Hi Guys,

I just replaced my IAVC. Turned the car on and let it idle for a while. That seems fine. After a few minutes of idling i got to gas it a little and the rpm gets stuck around 1500. It starts bogging unless I step on the pedal harder almost flooring it. When I floor it it doesn't bog or get stuck.

Please help...I searched and couldn't find anything.

I really don't want to give up on this car... I've work so much on it already...

Thanks all

PM me if you have any idea. Maybe it would be easier over the phone.

Thanks again!

E

 

Idle relearn procedure?

 

even though it idles fine? it idles around 700

actually i dont even think i can do the relearn because it gets stuck at 1500 when i gas it. an di can't even keep it at 2000

 

Was it a new IACV?

 

idle air control valve...it one of the most dreaded things for these cars...

 

Per the FSM, you need to do the Idle Air Volume Learning (EC-67) after replacing the IACV. Also, double check all your vacuum hoses to make sure they are all connected and in good shape.

 

okay. i tried it several times and it still happens..

 

okay i drove it into work this morning about 60 miles. did the relearn again and the same thing. could it be my ecu? its just that 1 spot between 1500 and 2000 rpm. If i press the gas soft it bogs in between. If i step on it with more pressure it goes fine.

If there anyone around the east bay in nor cal hit me up please. maybe you can have a better idea.

thanks..

 

anyone?

is it the ecu?

 

OK...

Auto or 5spd?

New IACV or used?

A new IACV will start up fine and idle higher than factory spec (~680-750). I would first try the relearn proc. and see if that works, if not, then take a look at your ECU (if auto). If you notice a "fried" chip, then your ECU is done.

 

auto

new iacv

relearned many time and idle is arnd 750. relearn made no difference from when i 1st put it in.

if i "fried" a chip, would i still be able to run the car? if thats the case, would you recommend getting the ecu rebuilt by the ebay guy? its like $70

thanks.

 

How many miles are on your car? Your ECM could be fried as well. Check out this thread I started a while ago: http://forums.maxima.org/5th-generat...-stalling.html. My IACV went bad and the ECM was fried as well. Nissan covers the ECM under an 8 yr 80000 mile warranty.

 

If it's auto, I believe your electronic motor mounts fried the ECU. But, there is a way to find out visually. Take out your ECU, it's four 10mm bolts to remove, then philips screws to take the cover off. After, you WILL see a burned chip if it's fried. Your ECU should accept the procedure if the ECU is good.

Check it and get back to us.

 

What he said

 

These symptoms could be caused by a bad Throttle Position Sensor. It might have a dead spot in the middle of the throttle pedal travel. It's an easy thing to check if you have an ohm meter.

 

What he said. You could have a flat spot on the TPS. It usually occors at the throttle position that you normally run at.


When my integra had it it was a real b###ch to pull out of anywhere.
Thing would bog so bad it would stuuter and almost stall.

Once I got going and kept the RPMs up I was fine.

 

I'll do this tonight


I know how to use the ohm meter but how do i test it? what kind of reading should i expect on the tps?


Thanks guys!!!

 

3. Start engine.
4. Warm up engine to normal operating temperature.
5. Stop engine. (Turn ignition switch “OFF”.)
6. Turn ignition switch “ON” and wait at least 5 seconds.
7. Turn ignition switch “OFF” and wait at least 10 seconds.
8. Repeat steps 6 and 7, 20 times.

Those procedures should reset the TPS if it needs it....

 

i replaced my iacv before and did the same thing. my problem was the throttle cable. check the slack on your cruise/throttle cable. i'm assuming in your sig you have a 2000 maxima which is throttle by cable

 

I feel guilty for not visiting this forum often once I fixed my problem.
Contact me pm, or here, plus my email should show any response here.
I have a lot of experience and research with this problem, and although the mounts may cause a chain reaction, it did not happen to me. I repaired my ECU, cost me a IACV unit, and a driver I.C. chip. As my profession is electronic engineering, it was trivial on the electronic side but much dissassembly of dash/engine stuff. But never would have done it without the help here.
You can also check my posts and see my progress. I promise to put a pictorial summary up 'soon'.
Some cautions, a bad ecu/ecm may burn out your new iacv.
replacing a ecu with a bad iacv may burn out your your ecu. If you don't fix your original ecu, the replacement will need to have your antitheft and keys reprogrammed by a tow to the dealer, unless there is some portable dealer machine that comes to your house.

 

or a faulty part? was it a brand new iacv?

 

He already said it was brand new. Now the question is... was it Nissan OEM or an aftermarket IACV?

Since you're auto, immediately disconnect the electronic motor mounts. You can drive around without this connected and since it's such a threat to your IACV and ECU, I would leave it DC. Do this and check your ECM.

 

Hi guys, its oem.

If i pull the ecu and open it, should i see anything?

Its kind of pointing more towards a bad ecu?

 

I know it's been installed, but check the IACV terminals for continuity as per book to be certain one isn't bad, or hasn't shorted out. 1-2, 2-3 top, then 4-5,5-6. The resistance should be equal across each set.

 

okay, i have another observation.

This morning when i was getting ready to pull out the ecu, the car seemed fine. I revved it up slowly passed 2500 with no problems, even drove it around the block.

After it warmed up, i revved it slow and it happened again.

WTH is it???

 

Well I have been experiencing the same problems as eazymax. I finally pulled my ECU and found a nice surprise. Im not sure what to do now but I will have to replace the ECU or something along those lines and the TPS (IACV is new).

eazymax, check your ecu, it will probably be burnt. Let me know.
I also have pics of mine if anyone is interested.

On a side note, this will be my last maxima because this car has been nothing but problems. Man, I should of kept my 94

 

94maxteamrtv - can you post some pics? I'm about to pull mine out. I found a company in tenn that will repair for $75. They do a diag on it before fixing anything. If nothings wrong its 55.

I totally feel you on the being your last max. I'm have the same thoughts! Especially after all the work I've put in it.

thankS!

------------


I just opened my ecu. It looks brand new! no signs of anything being burnt (leaking caps or burnt resistors) man, this is really frustrating!

 

So its not the damn TPS! I just put a new OEM in today and same thing.... eerrrrrrrrr

And I don't think its the MAF because it only happens once the temp goes up.

I'm am now going to resort to the stealership to put it on the consult. fck!!! I didn't really want to do that. anyway i may need a reflash and software update since i now have brand new OEM Coil Packs (6), OEM IACV, and OEM TPS.

the line is just getting thinner and thinner _______________________

 

Sorry to hear that. Are you absolutely sure the ecu is not damaged?

 

Pics of the ECU, please. Also, I would double check if the new IACV checks out fine. After all, although highly unlikely, the new IACV can be faulty...

 

do you check the iacv with it off motor,also how many motor mounts do you un plug

 

well if it idles high when you install iacv you will have to relearn

 

I have the same problem on my 01 maxima 5spd. I have 68k miles on it and have had it for just about over a month and i am really frustrated. Before i bought it the dealer said it was fixed and it wasn't and it's been back 4 times and i'm working on bringing it back for a 5th this week. B4 purchasing it they replaced the IACV & TPS but my idle/rpm's are getting stuck open. Most recently on the highway in traffic shifting from 1st to 2nd to neutral back to 1st etc and it acted up. RPM's were at 1500 and rose a little to 2000-2500. I had to shut car off on the highway and start it back up which fixed the problem for 2 seconds b4 it did it again. For me most of the times this happens is when i drive 30 minutes on highway shut it off and get back in 5-10 minutes later as soon as i put it into reverse or 1st gear my rpm's are stuck at whatever rpm's i had it at while backing up or going foward. I keep getting the runaround at this place to i am almost about to call news station and tell them to meet me at so and so place and i have a story for you. I eman if you can't fix it send it to Nissan unless you want me back here every other week for the same god damn problem. Sorry a little frustrated.

 

Be sure you have it in writing about the idle control system work and promises. This can be an expensive job, even with correct diagnosis the first time around.
Got your PM, will be checking email....
JH

 

I just went through a PIA puzzle to figure out why my 01 rpms would fall and stall the engine. Went to my buddy's shop (he is a auto mechanic genius). He was a little frustrated because Nissan has proprietary diagnostics as opposed to other manufactures and does not get a full stream of data. Anyway it boiled down to the IACV on the throttle body or the computer or both. Seems that when an IACV begins to and then goes bad it can damage the ECU. I was also told the ECU can go bad as well and could damage the IACV as well. Well my mechanic had the car over a week (lucky I have a backup) and called me saying he had it back working but it was not perfect...about 90%. Well it did run and drive OK but I could tell it was not like before. Like I said (and read a lot on this forum) it seems this is not an uncommon problem. If you have a bad ECU and put on a new IACV and TCS they could be damaged due to the bad ECU. I discussed this with my mechanic buddy and he told me to bring it in and we will pull the ECU. Sure enough there was a 8-10 prong component on the board that was burnt and cracked down the middle. A new computer is $1000 to $1200. The IACV is $325 and the TCS is $130. If you have a stealership do the job you are looking at over $2000 (diagnostic) reflash, labor etc.) Check this out on the forum as other members have attested.
I searched for anyone who could repair the ECU and went with a company in TN for $200. The ECU came back repaired but the instructions said to put in a new (preferably OEM IAVC and TCS) for the reason I said earlier where you could ruin a new IAVC if the ECU is bad.
My buddy ordered the IAVC and TCS (OEM) and when the repaired ECU came in I brought it over, installed the ECU, did the throttle relearn and called me to say the car was running perfect.
This overall problem can cause a number of weird conditions especially with bad idle, stalling, high rpms, odd shifting, etc. This little problem cost about $800.
Just thought I would offer my experiences to the forum for what it is worth.

 

That's a good summary of the problem.
I was lucky and got a 10.00 chip for the ECU (I even fused the V+ lines with pico fuses).
It still cost me 300.00 for a iacv from a parts box store.

It is just a simple stepper motor power chip, but the system was poorly designed for overload failures.

 

After staring my car the second time after running it for 10-20 mins, the rpms will drop to a point where it will shut down. Is it worth cleaning, or should I just go ahead and get a new IAVC and ECU?

 

Cleaning? I don't understand...
Start a new thread, your car is shutting down after running a bit. It could be a lot of things.
Glad to help, but I hope it is not the problem in this thread, and it sounds like it could be a number of things. You are smart enough to check here in online forums, so good luck.