So I swapped in a 1jz into my 90 supra and I just finished up the wiring and am trying to get it to start... It will start for like a second and then shuts off... Any suggestions to what my problem is?
1j starts for only a second!!
- Thread starter NokaoiMK3
- Start date
super.secret.supra.club;1376966 said:
yep i got that... Its a brand new map sensor from driftmotion too..
aphxero;1376970 said:
alright.. but i ended up running my fuel pump off a seperate fuse and relay because i was having problem with not getting power at the pump..
could my fuel dampner be causing me to loose fuel pressure and thats why it will only start for a second? should i get a bypass hose from driftmotion?
check your codes, and most likely youll throw a code 14, which means ur ecu is shot
my car did the same thing a while back
my car did the same thing a while back
aphxero;1377077 said:
Wait what? Sorry im a little confused.. What do you suggest I do with my circuit opening relay..
Make sure you have constant fuel pressure PAST the rail. If you don't already have an AFPR, get one and get a guage that goes in the front. Make sure you're getting at least 35psi to there or it won't start longer than you can get it to. I have seen the stock FPR go bad. AND ZOMG get rid of that fuel damper. Causes so many problems..
Also, make sure your crank sensor is good. Cam sensor also, but car should start without the cam sensor in there. CHeck your plugs, ignition etc..
Really does sound like a fuel issue. If it were me, I'd get a completely separate car battery and just plug it straight up to the fuel pump if you can and make sure it turns on and gives plenty of flow. If you don't have an AFPR like I asked earlier, then disconnect your RETURN fuel line (make sure you catch the fuel / don't start a fire.. lol) and make sure there's LOTS of fuel coming out. If its barely any or not a lot, there's a problem somewhere in your fuel system. If you DEFINITELY have 12V going to the pump (you know it for SURE) then it could be a few things. Could be the pump, fuel filter (I have seen no-starts on a clogged fuel filter, doesn't seem likely to some people..) those s***ty fuel dampers, or the pressure regulator.
Also make sure you're getting spark on all 6.. while you're cranking hold the plug to the head/ any ground and make sure it jumps the gap.
If you aren't getting fuel for some reason with it connected to the car's known 12V circuitry, it would probably be the MAP. If you aren't getting spark, would most likely be crank angle sensor. If neither of those are the problem.. your ECU sucks.
Good luck dude.
Also, make sure your crank sensor is good. Cam sensor also, but car should start without the cam sensor in there. CHeck your plugs, ignition etc..
Really does sound like a fuel issue. If it were me, I'd get a completely separate car battery and just plug it straight up to the fuel pump if you can and make sure it turns on and gives plenty of flow. If you don't have an AFPR like I asked earlier, then disconnect your RETURN fuel line (make sure you catch the fuel / don't start a fire.. lol) and make sure there's LOTS of fuel coming out. If its barely any or not a lot, there's a problem somewhere in your fuel system. If you DEFINITELY have 12V going to the pump (you know it for SURE) then it could be a few things. Could be the pump, fuel filter (I have seen no-starts on a clogged fuel filter, doesn't seem likely to some people..) those s***ty fuel dampers, or the pressure regulator.
Also make sure you're getting spark on all 6.. while you're cranking hold the plug to the head/ any ground and make sure it jumps the gap.
If you aren't getting fuel for some reason with it connected to the car's known 12V circuitry, it would probably be the MAP. If you aren't getting spark, would most likely be crank angle sensor. If neither of those are the problem.. your ECU sucks.
Good luck dude.
What happens when you hold the throttle as it turns on, mine was just like that and it was from bad grounds on harness, try someone else ecu on your car to see if the ecu is out, if u know someone in area with a working 1j ask him to swap out sensors , coils with yours
My guess is ECU as well. Its always a problem with these cars! If you can swing it, take the little extra time to swap to a 2jz ecu so you never have to deal with it again and can enjoy vastly improved driveability 
I checked the codes and the only code that the computer was throwin was a code 14... So i thought that my ecu might be bad so I went over to a friends who also has a 1j and tossed in my ecu and his ran great so it not my ecu...
juan jz;1379386 said:
Does the exact same thing if i hold the throttle haha the was one of the first things i tried... I have also gone through and added grounds and from what i can tell there all there and are grounded properly but ya never know i could be missin one.. And yeah i have a couple friends with runnin 1j's so they are defiantly helping me along the way given that they had a lot of the same problems that I am having... My friend billy's 1j was doing the exact same thing and throwing a code 14 to find out that one of his ignition wires was grounding itself out on the intake mani..
boostin300;1379367 said:
Thanks man and since i have my fuel pump running off of a seperate fuse and relay it has a constant 12 volts as soon as im in the "acc" position and same when in "on" and when cranking.. And its a brand new walbro so i know the thing is movin some fuel.. I can feel it pumping through on the return.. But i defiantly need to test the actual pressure to make sure that my oem fpr isn't bad... I wish i had an aeromotive..
So i just put back in my engine and dash harness real quick for some diagnosis and for kicks turned it over to see if it was doing the same thing.. And it fired right up.. Im pretty sure it was this one wire that my friend billy found that was disconnected and went to my ignitor.. So now i have to pull back my engine harness and wrap it up and put everything back together.. But im sooo stoked that my engine runs.. Its been way too long in the making.. Thanks for the help everyone..