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Discussion Starter · #1 ·
Hi guys. Well, my nightmare has started again. My SES light came on again tonight. Now, I can't even do the pedal trick to access and erase the code. I don't know why... I guess it's still that stupid fuel sys lean b1 (0171) code, same as always if you've been reading my threads. I'm starting to be really pissed out. It's not the S-AFC II, I don't have one anymore. What could be doing this? The fact that I run 94 octane? The fact that I have timing advanced to 17 degrees (although the light came on before the timing advance)? The fact that I have a bypass valve on the CAI?

My car is a 2004 SpecV and my performance mods are AEM CAI, HotShot 4th gen header, GReddy Evo 2 catback exhaust system, and timing advanced to 17 degrees...

Could it be an install problem? Maybe there is a leak somewhere and too much air is coming in? Because damn, alot of 2004 have the same mods I have I/H/E and timing advance, and no one has that problem. I'm really starting to be scared.

Can the lean condition blow my engine? Do you think it's sever? As I mentioned to you before, the tech at Nissan had checked my spark plug tips and they were white, no huge deposits or anything, but they were white. Should I be scared to death with this lean condition warning or is being rich even worse?

I'm getting ready to cry. Honestly. I try and invest colossal sums of money in a short period of time to get the car performing well (it does at 14.739 @ 95.033 mph), but I can't enjoy it when it gives me this bull****... I don't know if you understand my point. It's a brand new car and I wouldn't like the engine to blow and Nissan to tell me I'm ****ed because I'm modded...

Do you think my MAF is blown? Would it give me other problems if it was? I really don't know what to do at this point... Bring my car at the speed shop who installed my stuff and ask them to check for install problems? Bring the car to Nissan and have things checked out ($$$) ???
 

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Discussion Starter · #3 ·
I noticed the AEM CAI is for 2002-2003 inclusively. Also, the MAF on 2004 is different. Maybe my AEM CAI is generating problems with MAF readings?

Who knows, maybe the GEN II Nismo CAI will solve the problem? It's made for 2004 SpecV...
 

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Discussion Starter · #4 ·
Another funny thing is that a member of the club has a 2004 SpecV bone stock. He made a custom CAI and it threw the same error code as mine. He simply removed the tube that goes in the wing and connected the filter onto the MAF. No more SES light. Maybe the CAI gives problems on 2004 (which I doubt, so much people have some)...
 

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is your bypass valve by any chance AFTER the maf?
 

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Discussion Starter · #6 ·

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you have it right... the maf will be able to read air from the "valve" and the filter....
there goes that idea :(
 

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OrangeVee said:
I noticed the AEM CAI is for 2002-2003 inclusively. Also, the MAF on 2004 is different. Maybe my AEM CAI is generating problems with MAF readings?

Who knows, maybe the GEN II Nismo CAI will solve the problem? It's made for 2004 SpecV...
I Just got my AEM Cai and on the installation instructions it says:
 

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OrangeVee said:
I noticed the AEM CAI is for 2002-2003 inclusively. Also, the MAF on 2004 is different. Maybe my AEM CAI is generating problems with MAF readings?

Who knows, maybe the GEN II Nismo CAI will solve the problem? It's made for 2004 SpecV...
I Just got my AEM Cai and on the installation instructions it says for 2002-2004 specv. Also the instructions says that the AEM bypass valve cannot be used with this CAI, due to space restrictions and the MAF sensor. Try to take out the bypass valve and see what happens :cool:

BTW: Sorry for posting twice
 

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Sounds like you have an air leak somewhere after your MAF where unmetered air gets into the engine, causing a lean condition. Do you have the breather hose that comes from the valve cover connected?
 

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diwun67 said:
Sounds like you have an air leak somewhere after your MAF where unmetered air gets into the engine, causing a lean condition. Do you have the breather hose that comes from the valve cover connected?
I bet this is it...

Or...

by chance did you happen to do the butterfly screw fix at some point?
 

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Discussion Starter · #12 ·
No I haven't had the butterfly screw fix on mine, the butterfly screw seems to open fine and isn't loose.

I haven't checked for the breather hose, but I'm sure it's connected.

Maybe it's actualy the bypass valve then... Hmmmm...

Or maybe it's a dirty MAF sensor? If I try and clean it?

I hope one of you clever boys will be able to find the solution...

For now, my plan is to try and verify all connections tonight and clean the MAF sensor gently. On Wednesday, I'll have the code cleared and the stock air box reinstalled. That way, we'll see if the CAI was generating the problem, unless you suggest uninstalling the bypass valve first, and see what happens then.
 

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Discussion Starter · #14 ·
I checked in the AEM instructions manual and as you stated Black04SpecV, they say that you can't use a bypass valve with an AEM CAI because of space restrictions and because of the MAF... So maybe it's the bypass valve causing all this crap...

But it's funny, because the Nismo CAIs come WITH a bypass valve... Hmmm.
 

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OrangeVee said:
I checked in the AEM instructions manual and as you stated Black04SpecV, they say that you can't use a bypass valve with an AEM CAI because of space restrictions and because of the MAF... So maybe it's the bypass valve causing all this crap...

But it's funny, because the Nismo CAIs come WITH a bypass valve... Hmmm.
Try to remove the bypass valve and see what happens.

BTW: Very nice ride man I really like the spec in the orange ;) .
 

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From the FSM (02):
-Intake air leaks
-Heated oxygen sensor 1
-Injectors
-Exhaust gas leaks
-Incorrect fuel pressure
-Lack of fuel
-Mass air flow sensor
-Incorrect PCV hose connection
 

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^^ good info ^^
 

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Might be the bypass valve.... or if you can, see if you can relocate the bpv between the filter and the maf.... i have seen some come in between the maf and the throttle body..... don't make sense i know, but seen em.... good luck brodda.

-Alex B.
 

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Might be the bypass valve.... or if you can, see if you can relocate the bpv between the filter and the maf.... i have seen some come in between the maf and the throttle body..... don't make sense i know, but seen em.... good luck brodda.

-Alex B.
BPV is in the right spot... I'm almost guessing his maf is jsut reading wrong...that's the only thing I can think of.. it might be reading consistent, but with slight voltage issues... *Shrug*
 
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