I need to retard the timing a few degrees on my 91 lx sedan. I see in my manual that they say jumper the blue plug an then plug the vacuum tubes. My question is can you do it without messing with the vacuum or is that a must?

 

You probably have a manual that covers accords with a carb. Your car is fuel injected, so you only need to jump the connector.

The car has the timing controlled by the engine computer. So the ECU can fight the adjustment you do.

You really want the timing dead on, so the computer can advance or retard the timing over the whole range.

Why do you want to do this?

 

I failed A California smog test an the guy said i could probably pass if i retarded the timing.

 

so did it fail due to incorrect timing only? or did it fail due to emissions and the tech guessed that a timing adjustment would fix it? you are allowed 2 degrees in either direction from spec.

I think spec is 15 degrees advanced, what did yours come in at and what were the emission readings if it was an emissions failure?

 

The only thing it failed was the noc and not by much, i would give u numbers but the paper work is at home. My timing was right around 18 degrees advanced and he said there directly related so to retard it back to 15 degrees. He had me convinced what do u think?

 

Sounds good.
I think the spark timing is supposed to be around 15.deg, (+/-2) so if yours is at 18 then it's too far advanced.

Advancing the spark timing GENERALLY gives a little bit better MPG and a little bit worse NOx. So I'd set the timing back to 15 degrees. Got a timing light?

About the vacuum lines... Are there any vacuum hoses connected to the distributor? I'm guessing NOT?? That's what your manual is probably talking about.

 

the current timing is a functional failure of the smog check, so regardless that needs to be taken care of. i'd like to see the emissions readings as well. if they are close, the timing might just do it. if it still fails NOX we need to look at some other things, EGR, Cat, etc...

 

Thanks for the help guys im gonna go round two with the smog check friday so ill throw numbers up.