[benchen]

At idle on a warm engine, no fan or A/C, the idle rpm will raise from 600 to 700 or higher after I drive for a while, then remains idling smoothly at 700 rpm or higher, the idle rpm will be back to 600 until I restart the car. it happens everyday now, I have replaced plug, coil and injector but no use.

any thoughts / comments?
Thanks.

PS: My e90 335i is FBO with upgrade turbo.

[rmbaron]

Plug in your OBD meter and check the readout???

[benchen]

Originally Posted by rmbaron

Plug in your OBD meter and check the readout???

No error code...

[Gugs]

Whats the problem? The car adjusts idle? You could have build up and need walnut blasting. Your fuel pump or injectors could be on the way out.
Imo u prob have a vacuum leak-
*It also could just be normal.
Get a Bav tool on there if you really wish to read whats going on if anything at all

Imo u prob have a vacuum leak-

[Evil///M]

Sounds... Normal?

[benchen]

Originally Posted by Gugs

Whats the problem? The car adjusts idle? You could have build up and need walnut blasting. Your fuel pump or injectors could be on the way out.
Imo u prob have a vacuum leak-
*It also could just be normal.
Get a Bav tool on there if you really wish to read whats going on if anything at all

Imo u prob have a vacuum leak-

At idle with A/C on, everything is fine. Only happens with A/C off.
Weird.

[boostaholic786]

Have you done the injector recall yet on your car? I know this can make the car idle funny but I dont know if what your talking about has anything to do with that. Usually if its a bad injector its WAY worse and makes the car shake. My buddy had that problem and turned out it was the injector recall and replaced 2 of his injectors....I dont know why they cant just replace all the damn injectors when the car is known to have injector issues....Its not like they are an uncommon part that goes bad on 75% of their N54's.

[JamesM3M5]

If you have already cleaned the intake, replaced plugs, and injectors and STILL have the weird idle behaviour, try replacing the pre-catalyst oxygen sensors. I understand what you are saying - with the AC OFF, at idle, the idle will drop to about 650RPM, bump a few times and maybe run a bit rough, then the idle picks up to 750RPM to smooth it out. My car did the same thing until I changed spark plugs, injectors, pre-cat O2 sensors, cleaned the MAP sensors.

After that, I still have the occasional (very rare now) bump/light misfire at very light load under 2000RPM. I checked and cleaned the intake ports again last weekend, and it got a tiny bit worse. The only thing left is possibly a valve cover / crankcase vent problem. Each intake port has a direct channel to the valve cover PCV valve. That valve may be clogged or defective. Additionally, a leaking valve cover gasket can cause a lean condition and possibly increased oil vapors getting sucked into the intake. I am going to change my valve cover gasket next weekend and report back.

[AWD Addict]

Sounds like this:

http://www.e90post.com/forums/showthread.php?t=509274

Some of the later posts get pretty far off the highway, but the first few pages appear to match up to your issue.

[stratos_335]

Have you checked your oil level? Just a thought... I've noticed that when the engine is close to oil refill, it starts having the same issue

[Renus]

Originally Posted by benchen

At idle on a warm engine, no fan or A/C, the idle rpm will raise from 600 to 700 or higher after I drive for a while, then remains idling smoothly at 700 rpm or higher, the idle rpm will be back to 600 until I restart the car. it happens everyday now, I have replaced plug, coil and injector but no use.

any thoughts / comments?
Thanks.

PS: My e90 335i is FBO with upgrade turbo.

Your Vishnu is 2.5 or 3? With newest map and firmware? I have the same problem like yours on my V5 2.0, but solved after new map & firmware updated.

[Schnitzel]

Had the same problem when I replaced my plugs. 10.000 miles later the problem is gone. Might it possible that this "problem" could be caused by an adaption issue?

By the way: I have a Procede as well. Maybe it is Procede related, too.

[benchen]

Originally Posted by Renus

Your Vishnu is 2.5 or 3? With newest map and firmware? I have the same problem like yours on my V5 2.0, but solved after new map & firmware updated.

I have a Procede V5 3.0 with 9-10 map.
Plugs,coils and injectors have been replaced and carbon has also been cleaned but no use.
There is one thing strange that the idle rpm will rise when valve of Wastegate acts every time.

[marcvtec]

From my experience the car has always had a rough idle since the first day.
I've always asked if we can raise the rev to 750 steady.
But no tuner stepped up to the plate yet.

[messi]

Strange. Today I drove my car and my idle rpm was at 800 rpm and I found it a bit highs well. Car has 9600 miles. Idle is steady though. I noticed it bc I only just recently installed my PE. I will monitor it to tomorrow.

[Renus]

Originally Posted by marcvtec

From my experience the car has always had a rough idle since the first day.
I've always asked if we can raise the rev to 750 steady.
But no tuner stepped up to the plate yet.

In HK, the original idle's rpm would be around 550~580, which needle showed below 600, after I have the same problem like you guys, dealer has raised my rpm to around 700 when idel, and they said 100 rpm raise up is maximum in this car.

[benchen]

Originally Posted by Renus

In HK, the original idle's rpm would be around 550~580, which needle showed below 600, after I have the same problem like you guys, dealer has raised my rpm to around 700 when idel, and they said 100 rpm raise up is maximum in this car.

I have raised my rpm to 700 at idle, the trouble seems to disappear. I will try more days and report result.