94 G50 timing issue

[Black stallion]

My timing seems to only work with a particular type timing light. I used my buddies initially to set the timing. Car ran beautiful, but only got around 19-20 mpg on the highway.

Long story short I bought a $120 digital timing advance light in hopes of fine tuning/increasing mileage etc. Car didn't run as hard and had poor fuel mil. Borrowed his again and reset.

I also noticed the timing seemed to "dance" around the timing mark, intermittently.

I have bought two more timing lights since then and they show different from original light so I have not changed it.

Should I use a plain timing light without the advance feature?

Also I read something about centrifugal timing and vacuum timing in reference to the "dancing" time. Does this apply to the Q or just older cars?

Trying to fine tune ignition timing for optimal mileageThanks

[elwesso]

Are you unplugging the IAC? What you dont want to do is have the IAC trying to make the idle right when youre adjusting the timing... You can only advance the timing by adjusting the CAS im sure you already know that though.

whenever I adjust the timing i just use a cheapo inductive light...

Also, you cant adjust your timing very well if your KS are bad.

[Black stallion]

AT operating temp., IAC unplugged, KS and harness changed 2K miles ago.

From what I have read and can observe, the TL's with the advance feature start at a point then measure the amt. of advance you change. Problem is at Odeg. they start reading at 5deg.BTDC while the regular ones read 15deg.

Maybe I need to pick up a very simpl t.l. and match it to one thats proven

[qsiguy]

Another observation....19-20 mpg for a '94 is pretty good. Best I've got in the last few years is 19 for a full tank. I wouldn't mess with it too much if that is your only reason.

My $.02

[Q45tech]

The KS circuitry automatically advances the ignition advance until knock is sensed then backs off incrementially then starts the whole process over again every few seconds.

Initial advance is just one tiny number in the ignition total advance number.

Highway cruise [light load steady speed] will be ~~40 degrees BTDC vs 22-27 during acceleration.

[qsiguy]

I'm trying to check my timing and can't get it to work. I've read your tech guide about the connectors on either side of the motor. How are you connecting to the wires? Are you just clamping the clamp to it or hard wiring it? I checked that wire on both sides of the motor and it's just a 12 volt + wire. Can you elaborate more on how you guys are connecting the timing light?

[Q45tech]

I always use the special inline adapter [see FSM for specialty tools] to amplify the signal to timing light and a digital adjustable model.

[Q451990]

Just for fun I called Kent Moore to check on the adapter. It costs $65.73, with an estimated ship date of 11/13/2007.

http://www.nissantechmate.com/detail.aspx?id=317

Heath

[Q45tech]

Correct device has a plastic molded box with connectors with a loop made of what looks like spark plug wire. Page EC-4 of FSM

[qsiguy]

Let's assume I don't have one of those handy gadgets (since I don't). On Q45.org Wes shows three methods to check the timing. Option B shows using a single wire plug that exists on both sides of the motor to get a signal for checking timing. I test that wire and it's just a 12V+ wire. I was hoping for a better description of that option.

"Method B talks about a special wire you can clamp and check timing. This has sort of been in infamy, as everyone thought it either didn't exist or it didn't work. I am going to expand on this method as it's the easiest of them all"

"This is the passenger side. There is an identical wire on the drivers side but I don't think it matters either way. I used the one on the drivers side, but I forgot attach mine in the stock location, so right now it dangles."



Can anyone (Wes) clarify this method? Seems easy enough but I'm not having any luck using it.