you can see a whole article on that at
www.sentra.net and nissanperformancemag
Advancing the ignition timing is an inexpensive (free) modification that can make a noticeable difference in throttle response and through the entire powerband with the largest gains in the midrange, around 5500 rpm. Fuel economy is also improved if your driving habits remain the same with the additional power. Adjusting the timing can produce gains of up to 5 hp at the wheels on a GA16 for instance. The amount of gain, you can expect depends on where the timing is currently set now. If it is too low you will feel a larger SOTP difference. Timing advance helps produce more power by igniting the sparks sooner, providing more time for the fuel/air mixture to burn completely, increasing cylinder pressure, thus providing more power. Remember that our engines are sensitive to timing advance and can gain quite a bit of power by adjusting the timing over other, more performance oriented engines, like some Honda engines. So here's the procedure as described by FSM with some comments. Good luck!!! - Edgar S.
The procedure is from a 95 FSM, but it should work on all GA16DE powered cars, including 91-94, just be sure to verify the correct idle and timing specs, I remember 91-94 timing was 10 +/- 2 so you could safely run 12 degrees. Specs for every Sentra model built have been added at the bottom of the page. For a boost in power if you are willing to always run 92 octane gas, is to reset your timing to 15 degrees instead of 12. See the dyno chart in the engine part of the technical section to see what this does powerwise. Remember you must run 92 octane gas or you will experience detonation which will damage your engine. If you are not willing to buy good gas, do not exceed the factory maximum recommendation.
If you are running a tuned JWT ECU, do not exceed 10 degrees of advance as the JWT ECU already has extra advance built into it.
For non GA16DE cars, built before 1991, with 92 octane fuel you can probably go 3-5 degrees more timing than the factory recommendation, but we do not have dyno verifications of what the gains may be. A rock solid rule is not to tolerate detonation when experimenting with advancing the timing. Timed third gear 40-60 mph pulls is a good way to see if you are actually doing any good without a dyno.
If you are going to advance timing, the use of 92+ octane gasoline is mandatory, to fight detonation and pinging. If you live in a very hot place don't go past the point when engine starts pinging (you know this sound that comes from the valve train, it sound like a diesel engine). Also I have heard pinging when under extreme load like start moving on a hill. If you have this just retard timing until it disappears.
The following procedure has been copied from a 1995 NISSAN MOTOR CORP. Factory service manual (FSM) for SENTRA/200SX
Adjusting ignition timing without a consult:
Turn Off engine and disconnect throttle position sensor harness connector.
Start engine
Rev engine (2,000 – 3,000) 2 or 3 times under no-load, then run engine at idle speed
Check ignition timing with a timing light
Manual transmission 8° +/- 2° BTDC (please note that on 91-94 models, it’s 10 +/- 2)
Auto transmission on 95+ is the same spec, check the specs below for other models
Adjust ignition timing to the specified value by turning distributor after loosening bolts which secure distributor. Stop engine, and tighten the distributor (do not move it!). Restart engine and make sure the timing has not moved.
Check Idle speed M/T: 625 +/- 50rpm A/T: 725 +/- 50 rpm
For 91-94 models it’s M/T: 650 (750 for Canada) and A/T: 800
If idle speed is off:
.Rev engine (2,000- 3,000rpm) 2 or 3 minutes under no load, then run engine at idle
Adjust idle speed by turning idle speed adjusting screw.
Stop engine and re-connect throttle position sensor harness connector.
Linear Mode
