My 89 honda civic SI 1.6L – California model;
I have been told (by sources that were so-so reliable) that it is not necessary to adjust ignition timing since it is controlled by the ECU. However the shop manual (88 civic/crx) does show the procedure for checking/adjusting ignition timing. Have I been led astray? Does the ECU control the timing only within a marginal range?

Any facts would be much appreciated,
Ken

 

set the timing with the ecu jumped, so the computer can't make changes. It can make timing changes itself, but you still need to set the base timing.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by accordaffair &raquo;</TD></TR><TR><TD CLASS="quote">set the timing with the ecu jumped, so the computer can't make changes. It can make timing changes itself, but you still need to set the base timing.</TD></TR></TABLE>

that is correct. the ecu can only adjust timing in a small +/- range of degrees.

an example would be if we assume the ecu can adjust +/- 5 degrees, then setting the timing to -18 means the ecu can adjust timing from -23 to -13. in this case, the base timing is set to -18. you can then see how messing with the base timing affects the ECU's ability to handle timing.

 

With the ECU jumped? How do you do this. I tried adjusting the timing once but I did not know the ECU had to be jumped.

 

The ECU assumes the timing is set correctly. The ECU will not adjust the timing. It will advance it though, because it needs to.

There is a connector that you jumper that disables the computer so you can set base timing. It is a two wire connector that Honda put in different places to confuse us. It is either by the drivers strut mount in front of it by the motor mount, or to the rear of said strut mount by the injector resistor, or in the passengers side kick panel. However that said you don't really need to jumper it. If you just set it it will be close enough.

 

This might be a dumb question but if the ecu advances the timing as needed, what harm is there by having the base timing off by a few degrees? Not that I would leave it that way of course.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by flanker &raquo;</TD></TR><TR><TD CLASS="quote">This might be a dumb question but if the ecu advances the timing as needed, what harm is there by having the base timing off by a few degrees? Not that I would leave it that way of course.</TD></TR></TABLE>

The ecu will advance the timing to account for different loads, not for incorrect timing, It has no Idea where your base timing is, so it has no way to fix it.

 

It can only adjust by a small amount as he said. If you're off by a significant amount, the computer won't be able to catch up.

Jump the mil code connector and set your timing.

If it isn't jumped, the computer may adjust the timing as you try to fix it, it will be working against you because it thinks something bad is happening. The distributor should generally be somewhere near the middle when set. If you have it advanced or retarded all the way just to get it regular you may be off a tooth.

 

How do you jump the ECU and with what kind of wire? Does this wire come with the timing light kit? Thanks

 

I use a piece of solid copper wire i stripped the ends off. It is about 2 inches long or so.

 

I use a paper clip bent into a U that I've kept in my glovebox for years