Not getting spark

[Mr.Dean_Yates]

I have a 72 240z, im not getting spark, ive changed coils, ignition, plugs and wires are brand new, idk whats wrong, motor will crank but wont fire...if any one has pics of the wires for the coil pos and neg. any ideas or similar issues please let me know how you fixed it.

 

im running the xr700 because last time i had it she ran perectly...but for some reason nothing is working.

[ggzilla]

You haven't changed enough parts. Keep going, eventually you'll hit on the right part and it will run.

 

Or you could test parts, identify which is wrong, and replace or refasten only what is broken -- all you need is a voltmeter to troubleshoot the ignition system.

 

First, test that with KEY ON, engine off, there is 12V to one side of the resistor.

2nd, test that with KEY to START, there is 12V to the coil + terminal while engine is turning. If you only get 9 or 6 or less, that's a problem.

[Skib]

if yours still running a points dizzy check the condition and gap of the points.

[datzenmike]

You haven't changed enough parts. Keep going, eventually you'll hit on the right part and it will run.

 

 

 

Yeah replace the battery next. :lol:

 

Get a good $5 test light. It has a small length of wire with an alligator clip and looks like a screwdriver with a bulb inside and with a point on the end. Clip the wire to a good ground and touch the point to anything with 12 volts and the light goes on. Great for following power or finding the lack of it.

 

Clip it to the positive terminal of the battery and touch the other end to the negative side of the coil. Crank the motor and the light should go on and off. If it stays on the points are not opening. If it doesn't light the points are not closing.

[Mr.Dean_Yates]

I'm not running points, I have a multimeter, just ran outta daylight and time. Again I am running the xr700 ignition system, I'm thinking there may be something I forgot to ground, does anyone have experience with this ignition set up?

[banzai510(hainz)]

YOu you have power at the blk /wht wire with the key ON??? this usually goes to the ballast resisitor.

then go to the other side of thr ballast resisitor and you should have about 6-8 volts.

 

then there should be another wire at the coil. This will be the hot start wire. You will get 12 volt when key in START.

How I ck this is remove the wire from coil then put the key to start.

(I do remove the wire from he starter so it dosnt crank the motor)

 

Now if you have this the POWER SIDE is OK.

 

I asssume you ck for spark using the center coil wire to ground??????

 

Now if still no spark I assume the mudule or reluctor inside the dizzy is not working thus not making the signal to the - side of the coil. (as the - side is the trigger)

 

Im not a XR700 user or know how to trouble shoot them Im sure you can look this up. Ck or clean connections.

I dont know if a XR700 needs the Ballast resisitor or not in the system. Most systems DO as to run the POINT OHM SPEC COIL.

[ggzilla]

Yes XR700 is pretty simple. Ground, power and pickup/trigger wires are all it needs. It fires a stock-type coil with ballast resistor. Without external ballast resistor, the XR700 will overheat and fail. Better than points, but not a high energy system so not as good as a 1978 Datsun system. XR700 power comes from the the coil + terminal, so if coil doesn't get power it doesn't work.

 

But rather than guess what the problem is (guess it might be the XR700 maybe?) ... why don't you troubleshoot it?

[Mr.Dean_Yates]

I figured it out, just havent had time to correct it.

 

with the crane cams optically triggered ignition system, theres a shutter and its completely off time. the shutteres are not lining up with the optical module therefore not getting spark...after i get this finished i think im going to do a write up on the CraneCams Optical Ignition.

[banzai510(hainz)]

theres a shutter and its completely off time???????????

 

even if its off time the the shutter passes the optical trigger it should spark. Now weither its sparks at the right time as the piston is reaching the top of the cylinder is another story.

Meaning if you pulled the dizzy out and run a ground wire. you spin the dizzy with your hand it should still spark if power is suppley to the system

[Mr.Dean_Yates]

theres a shutter and its completely off time???????????

 

even if its off time the the shutter passes the optical trigger it should spark. Now weither its sparks at the right time as the piston is reaching the top of the cylinder is another story.

 

Yeah, motor is tdc, rotor is in first fire position, optical trigger unit is in between the shutters. no spark.

 

reset and re aligned everything...still no spark

 

my ignition is getting power but idk why im not getting spark...

 

possibly the ballast resister...i honestly dont know anymore :crying:

[datzenmike]

What method are you using to sell if there is spark?????

 

The ballast resistor is only used in the ON or RUN position... you should have spark on START.

 

With the key ON, momentarily ground the neg terminal on the coil and the coil should fire.

[banzai510(hainz)]

With the key ON, momentarily ground the neg terminal on the coil and the coil should fire.

 

Mike when you release the ground the coil should fire

 

grounding charges the coil. then release will collaspe the coil.

really a minor issue .

 

my ignition is getting power but idk why im not getting spark...?? maybe its just broke

 

S30kid,

a spare point dizzy might help troble shoot this better if you have one lying around.

But in my post it should work if you ground the dizzy and just spin the dizzy by hand and see if you get spark out the center coil wire if placed near the chassis.

 

figure 19 is what you want I think

http://triumphspitfire.com/images/cranemanual.pdf