timing problem with lq9 on a 2jzge with aem v2

[1986.5supra_kid]

Hi i have a 2jzge,aem, v2, and lq9 coils. the base timing has been checked. it will idle but the timing reads -17 when reving it up the car starts to build boost but falls on its face for any sort of measurable power. setting have been set to falling trigger, dwell is 3 ms, power is constant. not sure what is going on.

 

[hvyman]

Have you properly calibrated everything before trying to tune?

id suggest taking it to a tuner.

 

[1986.5supra_kid]

Car ran before conversion. Its straight forward. For some reason timing stays at -17 degrees with it set to trailing which is the instructions to do but when set to leading it changes

 

[1986.5supra_kid]

Head light problem fixed. Integration relay swapped out.

Still have a problem with cop conversion to lq9 coils. Timing isn't adjusting

 

[Radial]

What dwell values are you using?

My experience is that many LS coils from LS7 generation and newer "auto fires" if dwell exeeds 4ms. This is for self protection. Commanded timing will not be correct if this happens, and usually you will se "spark advance" while reving the engine. (detonation will probably occur as well).
Reduce dwell to about 2ms and see if it helps.

Its also very common that timing changes when you change from falling edge trigger to rising. There is a bit of time in between the two edges of the cam signal used to set the timing.

 

[1986.5supra_kid]

Dwell is 3ms. For some reason the timing is static at 17 just like it never sees something happen during startup. The TT car here will start at 17 but once running it will change degrees. Mine will stay at 17 even when idling and revving. But if its set to leading then it will change degrees

 

[hvyman]

What's on the timing map?

 

[1986.5supra_kid]

Map is 15 but the chart reads -17 on actual. While running we can change the map from 15 down to -17 and nothing changes on engine speed PR reaction. Run it up to about 24* and the car dies. Change the setting to leading spark edge on coil/in tab and the timing changes to the map designated degrees.

Ive checked continuity on all timing related wires and grounds. Even hooked jumper leads to dizzy to block and head to chassis for reduntant ground.

Gonna pull dizzy and check for the teeth aligning up with engine. Worst case scenario its off a tooth can that really through it off even though Aem was synced for base timing

 

[1986.5supra_kid]

dizzy was aligned and i assume coil phasing should be 0,16,8,20,4,12?

pulling straws now.........

 

[Radial]

I think I know what's wrong.

You are firing off the coils with a Trailing edge signal - Right?
But 99% av all LS and LQ coils needs LEADING edge trigger signal to work properly.

The picture below explains the difference inbetween Leading vs Trailing edge.



In a very simplified way, you can say:
The lenght of the Leading edge trigger signal to the coils are always changing with load and RPM.
The trailing edge of the coil trigger signal, is always constant and does not change with load and rpm.

This explains the behaviour you are seeing.
Use Leading edge trigger to the LS coils.

INFO: LS coils actually overheat if trigger settings are incorrectly.

 

[1986.5supra_kid]

good to know radial

and you wont believe what the problem was....


injectors 3 and 4 where mixed up. now that everything has been changed its time to get it tuned again. idle is hunting. I have to IAC so its all in timing or fuel settings