I sent my computer to Ed Wright for tuning. I am now having trouble with the idle. The RPM's hold about 650 at a stop light then after a few seconds the RPM's start dropping all the way to zero (engine dies). It doesn't do this every time but about half the time. It also died twice when going around a corner. I only have about 15 miles on the car since the computer was installed because I was concerned that this is a symptom of a bigger problem so that may have something to do with it. I did the idle learn procedure out of the Service Manual and that didn't help.

I called Ed Wright Automotive (didn't get to talk to Ed) and was told my IAC was probably low. They said to hook a scan tool and check the IAC and in Park it should be about 30. If it more than that I need to drill a hole in the throttle body blade. He didn't seem concerned that I only had about 15 miles on the new computer.

I have heard of this for Vettes with heads and cam but not for supercharged. Before I sent the computer it never died at idle but I had some surge problem (bounced between 600 and 800 RPM's). Any thoughts?

 

Just curious, did you have them reprogram your PCM because of the supercharger. The reason I'm asking is I'm getting ready to put a magnuson super charger on my car and when I do I was planning on sending my PCM to these people, so let me know how this turns out and good luck :cheers:

 

Drilling the TB is typical when introducing modifications to the engine ..and in most cases that would be heads and specifically a higher lift cam. I have a drilled TB (1/32) and the car idles at 900 rpms with Ed Wright programming..It soundslike drilling the TB would be a option to consider..The car is obviously looking for more air and the default program in the PCM is shutting down the car to minimize any damage..Start with a small hole in the TB blade of about 1/64 and drill larger until the idle stabilizes..Seems like a easy fix..I wouldn't be to concerned ..just my .02:D

 

With LS1 Edit you no longer have to drill the TB, you can program the throttle body to open at idle. I assume ED can do the same, so tell him to increase the IAC and throttle follower tables.

 

Mine was the same way but the problem went away by itself after a couple of days and a couple hundred miles of break-in.
Good luck.

 

I've tried the drilled throttle-body route on one of my non-Vette custom fabbed, supercharged applications, to no avail. It seems from my research and experience that there are a number of possible reasons for both idle and off-idle response difficulties in blown EFI apps. It is always most difficult to trace and correct when intermittant and with several significant mods applied at once (i.e. heads, cam, injectors, tb, etc.). Don't ask how I know! In my case I finally had to go to an auxiliary computer to allow modifying fuel parameters enough to get in the ballpark. Hang in there and all the best. :yesnod:

Wow my 1100th post! :rolleyes: I'm clearly spending too much time at the keyboard and not enough in the shop and on the road! :lol: :lol: :lol:


[Modified by Avanti, 11:24 PM 10/30/2002]

 

tcmc5,
Thanks for the response. Did you have Ed Wright do your tuning? Do you have a blower?