Nissan Tech said my car was running lean...

 

Simple. We see this all the time. Many intakes make the MAF equipped cars run lean. The intake pipe sometimes create resonances. Other times the MAF housing is incorrectly designed. Other times the car ECU just gets confused. We never change the intake on the Toyotas or Nissans with MAF sensors unless we measure the AF ratio and adjust if necssary. Case in point, I had an IS300 which we got in. Only had a cat back and an intake. We put it on the dyno, was detonating all over the place and running dead lean. After some fuel tuning with S-AFC we picked up over 25 ft lbs of torque at only 2000 RPM, car was running much better, no detonation. It was all caused by the intake. Nothing else. Modifying a car takes a lot more know how and expertise than just ordering up something from a website which CLAIMS to make power. Bottom line? Buy from a dealer who knows they they are doing. I have to say 90 of import parts dealers have no grasp of either the products they are selling or the engineering and tuning skills necessary to make the cars they work on actually function better.

 

So there's nothing I can do to remedy this problem save buying a $300 air/fuel controller?!?!

 

what about semi clogged injectors or a clogged fuel filter.

 

Why would it run lean? The closed loop program should be able to detect a lean condition though the 02 sensors and adjust the injector pulswidth accordingly.

 

Hm, according to my SES my O2 sensors are bad.

http://forums.maxima.org/showthread....hreadid=224240

 

Well then it's the 02 sensors and not the intake.

 

We'll see after I get the ECM reprogrammed next week.

 

Why not just replace the 02 sensors?

 

A few 5th gens have had the SES light up again shortly after replacing them.

I'm wondering if it is actually the ECM that needs reprogramming, not the O2 sensors that need replacing... at least for the early production 5th gens.

Usually, I'd think in MOST cases, dealerships perform a ECM flash when replacing the O2 sensors, so replacing them first would make it make it kind of difficult to deduce WTF is going on.

(I realize that I very well may have the SES light up again after the flash and have to get new sensors anyway, but... hey... I'm willing to give it a shot and see what I come up with.)

 

is detonation the same as pinging? Sorry for the newbie queston

 

I know a few maximas (including myself) that changed their intakes out and I've never heard of any of them running lean. The ECU should adjust for that. It would make more sense if the O2 sensor was bad.

 

Yes.

 

Bad MAF placement can create a lean condition under WOT at 5200 RPM. I have seen this with a variety of my test setups. Even my FCP midpipe on the stock airbox makes mine run a bit more lean than stock but it looks to be where I want it. Basically the MAF needs to be further away from the TB if there are any bends between them. And if the lean spots are too great the ECU can't compensate for them. The fuel trims have a wide margin but can be exceeded. All of you tards that use the crankcase filter are running lean too because your engine is now getting unmetered air.

 

I have big pinging problems but only when its real hot outside and when the a/c is on The dealer told me it was my intake because the piping goes right behind the radiator (Injen) and sucking in hot dense air.

 

Hot air is less dense. Cold air is more dense. Your intake could be adding to the problem but not causing all of it. What octane do you use?

 

91 chevron exclusively....various different stations not just one

 

I can vouch that using a crankcase filter will cause you to run lean as well as possibly causing your SES light to come on. I know that some people haven't had problems but the 2k2s & 2k3s are pretty **** about mods like that.

 

I can vouch that using a crankcase filter will cause you to run lean as well as possibly causing your SES light to come on. I know that some people haven't had problems but the 2k2s & 2k3s are pretty **** about mods like that.