Well, the good news is that the car is back in my garage and I will be putting on 1,000 to 1,500 miles at low boost (5.6 psi) before the full boost tune at SGP. The car runs perfectly with one exception. When the car is cold, the idle is fine, but when it warms up, after driving, the idle will bounce between 500 and 1200 rpms. The car never dies, and if you sit idle longer than 30 to 45 seconds, the idle returns to ~900 rpms. TS flashed the idle to raise it, but wondering if anyone else has encountered this and found a solution. I know idling with cams is always an issue, but can it get better? TIA

 

I have the Nismo cams and mine bounced around quite a bit . After I had the ECU flashed for the 550 injectors it did get much better

 

The cams, if you're running Nismo's, should have that big of effect. My guess is it's an injector problem. Looks like your running waaaay more injector than you need for this applications. I know of at least one other built motor running big injectors that was having issues with idle. I'm with booger... try the 550cc reflash. That should help.

 

they can flash for up to 750's I believe

 

Injectors are not the issue. I had them before the cams with no issues. I am using the VPro for engine management and had TS flash to raise the idle. The car can idle with the cams, but after driving, like when you come to a stop light, it bounces from 500 to 1200. After a few seconds, it stabilizes.

Do you still have an issue similar to this after the reflash?

 

A couple of times it did drop down to less than 500rpm and recovered quickly . I have my blower off right now so I cant say if its been doing lately .

 

Sounds like an idle fluctuation problem that Honda's have sometimes when the car hunts for an idle rpm. Odd that the Z would do that though Could it be an MAF issue??

 

I have the same problem exactly... with the nismo spec 1 cams (276 degrees with 10.7mm lift)... and running motec m600 with those setup and set the idle at 1000rpm.

my tuner reckons that the biggest problem with the unstable idle is due to the light weight flywheel that I have on... which is JUN flywheel... and I noticed that you have got the clutch swapped out (guess with lighter flywheel?!)... so that might be the problem too?

cheers,

richie

 

might want to try the TB close reset/learning procedure.. if the TB was disconneted it needs to relearn the close position or else it will do what you are decribing.. and/or try the idle learn procedure

 

ether might be correct.... when we used Motec to run with the standard DBW module (now is running with motec DBW), the idle was PERFECT when the car was warmed up.... but when we swapped it back to motec, we started to get the unstable idle, but not as bad as what t32 described...

cheers,

richie

 

just checked with my tuner..... then he told me that the injectors will have nothing to do with idle control at all.... so you should be able to get rid of that possibility already... running too rich or too lean will not cause idle problem!

Also I MIGHT want to get rid of the possibility of the flywheel too because of what I mentioned earlier when we were running motec with OEM DBW control, the idle was PERFECT even with the JUN flywheel... so what will be the problem? TUNING???

Awaiting for more different inputs here.... Thanks!

cheers,

richie

 

Possibly a vacuum level that the ecu uses for idle rpm reference. Different cams would throw off the vacuum amount and possibly cause the searching idle. Just a thought.

 

My nismo cams drop the the vacuum down to about 12 to 13 in. at idle . Whats normal ...17...18in. ?

 

g356gear - Most likely not a MAF issue, as I do not have a MAF anymore. The vacuum level is different and fluctuates with the idle. The perfect word is hunting for the idle. Once it finds it, it is fine.

z350lover - I did have the clutch and flywheel replaced, but there are others running this with no idle issues. I have the cams and the flywheel so maybe the combination of the 2, but I don't think that is it.

ether - I am going to Nissan on Thursday and was planning on trying this then. I'll let everyone know if it works.

When the car is cold it idles perfect, and when it is warm and being driven, after 30 to 45 seconds of idling it idles perfect as well. It only hunts for the idle after you have been cruising at over 3,000 rpms or so, and come to a stop. I will be trying the idle learn and TB fix at Nissan on Thursday. Keep the ideas coming, and maybe we can figure this out. Thanks for all the input.

 

Im wondering if my promblem is that my MAF is dirty with oil . My blower lost a seal and oil was getting into the intercooler pipe and plenum . Can I clean the MAF with carb cleaner ?

 

g356gear - Most likely not a MAF issue, as I do not have a MAF anymore. The vacuum level is different and fluctuates with the idle. The perfect word is hunting for the idle. Once it finds it, it is fine.

 

Sorry t......I forgot you have the fcon...my bad

 

With a new ECU, you should do the idle air learning, or take it Nissan and have them do the whole bevey of ECU learning procedures. Idle air, throttle plate closed, throttle plate open.

With a few hundred miles, the car might learn the proper way to reach idle more gracefully.

How does AF look at idle?

 

Go into your FCON ignition maps and make it so that the entire corner near idle is all the exact same number... such as 16 degrees. If they have any fluctuation in the ignition timing near idle area that can cause the idle bouncing that you are talking about.

If your ignition timing isnt steady in that area of the map, its very common to run into bouncy idle. Sometimes tuners will add timing to the lowest parts of the map to keep the engine from dieing if it hits those load cells on its way to stalling out... but without massive cams and with the TS raised idle flash that really shouldnt be a problem.

 

t32gzz,

You are correct there.... the flywheel should not change anything.... because I just swapped the worn clutch out and also try to run a heavier flywheel that I have got - Nismo flywheel (23lbs) instead of the JUN flywheel (14 lbs) and those flywheels do not make any difference as what you said.... but the car is surely a lot EASIER to drive, probably due to the new clutch, but it just cannot rev as fast as it used to rev anymore....


phunk:

So you meant if we set the ignition timing near idle to be exactly the same number (even on different ecu), it should be able to improve the idle quality? Can you please go more depth in this as I would like to understand why though... My idle was alright, it only bounces up and down "sometimes" and a lot more often with the air-conditioning turned on... according to my tuner, he said that he will still need to tune it with the air-cond on, but that will also compromise the quality of the idle when the air-cond is off... does it make sense to you at all?

Also... when the car is dead cold (every morning), the idle quality is BAD BAD BAD... it is like idling from 500 rpm to 1200rpm (sometimes nearly stall out), but after around 30 seconds of doing this type of bad quality idle, it stays at 1000rpm from then onwards until the next bounces (but the fluctuation is around 100rpm only).. BTW, I am running motec m600 with motec dbw (so nothing to do with the standard ecu anymore here)...

cheers,

richie