1987gt40ttop

so.. me and my buddy just put a new motor in his fox. It has a mild cam, 65mm t-body, headers, gt-40 intakes, 24 lb injectors..the usual bolt ons and thats about it. It was a speed density car that he converted 2 mass air. heres the prob.
When you first start the car when its cold its tough to start even draining the battery down some times once it turns over and gets running, you gotta give it gas like a carb. car or it will stall. Do that for a couple seconds almost like when your tryin to get the choke off fast idle and then itll run fine. shut it off start it up and itll run fine. come back 15 min later and itll run fine again. now he doesnt drive the car on the street and it only gets started every week or so. I dunno if its just from sitting or his mass air meter which is a pro m 77 by the way, but im kinda gettin frustrated with this one anyone got any ideas?

67mustang302

It sounds like you've never driven a carb'd car that was running right. Any codes? Are you sure all the sensors are working properly?

1987gt40ttop

i didnt say a carb car that was running "right" but the way this is running is more like a carborated car an injected car should never run like that. there are no codes, in fact since its a speed density car you can even unplug a sensor and it could possibly not throw a code.

67mustang302

You do realize that a carb'd car when properly set up will run just like an EFI car that's running properly, right? That's why saying that an EFI car isn't running right because it's running like a carb'd car is a somewhat useless statement. It doesn't say anything about what's wrong.

That's why you have to clearly describe what's happening. Is it only a cold start issue? Does it always crank hard? What does it sound like when cranking, how old is the starter, what starter, has the battery been tested etc. What's the condition of the ignition system? Does it come up to a cold high idle? What do you mean by you have to give it gas, you have to hold the throttle open to keep it running? You have to feather/pump the throttle to keep it running? Does it smell like gas when it's first started? Black smoke out the tail pipes? Popping through the intake?

Also, check the plugs. Put a new plug in one cylinder, get it started when it runs like crap and let it run like crap for a bit, then shut it down and check the plug. That can tell you tons about what's going on. Have the sensors been checked for proper voltage/resistance range?

lxman1

Sounds like an IAC problem along with probably other issues.

1987gt40ttop

that was kind wat i was thinking, that maybe the iac was sticking or not opening all the way because it acts like its starving for fuel when its first started, but then couple seconds after keeping it from stalling it runs fine