Setting Idle and timing on EFI???

[FrankSG]

I have set my timing to what I believe to be good, but would like to advance it a bit more, just to see how it would run at 13 / 14 Deg. The problem is that I am unable to lower the idle. The idle screw is retracted as far as it can go.

Has anyone else ever had this issue or can tell me how to fix this. Is there something else I can do to set the idle so that I can adjust timing?

Thanks,
Frank

 

[ScanmanSteven]

http://www.muscularmustangs.com/iac.php, try this, it might help.

 

[Viperwolf1]

The computer wants and needs to be in control of the idle speed. It should be near 750-800 rpm if everything is good. The idle screw is really just a throttle blade stop. You want to have it closed enough so the computer can control the idle speed with the IAC but not so much that the throttle blade binds in the bore. I like to set it so the idle speed will drop about 100 rpm when the IAC is unplugged with engine hot.

If it still idles faster than 800 rpm even with the IAC unplugged you likely have a vacuum leak.

For setting timing you just need to pull out the SPOUT plug. This will remove all computer timing control so rpm isn't really important.

 

[FrankSG]

Thanks for the information.

If I understand what you are saying:

1. First readjust blade setting screw just before the throttle bottle blade makes contact.
2. Set the timing with the SPOUT plug out., then connect plug and recheck timing.
3. When should I unplug and reconnect the IAC to have the computer set the idle. Or how do I adjust it?

It seems that when I set the timing from base 10 (SPOUT plug out). The idle jumps as I increase the timing. It seems that the timing is in control of the idle setting.

Thanks

 

[Blue Bastard]

Don't forget to adjust TPS after farting around with the idle set screw.

 

[Viperwolf1]

Thanks for the information.

If I understand what you are saying:

1. First readjust blade setting screw just before the throttle bottle blade makes contact.
2. Set the timing with the SPOUT plug out., then connect plug and recheck timing.
3. When should I unplug and reconnect the IAC to have the computer set the idle. Or how do I adjust it?

It seems that when I set the timing from base 10 (SPOUT plug out). The idle jumps as I increase the timing. It seems that the timing is in control of the idle setting.

Thanks

You're mixing 2 different adjustments. Set the base idle speed first.

1) With engine hot and running, unplug IAC and make note of idle speed difference. Speed should drop by about 100 rpm. If it doesn't, back out the throttle stop screw until it does. If it still doesn't drop you have a vacuum problem.
2) Plug IAC back in.
3) Shut off engine and restart. If you get a CEL you might need to play with the TPS but in 99% cases you won't. There is no need to set the TPS to any specific voltage. It just needs to be above a minimum and below a maximum.
4) Unplug SPOUT and set timing.
5) Plug SPOUT back in.
6) You're done.

 

[FrankSG]

Problems !!!

I have adjusted the timing. Perfect it idles between 86o and 900 RPM.

Timing is out of wack...Backfire's, I can smell fuel. What the freak is going on.

I pulled the SPOUT plug. Watching the timing mark it is not reading at 10 TDC. So I proceed to set the timing to be at where it should be. No Luck!! I even moved it back and fourth 2-3 degrees in either direction, but still same thing. It seemed to be running fine before the idle adjust. But once I started to screw with the timing, I'm back to problems with the timing, One note is that at some point I did hit the reset button on my timing light.

How can I get the timing completely reset so that it is truly at base 10 degrees?

Thanks,
FRank