• Hello there guest and Welcome to The #1 Classic Mustang forum!
    To gain full access you must Register. Registration is free and it takes only a few moments to complete.
    Already a member? Login here then!

EFI engine idle problem

1

1965Mustang

Member
I recently installed a 93, 302 EFI engine in my 65. Trickflow heads, Comp cam, all new sensors, computer, painless wiring harness, etc. I cannot get it to idle properly. I have changed IAC valves 3 times, readjusted base idle about 50 times. reset TPS, even changed computers and checked every ground. Still no luck. I have got it to idle consistently at 1200 rpms with the IAC disconnected otherwise it stays between 1500-1800 rpms. When the electric fan comes on it goes up another 300 rpm when the power to the computer drops to about 10. I have a new March Performance 100 amp alternator. I just got it back from a dyno tune at Roush Racing and have taken it back one time because of the idle problem, but still won't idle down. No vacuum leaks-used a stethoscope to check everything. Thanks
 
What are the cam specs? Larger injectors than stock? EEC4 computer? Checked Timing with the SPOUT disconnected?
 
"67 evil eleanor" said:
What are the cam specs? Larger injectors than stock? EEC4 computer? Checked Timing with the SPOUT disconnected?
Click to expand...

+1. If the cam is more than what the computer will handle, it will do the dreaded idle surge. It will want to run rich, and the computer over compensates and leans it out, then it goes back to rich...and so on and so on. Mine did that with the Ford E-303 cam (which is notorious for that), I had to get a tweecer and modify the tune to get it to idle. It's not perfect, but at least I'm not stalling out at stop signs anymore!
 
"67 evil eleanor" said:
What are the cam specs? Larger injectors than stock? EEC4 computer? Checked Timing with the SPOUT disconnected?

If I remember my number correctly, cam is 270/276. 24# injectors. Stock computer with a Roush tune and chip. Timing set by Roush. Don't remember the exact # but about 4 degrees above normal. Put in a different stock computer tonight, re-installed the IAC and it idles great but power is down. has to be the tune IMHO.
Click to expand...
 
You must log in or register to reply here.
Back
Top