Good afternoon guys. A few weeks ago I bought a 2001 Nissan Maxima SE 20th anniversary edition. The seller told me it was in great shape and it checked out via insurance inspection no problem.

However I'm having a very strange issue randomly.

After 15 minutes of driving when the vehicle warms up, the vehicle starts revving to 4K RPM whenever I release the gas and put the clutch in! If I take my foot off of the pedal and put in the clutch to shift gears, I'll hold the clutch in and see the revs shoot up to 4K, until I disengage the clutch and shift as usual.
In addition, whenever I come up to a stop light and I pop her into neutral the car just sits there with her revs stuck at 4K RPM.... This is both ridiculous and annoying, (By standers think I'm just flooring the pedal while I'm standing still)

The gas pedal is not stuck... I have tried pulling it back with my foot and it does absolutely nothing. Funny thing is, after about 10 - 15 minutes of this it suddenly stops and drives normal again.

My alternator did go the week I bought the car, so I replaced the alternator, serpentine belt, everything drives nicely accept this issue. It was happening before I fixed the alternator and is still happening.

I don't have allot of money to take this to the shop and say find the issue, so I'm trying to narrow down what this could be so I'm able to instruct a mechanic further.

Please help guys, thanks so much!

 

check your throttle cables and what-not, maybe something's being pinched and stuck when the clutch is depressed.

 

If you can replicate if in your driveway, I would see if its coming from the throttle cable or the cruise control cable.

If throttle, try an idle air relearn. Could be an issue with your IACV.

No codes, I presume?

 

Yup, it's not throwing any codes!

I can't replicate it in my drive way, it doesn't start until I've been driving for 10 - 15 minutes. But when it does start I could immediately pull my car over into a parking lot and check it out. How do I test for things sticking in my engine bay? I know nothing about vehicles... But I know enough that I have to figure this out BEFORE I take it to a garage, otherwise they may charge me 1 grand just for trying to figure out what the issue is..

 

S2KG, Ok, so you have a "high idle" problem.

You can search for it on this forum, but I have a a couple suggestions: 1) First, disconnect your battery (both terminals) for preferrably 3 days, or for at least 24 hours. This should erase any bad habits the ECU has learned, and it should start learning from the ground up. 2) If #1 does not fix the problem, have a look at the IACV and the MAF. The MAF is easier to get to, so start there. Clean it, if that does not fix it, consider replacing (buy the new one from Courtesy Nissan: the MAF for the 3.0L engine http://www.courtesyparts.com/kb_sear....php?keywords=[22680]+\(A33B&cPath=1956_1957_1973_1976 is only $77). I would consider the IACV last - it's a lot harder to get to than the MAF.

 

If you can replicate it post a video so someone smarter then I can see it. Maybe it will help you?

 

i think my dad just replaced my IAC AND cleaned the intake and it's still has high idle (slams the trans in gear it's so high)/ guess i could try un hooking the battery for a fewdays.
1 thing i'm concerned about is i think my dad may have no replaced the whole IAC but, just the electric element with the round metal thing so as not to remove the aluminum block it's mounted in from the intake. i'm concered the new IAC's round bit might be of slightly different diameter by some small degree i do not how accurate or sensitive the IAC is supposed to be but, from i can tell it looks similar to the enriching valve on the my GY6 scooter's carb.


I have codes:

P0505
P0455
P0430
P0420

I've been warned it could the be the dirty gas tank fill hole/vent return thingy or even the cut valve assembly.

I also have an air bag light, it was bumped/hit pretty good but, they never deployed. (it's in decent shape after my dad fixed, grant it this was before my owner ship) (my dad fixed and maintained it for the family member who owned it before me)



EDIT: okay dad says he can hear an vacuum leak but, he can't find it. the new IAC was crap and made things worse he said. He mentioned something about the intake being plastic and something about "pop off". he also said that there is a bolt that is fairly important that does some stuff that is corroded though he doesn't thinks it's avacuum leak and not the bolt but, that should probably be fixed but, that i will need to buy all new ****.

Oh also something about some hose that comes down off the intake that does nothing and that might be the "pop off"?

He is pretty smart he has like 30 years experience, i just didn't get any visuals for reference so i'm trying to remember what he said or at least the jist of it.

 

It sounds like you want to rely on your father more than us. If that's the case, go for it.

An idle air relearn procedure must be performed whenever an IACV is ever replaced. Was that ever done?

Also, I HIGHLY recommend telling your father to properly replace the entire IACV unit. They are very finnicky.

Unsure if the other codes are symptoms of the IACV issue, or separate. Start there and see if they come back once the IACV is properly replaced. Clean the TB while you're in there as well.

 

P0505 is associated with IACV malfunction (and so are the idle problems you are having). So, I would definitely consider replacing the IACV; I would buy OEM/Nissan, the aftermarket versions often don't work.

P0455 signals a problems in the Evap Control system, such as fuel cap off, or a leak, or similar.

P0420/0430 signal a problem with your catalytic converter. A fuel mixture that's too rich could cause this, and a faulty IACV could possibly make your mixture too rich.

Bottom line: Replace the IACV with an OEM part, clear all codes, and see what happens. Also, make sure the MAF is OK.

 

So he didn't do a relearn, i think he did replace the whole unit but, he told me he got mad and smashed the new one with hammer and threw it away. i'll have to find out if that's true or if he just said that because he is mad. He did not do a relearn and said it would make no difference though disagreed. grant it the deed was done and i found out after the fact.

the one i bought, http://www.ebay.com/itm/281284126129...84.m1497.l2649 in my mind it's simple part and the 150+ rock auto and Nissan charge is all price gouging. it's just a vavle an heating element/electromagnet.

 

Nope. Cheaply made aftermarket part. NOT reliable.

Spend where it's worth spending. This is one of those times.

 

what possible difference could there be. i guarantee it cost no where near $100 USD to make them. Quality control sure that makes sense but, i know they have to be making a killing off those.

sounds like i'm gonna need way more parts.

also it turns out he just put the new one back in the box and did not re learn the ECU. also supposedly vacuum or intake leak somewhere.

 

Listen man, we're just trying to help you. Up to you if you want to take our advice but we have no benefit in steering you wrong.

There are certain parts that require to be replaced with OEM as the aftermarket versions are simply too low quality or have a defect of some sort. This is a well known fact.

Examples include: IACV, lower rad support, strut boots, PS Hose.

 

This reminds me of the day i was getting out of my car and some tool at the parts store was helping a good looking chick fill up her ps resevoir on her 5th gen. And i told him he needed to use dexron III.... He looked mad and said i was wrong ...well she was also smart by having him go back inside and verify my statement i bet he felt stoopid!

 

I've already got the part might as well try it (right this time). All i was really trying to do is say is that maybe there might be more than meets the ey... price.

I just find it hard to believe that is really 150 USD worth of materials and manufacturing in such simple part in 2014 is all. I find it hard but not impossible to believe. There are definitely times when you get what you pay for.

 

What you're failing to factor in is the engineering costs set forth to develop that part from nothing.

It may not cost that much to manufacture it, but it took a few years to design it and get it right. Those historical costs are built into the OEM pricing (albeit still slightly high - but still worth it). Aftermarket/generic companies don't have those costs to recover, they just reverse engineer it.

Similar example - It costs fractions of a penny to actually manufacture a prescription drug. But it costs the Pharma company BILLIONS over the 10-20 year pipeline to develop, synthesize, test, get approval, and eventually market the pill. That cost has to be factored in somewhere. Can't just expect to pay for manufacturing costs only.

Seriously, get OEM. I'm benefitting in NO way by giving you advice so theres no reason to ignore it. Tired of trying to reason with this ridiculousness over a stupid $140 part.

 

When you are really poor like me $140 isn't so small. Or of one isn't as fortunate as my self. that could be two weeks of groceries.

I'm not ignoring you. if need OEM... I need OEM. If you say it's gonna last then i'll take your worked for it. it last this long since 01 i guess a new one will last longer. possibly even longer, my dad took note that it was getting some of the heat from the header and is gonna fasion a small heat sind to cover it once we get it fixed. (even if it's pointless it won't hurt any thing either)

any ways, i'm only going to TRY this aftermarket unit since we already have it. It seems i have other problems to address that might be masking or adding to the problem.


How do i know i'm getting an OEM part? Rockauto has "STANDARD MOTOR PRODUCTS" and "Airtex" both sounds like aftermarket. I know the dealer is gonna is probably gonna want at least $200. Or are one of those brands the original OEM supplier?

 

Courtesy or nissanpartsasap should have it for a fair price.

 

Hey CdoubleJJ,

I'm late to this party but buddy I've been in your shoes. No money and a bad infiniti

Here's the thing. There are a LOT of aftermarket IACV's out there. And they all fail or run hot/cold. You can't get a good one. Really. You can't. Infiniti doesn't share the programming process and the chinese manufacturers haven't perfected the copy yet. That might change in a few years, but for now they're just spitballing.

Save up your pennies and get the one from Courtesy. You'll be sure to have a good working part and you'll be glad you did in the long run. My hard headed ways got me buying and returning two different chinese IACVs from Rock Auto before I finally broke down and bought a good one. Cost too dang much, but my car runs now. Guess you can't put a price on that.


I'd still like to find whoever does the pricing on these and kick him in the hang-downs though.

 

I've seen OEM IACV's brand new from (online) dealers in the $140 range.

 

There are three types of parts
OEM Genuine Nissan parts(Dealership)
OEM Aftermarket parts (Rockauto)
Auto store or online aftermarket parts.
(Remove the code but failed to fix the issue)

 

Ehhh....Disagree. It's more like this:

(please note this is NOT necessarily in order of quality. There are plenty of low and high quality OEM Nissan parts, and low and high quality aftermarket parts)

1. OEM Genuine Nissan (source: dealers)
2. OEM Replacement (aftermarket parts) (source: auto store or RockAuto) - look for well known brands such as Moog, Beck/Arnley, AC Delco, etc etc
3. Cheap no-name replacement parts (source: auto store, online, all over except dealer)

 

Wow! That's a good bit of info there. I suppose that makes sense. Nissan parts fora Nissan car.

On a side note here, i'm just speculating and thinking and pondering, don't take this as a rebuttal... it seems to me be a lot like the enriching valve on my GY6 chinese scooter.

It opens up and lets more fuel in and increase the idle for warm up. Then as time goes by the element in side heats/moves and closes the valve or hole by moving the need which plus said hole/valve.... thusly we have a normal un-enriched fuel supply to the cylinder and a return to normal idle.

This IAC sure does look an awful lot like the GY6 scooter enriching valve, it has, has hole or port that a rounded head or need fits in to and the this head is attach to a metal rod which looks to be attached to an element or motor of some sort so that it can open and close regulating what i might guess is is either air or fuel and perhaps there is a sensor in there to the ECU how far open or closed that valve is.. perhaps calculated by resistance to element or motor or maybe even by some contacts in conjunction with the metal rod that head or needle is attached too.

All just speculation, with dissembling the back box part of the IACV for all we know there an IC or circuit board in there. Even with basic device like described i suppose there are few variable Nissan have nailed down that China might not.

The Nissan part might have specifically tuned motor or element in side, or even made of high quality plastics.... who knows but, interesting to think about at least.

When I first posted I was speculation the prior which at first thought, in 2014 seems like given the materials seen on part shouldn't cost much to make but, being proprietary i was thinking the MFG could charge what ever they want. "hhhhmmmfff what would make this any/much different from the clone part!?"

That may even be the case but, from what i'm seeing here no matter what way you look at it the Nissan IAC works the best.


It is what it is I guess.

 

You can have a relatively big vac. leak and it will throw the code for iac, since it's not able to regulate your idle anymore. Do a thorough visual inspection and listen for any hissing while the car is running (after warm-up).
My zx2 did a similar thing. There was a leak by the tb that was letting quite a bit of air in.
I'm still trying to soak in, wtf is up with all these iac threads and 5th gens. I just recently bought one that might have a shot iac/ecu, btw lol

 

Ya seems to be a common problem.
Even mine was acting up.
It would sometimes just shut the car off immediately after start up.

Taking it off and cleaning that whole assembly including TB fixed it for me.

 

If you are going the IVAC route (which I personally deem very possible with a high idle) do yourself a favor and pull the ecu and check if you have a burned sata chip. Its a 20 min awkward but easy job.

Search for further info but the short version is...
If your IACV is shorted, it will take out a part of the ecu. Replace the IACV and it will happen again. Replace the ecu and the IACV will fry. My understanding is you MUST replace both. First clue is the dreaded p505 code.

 

Oh no, i hear you, my dad is confident there is a vacuum leak. he thinks it might be coming from the intake. so I'm kind of glad to hear you say that so it confirms a few things.

He thinks he might even know where the leak is. He said something about a "pop off" or "plug" that might be in the intake, that could be cracked or missing.... if i remember what he said correctly.

Mine thankfully and un-thankfully is an Automatic.

"Sata" chip? is that the brand/name on the chip or does it stand for something?

i'll do some searching on P505.
---
http://www.justanswer.com/nissan/2te...ol-system.html
http://x.nissanhelp.com/forums/maxim...01-maxima.html
http://engine-codes.com/p0505_nissan.html

 

chip inside the ecm that's responsible for regulating the IACV. Take the ecm out and pop the cover, then examine how the chip looks. it might be fried...
See my thread on some of the issues I'm dealing with: http://forums.maxima.org/5th-generat...t-worklog.html

 

we have codes p0505 and p0420. we have replaced iac and working on computer now. We have the computer out and the sta509a is not burned but it did blow apart. we may attempt replacing the chip ourselves. Replacing the catalyst is next on the list to replace.

oye I wished we had replaced the iac before as preventative maintenance as that seems to be a 2001 maxima issue.

do it yourselfers as much as possible but along with all this we had no code for engine dying at stop lights/signs and surging etc. Diagnosed at evans automotive in nsl utah. They replaced one bad Engine Coil. He advised we do the others when we can. solved the problem of dying, surging. runs good.

we are also cleaning the maf sensor we special cleaner from napa so we get better mileage hopefully.

Evans Automotive in NSL if you live close and you can't diagnose your problems saved us a lot of time fishing for the problem.

2001 maxima with between 93000 to 95000 miles. the battery is out right now or I could say exactly. Second owners of this car.

 

Well Got to hear about a first hand encounter with aftermarket o2 sensors not working on a vehicle... it's a lot easier to see the Nissan IAC being the only correct replacement.

I think we are gonna check for a vacuum leak one of these days.