74 Duster (318) cranks, but no start. Need help.

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supersoap33

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I'm getting about 9v at pin one on the ignition control module plug and about 4.5v at the coil with the key in the ON position. It cranks but it doesn't seem to be sparking. The car will shake every once and awhile like it's bucking. Idk what's going on with it. I'm going to test the wire off of the positive terminal of the battery tomorrow. Maybe it's not getting to the ignition switch?
 
See post 2 here for a diagnostic
Not getting 12 volts to coil

Then get one of those spark checkers that plug into the spark plug wire. (Yea there are other ways but its like $5, safe and easy to use without a helper)

if its getting half decent spark then its probably timing.

remember theres only three things needed: compression, fuel, spark. if the spark timing is too far off then there isn't compression.
 
supersoap33 said:
I'm getting about 9v at pin one on the ignition control module plug and about 4.5v at the coil with the key in the ON position. It cranks but it doesn't seem to be sparking.
Click to expand...
Did you only check it in the RUN position? Check it CRANKING- with the key- (completely different circuit). Sounds like you may get lucky and it's just the ballast resistor.
If that checks out okay, don't discount the timing chain. You didn't mention if this is a fresh build, or a 150K motor; but the stock timing chain cam gear (mid-late seventies, maybe longer) had a nylon coating on the teeth that was notorious for cracking off and causing the timing to jump off spec.
 
Bucking is usually timing is way out. You should pull a plug, or use a spark tester to check for spark before you dig into the wiring too much. Has the distributor been removed recently? Have you checked for spark at the coil with turning key off/on?

Since it is cranking it is probably not the neutral safety switch or the '74 seat belt interlock box.

Crank but no start can be frustrating, but thankfully the electronic ignition system on these cars is pretty simple, and really only a few components. If it ran before, nothing has been changed, and the wiring is all intact, i would suspect the ballast resistor (burn box) or ignition control module are at fault. The ICM can do some weird things when they're on their way out. I was in a similar situation once with my '74, the car would crank fine, and was sparking, but it would only spark my test plug once every 5-10 seconds, really erratically. Replaced the ICM and the problem was solved.
 
I agree with Post #2 but you can jump out the Ballast and see if it's that. Just don't leave it like that.
 
1....Check for spark

"Rig" a test gap or wide gap spark plug to the coil tower. Use solid wire even low voltage wire "in space." Crank using the key not by jumpering the relay. You should get a nice blue spark at least 3/8 and more like 1/2 inch

2....If weak or no spark, hook meter to coil plus. Turn on key. voltage should range from around 6 ish to about 10V If near battery, near 12V it means module is not drawing current. If really lower it means ballsat is not getting full voltage from key/ bulkhead. Measure voltage at ballast from "key"

3...With meter on coil + as before crank engine using the key. Voltage should be very close to battery cranking voltage, IE 11v or so. You want to see at least 10.5 and absolutely no less than 10

This of course depends on whether battery is down or bad or old etc

4....If you have just installed dist you can check timing on the starter
 
All the electrical components are new... ballast resistor, ignition control module, voltage regulator, coil, distributor pickup coil. Engine isn't a new build. Who knows how many miles it has on it.
 
Grab the crank pulley underneath and try and turn it back and forth to check your slack in the timing belt.
 
supersoap33 said:
All the electrical components are new... ballast resistor, ignition control module, voltage regulator, coil, distributor pickup coil. Engine isn't a new build. Who knows how many miles it has on it.
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Nowadays, new doesn't necessarily mean good. Time to start testing as outlined above. Start checking the starting circuits, and the timing chain.
 
Professor Fate said:
Nowadays, new doesn't necessarily mean good. Time to start testing as outlined above. Start checking the starting circuits, and the timing chain.
Click to expand...
Posted this many times, and it's not just "nowadays"

I remember one time the magnetron started acting up in the GCA RADAR (NAS Miramar) Man!!! We turned to!!! Yanked the transmitter out of the bay and got it outta there while another tech roared over to the supply to dig out the spare. And........the.......spare.......was............no......damn......good. Of course it cost us a lot of time because we had a tough time convincing ourselves that was actually the problem, and not something else that we'd missed.
 
I have a good voltage reading coming through from the battery to the column connector, but testing the brown wire coming back out of the firewall from the ignition switch, I'm only getting 0.7 volts. Then when that wire is plugged into the ballast resistor, it's reading the 4.6v that I also see at the coil with the key in the ON position. This is a 74, so the brown wire also splits as soon as it comes out of the firewall into four browns that go wherever they go.

Should the brown be having more voltage or no?

Also, the connectors going through the firewall seem like they can't come loose. They have this black plastic **** around them like a cocoon.
 
supersoap a direction I'd be tempted to go.............

1...Check your spark I told you how. If there is none, first determine "what you are up against" that is an older OEM "5 pin" module, or a newer "4 pin." A 5 pin MUST have a 4 pin ballast, the 4 pin module can use either 2 or 4 pin ballast. To do this look at the diagram, determine where the module resistor feeds in to the module, and get on that pin with your meter in "ohms" or resistance. Check that pin to every other pin and the module case, then turn the leads around neg for pos and do it all again. If you read infinity at all times, you can assume it's a 4 pin module

WHY!!?? Because this makes troubleshooting easier.

2...If the module is 4 pin, now you can easily "hot wire" it without worrying about the resistor(s). For quick testing you can jumper power to the coil + with an alligator clip wire. If there is any question whether the ballast is good, bypass it on the side feeding the coil. DO NOT leave this all hooked up longer than it takes to test. 15--30 seconds at a time. If the engine is running, you can get away with this for longer periods

With the thing jumpered as above, now you don't have to worry about any wiring or circuits or switches in the car working, because you have fed power direct to the ignition

3...Now you can jumper the start relay to crank, and AGAIN check spark, which should now be VERY impressive, hot, blue, "big."
 
supersoap33 said:
I have a good voltage reading coming through from the battery to the column connector, but testing the brown wire coming back out of the firewall from the ignition switch, I'm only getting 0.7 volts. Then when that wire is plugged into the ballast resistor, it's reading the 4.6v that I also see at the coil with the key in the ON position. This is a 74, so the brown wire also splits as soon as it comes out of the firewall into four browns that go wherever they go.

Should the brown be having more voltage or no?

Also, the connectors going through the firewall seem like they can't come loose. They have this black plastic **** around them like a cocoon.
Click to expand...

I don't know under what conditions you are reading this. With the key "in run" brown is getting feedback from the coil, and it will read "same as coil" plus

The only time the brown is feeding "hot" "same as battery" to the coil is when you have the key twisted to start.

The "cocoon" you mentioned may or may not be foam There are little latches on the connector terminals you can release with a very small screwdriver.

An example of the female side showing the latch
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5950x1b__83941.1423164709.1000.1000.jpg

Latch on male terminal

RdO1EwOlRmOPFsjL3yeas09sqlO-RIN6u0AqtE8f3T1XLTQAdTeCWb3fcikWEJwaDVzXDhXcNYCvkBdeuAN2GfLr7XqBIjwg.jpg
 
Professor Fate said:
Belt?? :poke:
Click to expand...

I've checked play with belts on. If there is slop it will go back and forth. Think about it, am alternator spins easily, same with a water pump and so on. You can still check with a 1 1/4 socket and a breaker bar if you have no muscles. :lol:
 
Kendog 170 said:
I've checked play with belts on. If there is slop it will go back and forth. Think about it, am alternator spins easily, same with a water pump and so on. You can still check with a 1 1/4 socket and a breaker bar if you have no muscles. :lol:
Click to expand...
Kendog 170 said:
slack in the timing belt.
Click to expand...
Have a coffee, Ken! Just giving you a little grief for calling it a timing "belt" instead of a "chain"! :)
 
Don't get too hung up on specific voltage values for every wire. To start with, just see if its sparking at a spark plug when you turn it over. If not, you can jump a hot wire from the battery to the coil just to see if you can get it to start, but as a disclaimer, you'll melt your jumper wire if its too thin and its not something you would want to do longer than a few seconds. I read through your other post as well, and at least hearing it run might give you hope.

Something to consider-
NEW ELECTRONIC 318/340 ENGINE HARNESS 72-73-74 duster/demon/dart USA MADE | eBay
 
Fawkes said:
Don't get too hung up on specific voltage values for every wire. To start with, just see if its sparking at a spark plug when you turn it over. If not, you can jump a hot wire from the battery to the coil just to see if you can get it to start, but as a disclaimer, you'll melt your jumper wire if its too thin and its not something you would want to do longer than a few seconds. I read through your other post as well, and at least hearing it run might give you hope.

Something to consider-
NEW ELECTRONIC 318/340 ENGINE HARNESS 72-73-74 duster/demon/dart USA MADE | eBay
Click to expand...


I think I'm going to give this a shot today. I'll let ya'll know how it goes.
 
Alright, so I tried the Hotwire and got a gunshot backfire out of the carb. Also got a spark tester and I'm not seeing spark from the wire going from the coil to distributor or any wires going from the distributor to the cylinders. The wires are a cheap set, but they are new.

When I first got the car, I tried starting it myself and it didn't start so I had a mechanic come out and he said the timing was 180 degrees out, and he got it to fire up in just an hour of looking at it. It's doing that same **** now too--the backfiring through the carb, etc. Can a car just magically jump timing? I did take out the distributor to tighten up the pickup coil because it was wobbly, but I marked the distributor and rotor and put them back in as they came out. Could I rotate the rotor and see if turning it 180 degrees will get it to fire up without hurting anything?

Also the voltage value at the coil is still about 4.6v. The blue wire coming out of the ignition switch to the ballast is 9.5v. Resistor also got really hot on top (between the brown and blue wires) with the key in the ON position.

Don't know if any of this helps y'all help me diagnose the problem better.
 
If you removed the dist you likely got it wrong. There is NO REASON to screw with "is it" in time or "is it" 180 out. Learn to put the dist in first time every time and then set the timing, and THEN "start it up."

I've posted this hundreds of times

1...Remove no1 plug. "Rig" you starter either jumper the relay with a screwdriver with one hand or get yourself a remote starter button. All parts stores sell them. "Bump" the engine while you have your finger in the no1 hole until you begin to feel compression. You may have to go 'round once to confirm

2..Now watching the timing marks as they are approaching the TDC mark, do NOT set them on TDC, but rather "where you want" initial timing advance

3...Now set the dist in so the rotor points as near to the no1 tower you can get. IF it does not DO NOT worry, use another dist cap tower, or else "screwdriver" the dist gear up and out and move the gear until you can do so.

4...Move the dist CW (retard on a SB) and then slowly bring dist advanced (CCW) until reluctor is aligned with center of pickup coil. Rotor should now be approaching a tower. Put no1 wire in that hole, and run the others around in proper firing order.

If you did this right, if it has spark, and a bit of fuel IT WILL START
 
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