The old motor gave out at 199k, wouldnt circulate oil..bad. Brought it to a shop and sent them a new 2.8 crate motor. Well I was sent the wrong motor..for a carb'd early 80's s-10 or trail blaizer..we dont know. After swaping flywheel, valve covers, oil pan, the mechanic finaly got it running but gave up after a week. in open loop operation (motor cold) it will not keep idel and die. I have to keep my foot on the gas untill it warms up after 10minutes untill closed loop then ok.. WTF I dont want to deal with this. summer is coming (PHX) and i dont want to have to bake in my car untill it will drive. Any ideas? I know that in open loop the computer only reads from one sensor but I dont rememer(I think MAF). can we force a closed loop some how? Plz help.

 

In open loop the ECM only IGNORES one sensor, the O2, it relies on everything else to give it accurate information to get the A/F ratio as close to perfect as possible.

Did you guys put the correct engine in? Is everything hooked up correctly?

Sometimes parts fail with a new engine. People have this notion that just because the engine is new, that it will run like new, but the chances are that if you use the same sensors that had fairly close to the original milage on them, something is bound to fail and die during the swap process. Don't assume that just because it ran before that you definitly don't have a problem now.

How are you sure that it's acutally entering closed loop? Have you checked it with a scan tool and/or ALDL jumper? 10 minutes is a long time to enter closed loop and if it's actually taking that long, there is something else going on that you should fix first. It should only take about 2 minutes at a maximim to go CL. My 276K mi engine takes about 1.5 minutes to enter CL when started cold first thing in the morning.

 

get ur heads off ur old motor,if they sent u a carbed motor then more then liley the motor has small valve heads on it,and the cam will also be different,though that shouldnt make the car not idle cold though