found my paperwork and I bought it in March 2014. I'll call and see if they'll warrant it.
 
The FBO is a completely different box. One or more of the members here hid a GM HEI inside a Mopar box. In essence the same idea. The box looks similar, but the internals are different.

So no, I would not assume the grounded dist. wire is comparable. That is why I was not sure on test results, AGAIN referring to HEI which I'm familiar with, example:

On the Mopar system, "key on" coil NEG should be quite low because the box by default grounds the coil NEG terminal. This pulls current through the coil, and pulls down the coil + voltage through the ballast, making the coil+ voltage "some" low, around 6-8 volts perhaps

A "normal" HEI in the same setup is completely different........with engine stopped and key on, the HEI does NOT conduct. This means the coil is shut off, it means that coil + will be "same as" battery, and that the coil NEG terminal will also be high with battery.

Until the "inventor" of the FBO box comes up with some meaningful information on diagnostics for that system, you cannot assume much of anything
 
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