CEL on and Fuel Mixture too lean

Wakeboarder11 · 07-26-2007, 10:07 PM

Ok. This is my friends 2007 civic ex and we recently installed an AEM Cold Air Intake on it. Ever since, his CEL comes on. We went to autozone and had them plug in the diagnostic tool to his car and this is what it came up with.

What do you think we should start out with? Thanks for the input

07 Figi Blue Si · 07-26-2007, 10:21 PM

This is a common problem with most CAI/SRI (intakes). Exactly why I bought the Injen brand. They have a patented technology called MR that keeps the stock air-fuel ratio of 15:1, still making about 8 extra HP. Some other brands make more HP gain, say 11, but at the expense of air-fuel ratio.

Think about it. Did you upgrade the flow of your injectors when adding more air? So the air-fuel ratio has now changed. How the MR technology works, I do not understand, but it does so without having to worry about this, and is the only one on the market that does this. All others must matched with new injectors or remapped to keep the stock air-fuel ratio. Go to the Injen site and read about their MR technology. It rocks, its installed, and I have no problems.

Think the AEM was the one in the comparison graph I saw on the Injen site, and it was down to 10:1 air-fuel ratio. That's blowing it! AEM should be sued. Sure, you can get more power from a lean mixture and right timing, but it will damage the engine. Lean means it will run HOT. Rich means it will run cool COOL. Higher octane gas is less explosive than lower octane gas. Most people don't pay attention to these things, but if you tune on your ride, you'd better! Hence, why you get the code. Feel lucky. If the electronics weren't so sophistocated, you would have already fried your motor. Same about the knock sensor. 89 or even 87 gas will not damage this motor, but performance will suffer. It is just too smart of an ECU to let you damage your engine.

BigT · 07-26-2007, 10:44 PM

Quote:

Originally Posted by 07 Figi Blue Si

Think the AEM was the one in the comparison graph I saw on the Injen site, and it was down to 10:1 air-fuel ratio.

Are you saying the AEM had a 10:1 ratio? This is a much richer mixture than 15:1. 10 parts air to every 1 part fuel vs 15 parts air to every 1 part fuel. This would be a much richer mixture than the Injen.

Wakeboarder11 · 07-27-2007, 04:07 AM

yea he probably meant it the other way around. So i guess the only way to fix this would be to buy a new fuel injector then huh?

Subaru71 · 07-27-2007, 04:55 AM

nope, the way to fix it is to put your stock intake back in and reset the code.

Wakeboarder11 · 07-27-2007, 05:40 AM

well we reset the code on his car today when we went back to autozone. Not sure if it came back on yet though. He's not gonna want to put his stock intake back on though. Maybe he will have to get new fuel injectors to fix the fuel air ratio?

blueroadster · 07-27-2007, 11:10 AM

Check to make sure that the MAF sensor is clean. Other than that, it could also be that the air valve on the manifold that supplies air to the injectors has failed. I forget the exact name of the valve, but there is a hose that runs to it from the intake pipe and the valve connects to the intake manifold. You should test the valve for proper operation and replace it if it has failed.

Wakeboarder11 · 07-27-2007, 11:59 AM

your talking about the blower valve right? I wasnt aware there was a valve inside there, but i will look at it either today or tomorrow when i get the chance. If its not though, are there alternate fuel injectors that i can buy that will help to stop make my fuel mixture richer?

NIGHTHAWKSI · 07-27-2007, 12:01 PM

Quote:

Originally Posted by Subaru71

nope, the way to fix it is to put your stock intake back in and reset the code.

Wakeboarder11 · 07-27-2007, 12:20 PM

ah shit. He might just have to sell that 1 and get an injen.

07-26-2007, 10:07 PM	#1 (permalink)
Wakeboarder11 Senior Member Join Date: Jun 2007 Location: Yorba Linda, CA Age: 19 Posts: 1,026 Tyler iTrader: 4 / 100%	CEL on and Fuel Mixture too lean Ok. This is my friends 2007 civic ex and we recently installed an AEM Cold Air Intake on it. Ever since, his CEL comes on. We went to autozone and had them plug in the diagnostic tool to his car and this is what it came up with. What do you think we should start out with? Thanks for the input

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

07-26-2007, 10:21 PM	#2 (permalink)
07 Figi Blue Si Senior Member Join Date: Jul 2007 Location: N. Ca Posts: 198 Lance iTrader: 0 / 0%	This is a common problem with most CAI/SRI (intakes). Exactly why I bought the Injen brand. They have a patented technology called MR that keeps the stock air-fuel ratio of 15:1, still making about 8 extra HP. Some other brands make more HP gain, say 11, but at the expense of air-fuel ratio. Think about it. Did you upgrade the flow of your injectors when adding more air? So the air-fuel ratio has now changed. How the MR technology works, I do not understand, but it does so without having to worry about this, and is the only one on the market that does this. All others must matched with new injectors or remapped to keep the stock air-fuel ratio. Go to the Injen site and read about their MR technology. It rocks, its installed, and I have no problems. Think the AEM was the one in the comparison graph I saw on the Injen site, and it was down to 10:1 air-fuel ratio. That's blowing it! AEM should be sued. Sure, you can get more power from a lean mixture and right timing, but it will damage the engine. Lean means it will run HOT. Rich means it will run cool COOL. Higher octane gas is less explosive than lower octane gas. Most people don't pay attention to these things, but if you tune on your ride, you'd better! Hence, why you get the code. Feel lucky. If the electronics weren't so sophistocated, you would have already fried your motor. Same about the knock sensor. 89 or even 87 gas will not damage this motor, but performance will suffer. It is just too smart of an ECU to let you damage your engine.

07-27-2007, 04:07 AM	#4 (permalink)
Wakeboarder11 Senior Member Join Date: Jun 2007 Location: Yorba Linda, CA Age: 19 Posts: 1,026 Tyler iTrader: 4 / 100%	yea he probably meant it the other way around. So i guess the only way to fix this would be to buy a new fuel injector then huh?

07-27-2007, 04:55 AM	#5 (permalink)
Subaru71 Senior Member Join Date: Jul 2007 Location: Southern California Posts: 118 dSLR Squad #32 iTrader: 1 / 100%	nope, the way to fix it is to put your stock intake back in and reset the code.

07-27-2007, 05:40 AM	#6 (permalink)
Wakeboarder11 Senior Member Join Date: Jun 2007 Location: Yorba Linda, CA Age: 19 Posts: 1,026 Tyler iTrader: 4 / 100%	well we reset the code on his car today when we went back to autozone. Not sure if it came back on yet though. He's not gonna want to put his stock intake back on though. Maybe he will have to get new fuel injectors to fix the fuel air ratio?

07-27-2007, 11:10 AM	#7 (permalink)
blueroadster Senior Member Member Join Date: Aug 2006 Location: Maryland Posts: 3,573 iTrader: 7 / 100%	Check to make sure that the MAF sensor is clean. Other than that, it could also be that the air valve on the manifold that supplies air to the injectors has failed. I forget the exact name of the valve, but there is a hose that runs to it from the intake pipe and the valve connects to the intake manifold. You should test the valve for proper operation and replace it if it has failed.

07-27-2007, 11:59 AM	#8 (permalink)
Wakeboarder11 Senior Member Join Date: Jun 2007 Location: Yorba Linda, CA Age: 19 Posts: 1,026 Tyler iTrader: 4 / 100%	your talking about the blower valve right? I wasnt aware there was a valve inside there, but i will look at it either today or tomorrow when i get the chance. If its not though, are there alternate fuel injectors that i can buy that will help to stop make my fuel mixture richer?

07-27-2007, 12:20 PM	#10 (permalink)
Wakeboarder11 Senior Member Join Date: Jun 2007 Location: Yorba Linda, CA Age: 19 Posts: 1,026 Tyler iTrader: 4 / 100%	ah shit. He might just have to sell that 1 and get an injen.