Lean Issue...need Help!

[BlexusGS]

I have a 2000 GS400. I added the K & N intake on it (simliar to those that have the SRT). About a year ago I extended the piping into the wheel well for colder air. Two months ago I got a check engine light for days and then suddenly went out. I had the car scanned at a local shop and they said the car has a "lean" read-out. The same shop apologizes because they will not fix my car; they worked on vehicles before with aftermarket parts and got burned. I understand, however, if the dealership won't fix it how can I get my car fixed? :( :( The aftermarket shops on Long Island ABSOLUTELY SUCK; they are ONLY dedicated to american cars! Please advise; the shop that scanned my car said that it MIGHT be one of my O2 sensors. WTF, what do I just *BLEEP* away hundreds of dollars on O2 sensors and TRY to install them myself only to find that they weren't the real problem??? Please someone help and give me some advise! The car is running fine but I don't know if I should just re-set the computer and leave it as-is. :cries:

[BlexusGS]

Please.... any1!

[dcfish]

Please.... any1!

Clean the MAF sensor, Carefully they aren't cheap. Use a cotton swab and isopropyl alcohol. You probably have a buildup on the MAF. Careful now..............

[BlexusGS]

Thanks DC! I cleaned the MAF about 3 months ago, the check engine light came on about 1 - 2 months after. Is it poss that i could have damaged it? If i broke it wouldn't i still have the check engine light?

Thanks

[SRK]

Each code these engines produce is more detailed than simply "lean". The shop you took it too doesn't have a scanner, or the data, that can produce the full repair routine for the code they found. The Lexus dealer will, and IF they have good technicians, they will be able to identify a problem positively, so that you don't end up spending a great deal of money on things you don't need. Keep in mind that the simplest "lean" condition is caused by a leaking or blown exhaust manifold gasket. Find someone that knows what they are doing.

[andrecat112]

i had the same problem with my 98 es300. using an existing air intake tubing i just extended it into the fender with flex tubing and hooked up a k&n oval round filter at the end (to make it a CAI).

at first i didnt get the check engine light, even after driving it for ~300mi at 60-75mph. it wasnt a week later til i got the check engine light. i then reset the ecu and efi by pulling the fuse and disconnecting the battery. when i hooked everything back up and started the car, the car seemed to hesitate (like it was struggling to suck in air...and almost surging). so as a temporary fix i disconnected the flex tubing and just connected the filter to the intake tubing (regular intake) and after a day the check engine light disappeared. i know should have taken it to autozone and got the codes pulled, but i didnt have time.

after reading your post, just thinking maybe we had the same problem

[BlexusGS]

Thanks for your responses guys, I am bringing it to the Lexus dealer around here anyway to get an oil change, winter check-up and replace my old HID headlight housings with the new 2005 green tinted HID housings. I will get the car scanned then.

[andrecat112]

could it be possible that too much air through the intake can throw off the ecu causing it show a check engine light?

[BlexusGS]

Good question... I'm sure it could happen. What does every1 else think? If I am taking in more & colder air can it be that my car (stock ECU) cannot compensate by adding more fuel and therefore throws a lean code. Not necessarily that there is something wrong with my car... just indicating that for the amount of air (& temp.) coming in I am not getting the correct ratio of fuel. Is this right???

[darrylg33]

Blexus, the SRT comes with the piggyback for the ecu, which I assume compensates for the lean condition the old ecu would detect with the amount of air now coming through the system. Does your K&N system have the same setup? If not then the lean readout your getting would make sense as the stock ecu is just operating normally and can't adjusting for the excess air. Also, if you hook up a OBDII scanner the freeze frame data should indicate what condition the car was at when it encountered the lean condition. This may or may not give you some insight into what is causing the problem also. I haven't diagnosed my condition yet but I'll let you know what the deal is when I do...D

[BlexusGS]

Appreciate it...let me know bro.

[darrylg33]

Blexus, I think I've diagnosed my problem, haven't gotten to the fix yet though--I sprayed some brake cleaner from the beginning of the intake right through to the injectors and the only stutter occured on the No. 1 injector--Looks like that O-ring around the injector is bad and I'll have to change it. Give the brake cleaner method a shot, you'll figure out where extra air is entering the system pretty quick. Let you know after I switch out the ring if the code clears....D

[BlexusGS]

You the man! I appreciate the follow-up bro. Let me know what you find. BTW what part of NY are you located?

[92Lex]

Shouldn't you have sprayed the carb/brake cleaner directly at the injector o-ring to determine the o-ring leakage? Not to de-credit your method of diagnostics but by "spraying it" into the IM, it would distribute that substance throughout all the injectors (single bank). In that case, it would be extremely difficult to pin-point the exact injector.

[darrylg33]

Shouldn't you have sprayed the carb/brake cleaner directly at the injector o-ring to determine the o-ring leakage? Not to de-credit your method of diagnostics but by "spraying it" into the IM, it would distribute that substance throughout all the injectors (single bank). In that case, it would be extremely difficult to pin-point the exact injector.

When I said I sprayed from the IM through to the injectors I meant each individual part where air can enter the system...so yes I sprayed on each coupler, around each part of the manifold where it' bolts together, and yes each individual injector. This is how I diagnosed it was injector 1, and actually it wasn't a bad O-ring, the injector wasn't seated properly so it was letting just a little air seep in the sytem at idle. A bad O-ring and gas will usually shoot out through the the opening in the ring due to the fuel pressure. Still waiting to see if the Lean code comes back but so far so good.

Blexus I'm in Westchester...D

[92Lex]

Just to clear things up. A bad injector O-ring would actually result in additional, un-metered air to be "sucked" in through the gasket....not "shot out". Your motor is really "sucking" not "shooting". "Shooting" would be considered anything after the exhaust manifold.