i got a ls motor in my ef and it is not starting it has spark and fuel pressure and the main relay its brand new and it ran for about five minutes then i pulled it into the shop and turned it off and it wouldn't start after that and any sugestions would help

 

How do you know that you have both fuel and spark?

Check whether the timing belt slipped.

Also, is the spark bright blue or weak orange?

 

yeah definately check the timing especially if you just put the motor in. My buddy did a b16 swap and it turned over the first time but wouldnt run after that. timing.

 

are you using a good harness or a crapily put together one. <--- that caused me some issues.

 

i checked the timing thats good but it thorwing a code 1 on the ecu but i know that o2 isn't hooked up the spark is white ish i am going to check the coil to see if that s the problem

 

Do you hear the fuel pump prime? Have you measured the fuel pressure? Have you checked cylinder compressions?

When you eventually solve the no-start problem, purchase and install a new O2 sensor. Engine performance and mileage will be much improved.