When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Went to start car (66 with 427/425) and would spark only occasionally with intake flame only when key is released but otherwise will not start. Replaced transistor ignition module with no change ... any ideas? How to test distributor, coil etc.?
Stang - Welcome to the Corvette Forum. You do know it's a requirement for new folks to post pics of their Corvette...right ;-).
I saw you mention you own a 66 L72. We have a long running thread you might be interested in joining, or at least reading through.
It was started a few years ago when another Arizonan bought his Nassau Blue L72, about the same time I bought mine.
The thread has about 56 or so owners who've joined in posting pics and telling us their 66 L72 stories and posting pics.
We even have some folks from overseas like Sweden, Switzerland, Germany, France and the UK and I'm expecting a couple from Australia.
Some are bone stock, others not so much, but some great reading on all of them. Hope you check it out.
Here's the thread. C2 1966 L72 count - CorvetteForum - Chevrolet Corvette Forum Discussion
Mike T - Prescott AZ
I went through this a few years. Seems my problem was probably a ground issue. But lots of testing and input by TI guys contained in the thread. Pay particular attention to info from Rich5962 as he knows the TI system inside and out. Good luck.
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
The way the (original) circuit board is designed is that the coil is always turned on when there is power applied to the module, and the circuitry then uses the negative voltage swing of the distributor green wire (of the magnetic pickup) to momentarily(!) shut off the coil primary current (causing the coil/plug to fire). If the negative voltage swing magnitude is insufficient due to slow cranking RPM (or apparently, in some cases, due to the starter solenoid R terminal voltage raising the static DC voltage of the distributor sensor "too high"), then the waveform negative swing can't shut the dwell off, and the result is no spark until the starter circuit is released, or the ignition key is turned off.
IIRC a member or two here have run into this situation like you're seeing, and were able to get useful debug information by temporarily disconnecting the R terminal wire and then doing a cranking test. This gets rid of the change in sensor static DC voltage which removes one possible culprit, and it also allows the measuring of system/coil voltages to see if the ignition switch is feeding sufficient voltage to the module while cranking.
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Slideshow: A Jaguar designer's personal project imagines what a modern front-engined Corvette might look like if Chevrolet revisited the golden age of the Stingray.
Ignition issue, need some advice
