lopey idle with hesitations

IWantRWD · 11-15-2010, 07:23 PM

So let me start off by saying that I have recently bought a decently clean ('specially for a michigan car) NX2k. And it has been starting to through me for a loop.

First: The lopey idle. It happened after installing a new speedo cable. This isn't my first Nissan or my first rodeo so i know just removing the cluster wont effect the idle as bad as it has. It idles as though it has 280s and set for 700 rpm idle. Also the smell of unburnt fuel can occasionally be smelt.

Second: The hesitations. Light throttle, high gear low speed (read cruising in 3rd at 25mph) its got hesitation, sluggishness, and just seems down on power. Now, if i get into it, it feels like it pulls fine..but then again, ive only been driving this car 1 week.

So, having a CA swapped S13 and other modded rides, i went though the basics. Did a tune up, plugs, wires, cap, rotor, fuel filter. But i did all of this AFTER this started. Checked MAF voltage. The ground was alittle high at .015 no matter where i put the ground. But i tried to reground it a couple of times, and no such luck, gotta do the big 3 soon.

Here is also what i found. I can unplug the FPR vacuum. no change in idle. If i pinch off the return line, i get a much smoother idle, but i also get a raw fuel smell.

So, im stumped. I cant quite wrap my head around it. Im getting code 12 and 33. But i just replaced the o2 sensor and checked out the maf and the voltages at idle are 1.4, .015, 14.5. So maf checks out voltage wise, reset the ecu, codes came back. Idle didnt improve.

Oh, so i think i forgot this. 92 NX..sr20, half an exhaust cone filter and half assed removed emissions. 165000 miles 5 speed

iNISMOpowa · 11-23-2010, 12:51 AM

dude my 200sx is doing the SAMe exact thing. i figured it was plug wires because they are old. and mine throws codes every now n then, have not checked them ***. lemme know what you find out.

IWantRWD · 11-25-2010, 02:21 PM

here is a copy from what i've been posting on nissanforums

okay so just did some tests and diagnostics.

TPS is reading the proper voltage.

Fuel pressure is at 36psi at idle and raises to about 44 when vacuum is removed and holds fuel pressure after shutoff

o2 sensor is getting the proper voltage even though I'm getting a code for it, and unplugging the sensor does nothing to change the idle at all.

When i squeeze the pcv hose, nothing happens. Well, the hose cracks, but thats it.

Timing is at around 15btdc as it should be.

unplugging the injectors and plug wires one at a time does change the idle. But number 4 fuel injector doesn't change the idle as much as the rest.

Im now getting o2 and knock sensor codes. but i cant quite grasp the concept of turning the ecu to o2 monitoring mode. Even though ive read the FSM about 10 times and tried to do it like my s13 was setup.

ECU reported no self faults.

There is one thing that gets me and since i hate the highport intake setup so much it frustrates me even more. There is a definate air hissing sound coming from the intake, but since its such a cluster-f--- under there i cant find out where its coming from. All vacuum lines are pluged. The only vacuum lines i have are to the evap canister, brake booster, and FPR.

I did a simple leak check of the intake with soapy water and the injector seals are not leaking and didn't see bubbling on the head side of the intake. Now i guess i just have to find some air to do the good ole' boost leak tester.