Ignition Timing Delay (retard) while revving up

[Constant]

Hello ! , we have a G4 Storm installed on a 4 cyl toyota engine with COP using VR sensors on crank and distributor , the setup is 36-2 on trigger 1 (crank) and 1 tooth per TDC on trigger 2 (cam) . We were trying to fine tune the trigger arming threshold using timing light and we noticed that when the engine rpm are rising the timing has some seconds of retard before moving to the mark position. we could also describe our steps as follows : A. -start the engine and let it idle -lock ref timing to 20 deg -adjust timing light to show TDC at 20 deg -light the crank pulley mark at idle speed -make any nesessary adjustments on trigger offset -light the crank pulley mark at idle speed and confirm B. -we keep lighting the crank pulley mark -rev up the engine to 3000rpm while lighting the mark -we notice that the timing mark moves 15-20deg ATDC before eventually moving itself to TDC -we try changing the arming threshold values or the ignition delay values but with little or no difference to the effect. Our arming threshold values are Trigger 1 - 0.3~0.9~1.5~2.1~2.1~2.1~2.1~2.1 Level 1 Filt Trigger 2 - 0.3~0.9~0.9~0.9~0.9~0.9~0.9~0.9 Level 1 Filt i would appreciate any help on this , thanks!

[seized]

Have you verified the polarity of the sensors? Try reversing the wires and see if it still happens. This is often a symptom of having the polarity reversed on VR sensors.

[Constant]

We didnt verify the polarity using osciloscope or any other tool but we tried reverting the polarity on trigger 2 and the engine wont start , also we tried reverting both triger 1 and trigger 2 and the engine starts and idles smooth but when RPM rise timing mark stays ATDC and doesnt return to TDC as in my first post.

[Constant]

Forgot to mention that trigger 2 is wired using stock wiring diagram (G- for ground) and there is little or no chance of incorrect polarity...

[martin battye]

firstly.. try using a dumb timing light.. make sure the error is not in the equipment..

secondly.. this amount of drift is perhaps too much to be corrected by ign delay in the software..

i have used g4 storm on escort cosworth.. on a 36-1 reluctor setup.. and tooth cam sync.. so is similar setup yet didnt find an ignition drift..

although have experienced odd readings in the past only to find my 'tricked out' timing light was the problem

[Dtech Motorsport]

as per my reply on the efi forums on friday  start with a non dial back timing light and check again

Regards

Dave

[email protected]

[Constant]

Martin thanks for your reply ! , I'll check again this afternoon and will post results. Dave thanks again !

[Constant]

thank you all! It was the timing light's bug!

[martin battye]

damn im good...!!

 

glad you had success with this