well my friend comes over today he had been talking to another supra owner who knows alot more about car tuning then either of us put togther. well hes been talking to him about my car and its endless birage of problems. hes recomended i get the car leakdown tested to make sure i haveny bend or burnt a valve.the motor runs smooth and quiet idles steady and vacum decent . i dont think its the valves
im running 10psi of boost and got my new hot pipe on and iam and have been blowing alot of black smoke under boost. i hav for a while now . but we cant figure out where im running rich from. well tonight a new theory came about.
the walbro fuel pumps. which i and most of you use one are meant to run at 12volts all the time. well the CA and most cars have a system that runs pumps at a fluctuating voltage to quiet the pump and conserve power. this means that the pump isnt always running at the full 12v at lower RPM and idle its running between 6-8v thats about half of what the pump needs . and we think it maybe causing fueling issuse with my setup. as i get lean symptoms under cruiseing and i blow black clouds reminecient to early locomotives from the 1800s. there are products made in japan to elminate this but im not paying for it and so goes the weekend task of locating this system and taking it apart or just bypassing it so we get 12v to the pump at all times and hopefully keeping the fuel pressures constant and me running right
somthing interesting i just found out.
lotsa SR swaps and turbo KAs run walbro. They don't have any issues. No wiring mods.Can't see valves causing a prob if you're idling smooth. They are a prob in the CA, but it'll run crappy.Have you checked your fuel pressure under all running conditions?fuel pressure reg governs it.... u know *regulates*U sure u have no boost leaks... had a hose with a small split that I looked over a few times, but it obviously opened when pressurized. Ran stinkin' rich under boost. $4 later car was pinning u in the seat. no more black smoke
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Spectre_240sx
- Posts: 261
- Joined: Sat Mar 08, 2003 6:42 am
- Car: 1990 240sx SE
- Contact:
bottom of page check it out!
http://www.tomei-p.co.jp/_2003....html
also i am in the process of changing every single hose that passes air in my system and redoing the wiring, just need to get some free time an be awake before 3pm
http://www.tomei-p.co.jp/_2003....html
also i am in the process of changing every single hose that passes air in my system and redoing the wiring, just need to get some free time an be awake before 3pm
What about using a fuel pump from a Twin Turbo Z32? those are supposed alternate from low and high voltage...any reason why this would not work?
I've also heard that Walbros are prone to breaking, though no one I know has had problems with theirs. Might not be a bad idea to check if it's still good or not...
I've also heard that Walbros are prone to breaking, though no one I know has had problems with theirs. Might not be a bad idea to check if it's still good or not...
Im running a walbro 255 on mine. The car does not throw black smoke out the back. It does run a little rich, but im guess thats due to the Mines tuned ecu. Plus the car does not want to keep a steady cruising pace. Im either going fast or slow. Theres no in between. The car starts to "studder" when i try to keep a constant speed. Like its misfiring or something. But I can free rev it and its perfectly normal. It only does it under load/driving.
If I step on the gas a little bit more it goes away. I also recently checked my spark plugs, and they come out black every time.
Some one said the KA -T and SR's have no problem with this. And upon further inspection of the site slw240sx posted, it seems theres a relay that controls this feature and that harness would replace this relay.
Well it got me thinking, maybe this feature is specific to the JDM model with all the JDM wiring. Maybe the KA-T and SR's dont experience this because they use the wiring from here (USA).
Maybe there is no voltage control relay for the US models? Can anyone verify this?
My car idles smooth and runs perfect under boost. Its just the cruising part im having problems with.
If I step on the gas a little bit more it goes away. I also recently checked my spark plugs, and they come out black every time.
Some one said the KA -T and SR's have no problem with this. And upon further inspection of the site slw240sx posted, it seems theres a relay that controls this feature and that harness would replace this relay.
Well it got me thinking, maybe this feature is specific to the JDM model with all the JDM wiring. Maybe the KA-T and SR's dont experience this because they use the wiring from here (USA).
Maybe there is no voltage control relay for the US models? Can anyone verify this?
My car idles smooth and runs perfect under boost. Its just the cruising part im having problems with.