Well finally the HSR is on and functioning. The top end pull on the car is amazing compared to what it used to be, and the throttle response is great. Ive had numerous problems along the way, but Ive got one that I just cant seem to figure out. The car has great throttle response while moving, but when revved in park or neutral, the engine hesitates and sputters and sounds like it may be backfiring through the intake. The TPS is new and adjusted properly, the IAC is freshly adjusted, the timing is on, and the fuel filter is new. The ignition is fairly new as well, and since the car performs great at higher RPMs, I doubt that is the problem. If it makes a difference, Ive got the non-adjustable type regulator. Any ideas? Any help is appreciated.

 

You need the chip reprogrammed

 

I had considered that, but Ive read that the MAF has the ability (unlike speed density) to adapt to roughly 15% more airflow over stock before needing the tables modified. I dont think Ive gone beyond that. Maybe theres another aspect Im overlooking. Thanks for the suggestion Odyssey, thats something to consider.

 

Yeah but that's just somewhat educated guesses that people made. Nobody will know for sure, unless you talk to one of the engineers that designed the ECM I'd say the HSR is a totally different animal when compared to your TPI. And you better have more then %15 air flow going in there!!

 

Depending on how bad the hesitation is, and where your current settings are, you might be able to at least soften the tip in hesitation with TPS adjustments. If you haven’t done this already (you indicated it was new and adjusted properly), set your wide open throttle TPS voltage as close to 5.0 volts as you can – this can reduce or eliminate a tip in hesitation (depending on where your WOT setting is now). Also, while you want to keep the TPS idle voltage as close to 0.5 volts as possible, I’ve set a couple “modified” engines in the .7 volt range with gutted MAF sensors.

I’d suggest getting a scanner on it pretty soon, or at the least pull the plugs to see if you’re running lean. You’ll be extremely lucky if things check out under WOT with the standard fuel pressure. You may want to look at getting an adjustable regulator. Bumping the fuel pressure a couple pounds can do wonders for a tip in hesitation (if the maxed out TPS settings doesn't work for you). Even if you end up burning your own chips, the AFPR can help you dial in the chip settings.

What you described could also be timing related. It's hard to say for sure over the Internet. The StealthRam will want more initial timing than the TPI with the stock chip. However, it's imperative you make sure your fuel mixture is OK first.

Good luck!