weird problem

[donnie89240sx]

ok well i tried searching but i cant find anything to help me. ok this is the situation my other motor burned up. so i got another motor out of a salvage yard that had a couple of 240's. i grabbed a long block since my intake and everything is good. the motor currently has a new head,camshaft,rockerassembly,timing kit,and complete gasket set. the problem is this it wont idle. and when i have the RPM's higher then 2 grand it runs fine and when i drive it, it runs fine. when i get on it. it spits out black smoke from running rich. ok when i pulled codes it comes up 12,41. the first time i did it. it was just 41 so i replaced the air intake temp sensor. now its telling me mass air flow meter also. whats one thing i should try? how do i find out if the ecu is just bad or if it is actually the wiring or what not? i need help badly. any ideas would be greatly apreciated.

[180fan]

pull the plug on the mafs. see if it idles.

[donnie89240sx]

the only way it will idle is if i play with the gas pedal. otherwise it wont idel at all. rather its pluged or unpluged. thats y i am thinking its the computer but i want other opinions before i go and spend a fortune on a computer for it,lol

[180fan]

so did you try it with the mafs unplugged and even the tps unplugged?

[donnie89240sx]

yea i can unplug the mafs and tps and it still wont idle. whats that valve in the back of the intake that controls the flaps that run through the intake to restrict the air going into the head? i think thats whats causing it because when i pushed a screw driver to make it close the intake off and had someone turn the key then it started and idled a lil bit so thats one of my problems when i put suction on a vacuum line to it. it didnt move any.

[CrypticScorpio]

same prob here mag, email me your solution if u fix it. [email protected]

[CrypticScorpio]

have u tried cleaning ur IACV. havent got the time off work to try mine yet. i heard that throttle body cleaner in the second hose(bigger of the 2 hoses coming off the intake body

{} <-------throttle body[ ][ ] small 1 big one to iacv is the bigger one on the top \__===| |=========={*} 1 2 airbox

****ty pic but i cant upload pics from my pc, to many blocks

[donnie89240sx]

well i know that wouldnt help mine and i found out that isnt causin my car to fk up. i unhooked the arm and usin a screw driver i turned it and tried starting my car and the same thing so im not going to worry about that iacv. i wonder what the purpose of that dumb thing is anyways. imma just replace it later. i can go to a junk yard and get plenty of them things a dime a dozen.

[junkyard240]

i think you should probly get a better understanding of how a modern engine operates before you just start replacing things. it is not very often if at all an ecm goes bad either.

[donnie89240sx]

but see they do go bad. its not hard for a computer to go bad.and why cant i just start replacing parts? if i think they are bad and/or they look bad then i think it is time to replace them.

[180fan]

yeah it's possible for an ecu to go bad. figure it is almost 20 years old... just tough to tell when they do kick the bucket though. Usually it's by eliminating pretty much everything else that you do something like switch out the ecu from personal experience.

[donnie89240sx]

ok i fixed my car. i put a new computer and also unhooked a couple vaccuum lines that go to the back of the head only leaving the fuel pressure regulator,and the iacv hooked up and now she runs just fine.