Ken,

I installed the new chip today, definitely runs better than the last chip. A few things I noted:

I removed the saw and set the base timing at 10° at 850 rpm. When I plugged the saw back in, the computer moved the timing to 23° at 850 rpm.

Lean tune:
Idle is good, perhaps just a bit on the rich side, will not stall. Cold start idles at 1200 rpm, when it warms up it drops to 850. Throttle response is fairly smooth from idle through WOT, although when the motor reaches 3,000 under load it almost sounds like the valves start floating, it’s a real throaty kind of pre-det sound.

I would have to think this motor should turn 4,000 without harm; I use to hold the old 460 at 3,000 rpm when pulling up a steep grade.

Aggressive tune:
Idle is poor, seems too rich, black stuff out of the tailpipe. 1050 rpm cold, 625 warm and will stall. Throttle response is sluggish at first hit of throttle. It sounds and feels just like it’s running on 7 cylinders. The throaty pre-det sound is not heard until rpm’s reach around 3,500. I tried the stock tune position, and didn’t notice too much difference between these two settings.

It runs the best by far on the lean tune, but I would still say in general that we are throwing too much gas at it.


Both tunes will turn the check engine light on after approx. 5 minutes of driving. It sat and ran at least 20 min. while setting up the timing, the engine light never came on. After the engine light comes on while driving, shutting off the ignition will clear it, and it won’t come back unless driven for approx 5 mins. Sitting and idling, or revving the engine while in park or neutral will not induce the engine light to come on.

I would say its running good enough with the lean tune setting to send it to the dyno to get some air/fuel charts.

Any thoughts or ideas?


521_Ford

 

Put it on a dyno with the lean tune and we'll base it off that. How high is the fuel pressure turned up right now?

 

I can only assume 70 psi, I have not changed out the stock fuel pressure regulator. Would it be a wise investment to purchase an adjustable regulator? and if so, if I lowered the fuel pressure, would that in effect reduce the amount of fuel being delivered? It seems to be getting too much fuel at lower rpm.

 

Yes, with the build you're running, it would. Lowering the pressure will reduce the fuel but it will do it across the entire RPM range. You really need to get it on a dyno now so the entire fuel curve can be adjusted.