Justin Ward

Hello, I have bought a 73 duster great shape, We had the engine running good timing very close, But went to turn the car over the next day and it just cranks??? I checked for spark I have none, there is power to my coil but the light on the light tester isnt very bright. I was told by a couple old timers theres a ceramic resistor??? Could this be it. Also park will not engage and i can crank the car over in any gear? Im new to this overhauling a car but this car is great with no rust and a awesome 440 r/b is in it now with shumacher headers, holly intake, gentle cam. Please help gettin frustrated and want to quit.

Archer

JW -

Normally the ballast resistor(s) would be the first thing to look at and the ignition control box the second. (The 73 should have an electronic ignition.) But you said, that there was "a little" light from the tester, a blown resistor would result in NO spark at all. Just to confirm, did you check for SPARK coming form the coil?

Assuming you have a automatic trans, you may have a bigger problem if it won't go into park. It could be the linkage or something in the tranny itself.

The two issues are probably NOT related, in case you were thinking it was the neutral safety switch. If that was engaged, the engine wouldn't even crank. So, there might be a NSS problem, but that's "probably" not causing the lack of spark.

Sorry about the headaches, but welcome aboard.

Archer

Justin Ward

Thank you very much I will try a new balist resistor today and let you know.

440roadrunner

Several things to check

FIRST when you are cranking the engine, a separate contact in the ignition switch sends "HOT BATTERY" to the coil +. So "rig" your meter to the coil + and prop it up so you can see it

and crank the engine USING THE KEY. You should get close to "same as battery" voltage and in no case less than 10.5V

If that is OK, test the resistor, which is TWO resistors side by side if you have the 4 terminal resistor -- and test both sides.

A simplified diargram from MyMopar:
http://www.mymopar.com/index.php?pid=31

In the diagram below, the top two terminals are jumpered together and go off to the IGN switch. Turn the switch to "run" and use your light on the other two terminals to make sure you have voltage there. You will have "something less" than battery voltage.

http://www.mymopar.com/downloads/Ign...ystem_5pin.jpg

If the above is OK, pull the distributor connector off and work it in / out to "scrub" the connections clean. Do the same thing with the ECU connector.

If you have no spark, examine the reluctor / pickup for debri / damage/ dirt. Check the reluctor gap, which must be set with a .008" brass feeler ga. O' Reallys stock these, believe it or not

Take your meter, on LOW AC volts, and hook to the dist. connector. Crank the engine, and the dist. pickup should generate about 1 V AC.

If all the above is OK, replace the ECU.

IF you are not a restore freak, and the ECU is bad, you might consider converting to a GM HEI module. They are easy to wire up, you usually do not need your ballast resistor, and you can trigger them with the factory Mopar distributor.

Justin Ward

Thank you Im going to purchase a new resistor at lunch and see if it helps if not I will follow your help

Archer

JW -

Just remember that the ballast resistor is also called a "burn box" for a reason. If you try cranking the engine for a while and the resistor is good (at least one resistor core), it will be hot.

Archer

Justin Ward

Hey thanks guys, I took my old resistor off and it fell into two pieces I am thinking that was my problem lol. I have my new one and will have it in tonight, Also I have been told my times should be at 8-10 at idle. Does this sound correct Last night before the resistor failed i was running 15.5 at 2500 rmp. I have a mild cam, holly highrise intake and headers.

PK1

What cam specs and what are you pulling for vacuum?

Justin Ward

Ok so no luck I still have no spark, and put a new resistor on??? ughh

Archer

JW -

I had the same problem a few months back. Definitely try the stuff that 440 said, but in my case it was the ECU and replacements are in the $40 - 60 range for the HP Mopar stuff. (I'll stick with Mopar...) Dropped in a new chrome box, and it started right up.

Archer

Justin Ward

Ok I have a update.
I noticed the guy before had hooked up the power and ground backwards on the super coil. I did have the car running trying to set the timing. I also started tracing wires and found 3 horrible connections I am going to redo them tomorrow . Im wondering do you guys think my coil is toast now? Being hooked up opposite like that? I noticed when the power was off the coil theres lots of power but as soon as I hook it to my coil its very slim. Im hoping thats a simple wire redo.

440roadrunner

Only thing hooking a coil up backwards will do is reverse the polarity of the spark, and may knock down the output voltage some, may wear plugs oddly. Just turn 'er around correct.

You have a correct diagram?

Archer

JW -

The problem is that it was running and now it's not, so something had to have changed. The bad connections seems like a likely cause.

Archer

440roadrunner

This is WAY too high

There are several possibilities for overcharging:

A bad battery

bad ground at the regulator

Bad regulator

VOLTAGE DROP in the IGN harness

SO do thest tests:

Turn key to "run", engine off. Set your meter on "low DC volts." Put one probe at the "ignition run" side of the ballast, OR on the blue field wire at the alternator. Put the other probe directly on the battery POSITIVE post. You are measuring "voltage drop" in the ignition harness, and if you have MORE than .2V (two TENTHS of a volt) you need to find out where this drop is

The circuit path for this is battery -- fuse link -- bulkhead connector -- ammeter circuit -- ignition switch connector -- through the switch -- back OUT the switch connector -- back OUT the bulkhead connector on the BLUE IGN run buss -- to the IGN system, the regulator IGN terminal, the blue field wire at the alternator.

Your top suspects for the cause of a drop in this circuit is the BULKHEAD CONNECTOR, the IGN switch connector or the switch, or the ammeter circuit. In a few cases , the "in harness splice" shown in the MAD electrical article breaks and can cause this problem.

NEXT start the engine and get it running on a fast idle. Put one probe of your meter on the battery NEG post, and the other probe directly on the regulator mounting flange. Be sure to "stab" through any chrome, paint, or rust

Here again, you are looking for voltage drop, a very low reading, the lower the better. Anything over .2 (two tenths) of a volt means the regulator is not properly grounded

A simplified diagram:

which came from here:

http://www.mymopar.com/index.php?pid=18

Start at the alternator field, the blue/ white wire, and follow it back to where it "Y's" into the blue from the regulator "I" (IGN) terminal, and then goes to the ballast. Then note that it goes up to the IGN switch. This is the simplified version, but is the circuit path I was talking about above.

IF THERE is a voltage drop in either the ground circuit or the IGN harness, it will cause overcharging.

Justin Ward

I have lots of power out of the wire that goes on positive on the coil but when hooked to coil very small power when tested and no power threw the coil wire. I have checked my grounds and positive. they are good. I have also tryed a new coil.??????????

bremereric

Pull your distributor and test your pickup coil. You need and ohm meter. A digital one would be nice. Place the probes into the distributor connector and spin the shaft. You should get like 3 or 4 ohm then open....then 3 or 4 ohms then open as you spin it. If you don't your pickup coil is burned up. Happened to me with a brand new distributor.

440roadrunner

Sorry Brem that ain't quite right. A pickup coil is just that -- a coil. It never should "go open" on ohms.

The distributor is a tiny AC generator. Set your meter on lo AC volts and crank the engine or spin the shaft. With the voltmeter leads hooked to the dist connector, it should generate about 1V AC

Justin Ward

I tryed a new coil for hell of it, still no spark, 440 what your saying about checking with distributor how do I check what your saying, I am very new to the wiring and electrical, I need a good break down. I have tryed new balist resistor, new coil, fixed the hack connections in the wires, new ecu. Lets start from the beginning. I bought the car had to put new headers on and a mini starter. We had it running for 2 nights playing with timing, but on the third night I would turn the key and nothing but a slight slight click, after 10 min tryed again and it fired up. then another 20 min and No spark. so I changed my balist resistor tryed and none still. I tryed a new coil. Nothing still. Re did the hack wiring and sautered them together good. still no spark. The ecu is new. I have good power to the power wire, and good ground to the ground wire. but when they are hooked onto the coil there is no power to the coil wire<and the the plugs> to distributor. Im so lost and am a rookie when it comes to the wiring I need a real break down and help....

bremereric

I will get my MSD distributor tomorrow and spin it for you 440.

bremereric

Here's some more help for you. A points distributor acts the same as a magnetic pickup coil so you will have the same results.

http://www.youtube.com/watch?v=bl0Z6...feature=relmfu

http://www.youtube.com/watch?v=e66tA...feature=relmfu

Justin Ward

I did the first test video 1 and my test lights up but very weak, when i crank engine does it light up it on-off-on-off????

Justin Ward

I also notice when cranking the engine the distributor moves around a bit, ive never seen that before its not alot but its noticeable.

Justin Ward

But it did run before this problem, and it ran well with the distributor that it has, By chance could it be the ignition on the column inside the car, it looks easy to take apart and clean.

Justin Ward

I just did another test. I attached test light to negitive on battery and test light to positive its suppose to when cranked blick....test light is on bright it run and when cranking dims out? Also when test light end hooked to neg. on battery the test light turns on, on both sides of the coil....

Justin Ward

Using test light connected to body ground, probe coil POSITIVE WIRE with coil disconnected from it. - Bright in CRANK, dim in RUN.


Now, hook the coil back up. At the wiring harness connector that plugs into to the ECU (ECU unplugged):


Terminal 1 - Bright in RUN, dim in START.

Terminal 2 - Dim in START, even dimmer in RUN. - no light at all means open coil. circuit.
Terminal 3 - Dim in RUN, even dimmer in CRANK.

If these tests are good, the ballast resistor wiring and ignition switch are OK.

Terminal 4 and 5 - probe with OHMMETER for resistance through pickup coil and back. Should be 150-900 ohms.

If all this checks okay, inspect for correct pickup gap inside the distributor using a plastic or brass feeler gauge. Spec gap is .008 and no more than .010 with vacuum applied to advance canister.

Check the resistance between pin 5 on the ECU and body ground. It has to be less than .5 ohms. If it's more, clean and remount the ECU. If still shows resistance then ECU is bad.

Lastly, check resistance between pin 5 on the ECU and the battery negative terminal. If resistance is found then repair the battery body ground


I did all these tests and all passed also On the last test with pin 5 i have nothing show up on ohm meter so i take that as a pass for the ground, if i got anything over 0.5 ohm i would have to relocate or make better ground to ecu and body right?

440roadrunner

No need, you can test the supply voltage under the hood. If it's not OK, you MAY get to that point, you need to eliminate the bulkhead connector --a much more common cause--first


Sorry, I don't get what you are doing, here

You sound like you quoted this from somewhere --- where did you get all this?

For example, checking voltage at the coil + wire with the coil disconnected PROVES NOTHING. This is because there is no load on that wire from the coil.

440roadrunner

I'm not saying it won't affect the ohmmeter reading, I'm saying the reading is meaningless.

This is a COIL. It cannot "open." If it is open or shorted, or shorted to ground, or out of specified resistance range, it is bad.

But when you spin the dist, you are GENERATING an AC signal. This injects AC power INTO the ohmeter, which THEY ARE NOT DESIGNED for, and cannot measure. If the ohms reading is "going open" when you spin it, it is simply because the AC pulses are adversely affecting the meter.

So to summarize, there are two tests you need to do with any magnetic trigger type dist.

ONE is the specified resistance of the pickup coil, and whether it is shorted or leaky to ground

SECOND is if you do have a figure, to test for pulse output when turning the shaft.

This output is affected by such things as rust/ debri/ junk on the trigger wheel (reluctor), as well as problems including moisture in the pickup. It's affected by the reluctor gap, which has been mentioned, as well as DAMAGE to either the pickup coil or reluctor from mechanical damage.

Frankly, for a budget electronic system, I find the use of an GM HEI module VERY appealing. It's small and cheap to carry a spare module, you don't need a ballast most of the time, and so the 4 wire hookup just makes troubleshooting all that much easier.

Justin Ward

I took my distributor off today and noticed the piece under the rotor, it looks like a tractor tire ( sort of) its got lugs there was a pin broke that hekd it in place to spin on the shaft, i replaced it, and still nothing... Im so close but not. Also the resistor gets hot hot! i tryed cranking for 3 seconds about 4 times and its so hot i cant touch it!

440roadrunner

That's called the "reluctor." About that pin. Notice there are TWO grooves in the reluctor, and should be an arrow on top of the reluctor. The one you want is the arrow going to the right, IE your distributor goes CW. The left arrow is for the B/ RB engines

In the photo below, the pin is installed in the lower slot, at the "left" (CCW) arrow. This would be INCORRECT for a small block

Justin Ward

This is a pic of my distributor cap off, and of the 4 point ecu. Now I had a huge problem! I read over and over and over the wiring map for this, and i switched two wires and had key in on position for 20 mins i was outside garage, and coil EXPLODED! so now I have the wires back like they were, the tape i took off the wires I switched have been like they way they were for years and years I should have not switched them, when key was on the coil got very hot, the ecu and ballist did to, so I will order new ballist, ecu, and voltage regulator. I have another new coil. Should I just take this thing in! Im so stressed out. I can not get spark and dont wanna wreck more things
Is my reluctor going the right way I have 440 r/b big block