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View Full Version : Ignition Timing, whats the truth?!



alwaysoffboost
06-13-2006, 12:19 AM
1995 KA24DE
I have performed ignition timing on various cars carbed and injected and every car I do this on gets more and more specific, and complex,on how to adjust the ignition timing. Very breifly ( and just off the top of my head so im gonna miss a few things so bare with me) this is how I understand the timing process (from the chilton and nissan service manual)

-let engine idle up to operating temp.
-run @ 2000 (no load) for 2 minutes
-perform on board diagnostics ( i didnt do that ) and fix any fault codes
-run @ 2000 (no load) for 2 minutes ( didnt do it because i didnt check fault codes)
-rev 3 times 2000-3000 rpm and idle for 1 minute
-switch off engine and disconnect TPS harness
-restart engine and check timing at idle

*phew*, 10 minutes later we can finally adjust the demon

From sight, the timing was approx. 25 deg. advanced ( according to the 6 notches on the crank pulley ) I adjusted the timing to 20 degrees. lined up with the last notch on the pulley.

Changing it from 25 deg. to 20 deg. I noticed:
Running the car: I experienced bogging from idle to about 2000rpm and slower revving throughout. While driving it felt like I had lost about 15hp on the butt dyno. I was surprised because It seemed like putting it back to 20 deg. ( stock setting ) would make it not bog. Before fiddling with the timing ( when it was approx. 25 deg.) it ran great and pulled hard. My motive for adjusting was to correct any distortion or change that may have taken place and just get things back up to spec but putting it back to spec made for worse performance.

-Question time-
1. what is the significance of the different steps such as revving it and idling it. Im under the assumption that as long as its warmed up, at idle , and has some form of intelligent timing adjustment in a coma ( unplugging vaccum hoses on carbed cars, unplugging the coolant temp sensor on VW's , and apparently the TPS on the KA24) that everything is just peachy and ready to time.

2. Is it mandatory to check engine codes, or is there a simple way to just adjust the timing and move on with life?

3. Is there a timing setting for optimum performance? stock? ( assuming healthy engine , pump gas, normal compression ratio)

4. Does slightly retarding or advancing the timing allow better low end / high end performance ( similar to cam timing )

I really appreciate your input, I know this is going to help me and a whole heap of other people who will read it , that is when you intelligent beings respond . thanx -brian
and a pic for the heck of it

http://i83.photobucket.com/albums/j292/alwaysoffboost/IMG_4753.jpg
http://i83.photobucket.com/albums/j292/alwaysoffboost/deeEsanstee.jpg