SES light came on (running lean)

S

scott mo

Member
Location
Chicago, IL
Hey guys. My SES light came on today when i started my car. Ive noticed in the early mornings that my fx kind of sputters and shakes for a second and then runs fine. I figure its just the cold weather and not anything too serious?(i think)... anyways i started my car today. it did a little sputter but went away and then i looked down and my ses light was on. I turned off the car and tightened the gas cap....nothing. So i took it to autozone

the guy at autozone ran the computer and It said something along the lines of "one side of the engine is running lean". They guy said like my 2nd half of my engine??? and he also said it could be something with the vacum hose and it could burn up my catalytic :ehh:

NOTE: In the begining of the summer I put on a Fujita intake system. I never reset any ecu's or ANYTHING. I just hooked it up and drove. could this be the problem??

thanks in advance guys. Let me know what you think....
 
the same thing happened to my car last winter. but ses didn't come on in my car. it cranked a few times, it started shaking all of a sudden but after a while it went away. air intake might be a problem but this late??? is what i am sure. trying doing this

///799

if it doesn't solve your problem.. then huh!!! injectors?
 
bleedingsujit said:
the same thing happened to my car last winter. but ses didn't come on in my car. it cranked a few times, it started shaking all of a sudden but after a while it went away. air intake might be a problem but this late??? is what i am sure. trying doing this


///799

if it doesn't solve your problem.. then huh!!! injectors?
Click to expand...

I think the problems might be separate for some reason but i dont know...The shaking has happened ever since it got cold here which its been like for the past month and it also did it in the beginning of last winter... Then I put my FX in storage until summer so it never was a problem until now....also, Which reset should I do? The ecu one? or all of them?? thanks
 
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I am having this same issue. My cars idle is inconsistent (similar the the description in the first post) and my service engine soon light is on. I brought it to the dealer and they replaced the MAF. I got the car back and a day later SES came back on. I bring it back in and they say it is reading "fuel lean" meaning my engine is running lean. I currently have the Kinetix V+ plenum, throttle body spacer, LMS intake tube, and Stillen/K&N intake filter. They think it has something to do with the plenum and throttle body spacer. It makes sense to me since I am allowing more air into the engine, but I wanted to know what you guys think. Really don't want to take off my plenum (don't care about spacer) and tuning the ECU is not an option for me right now because I am still under extended warranty. Does their assumption sound correct to you? Thanks. Also, how bad is it for my engine to be running lean? They told me if anything you want your engine to be running rich. I have had my plenum for well over a year, maybe 2, and the throttle body spacer for about a year I think.
 
My initial guess what the throttle body spacer. As I read more, you said you had it for a year and I'm assuming you had no issues prior to this. I had a different throttle body for two days and I also had the Kinetix V+ too. The first day it drove fine and then the second day my SES came on. I removed it, reset the light and the car ran just fine. Maybe remove the TB spacer for a few days?
 
You need a UniChip or UpRev tune to adjust your A/F ratios.

You are right, you are getting too much air for too little fuel, you will get a few more HP but risk detonating your engine! Probably not this bad, but still should get it adjusted.

I ran lean with a LMS intake. So try swaping out the LMS tube for the stock or Stillen Z-tube with OEM MAF tube.


drew855 said:
I am having this same issue. My cars idle is inconsistent (similar the the description in the first post) and my service engine soon light is on. I brought it to the dealer and they replaced the MAF. I got the car back and a day later SES came back on. I bring it back in and they say it is reading "fuel lean" meaning my engine is running lean. I currently have the Kinetix V+ plenum, throttle body spacer, LMS intake tube, and Stillen/K&N intake filter. They think it has something to do with the plenum and throttle body spacer. It makes sense to me since I am allowing more air into the engine, but I wanted to know what you guys think. Really don't want to take off my plenum (don't care about spacer) and tuning the ECU is not an option for me right now because I am still under extended warranty. Does their assumption sound correct to you? Thanks. Also, how bad is it for my engine to be running lean? They told me if anything you want your engine to be running rich. I have had my plenum for well over a year, maybe 2, and the throttle body spacer for about a year I think.
Click to expand...
 
AeroBFA said:
My initial guess what the throttle body spacer. As I read more, you said you had it for a year and I'm assuming you had no issues prior to this. I had a different throttle body for two days and I also had the Kinetix V+ too. The first day it drove fine and then the second day my SES came on. I removed it, reset the light and the car ran just fine. Maybe remove the TB spacer for a few days?
Click to expand...

Ok thanks. Yes, no issues prior to this. I will try removing the TB spacer and see if that changes it. I remember someone telling me, I think GTO-Dave, the throttle body makes the engine run pretty lean.

---------- Post added at 08:35 PM ---------- Previous post was at 08:34 PM ----------
Chedman13 said:
You need a UniChip or UpRev tune to adjust your A/F ratios.

You are right, you are getting too much air for too little fuel, you will get a few more HP but risk detonating your engine! Probably not this bad, but still should get it adjusted.

I ran lean with a LMS intake. So try swaping out the LMS tube for the stock or Stillen Z-tube with OEM MAF tube.
Click to expand...

Thanks for the response. If removing the TB spacer doesnt help I will try removing the plenum, if that doesnt help I guess I will go back to stock until my warranty runs out and I can get a tune without risking voiding anything. I wish I still had the stillen tube so I could swap it back. I do still have all the stock parts though.
 
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