No start hot or cold with out opening throttle a little bit.
440 Mopar Tunnel Ram with twin throttle bodies, 654 lift 308 duration. Fuel Pressure 58psi, IAC SET AT 6-10, Prime Fuel Multi 259, Idle AFR 13.9, Crank IAC 0.0. Have adjusted Prime Fuel Multi up and down from -100 to 300 no difference, adjusted Crank IAC up and down set at 0.0 right now. Eng will crank and try to start but until I open throttle blades slightly will not fire up, open them too much and it back fires thru throttle bodies. Tech support suggested I check and adjust Prime Pump Time was 2 brought up to 8 going up by 2 at a time ( no difference)! Changed cam setting from to 3 to 2 no difference. Engine runs well once started will idle down crisp throttle response. Have also change cranking fuel up and down at 20f 65f and 170f. Nothing has made a difference!
Any help would be appreciated??
That's a lot of duration for cam setting of 3 even. What is your idle vacuum? I've got .790 lift in my small block chevy with just a tad more advertised duration and had to set my cam setting to 4, since I only have about 5 in Hg at idle. I also had to set my idle AFR to 16.4 to keep from fouling out my plugs because of the cam duration sucking in fresh air from my exhaust at idle. It was trial and error for me to get good plug color and have it idle and start nicely. Hope you get it resolved.
So it turns out the two vacuum plugs on the back of the main throttle body blew off when it backfired and I did not notice it while we where tuning, I put them back on and now my IAC settings wont come down past 180, engine vacuum at idle is 1.5 in of vacuum changed the cam settings back to 4, still wont start with out opening up throttle blades ??
Yes, that makes sense. To get your IAC down I had to turn the idle screw in about a half a turn, shut the car off for about a minute, so the TPS went to zero, then fire it up again, and if IAC is still too high, turn the screw in some more, shut the car off, etc. I finally with my engine had to turn the screw in a total of about 2 full turns before it got the IAC steps down. I think that will then fix your starting problems.