weird starting problems on s13

[swodell1]

The car is a 1990 stock ka hatchback, but the motor was just swapped in from a coupe. After I finally got it started up after the swap, it has been having a weird problem starting up when cold. I also swapped the gas tank and fuel pumps from the cars, and all of this stuff worked perfect on the coupe before the swap.

Suppose I go out in the morning to start the car.. if I don't hold down the accelerator pedal when cranking, the car will not start. After some rough cranking, the car will fire up and run, but it will cut off if I don't keep my foot on the pedal for a few minutes. Let it be known that when it DOES start up initially in the morning, it will let out some loud backfires and popping noises.. sounds likes its running really rich or something. After I run it for a few minutes, it will hold an idle just barely. The idle slowly starts becoming more normal the warmer the vehicle gets, but it is never perfect. The car just runs pretty rough even when it has fully warmed up, and I don't know why. A friend said it could be the Idle Air Control Valve? Is it possible that my fuel pump is week and that is the reason I have to hold the pedal down when first starting?

I've been looking over it for days and weeks and don't understand. Luckily, its reliable once its warmed up.

I'd appreciate any help I can get. Thanks in advance!

[Homer_Simpson]

Have you checked the start signal wire? I forgot the exact pin location but IIRC its an orange wire. Do a search, it has been covered extensively.

[swodell1]

I searched and I could not find anything about the start signal wire.. does it have another name? Where is the start signal wire?

[swodell1]

I would also like to note that the car has been running very rich and my gas mileage sucks horribly ever since I swapped it. I used to get about 20 city 28 highway with this same KA when it was in my other car.

[93nismo]

is the egr stuff hooked up? that could be the idle and the runing rich part. and it might be backfireing and such when u start it becaus you have to hold the gas down when you start it. did you swap the harnesses when you did the swap? maybe you forgot to plug something in? are all your vacume hoses on right?