Perplexing no-start issue (Page 2/3)
Yorgle OCT 21, 03:57 PM
Update- no start again this afternoon but I saw that the tach worked while the engine was cranking- about 400-500 RPM. For the heck of it, I stuck the timing light on the #2 plug this time and it still didn't start. Stuck the light on the #1 plug and it started. Very strange.
Gall757 OCT 21, 09:40 PM
New spark plug wires? Cracks in the insulation will sometimes prevent sparking...especially in high humidity.
theogre OCT 22, 12:33 AM
Now Find tach filter and pull the plug and leave it.
Is "bolted" on 1 of trans bell housing bolt head.

even if tach works filter can cause problems.

If still happens
Buy new plugs, wires and cap/rotor set. New parts you have can "die."
Before buying cap... check center part hits the rotor... that must have a spring and easy pops up when pushed in.
If that doesn't help save the olders as spares.

What plugs do you have? Gimmick plugs claiming add HP etc and some others can fail.
AC Champion Autolite & other "basic" plugs or their platinum tip are good and cheaper them some others and most shell made so won't rust.

If still happens buy a coil. Wells/WVE or Standard Blue Streak (Not Standard w/ T at end of part #.)
Make sure is bolted to engine w/ OE coil bracket. "iron" core needs good grounding or that can cause weird problems even tho not connected to the windings.
In fact If coil you have now is loose rusty, fit that before buying new coil.
Yorgle OCT 25, 01:15 PM
Ok, now things are worse I disconnected the tach filter but after several trips, it quit and now she won't start at all- even with the timing light connected. So I replaced the plug wires and reconnected the tach filter and still no go. I'm going to order a new coil and ignition module and as those would appear to be the only two things left in the ignition system.
Patrick OCT 25, 03:26 PM

quote
Originally posted by Yorgle:

I'm going to order a new coil...



Which one... ignition coil or pickup coil?
OldGuyinaGT OCT 25, 06:57 PM
What is the condition/age of the distributor cap and rotor? I've been working on cars since they all had distributors with points, and in my experience, a worn cap/rotor combination can cause:

A V8 to run rough;
A V6 to stutter and run very rough;
An I4 to not run.

I've found this to be true whether the distributor has points or electronic pickup. I had kind of forgotten about this, with several cars in my family being distributorless, but my 2000 Blazer reminded me a couple of months ago. Assuming the cap/rotor are worn but not damaged, and have no carbon tracks or other problems, I know of no good way to visually inspect them for wear (maybe the carbon button, but not the electrodes). They just gradually degrade until they cause problems. They seem to last a little longer than standard spark plugs, but I like to change them at the same time.

If you replace these parts, choose carefully - there are a lot of crappy ones out there. I realize this may seem like throwing parts at the problem, but if you don't know/remember when they were last replaced, they probably need it.

Also, if you haven't already done so, check all connections in all wiring related to the ignition. I had a problem like this once, only with a V8 I had put into an '82 Grand Prix. I finally (after months of searching) found a bad connection in a ring lug. It was one of the self-soldering types that never made a solid connection (I will never use another). Finally found it with a wiggle test, but it took nearly forever. A bad crimp or a loose pin can cause real headaches.

A no-start is always is a fuel/air/spark thing. Are you sure the no-start is no spark?
Yorgle OCT 27, 09:51 AM
Ok, I've made some limited progress. So far I've replaced the cap, rotor, wires, plugs and ignition control module without success. The timing light thing seems to have been just coincidence. Last night, just for the heck of it I shot some carb cleaner into the throttle body and cranked it over and she fired right up. Tried it again this morning, no start, but shot a tiny squirt of carb cleaner into the TB and she fired right up and ran fine. So maybe I've been chasing the wrong thing- the problem appears to be whatever tells the injectors to fire when cranking isn't happening, but once it starts, everything seems find.

EDIT: I should add that I can hear the fuel pump solenoid click and the pump run so that appears to be working fine.

[This message has been edited by Yorgle (edited 10-27-2021).]

Patrick OCT 27, 11:47 AM

quote
Originally posted by Yorgle:

I should add that I can hear the fuel pump solenoid click and the pump run so that appears to be working fine.



Doesn't mean you have proper fuel pressure.
Yorgle OCT 27, 12:17 PM

quote
Originally posted by Patrick:

Doesn't mean you have proper fuel pressure.



Good point. I'll dig out my gauge and check it.
Yorgle OCT 28, 12:48 PM
I get 12psi fuel pressure and the car now reliably starts with a shot of carb cleaner or ether into the TB immediately before cranking. Here's a question, with the engine running, should both the blue and red wires from the injector be a steady +12V? My service manual is confusing and seems to suggest that I should see a pulsing voltage on the red wire, but it is unclear what I should see on the blue wire. No pulsing would seem to suggest that my ECM isn't doing its job.