Running Lean
10-05-2006, 10:08 PM
#1
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Join Date: Jun 2006
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Posts: 8
Running Lean
I've got an 06 Mustang GT and I've been running lean since I installed a C&L CAI with a Predator tune. I tried all three of the octane tunes but it kept throwing a check engine light and I'm running lean in bank 1 and 2.
I took it to a dyno last week and I thought that they took care of my problem. The check engine light stayed out for days so I know that they tuned it right on the dyno because every other time it threw the check engine light after the 2nd or 3rd cold start. But then yesterday, the light came back and I could feel a noticable difference in performance. I got home and used the Predator to re-installed the custom tune that they created for me at the dyno. This morning, performance seemed to improve but on the way home tonight, the light came back.
Does anyone have any ideas? Could I have a faulty MAF sensor or maybe even a bad ECU?
I took it to a dyno last week and I thought that they took care of my problem. The check engine light stayed out for days so I know that they tuned it right on the dyno because every other time it threw the check engine light after the 2nd or 3rd cold start. But then yesterday, the light came back and I could feel a noticable difference in performance. I got home and used the Predator to re-installed the custom tune that they created for me at the dyno. This morning, performance seemed to improve but on the way home tonight, the light came back.
Does anyone have any ideas? Could I have a faulty MAF sensor or maybe even a bad ECU?
10-05-2006, 11:01 PM
#3
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Join Date: Jun 2006
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RE: Running Lean
Well, currently, I've been running 93 oct with the 93 oct tune. When I tried the other tunes I was running 93 during all of them. I would get the CEL within a day or so after trying the different tunes so there was never enough time to go through a whole tank of gas. Funny thing though. Yesterday morning, I filled up for the first time since I had the dyno tune done and it was the 1st cold start after the fill up that the CEL came back on. I put 93 oct in it but could bad gas have somehow caused this? I could see bad gas causing a drop off in performance but would it cause the engine to go into a lean condition?
10-06-2006, 11:04 AM
#5
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Join Date: Jun 2006
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RE: Running Lean
When I took it to the dyno, they knew that I had already been having problems with the Predator tune. They also thought that a vacuum leak could have been causing the problem. They checked but did not find any.
10-06-2006, 01:49 PM
#6
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Join Date: Apr 2006
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RE: Running Lean
The only time I got a running lean code was when I was coasting down a big hill with my clutch pressed in..
It seems that at the high speeds, but very low rpm's, the free flowing air was actually pusing istself into the intake faster than normal..
I cleared the code, and Never had it show up again...
Just wondering if you may have a similar 'coasting' experience in your daily traveles..
otherwise, check for good seal on your intake (especially after the Mass Air meter), as any sort op opening (even in the vacuum line) will let in more air than your pcm thinks.
It seems that at the high speeds, but very low rpm's, the free flowing air was actually pusing istself into the intake faster than normal..
I cleared the code, and Never had it show up again...
Just wondering if you may have a similar 'coasting' experience in your daily traveles..
otherwise, check for good seal on your intake (especially after the Mass Air meter), as any sort op opening (even in the vacuum line) will let in more air than your pcm thinks.
10-06-2006, 09:45 PM
#7
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Join Date: Jun 2006
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RE: Running Lean
How can you tell that you're running lean when you're costing? I can't tell when exactly I'm running lean, I have to check the error codes after it throws the check engine light to see that it's running lean.
I do see something odd when I'm coasting though but it only seems to happy around town after I've done a lot of stop and go driving. When I put in the clutch, my RPM's drop down to like 500. But at the exact moment that I come to a complete stop, they go up to around 1200 and then drop back down to normal which for me is around the 800 range. This also did not start happening until after I installed the C&L CAI.
I do see something odd when I'm coasting though but it only seems to happy around town after I've done a lot of stop and go driving. When I put in the clutch, my RPM's drop down to like 500. But at the exact moment that I come to a complete stop, they go up to around 1200 and then drop back down to normal which for me is around the 800 range. This also did not start happening until after I installed the C&L CAI.
10-06-2006, 11:12 PM
#8
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Join Date: Apr 2006
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Posts: 106
RE: Running Lean
I only know that coasting caused it, because the code popped up while I was flying down a hill at a pretty good speed with the clutch pushed down..
( I was playing with the gas mileage gauge and looking to see how high I could get it going down the hill)
your idle sounds similar to what mine did prior to my sc install.. and I would have to say seems to be fairly normal from what I hear...
also, If you were at the dyno, did they chart your air/fuel ratio?
I've never been to one yet, but That should be a decent indication as to where the problem may be..
clear the code, and try and see if you can find when exactly it comes up again.. if you catch it as it happens, this may help determin what exactly your doing at that time..
also, don't run that thing to hard till you get the issue solved, as running lean at high rpm is dangerous..
best of luck..
( I was playing with the gas mileage gauge and looking to see how high I could get it going down the hill)
your idle sounds similar to what mine did prior to my sc install.. and I would have to say seems to be fairly normal from what I hear...
also, If you were at the dyno, did they chart your air/fuel ratio?
I've never been to one yet, but That should be a decent indication as to where the problem may be..
clear the code, and try and see if you can find when exactly it comes up again.. if you catch it as it happens, this may help determin what exactly your doing at that time..
also, don't run that thing to hard till you get the issue solved, as running lean at high rpm is dangerous..
best of luck..
10-07-2006, 12:25 AM
#9
2nd Gear Member
Join Date: Jul 2006
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Posts: 328
RE: Running Lean
i'm having the same problem you have,i had my c&l and predator for a month now,i had to download the file into my predator from my cpu.everytime i install it i was lean and it feels like it idles rough.it sucks because i'v had my c&l off for 3 weeks and i'm just running my predator with 93 tune.i would like to know why also.