Bad Idle Troubleshooting - Infamous Nissan

jooshway · 04-26-2022, 02:59 AM

Hi everyone, new to Hardbodies and to this forum, so forgive my ignorance in advance.

My '96 with the KA has a lean code (P0171) and a bad idle. With throttle, it doesn't really care. At idle, it jumps between 300 and 1000 RPM, and will occasionally drop low enough to stall.

My research lead me to believe the fuel pressure regulator was to blame, so I threw a set of gauges on the fuel rail and read 39psi running, and 45 psi when I pulled the vacuum line off of the FPR. All of that sounds normal, right? Seems like the FPR is doing its job, and my running fuel pressure is within spec. Correct me if I'm wrong.

Does anyone know where I should go next?

Thanks!

91nissan94 · 04-26-2022, 05:12 PM

I would look for a vacuum leak.

cadillacdude1975 · 04-27-2022, 12:55 AM

Connect a good scan tool to the obd2 port and read the data.

89'HBV6 · 04-27-2022, 08:17 AM

Welcome...
Yes, OBDII reader should help. Find the port, but be careful..... the wires are how old?

...and DL a FSM, from the link in my sig. Look for Hardbody.

alabama_lowlife · 04-27-2022, 02:32 PM

I would also recommend looking for a vacuum leak

Marineengineer56 · 06-21-2022, 07:40 PM

89'HBV6
. . Factory Service Manuals: https://www.nicoclub.com/nissan-service-manuals

Thanks for This. Just handed an 96 HB KA24E that stumbles and shuts down when warmed up. No check engine light.

Cusser · 06-22-2022, 01:02 PM

Quote:

Originally Posted by Marineengineer56

89'HBV6
. . Factory Service Manuals: https://www.nicoclub.com/nissan-service-manuals

Thanks for This. Just handed an 96 HB KA24E that stumbles and shuts down when warmed up. No check engine light.

Still could have a stored code....

89'HBV6 · 06-22-2022, 06:02 PM

Quote:

Originally Posted by Marineengineer56

89'HBV6
. . Factory Service Manuals: https://www.nicoclub.com/nissan-service-manuals

Thanks for This. Just handed an 96 HB KA24E that stumbles and shuts down when warmed up. No check engine light.

Welcome...

Like Cusser said, check for stored codes. Got an OBDII reader? They're cheap, but you do also get what you pay for... so spend a few $$ and get one that will work on EVERYTHING. Personally, I prefer a cabled unit...

04-26-2022, 02:59 AM	#1
jooshway Jooshway Join Date: Apr 2022 Location: Greater Fayetteville, AR area. Posts: 1 Vehicle: Nissan D21 1996 Thanks: 0 Thanked 0 Times in 0 Posts	Bad Idle Troubleshooting Hi everyone, new to Hardbodies and to this forum, so forgive my ignorance in advance. My '96 with the KA has a lean code (P0171) and a bad idle. With throttle, it doesn't really care. At idle, it jumps between 300 and 1000 RPM, and will occasionally drop low enough to stall. My research lead me to believe the fuel pressure regulator was to blame, so I threw a set of gauges on the fuel rail and read 39psi running, and 45 psi when I pulled the vacuum line off of the FPR. All of that sounds normal, right? Seems like the FPR is doing its job, and my running fuel pressure is within spec. Correct me if I'm wrong. Does anyone know where I should go next? Thanks!

04-27-2022, 02:32 PM	#5
alabama_lowlife Owner and Administrator Join Date: Sep 2008 Location: jack, alabama Age: 42 Posts: 10,819 Vehicle: 2012 370Z, 1970 Datsun 521, 1995 Nissan Hardbody x2 Thanks: 1,109 Thanked 2,244 Times in 1,841 Posts	I would also recommend looking for a vacuum leak __________________

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04-26-2022, 05:12 PM	#2
91nissan94 Join Date: Sep 2008 Location: Crescent City FL Posts: 1,754 Vehicle: 91nissan hb Thanks: 106 Thanked 253 Times in 224 Posts	I would look for a vacuum leak.

04-27-2022, 12:55 AM	#3
cadillacdude1975 The Gear Jammer Join Date: Apr 2013 Location: Chattanooga, TN Age: 50 Posts: 10,713 Vehicle: 87 VG33 Pathfinder SE 4x4 & 87 D21 SE Thanks: 461 Thanked 1,406 Times in 1,271 Posts	Connect a good scan tool to the obd2 port and read the data.

06-21-2022, 07:40 PM	#6
Marineengineer56 Join Date: Jun 2022 Location: Florida Posts: 1 Vehicle: 1996 Nissan Hardbody truck Thanks: 0 Thanked 0 Times in 0 Posts	89'HBV6 . . Factory Service Manuals: https://www.nicoclub.com/nissan-service-manuals Thanks for This. Just handed an 96 HB KA24E that stumbles and shuts down when warmed up. No check engine light.