Setting Timing, Verry Intresting

[got2b240]

I know to set timing and such you need correct idle and tps voltage to keep car running pristine when properly timed.

When I timed my car and adjusted the above mentioned, I held my car at 2k for 2 minutes, then revved past 3k 3 times and then let idle for a minute. Turned off the car, then disconnected TPS harness clip, then restarted car. Then I adjusted my idle to 850. It stayed at 850 untill I corrected timing, which I had to keep on going back and forth untill timing and idle matched specifications, which are 850 rpm and 15 degrees.

My question is : is this supposed to be the way timing is done, it has to read 850 idle speed and 15 degrees at same time, or just adjust idle to 850 and then do the timing and whatever it does to idle leave it?

I seemed to keep on chasing the 2 set at the same required at the same time and I got the car to run sooo mint, I did notice a little bit less of power then that of Im used to, that is due to the retarding of timing that I adjusted to read 15 degrees.

Anyone have any input on this. I would greatly appreciate advice from anyone with experience with this.

[got2b240]

bump to no replys

[Hijacker]

i've never disconnected my TPS plug when setting my timing, and i have never adjusted my idle speed to 850, although it stays between 800-900 normally anyways. I have never had a problem with my timing, either.

[junk240sx]

correct me if i'm wrong but idle shouldn't matter to check idle. timing light flashes whenever the 1 spark plug gets a spark. It flashes on the crank pulley to show you where the crank is at when 1 spark plug sparks...so if the idle is higher or lower, the interval of the flashing will be different but that's because it's just keeping up with however fast/slow the crank is spinning at to show you the current timing set.

[robbbby]

FIRST set your base timing to 15 degrees. Once you are all set doing that you can set your idle. You should not be adjusting your base timing to smooth your idle out to 850rpms.

[msaskin]

True, however you want to keep the idle consistent because at varying RPM/Airflow numbers the ECU will try to adjust the timing numbers based on it's timing map.

~matt

[got2b240]

ok Junk 240sx, you take your timing light and hold it at the crank , and rev the motor and tell me if you get the same reading at all rpm's? You dont. So you have to make sure that your around the 850 900 area when you set your timing i believe. and you have to get your car into timing mode just to let you ALL know otherwise your car wont accept the changes too well i heard.

no harsh words just truth

[Hijacker]

i've never disconnected my TPS, and the car accepts all the changes I give it.

Anyways, as long as your car is idling, and not revving, you shouldn't need to worry about the idle speed. If you set your idle speed to 2500, that would be different. I've checked my timing before when it was idling at 1100, and it came out fine.

What you're creating is a strobe effect with the light, and even with the light, it's not completely accurate. Also, all lights aren't created equal, so some will not read as well as others.

[msaskin]

To give the real reason why timing mode is somewhat important:The car's ECU has multiple tables related to ignition timing. The main one is RPM vs. Airflow. In addition the ECU alters ignition based on multiple trim tables, it will alter the main timing table based on coolant temperature, air temperature, etc...

By putting the car into "timing mode" you are telling the ECU to ignore all of the ignition trim tables and simply use the main timing table. Add to that the constant RPM (850-900) or whatever it is and you've got the ECU narrowed down to one specific ignition timing value while you're trying to set timing.

Make sense???

~matt

[darkone]

what is timing mode?

[cvex]

Yeah, how do you put the engine to timing mode. i never heard such thing

[Onizuka]

"timing mode" is simply disconnecting the throttle posission sensor in order to force the car to idle according only to its base fuel map (the one that is active at 0% throttle). This prevents the ECU from messing with the timing, which it can do because timing on our cars ignition system is controled electronically, instead of mechnically like the KA24's distributer system. Thats why it is also important to have the engine at operating tempratures, so the ECU doesnt play with ignition and fuel due to coolent temps either.