hard idle on new engine

greengoblin95

Member
Sep 29, 2009
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hey guys, new to the boards, but have scrolled through them quite often. i just recently built a 306 with roller 3/8 stud 1.6 rockers, typhoon intake with 1 inch spacer that it made, 70 mm tb, 42 lb injectors and calibrated maf,adjustable fpr, trickflow stage 1 cam, pro comp heads with 2.02/1.62. i have my sq installed but left the belt off to make sure that the engine was sound, i knew that i would be running rich from the bigger injectors. its in my 95 gt

well when idleing, if i tap the gas, the car shoots to 3 grand and holds a bit then climbs back down. if i try to hold the gas passed 3 grand it starts to sputter. im sure that its just loading up and is just too rich and that my computer is pretty much fighting itself with the fuel (trying to lean it then dump it back in when it does lean out). i am thinking this because i will smell the burnt fuel then i hear a small backfire in the intake which tells me that it did lean out. i am hoping if i do put the belt on the blower that the extra air from it will equal out the excess fuel. i am planning on getting the car tuned as soon as possible, i was just making sure that my theory was correct. i have also checked my tps and i have it adjust to .931 volts (seemed to climb down faster when reved at idle, i know that perfect is supposed to be .96-.99)
i do have a set of 24 lb injectors with calibrated maf if i have to go that route before i take the car in for driveability. again, the blower belt would be off until the tune. just seeing what you guys think about this
 
Check for vacuum leaks first. Being it's a new motor there could be one off or cracked. Sounds an awful lot like similar situation I helped a friend chase down several years ago on a new motor. He was at his wits end after a couple weeks and one shop visit. Was fed up and goin carbed the next day when I found it. lol


PS: Those are some huge arse exhaust valves on those heads.?????? lol
 
yea, i meant 1.62 lol, been a long day. i have sprayed the upper end with throttle body cleander and the motor didnt bog down or kill over. i kept my vacuum system simple and the hoses didnt have any hard wear on them. the vacuum tree didnt appear to have any leaks as well, but its hard to say.