this will sound like a dumb question but i need to know. when i want to advance my timing i turn the disributor away from the fire wall or toward?

 

towards the firewall

 

If I remember right, the ECU will figure out that you advanced the timing and will adjust to fix it to stock. I think your only option to advance ignition timing is to tune your ECU. But then again I have no experience with ECU's so someone correct me if I'm wrong and made myself sound like a retard.

 

anyone know?

 

towards the fire wall

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Hatch_R &raquo;</TD></TR><TR><TD CLASS="quote">If I remember right, the ECU will figure out that you advanced the timing and will adjust to fix it to stock. I think your only option to advance ignition timing is to tune your ECU. But then again I have no experience with ECU's so someone correct me if I'm wrong and made myself sound like a retard. </TD></TR></TABLE>

OBD-II will correct the timing... OBD-I will not have a problem. :D

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by red92si &raquo;</TD></TR><TR><TD CLASS="quote">

OBD-II will correct the timing... OBD-I will not have a problem. :D</TD></TR></TABLE>

yay

 

thx

 

You should be able to set it with the service connector in and it should stay at the predetermined setting. If you don't set it with the service connector jumped it will want to try to set itself back to stock.

 

ok so obd1 timing will just go back to what it was set at even if you try to advance it?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by red92si &raquo;</TD></TR><TR><TD CLASS="quote">OBD-II will correct the timing... OBD-I will not have a problem. :D</TD></TR></TABLE>

No it won't...

Realize that the sensors contained in the dizzy give the ECU a starting point from which to synchonize fueling and timing efforts.

Since the relationship of where the sensors on the shaft is to where the pickups are mounted can be altered (when you turn the dizzy, you aren't turning the shaft inside the dizzy which is connected to the camshaft, you are turning the housing which has the pickups mounted to it), this in effect give the ECU a new synchronizing point.

You short the service connector when checking/setting timing because in doing so, you are not allowing the ECU to add timing to the base #. Shorting the connector has nothing to do with the ECU learning some new base ignition value.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris &raquo;</TD></TR><TR><TD CLASS="quote">

No it won't...
Realize that the sensors contained in the dizzy give the ECU a starting point from which to synchonize fueling and timing efforts.
Since the relationship of where the sensors on the shaft is to where the pickups are mounted can be altered (when you turn the dizzy, you aren't turning the shaft inside the dizzy which is connected to the camshaft, you are turning the housing which has the pickups mounted to it), this in effect give the ECU a new synchronizing point.
You short the service connector when checking/setting timing because in doing so, you are not allowing the ECU to add timing to the base #. Shorting the connector has nothing to do with the ECU learning some new base ignition value.</TD></TR></TABLE>

hmm.....where did you read this info i need to know more..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris &raquo;</TD></TR><TR><TD CLASS="quote">

You short the service connector when checking/setting timing because in doing so, you are not allowing the ECU to add timing to the base #. Shorting the connector has nothing to do with the ECU learning some new base ignition value.</TD></TR></TABLE>

I'm also confused.

So, are you saying it doesn't matter whether the service connector is "jumped" when changing the ignition timing on OBD2?

How do we effectively adjust the timing manually on OBD2 cars then???

 

It matters to your timing gun - if the jumper is connected. The ECU doesn't know where the dizzy is set to, but it certainly knows when to reset/set a counter and do some arithmetic according to when the sensors create a negative going pulse (pulse polarity, and thus the wiring, does matter here).

And honestly, I would say, for OBD2, that since the CKF is present, that the ECU can tell if the dizzy was just way the hell off by comparing it to the CKP - but for OBD1, there is nothing comparable.

So...jump the connector to make sure the ECU isn't adding any advance and set the timing (just realize the ECU isn't learning something new by you jumping the connector, thats all).

 

Are CKF and CKP ignition maps? Sorry man. You're still way over my head. But I'm willing to learn if you have the time!!

The way I understand it, "jumping" the service connector, and moving the distributor establishes a new "baseline" from which the ECU calculates ignition maps. Where am I wrong in my description? (or am I?)

 

Three sensors reside inside the distributor: TDC, CYL, CKP. These sensors coordinate the synchonization of fueling and timing efforts. The CKF, used for OBD2, outputs the same signal as the CKP, but its used in misfire detection.

The magnetic part, and its pickup, are seperate from one another (inside the dizzy) - so when you turn the dizzy, you are only playing with the location of the pickups since the magnet part is mounted to the distributor shaft. So in unison, the cam/crank is spinning, which means these magnetic sensors are spinning, however, WHEN the synchonizing pulses are produced has changed. Its WHEN the pulses are produced that establish this baseline.

You know how when you install a cam gear and play with cam timing, they always say "after you set cam timing, RESET ignition timing". Since you're playing with the cam, which directly drives the magnetic sensors, advancing/retarding the cam is doing the same thing to your ignition timing and thats not what you want. You want to adjust cam timing but keep the ignition timing the same which means rotating the dizzy again after any cam change is made.

GOOD waveforms



BAD waveforms

 

if you dont have a timing light ( which im assuming you dont since you dont understand the relationship between the timing marks on the pulley and timing cover, advance vs. retard ) then do not mess with your timing.

 

so should i advance mine to 18degree BTC bcuz im running 91 octain and my engine is running kindda rich...backfire alot.....and i dotn have FPR to adjust anything...the engine bay is pretty much stock...just some bolt on like h/e/cai

i know stock is 16BTC and the red mark 18dgree BTC, is 18BTC is the maximum advanced timing you can do? im sure i dont want 14dgree BTC

anyhow im stuck with OBDII and i wanna advance my ign timing should i do it

 

18* is within spec - no reason you can't adjust it that high.