Control selection

[Eric Elliott]

Hello,
Still reading DIY_EFI archives, number of EFI & ignition questions growing,
required reading list growing fast, need to study more C, not enough hours/day.
An introduction might be a better way to start, but perhaps my questions will
adequately describe me. 

How can the C3 TBI ECU do a smooth idle with large roller cam?

How can the C3 TBI ECU do the increased timing advance needed with Dart
Sportsman heads?

Given these problems:
	High MAP due to a cam  of 208/221degrees @0.05" valve lift, 0.474/0.51"
valve lift.
	Less ignition advance due to high MAP.
	Idle rough when MAP sensor connected.
	Old stock engine & ECU had needed more small throttle ignition advance.

An amplifier was inserted between the MAP sensor and the ECU, referenced to 4.73
VDC (the 	MAP output @ 1 bar), with 1.3 voltage gain.
The result was worse idle, increasing oscillation till engine stopped. No load
operation was smooth at 1200 RPM, but operation in gear was not tried.
Tentative conclusions: ECU samples vary wildly @ idle due to long cam, ECU
compensates, idle is worse. the added amplifier multiplied MAP variations by
1.3, increased idle instability.

Would a high pass filter at the MAP sensor output, maybe 60 Hz cutoff, followed
by a variable gain amplifier help? 

Am I on the right track? I have the often mentioned soldering iron, a Fluke 97 2
channel digital storage Oscilloscope, Fluke 87 DMM and a laptop computer. Any
help will be appreciated, this is my daily driver while working in NY till June.

Is an interface and program available to use the ALDL with a laptop PC?

Is a program for analysis and modification of C3 PROM data available for PC?

Does the C3 optimize ignition advance for power/# of fuel or only retard if
knock is sensed?

Eric Elliott
800.827.5038	315.343.5657	75771.3640 at compuserve.com
Permanent address: 68 Carol Lane, Batesville AR 72501.8023 Ph.501.251.3659
Temporary Address: #2, 67 Albany, Oswego NY 13126-3244   Ph. 315.343.5657