Start timing

2JZGTE 80 series landcruiser, the car was tuned without a IACV 8 years ago (could not get the stepper motor to work properly) i fitted a ford 2 wire IACV about a year ago.

For some time now I've been working on cold start with good results, something that bothers me though is the starting ignition, for some reason the cold start timing is set at 35° which was setup when the car was first tuned at a pro dyno shop.

The car starts fine but I'm concerned about how far advanced the start timing is, everywhere I've looked suggest the start timing to be set around 10°, so why did the guys at the shop set mine so far advanced.

Hi Mark,

can you screen shot the ignition map to see what values you have? I have some ideas but would like to see the table first if possible?

Main ignition map

I don't understand what the special trim is for or what it does in relation to start timing.

If it matters, the ecu I'm running is a wolf v500.

Hi Mark,

I'm not overly familiar with Wolf EMS but looking at your ignition map i would say you're right. Typically the bottom row or 2 will be set around +5 to -10 degrees; your load break points look a little too spaced out around that low load area, changing to smaller steps will allow more resolution rather than relying on linear interpolation (rough example - 2.5,5,8,12,18,28,45,60,80,99,101%).

I guess your concern is with more advance leading to knock...this shouldn't happen as there's no load on the engine at idle

Scanning the Wolf EMS manual it looks like the the variable in the 2nd pic is a temperature adder and the language isn't quite clear, it says the ignition value is 'adjusted' by the value suggesting its an adder meaning 35+24 degrees advance but the bottom statement reads that the ignition will change to the selected value meaning it ignores the base timing map for starting...

the 3rd pic shows a custom modifier that will have been calibrated by your previous tuner so it will be worth asking them for the logic behind it. There is a switch to deactivate the function but its worth doing some digging to find out what it does. if a tuner has put the time in to calibrate it then it could be necessary, sometimes software/firmware can be release with bugs or code that hasn't been fully validated so a work around in the calibration is sometimes required.

As a next step I'd suggest taking a log of it cranking and idling to find out exactly what is happening to reverse engineer the logic. Based on this apply some more academic calibration changes and see what happens from there. feel free to share a .csv file or screen shots if you'd like some more input.

The Practical Standalone Tuning course should cover what you need to know and have a scan through the HPA webinars to see if there's something in there that could help

https://www.hpacademy.com/dashboard/courses/practical-dyno-tuning

https://www.hpacademy.com/webinars/

regards,

Scott