Idle issue and other problems

[DanDriftS13]

I have a 93 with the stock ka24de in it with about 160k miles on it. Whenever I start the car when it is cold the car misfires at idle and at steady rpm in gear. If I accelerate or let off the gas in gear the car doesnt misfire. Once the motor warms up the misfire goes away. Also the car doesnt like to idle anymore. A few weeks ago my fuel pump went out and I replaced it with a walbro that I had already and once the walbro was in the car stopped idling properly. If i push the clutch in any higher than about 2k rpm the motor will stall out. If I clutch in lower than 2k rpm sometime it will still stall but most of the time it will idle around 1400rpm and after about 10-15second will stall out unless I hit the gas to keep it on. Before I changed the fuel pump the car would idle at about 900rpm very nicely.

Any help is greatly appreciated.
Thank You

[DPRACING]

Sounds like you should do a complete tune-up...

change spark plugs, clean all sensors, check fuel pressure, and change filters.

Is your check engine light on?

[lou's40sx]

^^ Hooked up my car to the Nissan Diagnotics. My problem was that the TPS (throttle position sensor) was on the OFF position, instead of on position.

But since you changed the fuel pump, I think that may be the issue. Try finding another OEM pump from the junk yard or borrow from a friend, and replace the Walbro that may solve the problem. Maybe the new fuel pump is starving or flooding your cylinders. Did you purchase a high volume pump or was it oem replacement?

Whenever I have an issue, I reminisce about what I did prior to the issue and most of the time tracing back your steps helps you step forward.

Try putting a GOOD stock pump back in and see what happens.

[s13silvia123]

adjust your TPS to the correct voltage. its most likely the TPS i've been working on that for a whole trying to fix the idling problem lately

[DanDriftS13]

adjust your TPS to the correct voltage. its most likely the TPS i've been working on that for a whole trying to fix the idling problem lately


my tps went bad a couple months ago and i changed it and when i replaced it i got the voltage set at about .52 volts which from what I found is inside good voltage ratings for it. The tps was changed before the fuel pump and after I changed the tps the car still idled fine until I changed the pump.

[DanDriftS13]

I noticed yesterday that when the motor is cold the car is just dumping fuel into the motor and running EXTREMELY rich with a lot of black smoke coming out of the exhaust at idle and when revved. the black smoke goes away after the motor is warmed up but it is still running rich and my gas mileage is horrible. The guage on my fpr reads about 37lbs at idle so its not like my fuel pressure is ridiculously high.

I also forgot to mention that the check engine light comes on sometimes. It never stays on for more than about 30 seconds. If I accelerate the cel turns back off and stays off for a lil bit and then comes back on for no more than 30 seconds. I have checked the error light on the ecu and it reads a 55 so theres no error there.

Any ideas other than what has already been said?