RyRy

iTrader: (6)

I just installed my Predator on my car and had a question.

1. After installing it, I drove out to an open road and when I went WOT, I heard this noise like crunching plastic. Im assuming that it is spark knocking but Im not positive. It only happens at WOT. If this is the case, How do I advance or retard the timing to solve this problem? Im confused as to which way I need to tune it to get rid of it. Do I need to wait a while after installing the tune to go WOT? Any advice will help. Thanks

RyRy

iTrader: (6)

ttt, anyone?

SSpdDmon

iTrader: (10)

If it's knock you are hearing, it would show a certain number of degrees knock retard (KR) on the live data feedback as long as your knock sensors are still good. Get a friend to ride with you and watch the live data. Have them make sure there's no KR at WOT. Also, check your spark advance. A good starting point is to stay under 28.5* max WOT advance. If you're getting KR, you can reduce WOT spark in the modified tune section. To figure out what your advance will be with in the modified section, take the highest observed spark advance value (say your friend saw 28.4*) and multiply that by 1 plus the percent change ( 1+(-5)=.95=5% reduction). In the example, your max spark advance should now be close to 27*.

You can also monitor your HO2S (B1S1 and B2S1) to see what voltages are coming back at WOT. But, these can't be trusted. That's why we need wideband O2's to tune. However, some say .890-.910 are normal readings for stock manifolds and .910-.930 are normal for long tubes at WOT. The higher the number, the richer the AFR.

I got rid of my Predator due to the limitations I had in tuning my car. You can get custom tunes over the net from some really nice people (cough...RWTD...cough), but I wanted to do it myself.

RyRy

iTrader: (6)

Thanks, I will give that a go and see how it works out.

2001NBMZ28

Don't know if it's absolutely required, or even necessary - but I always give my car a few ignition cycles/50+ miles after making any changes before beating on it too hard.

RyRy

iTrader: (6)

I figured it would be something like that. If I am getting KR, which way do I need to tune the spark timing? Advance or retard it? Thanks again

SSpdDmon

iTrader: (10)

You need to remove spark if you are getting KR. So, retard it.

mrr23

iTrader: (3)

or add fuel to get rid of the knock. you'll just have to try different things to see what happens.