It seems to me like I have a bad sensor somewhere. I have a new O2 sensor, CTS sensor, and several extra MAF sensors (MAF isn't the issue here).

Symptoms:

"Hunts" for idle (idle fluctuation)

When I put it in neutral/push in the clutch coming to a stop it will usually hang out around 1500 rpm for 5 or 10 seconds. Sometimes it will fluctuate up and down by about 200 rpm either way.

This morning it was unseasonably cold out (25 degrees). I started it and it died. I started it again and gave it a bit of throttle input to keep it running then it was fine after 10 or 20 seconds. Although it doesn't seem it idle higher when it's cold like it should.

Also seems like it takes longer to crank than it used to.

Does this sound like a bad TPS to anyone? If not, what else are you thinking?

 

IACV

 

The "hunting" for idle can also be a sign of problems with the throttle body/idle bypass circuit. A very good cleaning can sometimes solve that.

 

I cleaned the throttle body and IACV thoroughly then I installed my phenolic spacers less than a year ago. Otherwise I would have thought maybe the IACV had something to do with it.

 

Vacuum leak somewhere? - cracked hose etc etc

 

All new vacuum lines, but maybe I will get some starter fluid and double check...

 

MAF and airflow obstructions (abnormal air vortexes) before the sensor element can cause idle fluctuation. Have got new filter? ...Also temp sensor. And related connectors/wires - also at ECU.

O2 is not in play during first cold '5minutes'.

TPS is easily tested: http://www.cardomain.com/ride/748507/6

Start from checking charge voltage at batt, at ECU.

 

when i replaced the cts, my hunting stopped(except when the broken connector wiggled off a little...)

 

with the car in neutral and a/c on, does pushing the clutch all the way cause the RPM to go up?

before i ask that, what's your wiring like post-swap? Do you have to push the clutch to start in gear? Can you start in gear w/o pushing the clutch? Can you start whenever you feel like, regardless?

 

how is the battery condition?
I had issues keeping an idle on the I30, until I replaced the battery. then it ran perfect (other than the coolant loss :P )

 

I think that the car failing after starting it at colder temps must say something because I'm in colorado and mine will start at negative tempertures just fine, also what kind of plugs do you have, I heard certain types cause a fluxuating idle

 

The battery is fine.

 

This issue just started...It's not the damn plugs.

 

sorry, another noob question when did you last change your oil? what did you put in? 5w-30 or 10w-30

 

I changed my oil a week or so ago with Castrol 5W-30 and a Napa Gold filter...but what could this information possibly have to do with my probem???

Anyway, back on topic. I have a friend with a high-end Snap On scanner. Can the TPS be checked (resistance, voltage, etc.) using it?

 

what about what i asked?

 

The car must be started in neutral, clutch position doesn't matter as I never wired it into the circuit.

I will try what you asked and get back to you, but what is it supposed to test for?

 

...10W30 -info is likely linked to spare tire pressure

Digital multimeter is enough. Resistance test at TPS, continuity is important.

Why you say MAF isnt an issue? There may be multiple bad MAF's (... or air leak) Have you measured voltage for fluctuation, when problems are acute, at MAF pin B?

 

well basically my car idles weird sometimes b/c my N/R switch is busted and it thinks it's out of N when in fact it's in N, so it compensates and increases idle until it figures out "oh i'm not in gear after all". but my a/c idle is always way high until i push the clutch, which activates my N circuit (i wired the clutch and shifter in parallel... just the switch is broken for the shifter position).

 

Clutch position doesn't matter, but the idle increased from 800 to 1100 when I switched the A/C on.

 

I've dealt with a bad MAF before and it exhibits completely different symptoms.

 

MAF units contain electronics components and all of em can have many kinds of problems. This translates to myriad individual symptom possibilities. I think youre right assuming that 90% have few common ways to break down, but then there is the marginal group that exhibits unknowns...

What one does not know, one knows not how it can be known ... swap and test is the only reliable 100% way to find out.

 

Clogged air filter will do this.

 

yeah it shouldn't do that... it's supposed to go up by 100rpm not 300. I can't accurately set my idle until i get the switch fixed tho, or by having someone hold down the clutch switch button. idle is set in neutral w/ IACV off and i couldn't do that so i'lll have to wait until i can before i can reliably say what my car is doing wrong where idle is concerned. but yours seems to be having the same sort of stupidity as mine.

 

= whatever causing abnormal turbulences at MAF sensor element may have depicted effect.

 

IT'S A SWITCH. Wire open or closed to simulate the position you need to start. I did that on my ex-wife's Mustang when it's switch went bad. No big deal and got her by until the new switch arrived. Just REMEMBER that you have you're switch wired!

 

my clutch switch works but the tranny switch doesn't. car starts when i push the clutch to start it. i wired them in parallel.

so the only way it affects me is that the iacv idles up thinking i have an a/t and am in a gear, so it bumps up the idle to compensate. when i push the clutch it goes back down to normal. so once the tranny switch works then it'll know when it's in neutral and behave accordingly. it's just a minor annoyance. switch is in transit, along with a bunch of other goodies, and will be here this week.

tho it's nice to have the error sometimes... like when i'm in a drivethru and i let the idle shoot to 1300, it makes it easier to drive w/o the gas pedal b/c the idle is higher. or when the light turns green on a hill for the front of the line it holds me better when i'm launching. not that hill launches are a problem for me, it's just kinda like "oh.. that's cool"

 

Well, I haven't located a multimeter yet, but I cleaned the TPS connector today. It was a bit corroded, but cleaning it didn't seem to make a difference.

 

keep in mind that the fuel cuts in at 1600rpm at 0% throttle. put it in 1st, launch and accelerate to 3000rpm then lift... you'll feel it turn the injectors back on at 1600rpm.

anyhow when was the last time you adjusted your IACV FSM-style?

 

hey my 92 maxima needs a new maf and i really dont have the money and i need the car for work i would greatly appreciate it if any body had a spare maf laying around
email-xclouserx@yahoo.com
cell 267-897-0426
thankyou
-david

 

After going over the engine bay with a fine tooth comb, I spotted a vacuum line that I must have overlooked when I replaced them all last year. It looked like it very well could have leaked. Anyway, high idle doesn't seem to be much of a problem anymore. In fact, it's just the opposite!

Current behavior: When I start it when the motor is completely cold it wont hold high idle like it should to warm up. It starts, revs up for a second, and dips down to 600 or 700 rpm. When the ambient temp is cold enough it will stall. Otherwise, it runs kind of rough (stumbling) for a short while and I give it a little gas to help it. When it warms up a bit it's pretty much fine.

 

same here on the current situation for the most part. mine starts at 2000 and when it should dip to 1400 it instead drops to 800.

 

my 1992 se auto is jurking at idle and takeoff and on takeoff its making a wierd nose does anyone know what it might be? my friend told me it was ahose leak idk

 

could be a vacuum leak. I am assuming that your friend was referring to the vac. lines. It's pretty typical of a 16yo car. go through the engine, and see if you spot a bunch of the lines being cracked.

 

i only found one hose that looks a little cracked its the little hose on the back of the intake manifold when i went to take it off its broke into 3 pieces so im replacing that tomorrow but i hope this fixes it if not what else can it be?

 

always make sure to check your ECU's stored codes. the check engine light on these cars is LAZY. only about 10% of the error codes will even cause the light to come on. so you have to hunt yourself.

http://forums.maxima.org/showpost.ph...4&postcount=18

top link tells you how to find your code and the bottom link tells you what they mean.

 

After warmup, TPS loses the power to shake the kingdom, O2 steps in...

How many miles after latest IACV cleanup?
http://www.cardomain.com/ride/748507/4