Rochester

iTrader: (3)

I’m feeling somewhat confused about my idle, and would like some feedback from 6MT owners concerning their proper idle behavior.

Three weeks ago, I had my dealership perform the BG Products “Upper Engine Cleaning Service”. I was trying to address engine pinging that I’ve heard since mid-summer. With hindsight, I probably should have tried a $10 can of Seafoam first, but I figured $100 was a fair price for a thorough chemical cleaning process, sprayed under pressure directly into the fuel rail.

Well, the pinging went back to normal, to where you have to be seriously attentive to sense it now. “Normal”, because there’s always some pinging in our cars, by design. There have been a number of posts with the technical reasons for that… so if you’re wanting to ask me what I mean, try to search first instead. (I’m a Software Consultant, not a Mechanic.)

Anyway, the cleaning service for the upper-IM also whacked my Throttle Body Valve, giving me a high idle that the dealership couldn’t resolve. Since BG Products fully warranties their service by an authorized shop, they also paid in full for parts & labor on the new Throttle Body. I just got it back yesterday, and there’s a shiny new throttle body attached to the intake plenum, at no cost to me except inconvenience. That was pretty impressive of BG Products, IMO.

So now my idle is normal… or is it?

When driving the car fully warmed up, the idle will hover somewhere near 950 when I come to a complete stop. Then, with the clutch engaged (or the car in neutral), I have to wait about 2 seconds before it will drop to approximately 700 rpm. Now, I know that around 700 rpm is normal idle. My confusion is in the way it gets there in this two-stage behavior. Is that normal?

I can’t answer the question because I wasn’t as sensitive to idle behavior until all this crap happened. Now I’m hyper-sensitive, and I don’t know what to think.

MoncefA33

iTrader: (6)

The dealer performed an Idle Relearn correct?

BTW: Your avatar = awesome.

Rochester

iTrader: (3)

Yes, with the Consult tool. I haven't talked to the service manager about this yet, or my mechanic for that matter, since I don't know if there's an issue or not. Either way, I was thinking I'd try the pedal dance this weekend with the kitchen timer.

Thanks! I just decided tonight to be a supporting member. Thanksgiving and all.

MoncefA33

iTrader: (6)

Do that and report back

Very appropriate timing

rroderiques77

iTrader: (45)

John,

Love the avatar. Is that one of your rascals?
As far as your idle, try it for one to two weeks. I had a similar issue with mine when I did an engine decarb a few months ago. Afterwards, although I did not need a new throttle body (thank heavens), I had an idle hanging out around 1K RPM. Try the famous (or infamous) procedure with a watch and couldn't quite nail it. Ended up at the dealership for Consult II time (idle relearn procedure). Idle went down, but was still erratic at times. Took about two weeks for it to go back to normal. Now, believe it or not, it is actually too low. Hard to explain it. The idle is hanging out around 650 without accessories being on. I am starting to think the idle relearn did not stick and I may have to end up swapping throttle bodies.
Long story short, wait a few weeks. Your idle will probably go back to normal. It takes your ECU some time to adjust.
BTW, while you had your car at the shop, did you have them bump up base idle?

Rochester

iTrader: (3)

Not my kid, Roy. I just liked the whimsy in the image. Anyway, I appreciate your similar experience, but I think you missed my question. Here, follow this:

The car is warmed up and I'm driving. When I stop (or put it in neutral), the tachometer will drop to just under 1000 rpm. Wait 2 seconds, and it will drop again down to around 700; (normal).

My question: what is this 2-stage behavior? I'm asking because it wasn't until this TB screw-up that I started obsessing over the idle speed.

So is this the way your 6MT behaves? Watch the tach for me next time you take the Maxima out.

Rochester

iTrader: (3)

You know, one of the worst aspects about being sensitized to your car... is being sensitized to your car.

One day you hear and feel every little creak and groan, every thud, bump and crunch, and you swear it's falling apart. The next day you drive the car and it's this amazing monster, strong and nimble, with a sexy growl that speaks to you like music.

But it's the same car. Crazy, huh?

Sometimes it makes me weary. That's why the Maxima is my personal car, but for family outings we take the Honda.

mist max2000

iTrader: (16)

off the top of my head im not sure on the specifics of my idle.. i know that when its cold i idle around 650-700... but i think when its warmed up it idles higher,.. maybe around 900,.. the next time i drive(tomorrow) ill monitor it and report my findings for you..

sorry for the confusion but..i read what you said a few times and im not really sure of the issue,.. your saying that you think the idle is high when its warmed up? ie. 700 v 900? and its at 900 at a stop and then kicks down to 700 after a few seconds?

EDIT: i know what you mean about the knocking and performance... i made a deal with myself to start recording where i get gas from and results from it,.. and then im going to determine whos gas i think is better and if it acts differently between 91 and 93.. because sometimes when i get on it the thing pulls like a train and others its like.. hmm.. that was okay..

Rochester

iTrader: (3)

Thanks, mist_max.

The issue is that normal idle occurs in a 2 stage behavior. It idles at 900 for 2 seconds, then drops down to 700. And I just don't remember it that way before all this with the BG cleaning and the new throttle body. It's possible, but it seems weird.

MoncefA33

iTrader: (6)

Mine does this too.


But it's because of my 5 or 7 degrees of timing advance

Rochester

iTrader: (3)

See, now, I can never tell if you're serious or if you're joking. And you're not driving a 5.5 6MT, so I don't know if we're comparing apples to apples.

MoncefA33

iTrader: (6)

I'm serious. Advancing the ignition timing (using e-Manage) makes the car idle higher (900-1000) but then the idle drops down to the appropriate level after a moment or two.

rroderiques77

iTrader: (45)

I understood it. Didn't mean to go on a huge tangent or anything.
It may take a few weeks for your ECU to get used to the new throttle body and the programmed idle speed.

I don't think this applies to you Rochester. Isn't your ignition timing stock?

Rochester

iTrader: (3)

Yup. Although I didn't find out where the timing was set when I picked up the car. (I forgot.)

byrdman164

iTrader: (4)

If I'm not mistaken, isn't that the engine stabilizing? I know it's a different car altogether, but I had a 98 200SX that upon revdown would stop at about 1k rpms and then go back to normal idle. I think that maybe since you had the throttle body touched you're noticing the idle characteristics more because it's on your mind? I read somewhere on a forum for it (the 200SX) that it was normal and the engine RPM was stabilizing so it didn't stall or stumble, but who knows. You'd think being an ETB it wouldn't have to do that, but that might be what it is.

HotshotVQ35

iTrader: (5)

i just came back from a ride, and in MY car, when im on the highway and put in the clutch, the rpms go right to 700. when i come to a stop, same thing. it doesnt goto 900, sit for a second or 2, and then drop to 700. it goes to 700 everytime. not sure if this is what you wanted to hear or not...lol

and this is when the car is fully warmed up.

Rochester

iTrader: (3)

You're right, I was hoping to hear my idle behavior is normal. Thanks for watching that for me, Hotshot.

How about you, Mist_Max? Anybody else have an opinion on this before I push back on the service department again?

mist max2000

iTrader: (16)

well.. when im driving and either push in the clutch or go into neutral..it goes right down to 900.. and then exactly 1 second later its at 800 and then one more second its at 700-675,....so im not sure if that helps.. but it def stops/slows at 900 and then goes to 700 almost immediatly (~1-2 seconds).. but there is no step, persay.. more of a slow constant drop till it levels at ~700

..if you have any time specific questions or w/e let me know ill keep observing..

i mean you know your car.. if you think something is not right.. call them

Rochester

iTrader: (3)

Here's a theory a friend of my just proposed:

When the engine speed drops in neutral (or with the clutch engaged), the RPM's on my car momentarily drop below 700 (which it does; I neglected to mention that part ), before it immediately bounces back up to 950 to over-compensate for the drop, maybe interpreted by the ECU as a near-stall or something. After a few seconds of stable engine speed, it drops down to normal idle (700 rpm).

The theory why RPM's drop below 700 is because of the light-weight Unorthodox Racing Crank Pulley on my car. There's probably some variable to the equation for engine speed control that expects a certain amount of inertia, and those conditions have been altered by the crank pulley.

What do you think?

(BTW, you guys have been great, helping me out with this snipe hunt. Thank you.)

byrdman164

iTrader: (4)

I can maybe see that being a concern. Less rotating inertia and all. Maybe the car will just have to "learn" and compensate faster for it?

Rochester

iTrader: (3)

It does seem reasonably possible.

As you suggested here, I've decided to give this behavior a few more weeks before bringing it up with the Service Dept who did the TB swap. Things may improve over time as the ECU gets used to the new Throttle Body.

If the idle behavior changes on its own, I'll let you guys know. Ditto if I take the car back to the shop.

All in all, I'm actually ahead and feeling pretty good: 1 new TB, no more pinging, and a normal idle (after the drop).

mist max2000

iTrader: (16)

wow good point on the udp..i guess thats possible.. but what about someone with a lightweight flywheel AND udp lol.. idk.. need someone like that to chime in..



and kinda OT but(if you would rather PM go ahead).. i need a good honest opinion on a pulley..and you would be one of the best for that , you seem to be real in touch with the car ..assuming its lightweight and not underdrive.. whats your ''review'' if you will..

Rochester

iTrader: (3)

What would be interesting to know is if Technosquare takes into account a UDP or lightweight flywheel when determining the proper flash for the ECU?

Um, thanks for the compliment, Mist_Max. I don't know how deserved that is, because there are some serious gearheads on this forum... but thanks anyway.

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

For brand, I went with Unorthodox Racing. A few months of web research led me to the opinion that UR pulleys were high quality.

For size, I went with OEM diameter. I didn't want to deal with any of the potential under-drive issues, and had come to the opinion that under-driving the accessories was a very minimal gain compared to the reduced weight of the pulley. That, and OEM spec'd belts are a no-brainer. It's really fascinating to hold the OEM pulley in one hand, and the UR pulley in the other. It's kind of one of those "Holy Crap!" moments, because the difference in weight is incredible.

At 50k miles, I replaced my original belts, and if ever there was a good time to replace the crank pulley, that was probably it.

When I bought it direct from UR, it was $200. It's since gone up to $250. Both of those numbers should give anyone reason to pause. Kind of pricey, IMO.

The UR crank pulley was installed on the same day I had ES mount bushings installed, and the STS mod... so I had a few things going on that made it a little difficult to isolate the changes specific to the UR pulley.

However, you immediately notice the engine revs quicker in neutral. (That's a duh, and kind of pointless.) Under load, the quicker revs are real, but much harder to recognize. Still, there was more "snap" in the launch than before; not huge, but real nonetheless. Once you get moving, any gains are totally masked. In other words, this is a low-end mod. Period. It's one of those mods that becomes the new normal in a matter of days. If you feel any appreciation for the changes, that feeling will fade quickly.

With hindsight, my advice is to steer those funds into more worthy mods, like better quality tires, or phenolic spacers. (Personally, I'm jonesing for the NWP Torque Link.)

My 2 cents. Hope it helps you.

mist max2000

iTrader: (16)

def helps.. spacers are next on my list lol.. well.. maybe actually install my headers that are just collecting dust ha..and yeah.. i think its safe to say anything that NWP puts out is a great product ( i want that tq link too )

D's036spd

iTrader: (1)

Ya same thing happens in my car when I let off the throttle it stops around 900-1000 and slowly moves down to 650-700 RPM. I just changed out my throttle body, also got the ECU updated at Nissan and did the whole relearn process. What's interesting is it will only slowly come down, when moving at any speed. I think the ECU is monitoring your speed and it knows to drop the idle more slowly in that case, so I'm thinking it's normal and kind of helpful. Try it out, rev when parked and watch the TACH, and then see what happens again when rolling to a stop. Anyway, hope this helps ur peace of mind!

rroderiques77

iTrader: (45)

John,
Have you been having problems with your belts squealing after the pulley mod? I've got the same pulley as you and I get this occasional belt squeal coming from my p/s belt. I've replaced it with a different brand and it comes back. The noise goes away if I run a wire bruch on the belt while the engine is running. Is it because of the fact that it is aluminum or what? Or am I just

Rochester

iTrader: (3)

I don't hear any squealing, but I have observed a layer of black film around that area (not oil) which my mechanic says is residue from the new belts. It's not excessive by any means. I cleaned it up and am keeping an eye on it. We'll be looking for that again next spring when I go back for suspension and brakes.

But no squealing, Roy. (knock on wood)