88 Caprice won't start cold

Hello Everyone, I’m new here hope someone can help! In the 14 years I’ve owned my ’88 Caprice I’ve never had any major problems. She always started and always ran very well. I’ve regularly maintained her and have done minor tune-ups. She has 425000 km’s on her 305H engine. Recently, after a long trip of 2000 miles, from which she ran well all the way, I could not start her. It was after she had been sitting for 3 days. Gas is present (carb rebuilt 1 year ago), and spark is present. Turns over but won’t fire up. While a helper cranked, I rotated distributor CCW and Voila she started! After heated up I readjusted timing to 0 BTDC. Next day no start. I repeated last procedure and she started. Suspected timing chain. Changed it and dist cap and rotor. Still won’t start cold. Changed EST module and tested pick-up coil and resistance in ignition coil. All passed. At wits end. How can the motor start when manually rotating dist while cold. Another thing, typically when the car was left after a day at the office (8 hours), she would always start after ½ cranking (very efficient), but during my present problem even after I succeed in starting her with the above procedure, after ten minutes of running (smoothly, I might add), it took about 4 cranks of the starter to fire her up.

In my not-so-expert opinion, it sounds like the ignition control module (under the distrib cap, has two harnesses connecting outside) is failing. If indeed, this is the problem, and unless you have an affinity for being stranded in the middle of nowhere, buy ONLY the AC/Delco replacement. Wells (Autozone) are especially horrible.

Thanks, I thought that too, but EST module has been changed. Look, everything that has to do with "timing" mechanically has been changed or checked and the gas end seems to be ok (gas squirts thru the jets). In my limited expertise, when a car works every day for 20 years (14 of them with me) then poof nothing- it must be electrical or electronic. Now we are in the colder days of November here in Montreal (typically 0 celcius), and I'm about to store the car for winter. Should I consult a GM mechanic? Are there still ones with this old-to-new design technology?

When you were adjusting the timing, did you disconnect the EST wire?

If not, ou may have it so far off that the car won't start.

Blue Car is now working fine. It was the ignition coil. Although I did test for opens, resistance and grounds, the output voltage (something I cannot verify) was not up to par. After my question was posted I decided to speak to a seasoned GM mechanic who definately knew his stuff. After hearing the symptoms he suggested the coil. Although there was a spark, it was not strong enough to start a cold motor. He told me the reason she started when I "de-timed" the dist (advance or retard) was because the explosion would occur when the compression was not at its highest (either after of before TDC). The lower pressure within the cylinder at this point allowed the inefficient spark to ignite the gas. Basically a cold, high compression mixture is more difficult to ignite than a warm, low compression one. Once she was warmed up and re-timed she worked. Of course, the next morning it happened all over again. I have written this so as to aid anyone else out there whose engine parts seem to be in working order yet the engine doesn't work. Sometimes what we see isn't what is!

Thanks to everyone who helped,

Gratefully,

Blue Car (1988 Chevrolet Caprice Classic LS Brougham)