I need some help with my 96 SE-R. It has 76,000. Latley, the car will shut down when I shift into neutral before stopping at a light. Also, while cruising on the freeway and on the street, the car will begin to stumble and stall, as if was about to shut off, and as soon as I put it into neutral, by the time I reach the stop light, the car will shut off. Seems like either an air or fuel problem. Could it be time to change the O2 sensor? I'm running hotshot headers, if it makes any difference.
I have similar problems, dive bombing rpms when putting it in neutral and it sumbles when accelerating at anything but WOT. I've checked my IACV stuff and all seems to be be ok. I don't appear to have an intake leak. So I'm going to keep doing all the tests I can find in my FSM for the symptoms I'm experiencing. Some quick and easy things to do without giving much thought is to check timing, check tps voltage, check your MAF ground. Here's a link to a thread which lists stuff you can check.
If it accelerates fine, and idles OK most of the time, then it's probably the AAC valve going bad; our engines are notorious for having this unit go out prematurely. Unfortunately, it's an expensive replacement $150 or so, and a total b*tch to remove due to it being buried behind the oil filter.
I didn't think removing the AAC was all that bad, I took mine out, cleaned it up, tested the solenoids (there's two, one is the AAC and one is the FICD) and put it back in. Didn't solve shit. Thought my IACV-Air Regulator might be it so I checked it out and it's ok. I'm back to thinking it's my AAC since since unlplugging it has no effect on the car. Although the solenoid works if it isn't being told what to do, it can't do it. Here's some diagnostic processes you can try. I needed to type it up for use in the garage so you might as well have it as well.
Unstable Idle
1. Check EGR valve for sticking.
2. Perform Power Balance Test
When disconnecting each injector harness connector one at a time, is there any cylinder which does not produce a momentary engine speed drop? If not got to step 6.
3. Check Injector
Does each injector make an operating sound at idle? IF N.G. check injectors and circuits.
4. Check ignition spark
If N.G. check coil, power transistor and circuits EF&EC 84.
5. Check spark plugs
6. Check fuel pressure (after filter depicted)
a. Release fuel pressure to zero (refer to EF&EC 191) To do this, merely take out the fuel pump fuse, and start the car and let it run until it dies. Then crank the engine a few times to release the pressure. Put the fuse back in, connect the fuel pressure gauge. Pressure should be 36 psi at idle. If N.G> check pump and circuit.
7. Check O2.
a.Set "Heated oxygen sensor monitor" in Diagnostic Test Mode II. (EF&EC 50) Turn ignition switch to on. Turn ECU test mode selector fully right, wait at least 2 seconds, turn selector fully left, start engine and let engine warm up until coolant temp is in the middle of the gauge. Run engine at 2K for 2 minutes.
b. Maintain 2K rpm and check to see if red ECU led or malfunction indicator lamp goes on and off more than 5 times during 10 seconds.
8. Check for intake air leak.
Pinch PCV hose, does engine speed rise? If so there is a leak.
9. Check IAC screw for clogging. Disconnect TPS and try to set idle to 750 +/- 50 RPM. If N.G. check for IAS clogging or throttle valve clogging.
10. Check compression pressure.
Standard 178 psi, minimum 149psi with a amx of 14 psi difference between each cylinder.
11. Check ECU harness.
11a. Check ECU power supply and ground circuit (EF&EC 73).
12. Try a known good ECU.
Engine Stalls after Decelerating
1. Check IACV-AAC valve.
When disconnecting IACV-AAC valve harness connector, does the engine speed drop? If N.G. check IACV-AAC valve and circuit (EF&EC 121).
2. Check IAC screw for clogging. Disconnect TPS and try to set idle to 750 +/- 50 RPM. If N.G. check for IAS clogging or throttle valve clogging.
3. Start at step 2 in the Unstable Idle diagnostics.
Lack of Power and Stumble.
Follow steps 6 and 8 in the Unstable Idle diagnostics.
__________________
Rob '93 SE-R
PM or e-mail me for Progress swaybars $190 shipped, B13 Progress coilovers $1300 shipped and B13 Progress LCA brace $160 shipped.
Last edited by toolapcfan : Mar 28th, 2003 at 07:06 PM.
Yah but you mentioned your acceleration had problems, a bad AAC will not affect the engine when the throttle plate is opened even slightly. Something else is definitely going wrong with your setup. You'll know when you have the dredded AAC issue when the engine tumbles and dies (or nearly so, you need to blip the throttle to prevent) when you let off the gas, usually after accelerating a bit and with the AC on; acceleration and performance issues are otherwise unaffected.
Quote:
Originally posted by toolapcfan
[b]I didn't think removing the AAC was all that bad, I took mine out, cleaned it up, tested the solenoids (there's two, one is the AAC and one is the FICD) and put it back in. Didn't solve shit.
Yeah, my car almost dies when i put it in neutral and the idle jumps all over the place before stabilizing, and everything it my FSM points to that as being the problem, and considering when I unplug it nothing happens, my AAC is definately part of the problem.
__________________
Rob '93 SE-R
PM or e-mail me for Progress swaybars $190 shipped, B13 Progress coilovers $1300 shipped and B13 Progress LCA brace $160 shipped.
Where and what is the FSM? Sorry, but not too familiar with these terms.
Update: I think I solved part of my problem yesterday. As I was taking a look under the hood, I noticed that the ghetto intake was coming loose from where goes onto the intake tube. It was pratically coming off. So I fixed that and I also replaced my fuel filter. Sure enough, the car felt a lot better. But I still feel some stalling while I'm flooring it. Where should I go from here?
FSM is the factory service manual from Nissan...I got mine for $73 and it's paid itself off 5 fold so far. If you're going to modify it or repair it yourself, you'll need one.
Well, part of my problem is defenitly solved. The car is no longer shutting off on me. But now I'm feeling a stall that I didn't feel before at low RPM's, about 3000-4000. My gas milage also seems to have improved a bit. I don't have a timing light, so I'll probably have to take it somewhere. What should it be set at? Also, as far as checking my ignition, I should check plugs, wires, distrubutor cap, etc, right? I appreciate everyone's help.
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