i have a 89 gts-t with an rb25det swap. The engine cranks but just wont fire i dont know why? any help would be much apperciated.

Well.. to run you need three things, compression, fuel, and spark. Go through and see which you are missing. Check you have fuel in the rail and injectors are opening, check you have spark. Small steps make up a marathon.

You also need power to the ECU during "start".

thanks ill try that out and ill keep posting if the problem keeps happening.

Your post is totally useless in helping people help you diagnose your problem. Perhaps if you outline what you've done. e.g. whether it's a new engine swap, or whether you bought it like that, whether it's ever started, whether you have or think you've done anything stupid or dodgy etc.

Spray some nulon brand 'start ya bastard' into it

Edited May 4, 200719 yr by MANWHORE

so i purchased the car with the swap already in it, it was running fine when i got it then it started to idle funny and die at random, so my brother thought it might have a plugged fuel filter in the processe of checking it out he dropped it on the headers and my whole engine bay went up in flames i put the fire out and the insurance company "fixed" it after about 8 months of fighting with them and the shop that was supposed to be working on it. when i got it back it can poorly it hunts durring idle untill it wwarms up and then evens out at about 750rpm it also surged under boost now. about a month ago it kept dieing so i checked the spark plugs and they where covered in black what seems to be carbon which im asumeing is from it running to rich, so i changed the plugs out. after about 15km of run time i parked my car and i havent sarted the car for a while the other day i started it up and it hunted like usuall then just died. since it has died i have changed out the vacuum lines other then that i have no idea why it wnt start it cranks there is fuel getting to the fuel rails my ECU is turning on but it just wont start the plugs are aleady black again but the tips are still cleanish and should spark. i hope this is a little better info on this cars history and some one can help me figure out what i need to do to get it running again

thanks Brent

DO YOU HAVE SPARK - definitely?

so today i sand blastd my plugs and after about 10 min it the car finally turned over and started but only ran for a couple of seconds then died again and wouldn't start again after that... is it possible that there is a faulty sensor that would cause this because i have fuel and i have spark the only thing i have not yet checked is compression but im wondering if theres anything else that could cause this

It sounds like the fuel pump is losing power as soon as the key returns to "ON". Even if you had poor compression, the engine would still run once it started.

You need to fit a fuel pressure gauge to confirm that the pump and FPR are working correctly.

i can hear the fuel pump turning on once i turn the key to the on position but now that you say that it does seem to turn on and keep running for a longer period of time then usual once i turn the key to the on position i can hear it for probly about 15-20 seconds ill try and see if thats the problem thanx ill keep everyone posted on the progress