: Question About Ignition Timing & Preparing For Emissions Testing



nebulosity
07-29-13, 03:25 PM
I'm soooooo nervous!!! I finally have my appointment tomorrow to have my Caddy's emissions tested to finish the registration process of the car. I'm super nervous that California is strict and might make it hard for my Caddy to pass considering it hasn't been running regularly in years.

One of the last bits of the puzzle I want to nail down are about timing, since I'm sure the way the engine is timed will have an effect on its emissons test results (right?). I probably have a few questions, so I'll number those and put them in bold for you guys to make it easier.

Right now the ECM is telling me that the "spark advance value" is 30 degrees (assuming "the base timing was set correctly"). My husband timed it by ear while the engine was running because that's how he's done his project cars in the past.

It turns out that............ I forgot to put on the timing tab before I bolted the crankshaft pulley on (.... OOPS :hide:), and so all I have right now to gauge the timing is with the ECM. I might try to put it back on this evening if it's absolutely necessary to time it with a timing light, but I'm short on time, and it's a pain in the butt to put that timing tab back on. My husband says that they probably won't check the timing with a light, and if they needed to, I could have them put the timing tab back on, which I won't do because that's too embarrassing for me.

Anyways, onto the questions....

1. What is "base timing" and what does it mean to "set the base timing correctly" (as phrased by my shop manual). I tried to find this info in the section on "ignition timing" and didn't see anything mentioning it

2. Can I reliably adjust the ignition timing just referencing the "spark advance value" reported by the ECM during diagnostics?

3. Am I gambling passing my emissions test by not timing it with a timing light? I can try to quickly put the timing tab back on tonight, but it'll be a big pain in the a**, so I'm hoping that the ECM value is enough.

4. The emissions sticker says the ignition timing should be set to 10 degrees, but the shop manual says it should be 20 degrees +/- 2 degrees. Since the emissions guys are going to look at the sticker, should I make sure the ECM is reading a spark advance of 10 degrees?

5. Am I confusing or getting any of the terminology wrong? Please correct me if I am.

6. Are there any other tests I should run on my Caddy before taking it to be tested? Any simple vaccum system tests I should do?


So far, here are the things I'm doing to make sure I pass emissions.

1. I'll run the Caddy to get it up to operating temperature (engine temp ~85C, right?)

2. I didn't put any cleaners into the fuel or oil to minimize the amount of gunk/dirt getting into the exhaust.

3. Made sure all my vacuum lines are hooked up, especially according to the emissions sticker.

4. Ran diagnostics and resolved/cleared all the codes thrown by the ECM, both engine running and not running.

5. Haven't figured out exactly why the service lights are coming on without codes being thrown... hoping they go away after I warm the engine up..? o_O :hmm: I'm going to run through the diagnostics again tonight and take a video of it.

Let me know if you have any other recommendations.

Thanks in advance to anyone who can help me with my questions.

As always thank you SO MUCH(!!) to everyone who has been giving me advice on my project thread. I don't know how to thank you enough!

carnut
07-31-13, 02:25 PM
The car will not even be tested if the service soon or service now lights are on. And they will verify timing with a light so the timing tab MUST be there! They will also test the gas cap! Make sure its fairly new and not a locking cap (they leak) The timing is 10 degrees BTDC and you are allowed 2 degrees on either side to pass. 12 degrees is where it runs the best. There is a green connector by the distributor that must be unplugged prior to checking base timing. Its mentioned on the decal on the radiator support. My car failed because of a worn out Cat. Converter. So be ready for that as well! Converters installed aren't expensive, maybe 150.00. Set the timing, get rid of the lights and hope for the best regarding the converter.

turbojimmy
07-31-13, 03:08 PM
Wow. Gotta love Kalifornia.

NJ, believe it or not, went the other way over the past few years. Things got easier. They just check the gas cap and plug into the OBDII port. Non OBD-II cars get a tailpipe test at idle, that's it.

Good luck with that - just another hurdle you will be proud of overcoming.

nebulosity
07-31-13, 03:52 PM
The car will not even be tested if the service soon or service now lights are on. And they will verify timing with a light so the timing tab MUST be there!

Yeah, we went ahead and put it on yesterday morning by unbolting the crank pulley and sliding it out a bit (without taking off the belts, and then retightened the belts when we were done). :)


They will also test the gas cap! Make sure its fairly new and not a locking cap (they leak).

I'll probably get a new one then, thanks!


The timing is 10 degrees BTDC and you are allowed 2 degrees on either side to pass. 12 degrees is where it runs the best. There is a green connector by the distributor that must be unplugged prior to checking base timing. Its mentioned on the decal on the radiator support. My car failed because of a worn out Cat. Converter. So be ready for that as well! Converters installed aren't expensive, maybe 150.00. Set the timing, get rid of the lights and hope for the best regarding the converter.

Good to know. :) I had replaced the catalytic converter about 1 year before I stopped driving it, so I hope it would be okay (unless I've clogged it up while trying to get it running again).

The car isn't throwing any codes again, and still the service lights still come on. I'm REALLY baffled by this you guys! I'll check the lights again when I go to see the car at the shop.

brougham
08-01-13, 09:19 PM
Good luck. Emission tests suck.

nebulosity
08-01-13, 11:12 PM
Good luck. Emission tests suck.

Thanks. I probably need it. :( Crossing fingers.