Alright here's the problem....

In the morning when I leave for work, the car starts up no problem. I can drive out of my subdivision, but when the car gets to the stop sign and I have to idle there waiting for an opening in traffic, the car will suddenly seem to try and pull away from me, the brakes stiffen a bit, and the RPM's will drop down to 400 and flutter up and down quickly between there and 600 RPMs. If I don't kick it into neutral, the car dies. When I kick it into neutral, the RPMs shoot up to like 1200, and slooowly drop to normal idle speed of ~700 RPMs. If it dies, it'll start right back up again.

Also, if I kick it in neutral at the stop sign, wait for an opening, then put it in drive and go.....the car will drive without a problem. So basically this is just occurring when I'm stopped, and the engine is cold, and in the morning. By the time I've driven ~5 minutes the problem is non-existent. Also, if the car sits at work all day (8 hours) it won't do it when I leave to go home or any other time during the day. So somehow, the problem is only occurring in the morning, has no dependency on lengh of time it's been sitting there, and only occurs during the first few minutes of driving.

What could it be? I'm thinking vacuum leak or something, but then why wouldn't it do it after sitting out during the day? Is it a moisture problem (because of dew or something??) or tranny problem??

 

When the GEARBOX is cold actually ................

I have seen the same behavior on a friends VG - many many miles on it and quite dirty (nearly black) ATF in the autobox. We replaced the oil with nice fresh oil after a flush (including extra cooler and all plumbing) and problem was gone. We are keeping an eye on it now and replace the ATF every six months or so as its obvious the box is showing its age and crapping in its oil, turning the ATF from nice bright red to near brown within a few weeks.

I suspect a sticky valve/valve-body because of the dirt in the oil - when its cold, tolerances are a bit tighter and things (that shouldn't be in the oil) get trapped where they shouldn't be.

 

How about you warm your car up for a whole week before driving off and report back to us?

 

I don't think this is a transmission issue on traxtar's car,it sounds more a iacv/vacuum leak issue,due to the erradic idle even after he puts it in neutral..

It may even be a maf related issue..

 

If it were not for the words "the car will suddenly seem to try and pull away from me, the brakes stiffen a bit, and the RPM's will drop down to 400 and flutter up and down quickly between there and 600 RPMs. " and basically the same words getting used by my friend I would go along with you.

Let me suggest this to confirm and see who is right:

When you next experience this strange behavior, take very careful note of the "feel" of the shifter and smoothness of shift as you move it into neutral - our shifters are quite smooth imo, but if you have the situation I described, you will almost feel the engine "jump" when going from eg drive to neutral, and the shifter will exhibit a distinct and harsh mechanical "clack" (as opposed to the normal smooth "click") sound.

Even when the box/engine is cold with the revs "fluttering between 400-600rpm" for whatever engine related reason, the box should not be transferring huge detectable and varying amounts of torque requiring more brake pedal pressure to be applied than at normal idle speed of say 800rpm when still cold ........................ lets see/hear what traxtar944 report back with.

Based on "When I kick it into neutral, the RPMs shoot up to like 1200, and slowly drop to normal idle speed of ~700 RPMs." I don't see any mention of "the erratic idle even after he puts it in neutral" especially if it stabilizes around 700rpm in neutral............................. IMO the revs shooting up to 1200 is an indication that the IACV is actually aware of the impending engine speed disaster, and soon as the engine load is reduced when the box is dropped in neutral, it immediately tries to up the revs - and because it has a finite and pretty slow mechanical response characteristic, it will first overshoot before stabilizing - again IMO quite normal and in fact to be expected.

 

great breakdown of situation. bad to no this may happen to me. more reason for a 5 speed swap

 

 

well since the RPMs are already higher than normal...shifting it into drive is almost like neutral dropping the car, so yes it's a bit jerky. Your last paragraph is exactly correct. That is what the IACV is doing. It can sense that the load of the transmission is no longer on the engine and speeds it up accordingly, then gradually slows down because of the lag in response time. Going from drive to neutral is relatively smooth though. I don't notice much of a difference from a normal shift to neutral, other than the fact that the engine is already fluttering in RPMs.

I did try an interesting experiment though. I put the car in drive this morning, popped the hood, then engaged the parking brake to keep load on the engine. Strangely enough...nothing happened. The car drove totally normal the whole ride to work...dammit.


Also on a side note....I had noticed this problem a bit before, but it would come and go so I disregarded it. The other day, however I noticed that there was an open vacuum line just sucking dirty air right into the manifold. Turns out that it was a vacuum line for the water **** valve, which controls the heater inside the car. I connected the hose, and thats when the problems got worse. I'm thinking that the ECU had been adjusting itself for so long to drive with the vacuum leak that when I fixed it, it took awhile for it to reconfigure itself back to how it should be...is that possible??? Perhaps thats why it drove normally today??

 

No its not. The MAXIMA's ECU is as dumb as a they come ................. pre-programmed and fixed and it doesn't learn anything - nothing at all.As did my friend's car. ................. If your problem is not present though (his was there about 3 out of 5 mornings) then surely there is nothing to troubleshoot and no conclusions to be made.
Was the other day yesterday?

With these sort of intermittent things, its very important to supply/post all the relevant facts up-front lest everybody will be posting gobbledygook like I possibly just did when you only now say the loose vacuum hose was in fact present. ???????????????????????????? neutral dropping the car?????????????????????

English please?

 

Sounds English enough to me. I believe he's referring to RPMs being so high while he shifts onto Drive that the car jerks. As if it were a neutral drop but not intentional nor at high RPMs.

Hey Matt how are your mounts by the way? I still think that if you were to "warm" up your car before driving it, your RPMs wouldn't be so high to the point where it feels like this neutral drop you here speak of

 

In which case you can ignore me .....................

I was only speaking of/interested in going from D to N while the funky idle fluttering is going on as per the first post here.

I agree with what you are describing - it is to be expected (jerky with high idle going from N to D)

 

how's your O2 sensor?

 

The O2 is not too bad, old but working. I don't have a check engine light going on so thats good. I think I found the problem though....

When I'm driving out of the neighborbood the car will get up to third gear or 2nd with overdrive or something, and doesn't feel like it downshifts. The RPM's will hang a bit and the tranny slows down the engine. Those of you with manuals will know what I mean. It feels like the engine is slowing down the car instead of downshifting. When the car stops, it might still be in third gear....which would explain the erratic idle. If you've ever tried to start a car in third gear, you'd also know exactly what I'm talking about. The symptoms sound perfect to me, straight down to the jerkiness when I let off the brake. To an outsider, I imagine it looks like I'm trying to drive a stick and can't tell the difference between third and first.... what do you all think about that?? sounds possible??

 

Remember me?

 

should I? I've seen you around the forums a bit. Did I see you at a meet ever?

 

Never met you no, but I did introduce myself to your exact problem on Thursday last week in this here thread.

 

right....so what are you asking then? In response to your second post...the pre-programmed ECU makes sense...but I did think that our ECU's had the tendency to sort of "hardwire" themselves to run a certain way if it's been doing it for long enough, similar to other electronic devices, they can develop a "memory" of sorts....this could be totally off base for ECU's. I was just comparing my experience with other electronics.

My possible diagnosis made today explains why nothing happened when the car was just backed out of the driveway and parking brake engaged...just like your friend's problem. If the transmission doesn't shift into third, then it wouldn't have a problem going BACK to first....since it would be there in the first place and have no problem idling....comprende??

When I made the post you responded to, "the other day" was referencing 2 days before I created the thread, or July 9th. Either way, I do not believe that the problem discussed in this thread is related to the vacuum line at all, since it only operates the water valve for the heater. There is no reason for that line to affect idle speed....plus it was disconnected for months before I finally connected it...so who knows about that issue, it's a topic for another thread I guess....

And yes, neutral dropping is a really bad thing stupid people do to their transmissions where they rev the engine in neutral and then drop it into drive. The tires spin and peel out, the car feels like it's about to fall apart, and the transmission propably WILL fall apart. It's a great way to scrap a car you don't like anymore.

So that should answer everything, LvR....nice to meet you, btw.

 

Sure I do.

NOW

Till your last post I wasn't too sure that YOU actually did because of your posting the comparison of the shifter "feel" and "sound" and "absence of jerkiness when moving from D to N" when the problem was not present on your vehicle at the time.

Your latest description is a real nice description of what my friend experienced - the experience makes one think that more than just the required (for D anyway) clutch/belt/overdrive/torque converter gets activated in the box, and the box then actually starts working against itself internally and thus effectively kills the motor by gobbling up the all the power delivered by the motor (forcing revs to drop to the point where the engine's power delivery is such that the the amount of torque transmitted by the low-speed torque converter is just enough to be overcome) - hence my initial suggestion/guess of dirty oil causing the valve-body on the box to do all kinds of strange things (in my friends case we cleared the GCU by replacement with a known good unit only to experience the same)

My "remember me" post was sorta jokingly directed at MyGreenMax94 because of his feeling that the problem didn't sound like a box problem - sorry if you (apparently) took it the wrong way.

 

I'm going to shoot in the dark and suggest the coolant temp sensor.

 

if you're 100% sure it's the tranny then your valve body is shot (shift solenoids are stuck) and if you have been driving like this for a while the clutch packs are probably gone too.

 

I feel sure that in my friend's case that is the reality of it, yet with the regular ATF changes I mentioned, he has covered around 40000Km in the last 3 years in that condition ..........................heres hoping for quite a lot longer yet - just baby the thing and warm the box properly

 

Saying that the ECU doesn't make adjusments for certain kinds of driving isn't quite accurate. I know with my car if I drive it like an old man for a week or two and then get on it, it feels very sluggish. However, if it stay on it by the end of the day it's pulling a decent amount harder. My friend and I have both agreed that the car can be "moody". Has nothing to do with the knock sensor either for mine is bypassed.

 

Well - the FSM has absolutely no mention of any "intelligence" wrt the ECU (a std Nissan supplied one anyway) - it shows/mentions/describes pre-programmed maps of reposes for certain parameters depending on other parameters and nowhere is there mention made of any "historic" parameter value being used as input.

Arsedynos are notoriously difficult to calibrate and are even more sensitive to environmental parameters than mechanical dynos - could it be that your's is in need of a calibration?

 

sure?

 

LvR...there was no offense taken. I was just joking back at you. I'm not 100% sure it's the tranny, but I'm thinking the torque converter is locking. That could explain why it's not downshifting.

 

About the FSM's contents? - yes. As for your arsedyno requiring a recalibration - couldn't hurt - either way.

traxtar944 - I am not sure what exactly is to blame inside/around the box either - I just know from a lot of experimenting and testing that it is something mechanical - guess we will only know when one of these boxes with the particular hassle eventually packs it in and one of us strip down and investigate ....................... here's hoping that honor will get bestowed on you.

 

the TC locks up in overdrive...but you're talking about taking off from a stop and you feel you're in 2nd or 3rd gear then it's usually not the TC. either way the car sounds right now it's due for a tranny rebuild.

 

UPDATE...after a long drive I have almost completly lost OD, reverse is pretty sketchy, and it takes about 15 min to shift into third. I'm going to have to scrap the trans and do a 5 speed swap....oh well. The real bummer is that now I'm going to have to wait on my tail light project and paint so I can spend that money on the trans... I'm guessing that it's the torque converter thats the problem. Oh well....f**kin transmissions. $1400 later I'll have a 5spd with LSD...so thats still pretty cool.

 

No its the internals are dying not the TC. My car had a bad TC, and it didn't move. Either way your going to end up with a 5 speed so w/e...

~Alex

 

I'll sell you a temp fix dirt cheap its auto but it'll get you back up and running with a direct swap

 

Well,
For Traxtar944,
I certainly hope you have explored the options of running the Scan Data from an on board vehicle scanner like I have from Snap-On. It will tell you if the individual solenoids that control the shift are functioning as they should. Your transmission is controlled by a computer that is also aligned with the engine. If any of the engine OR the transmission sending units have a problem, then you may have a shift , or another problem.
Don't be too particlular here. Take the vehicle to someone that has a scanner, and can tell you what's wrong. It's worth it. !!

 

me and maxpwer are doing a swap this weekend...or in a few hours from right now. whichever is more convenient. John, unless you can beat $100 to swap the tranny I'll be a Chris' place...LOL. I do appreciate the offer though. Now if anyone has a VE5....let me know!!

 

you mean parts car right?

oh and I didn't make it to the jy before they closed. Im sure I can tomorrow though.

~Alex

 

I found a VE5 for $500 with 160k on it.
only 2 problems:
1. it's a VE5, and I don't do stick
2. it's $500 and I can't afford it

 

Saturday? if so I'll probably stop by...I'm trying to acquire that taste for beer...I'm almost there.

 

alex, let me know about that parts car. I'm pretty sure I'm getting nismosleeper's tranny. He's giving me thae transmission, spindles, axles, and all the other little doo-dads that are needed for an auto to manual swap......all for $750 shipped. It's a fair price, and I need to do it anyways. It just sucks that the tail lights and paint job need to be put on hold so I can invest all my time in this job. Oh well.....at least Im getting a VE-5!


-Do I need an ECU or TCU for that swap?

 

Your current ecu will work fine with the manual..

 

and soon you will be the TCU

 

what does that even mean?

 

The tcu(transmission control unit) shifts for you in an automatic..

With a manual trans,YOU will be the new "TCU" so to speak..