Engine dies via throttle release - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

TachPHD · 10-26-2012, 06:21 PM

Hello Zilvia,
I'm in dire need of help on diagnosing this issue of mine. I need help to fix this so I can go do emissions.

Symptoms / observations:
Engine idles just fine until I press on the gas and release it. RPM drops to stall, or sometimes sputters then dies. I can keep the engine going with the touch of the throttle. To maintain idle again, I release the throttle slowly until no more. The engine seems to maintain idle by doing this.

What I've done so far are the following:
- Walbro install (I had an extra one laying around). Fuel pressure at idle is 41.5 psi, with vacuum line off it's at 44 psi. I wanted to make sure the fpr was okay and pressure was all in check. Seems about right, correct? or is that too high at idle? Should be lower at around 34 psi?

-I've ran the codes and it only showed a 12 for maf sensor. I went ahead and borrowed a friends maf sensor and switched that out. With the engine running, I unplug the maf sensor and it drops to a suffocation-like idle, near death, and continuously sputters, also along with not being able to idle pass 2500 rpm. Hook it back on and idle is back to normal.

- I've cleaned the iacv. No change. Unplugging it also showed no change.

-I've checked for vacuum leaks.

My car ran before any of this. I had an intake gasket leak near the head and fixed it. By doing so, I'm having these issues now. It's a stock ka24de, S13 btw.

Any ideas? I'm just dreaming to drive this thing.

Frank_Jaeger · 10-26-2012, 06:24 PM

Have you checked the TPS?
Is your throttle body adjusted correctly?

Amazee · 10-28-2012, 09:56 PM

When you decelerate you are applying the most vacuum to the intake. If you accelerate and then slowly ease off the throttle/cable, does the engine continue to die? If not, I'd suspect a large air leak. Apply some propane (or some other flammable gas) to the intake and try snapping the throttle while your adding the gas. Does the engine continue to die? does it run fine?
If it runs fine, suspect a massive air leak or timing issues. Leaks are easy to pinpoint. apply water via spray bottle over the hoses/intake. Water should temporarily fill cracks and stop air leaks.

10-26-2012, 06:21 PM	#1
TachPHD Leaky Injector Join Date: May 2006 Location: Westminster, CO Posts: 51 Trader Rating: (5) Feedback Score: 5 reviews	Engine dies via throttle release Hello Zilvia, I'm in dire need of help on diagnosing this issue of mine. I need help to fix this so I can go do emissions. Symptoms / observations: Engine idles just fine until I press on the gas and release it. RPM drops to stall, or sometimes sputters then dies. I can keep the engine going with the touch of the throttle. To maintain idle again, I release the throttle slowly until no more. The engine seems to maintain idle by doing this. What I've done so far are the following: - Walbro install (I had an extra one laying around). Fuel pressure at idle is 41.5 psi, with vacuum line off it's at 44 psi. I wanted to make sure the fpr was okay and pressure was all in check. Seems about right, correct? or is that too high at idle? Should be lower at around 34 psi? -I've ran the codes and it only showed a 12 for maf sensor. I went ahead and borrowed a friends maf sensor and switched that out. With the engine running, I unplug the maf sensor and it drops to a suffocation-like idle, near death, and continuously sputters, also along with not being able to idle pass 2500 rpm. Hook it back on and idle is back to normal. - I've cleaned the iacv. No change. Unplugging it also showed no change. -I've checked for vacuum leaks. My car ran before any of this. I had an intake gasket leak near the head and fixed it. By doing so, I'm having these issues now. It's a stock ka24de, S13 btw. Any ideas? I'm just dreaming to drive this thing.

10-26-2012, 06:24 PM	#2
Frank_Jaeger Zilvia FREAK! Join Date: Jan 2012 Location: Port Charlotte, Florida Age: 32 Posts: 1,352 Trader Rating: (1) Feedback Score: 1 reviews	Have you checked the TPS? Is your throttle body adjusted correctly?

10-28-2012, 09:56 PM	#3
Amazee Join Date: Apr 2012 Location: Bay Area Posts: 6 Trader Rating: (0) Feedback Score: 0 reviews	When you decelerate you are applying the most vacuum to the intake. If you accelerate and then slowly ease off the throttle/cable, does the engine continue to die? If not, I'd suspect a large air leak. Apply some propane (or some other flammable gas) to the intake and try snapping the throttle while your adding the gas. Does the engine continue to die? does it run fine? If it runs fine, suspect a massive air leak or timing issues. Leaks are easy to pinpoint. apply water via spray bottle over the hoses/intake. Water should temporarily fill cracks and stop air leaks.