Engine runs fine but seems to seize after wot

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In post #41 you said it cranks and has spark.
-I re-read the entire thread and didnt see what youre running for an ECU.Assuming; its a factory type,AND all the wiring AND the ballast resistor are ok,then the only test I know of is the "one spark test".
-Pull the coil wire out of the cap and rig it up with a gap to ground where you can see it from the drivers seat. Then turn the key to run, and then off. Every time you cycle the key it should spark, one time.Do this several times.You dont need to crank it for this test.This proves the coil and all the "run" wiring, including the ballast resistor, are ok, and PROBABLY the ECU as well.If no spark, clean the ECU ground. If still no spark, either temporarily bypass the B-resistor or sub in a known good one.If still no spark and, Again, assuming the wiring is ok,test the coil. If the coil is ok, replace the ECU.
-FYI; the ballast resistor is probably the weakest link in the system.I have experienced multiple failures of those, and Always carry a spare.
-Here is a simple coil test;Remove the wire from the coil negative terminal.Rig the coil hi-tension wire as before. Find a jumper wire, ground one end, and bring the other end to the coil. Turn the ig key to run.Now, take the bare grounded jumper wire and strike the coil neg. terminal, several times. Sometimes its easier to clip the jumper to the coil neg. and strike the other end to ground instead. A good coil will send a spark at every strike.If you cant get the hang of striking it, try this:first make sure your jumper wire has only one strand poking out by folding any other ones back.Next lightly rub the wire ACROSS the threads on the neg. stud. As the wire jumps from one thread to the next it will connect and disconnect, sending a stream of sparks across the rigged spark-gap.You can also do this by clipping the jumper to the coil neg. and rubbing the bare end across a metal file that is grounded back to the battery or engine. This works really well, sending a stream of sparks out the coil tower.Of course, you could ohm it out, too; but its not nearly as exciting as watching those sparks.
-Next, turn the key to crank and rotate the engine. If you see a steady stream of sparks this proves the ECU and crank circuit and mag trigger are working. If it fails either test, clean the ground between the ECU case and mounting surface.The ECU must ground back to the battery. The ECU needs about 5 to 6 volts minimum.The coil likes a bit more.If it still fails the Cranking test you will have to check the mag.trigger.
-So pop the cap and rotor.Now find the trigger unit.(Here is a short explanation of how that piece works. You see that little projecting strip of metal thats pointing towards the dist shaft? Well when the power is on and the trigger is working,then every time something IRON passes by it,it will send a signal to the ECU to make a spark. It doesnt care if the thing passing by is the reluctor tooth, a feeler guage or a screwdriver blade.If iron PASSES BY it will send the signal.So now, lets get back to the set up.) I usually rotate the engine to put any reluctor tooth just approaching that trigger projection,but not aligned, in such a way that I can manually rotate it past the projection against the advance weights. Next rig the coil wire back up as before with a small gap to ground. Go turn the key to RUN. Come back, grasp the reluctor and rotate it past the trigger.If the trigger is ok it will cause a spark every time the tooth PASSES BY. You can remove the trigger, hold it in one hand,and, with it still energized, pass something iron in front of it, and it will send a spark signal.It doesnt matter the direction, or speed, or if the iron momentarily touches it; as long as its moving past the projection.
- Now if it fails to spark, but it passed the "one spark" test, then you will have to test the trigger coil.Some guys like to ohm them out, but that means you have to know the spec. for one thing and assumes it will still function when energized. So I like to do the voltage output test.Simply put the analog ohmmeter probe clamps on the disconnected ends,set the selector switch to millivolts, and pass something iron past the projection.If its ok,it will it will send a signal every time the iron or tooth passes by.If you have a digital meter,you can catch it with the peak-hold feature.Without the peak-hold, you will have to interpret the results carefully.
-Now, finally, if the trigger passes; by process of elimination the no-spark condition has to be the ECU.
-Or you could just plug in a known good unit, back in the beginning. I used to carry a spare ECU and trigger in the glovebox. After several years with no trouble I removed the ECU to the shop.I did have a trigger failure once, about 10 years ago. In 45 years of running Mopars I cant remember ever having an ECU failure.Others here havent been so lucky.
-Oh yeah,When you rig up for the spark test: A) dont set your car on fire by sparking too close to a fuel source and B) dont spark yourself.You will be "shocked" to find how quickly and how far you can move,and bang body parts into immoveable objects.The shock doesnt hurt that much, but the sudden stop when your head or elbow hits something sure can.
-So to recap;the only test for a factory type ECU is the "one spark" test, and then process of elimination.
 
Going to make sure batt is good. Then pulling plugs to ck for deposit. Then ensure 1 tdc and verify rotor matches position. Then try to start. If nothing then I will ck open air spark. Then idk. I guess ck grounds and box gnd. Orders a blue hi rev box. Ballast is good
 
So after some research and much needed info from you all, I got it started. Turns out that the gas tank was low enough to not get fuel to carb but no so low that the gauge indicated. Also there is too much resistance in the wiring going to the ign switch but works when I jumper the starter switch. It starts but there is a chirping coming from the engine while running almost like a belt but more like a chirp.
 
I'm guessing take off the oil pan and check?
 
You called it dude. Nice diagnosis. #1 rod bearing spun. Does anyone know if an x on a rod bearing means it's a std size because there is no 10 or 40 etc
 
Glad I could help, when ya get it back together, take it easy on the ol boy, it`s 40+year old tech. not a modern crotch rocket! Don`t free rev it WOT!
Enjoy:glasses7:
 
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