MohawkDan

Hello everyone!

I have an 06 xB manual trans with about 700 miles on it. A week ago I installed a K&N cold air intake. Two days later I installed a Magnaflow catback exhaust system. I disconnected the battery before each install so the computer could reset.

Now, as I'm sitting at a light in idle the RPMs flutter from about 800 rpm down to 500 rpm at which the car begins to shake a little.

Is it possible the computer has had a sensor overload? Did I damage an o2 sensor on accident? Or is my air/fuel distribution of a little, meaning I need to get an ECU programmer?

Also, if this issue is out of my hands, would the Toyota service dept still work on my car for being under warranty even though I have aftermarket mods??

stew32

The computer should be able to adjust to both the intake and exhaust change. If you'd damaged a sensor, I'd think you'd probably have an error code. I'd check that everything is connected securely with no possible air leaks. If everything is ok, put some miles on it. Maybe it takes a while for the computer to learn.

Don't expect the Toyota service department to help. My experience with dealer service is they'll blame the aftermarket parts without looking further. By your own admission, the problem started after they were installed.

burstaneurysm

Check to make sure that your intake is tight against the throttle body. Then make sure that the MAF sensor is properly seated. It's unlikely that the exhaust would affect the idle at all.

MohawkDan

I figured Toyota would pull something like that. I think I am going to check everything once over for leaks and then reset the ECU by disconnecting the battery and then reconnecting.

If it is still happening, is there another route I can take... like reprogramming my ECU to work in conjunction with present and future parts?

Who makes a killer ECU programmer for xBs??

stew32

You don't need to do anything with the car's computer. If everything is installed correctly, it will adjust. The intake and exhaust only add 10 HP or less. Remember that Toyota sold a CAI (AEM) and exhaust (TRD) through the dealership. You'd only need to worry about the computer if you did some major internal work or forced induction.

MohawkDan

You are probably right. I guess I was quick to assume that the computer would adjust automatically. I didn't know it took time for the computer to learn the new intake and exhaust flows.

I did some more research regarding this before you post your last response. This link from the ToyotaNation forums was interesting... http://www.toyotanation.com/forum/ar...c/50915-1.html

Here 'toyota tech 01' addressed the common issue with the 04 manual xBs. Apparently there was some throttle play that eventually became more loose. To fix the problem some adjustment of the throttle cable was required.

I don't believe this is something I am going to have to do. I'll take stew32's advice and let the ECU catch up in the next couple of days and hopefully the problem will be worked out.

stew32

After I put on my intake, I drove around for over an hour. It may have run a little rough at first (was out in the suburbs, no stop and go), but it was running fine by the time I was done for the day. If you've still got the rough idle after putting on 50 - 100 miles then you've got a problem.

vintage42

The ECU works instantly in real time with data from the sensors. Resetting the ECU so it will "learn" something new is a misconception.
On the other hand, it can lead to interesting discussion. For instance, one person reset their ECU after some mods, and the engine ran badly. After day they removed the mods, restored the car to original, and reset the ECU again. However, the ECU failed to remember its orginal settings, but instead began to remember the mods, and so the engine still ran badly. But then he began to think he had not given the ECU enough time to learn the new settings and overcome the memory of the old settings. So he put the mods back on and let the ECU learn for a whole week. And still the engine ran badly. It turned out his ECU was just a poor learner

MohawkDan

Would adjusting the throttle cable to raise the idle up to the recommended 700 +/- 50 rpms work? Or would that just put a blanket over the problem?

vintage42

You first said "RPMs flutter from about 800 rpm down to 500 rpm at which the car begins to shake a little". So the problem is not so much a rough idle, as a fluctuating idle that drops below smooth-running rpms.

I think the idle rpms are controlled by the ECU. If the throttle cable can be adjusted, you can probably get a feel of what would happen by pressing your foot on the throttle a little. I wonder if the resulting fast idle would be steady, or would be satisfactory to you and the engine. The underlying problem would still remain, and it may be affecting the engine in more ways than the fluctuating idle speed.

I doubt whether the dealer will consider a problem caused by your mods installed by your labor to be a warranty claim. Since you mentioned the problem only began after the exhaust was installed, I would remove it first and see what happens, then remove the CAI if no improvement, then take it to the dealer all stock as a warranty claim if still no improvement.

MohawkDan

Wow... that sounds like quite the endeavor. I just may have to do that since, yes, this problem did occur AFTER the mods.

Would flashing the ECU help any? I've heard from another source that I may have to do this.

EasysBox

so long it doesnt happen all the time and it is a minor rattle after which the RPMs pick back up, i wouldnt even worry about it. it might just be that your intake is helping the air to flow better so the ecu is having a little difficulty maintaining the correct rpm. the reason the car shakes a little is because the rpms drop to a low level, providing it picks back up after that you should be fine...

MohawkDan

That makes sense EasysBox since that is exactly what happens. The idle never drops below 500 at which the engine will pick back up and go to 750ish rpms. I've noticed it has been a little better after I took the intake off and reinstalled just to make sure everything was tight.

Also, oddly, this only happens when the car is nice and warmed up... usually about 10 minutes of driving.

I'm thinking I am going to up the throttle like .5mm just to compensate for the new fuel demand that the intake requires. Would this make any sense to do?

Shutterbug

i just put a SRI on my 06.5/auto and it idles around 550 rpms now, it's been that way for almost a week, but i'm not seeing any bad side effects on my car, so i'm not gonna worry about it.

EasysBox

i wouldnt even mess with the throttle. sometimes if you mess with the throttle to get it to idle at a higher rpm you end up fighting the computer who is trying to keep it at a predetermined rpm and your idle will become rough, and or you will throw a CEL. just reinstall your intake and enjoy.

MohawkDan

Thanks for everyone's help.

I really don't see any other problems either so I'm not going to worry about it.

Winter

i noticed about a week ago, i disconnected my batter to get to the batterie's model number to look it's specs up. after reconnected it, for a couple days the idle was a little out of wack. i would be driving, i'd put the clutch in before stoping at a red light and the rpm's would bounce a couple times from around 500 to 1200 and back down to 800 then to 1000 and then level again at about 700. only did it for a couple days and i don't drive much more then about 10-30 minutes a day right now so within that time frame i could see the ECU adjusting it's self cause it gradualy came back to normal after a couple days.

vintage42

You have what is called a slow-learning ECU. I disconnected my battery to install foglights, and the ECU relearned how to run the engine immediately. I hear there is a flash download to cure a slow learning ECU

Winter

lol i'm not worried about it, it's not staying around too long so

MohawkDan

I emailed K&N about my issue and I got a reply a few days later. The reply was:

'To reset the [computer] you need to disconnect the battery for at least 2
hours. Then drive the vehicle for at least 250 miles for everything to
re-adjust. If you have any other questions give us a call."

So, to tackle this problem, I reinstalled the CAI to make sure everything was intact and tight. I disconnected the battery for 2 hours, but have only put 10 miles on the car since then. It seems to be idleing smoother...

I'll give an update post 250 miles.