Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum - View Single Post - Rough idle, running rich. Can't figure it out

NiSilS14 · 10-22-2010, 04:47 PM

My gf's car started to acting up with the fuel pump not turning on. In short I replaced the fuel pump and the relay. The car already had a walbro 255 in it so I just replaced it with another one. After I got the car running it was running really rough, idling very bad with black smoke out of the exhaust. I figured it was a fuel pressure issue, installed a fuel pressure gauge. Gauge read 46psi at idle with vac. I installed a AFPR and readjusted it to 34psi with vac. Car ran fine for about 15-20mins and just crapped out. I thought it would be a coolant temp sensor. i tested it out and came out good, but replaced it anyway. No effect. I also replaced the MAF, injectors, O2 Sensor, cap, rotor, spark wires and plugs with known good ones or new, and cleaned out the IACV. I got to run a little better but it still stutters pretty badly. I dunno what else to check other then the TPS and/or ECM. Weak ignition maybe?

Cliffnotes:
-Car won't turn on fuel pump
-Replaced fuel pump and relay
-Rough idle and running rich
-Readjusted fuel pressure with afpr and gauge
-Runs fine and craps out 20mins later
-Installed CTS, MAF, O2, Cap, Rotor, Spark wires, Plugs, with known good items or new.
-Runs slightly better, still stutters.
-TPS, ECM, Weak iginition?

10-22-2010, 04:47 PM	#1
NiSilS14 Zilvia Junkie Join Date: Sep 2003 Location: Denver, CO Posts: 569 Trader Rating: (20)	Rough idle, running rich. Can't figure it out My gf's car started to acting up with the fuel pump not turning on. In short I replaced the fuel pump and the relay. The car already had a walbro 255 in it so I just replaced it with another one. After I got the car running it was running really rough, idling very bad with black smoke out of the exhaust. I figured it was a fuel pressure issue, installed a fuel pressure gauge. Gauge read 46psi at idle with vac. I installed a AFPR and readjusted it to 34psi with vac. Car ran fine for about 15-20mins and just crapped out. I thought it would be a coolant temp sensor. i tested it out and came out good, but replaced it anyway. No effect. I also replaced the MAF, injectors, O2 Sensor, cap, rotor, spark wires and plugs with known good ones or new, and cleaned out the IACV. I got to run a little better but it still stutters pretty badly. I dunno what else to check other then the TPS and/or ECM. Weak ignition maybe? Cliffnotes: -Car won't turn on fuel pump -Replaced fuel pump and relay -Rough idle and running rich -Readjusted fuel pressure with afpr and gauge -Runs fine and craps out 20mins later -Installed CTS, MAF, O2, Cap, Rotor, Spark wires, Plugs, with known good items or new. -Runs slightly better, still stutters. -TPS, ECM, Weak iginition?