Is there something wrong or is this normal??

[Speed3girl]

Ok does anyone else's fuel gauge drop super quick on them. I have 73 miles on mine and my gauge is already more than 1/4 gone. I mean it slows up a bit and then drops quick later. This is my 1st tank with the CAI and just wondering.

[Kosh]

It seems like the first 40 miles it stays well above the F mark and then the next time I check it the needle has gone down 1/8 below the F.

Notice this happening while on long trips mostly while going 75 with cruise control on.

I have MS CAI.

[knowledge007]

Did you disconnect the battery before install?

[Speed3girl]

Did you disconnect the battery before install?


No why? Well I don't think so.

[knowledge007]

That is the problem. You must reset the ECU. Disconnect the negative battery cable for approx. 30 min to an hour and press the brake pedal to discharge any existing energy. Comp must reset and adapt to the changes you have made?

[Speed3girl]

That is the problem. You must reset the ECU. Disconnect the negative battery cable for approx. 30 min to an hour and press the brake pedal to discharge any existing energy. Comp must reset and adapt to the changes you have made?



Hmmmm did the directions say to do this??

[crashkelly]

dude i really dont think the battery needs to be disconnected for "at least a half hour" for the ecu to reset....from what i understand if you unplug it and then press the brake pedal five times it resets. I might be wrong, but waiting a half hour to an hour just for the ecu to reset doesnt seem right.

[crashkelly]

Hmmmm did the directions say to do this??

well you should always reset the ecu after you modify the engine so that the car can relearn and adjust the a/f ratios and whatnot

[knowledge007]

Dude, I say that just to make sure you the ECU is drained.

[knowledge007]

Listen sweety, DISCONNECT the NEGATIVE battery cable and drive easy for the first 50 miles and then drive normal. ECU must adapt and correct itself as CRASH has stated. Forget about the directions. If they didn't say then they are whack.

[Speed3girl]

Dude, I say that just to make sure you the ECU is drained.



Ok so did it say this in the directions...am I hurting my car or what? :(

I have NEVER had to do this with any other car. WRX, EVO, SI and so on.

[knowledge007]

No how are going to hurt the car. All your doing is reseting your ECU Thats it. Trust me I have done it millions of times already with the mods I have. This is done by the dealers as a shortcut when ECU needs to be reset.

[crashkelly]

Listen sweety, DISCONNECT the NEGATIVE battery cable and drive easy for the first 50 miles and then drive normal. ECU must adapt and correct itself as CRASH has stated. Forget about the directions. If they didn't say then they are whack.

+1 and anytime i have ever installed a CAI or SRI the directions definately say to disconnect the battery...usually it is the first step actually

[crashkelly]

Ok so did it say this in the directions...am I hurting my car or what? :(

I have NEVER had to do this with any other car. WRX, EVO, SI and so on.

dont you have the directions...
It is not going to hurt the car...it will help you in fact...probably a lot. Your ecu kind of tunes itself to how you drive and now you changed the amount of air flow and the temp is cooler. So if you dont reset the ecu it will see it as an out of the ordinary change and wont perform the way it is supposed to. You absolutely have to reset the ecu when changing anything on the engine....this includes intakes, exhausts, headers, etc...

[Speed3girl]

+1 and anytime i have ever installed a CAI or SRI the directions definately say to disconnect the battery...usually it is the first step actually


Hmmm makes me wonder. I guess I should have done that. Is it too late to do it now???

[knowledge007]

No nothing is to late. Just do it...lol yeah yeah do it...

[gsrtype1]

gas guages do that its perfectly normal, mine does that

[Speed3girl]

gas guages do that its perfectly normal, mine does that


Ok good. I thought so....but we got onto the resetting the ECU. LOL

I will try to see what my husband wants to do with that. :)

[knowledge007]

Husband or not. We are trying to tell you something. When ever you mod any car for that matter you must reset the ECU. It is only common sense. You are bringing in more cold air. ECU must adapt and recalibrate for the cold air coming in. How is the ECU going to know what you have done if you have not reset. ECU right now is not trying to justify for the cold air and a/f has not adapted. Therefore could be the leading cause that your going to through gas like water.

But you know what, if you don't want to listen to all of us, good luck. Just don't understand why anyone would ask a question, receive an answer, the correct answer for that matter, and then not do anything with it or seems like not even believe it.

Good luck...

[Speed3girl]

Husband or not. We are trying to tell you something. When ever you mod any car for that matter you must reset the ECU. It is only common sense. You are bringing in more cold air. ECU must adapt and recalibrate for the cold air coming in. How is the ECU going to know what you have done if you have not reset. ECU right now is not trying to justify for the cold air and a/f has not adapted. Therefore could be the leading cause that your going to through gas like water.

But you know what, if you don't want to listen to all of us, good luck. Just don't understand why anyone would ask a question, receive an answer, the correct answer for that matter, and then not do anything with it or seems like not even believe it.

Good luck...


No no that is not what I am saying. I am saying I will ask him....and have him do it. I do appreciate everyone responses. I am never rude. I am just not about to walk outside myself and do that. I will go home and while the car is in the garage do that.

[SPEED305]

Husband or not. We are trying to tell you something. When ever you mod any car for that matter you must reset the ECU. It is only common sense. You are bringing in more cold air. ECU must adapt and recalibrate for the cold air coming in. How is the ECU going to know what you have done if you have not reset. ECU right now is not trying to justify for the cold air and a/f has not adapted. Therefore could be the leading cause that your going to through gas like water.

But you know what, if you don't want to listen to all of us, good luck. Just don't understand why anyone would ask a question, receive an answer, the correct answer for that matter, and then not do anything with it or seems like not even believe it.

Good luck...(boom05) (drunk)

[controlo]

what's your trip computer reading for gas mileage?
mine is at 21.8 right now, which i think is pretty good for never driving on the highway and it being 100 degrees here every day. i don't ever fill my car up so i can't say anything about the rapid drop...

[knowledge007]

Nice Speed3girl, let me know when the car hits its sweet spot...

[justa4banger]

knowledge007, it is not required to reset the ECU for every mod, BUt when you do the car tends to learn and adapt faster, THATS ALL.

as for decreased mpg or the gas gauge, ye mine drops fast also at 60-70 miles. i also recently installed a MSCAI and last tank of gas got me 14 mpg.

I was hard on the car trying to verify i had all of my extra ponies. i'm pretty sure i accounted for all of them :D

[Young Roids]

last tank of gas got me 14 mpg.



OUch! Gas mileage goes down that bad with the cold air intake?

[Speed3girl]

what's your trip computer reading for gas mileage?
mine is at 21.8 right now, which i think is pretty good for never driving on the highway and it being 100 degrees here every day. i don't ever fill my car up so i can't say anything about the rapid drop...


For MPG...that seems to always be the same 24.8 or so....but I NEVER get that mileage per gallon. :(

[Speed3girl]

Nice Speed3girl, let me know when the car hits its sweet spot...

Will do. :)

[SwampAss]

If you followed the DYREKSHUNS on the install of the CAI, you already had the battery disconnected for the length of the install.

[SwampAss]

p.s. I had heard that disconnecting the battery and pumping the brakes will bleed all the power from the car's ECU. Draining the caps is something will refer to it as @ work.

[smoknspeed3]

I know I'm pretty much a new unknown member but I have plenty of years modding Focus's. As a rule of thumb always disconnect the neg. battery terminal for anything the ECU may effect. If you just throw on a CAI and fire the car up the ECU is going to think there is a problem due to the fact the car isn't running the same way it did before the mod. The result will be the ECU trying to compensate with increasing the fuel flow. You will pretty much be telling it the air is actually cooler outside then it really is, thus leading to the crap MPG. If you reset the ECU, when the battery is hooked back up it recognizes a change and sets the air fuel to were it needs to be. Although I have never used the brake thing before interesting idea. Bottom line is, it's always better to disconnect the battery to be safe. Not only does it make it easier for the car but it can prevent any shorts or problems depending on what your working on.

[smoknspeed3]

p.s. I had heard that disconnecting the battery and pumping the brakes will bleed all the power from the car's ECU. Draining the caps is something will refer to it as @ work.

The reason it has to be disconnected for a period of time, or use the brake method is the ecu will hold a small amount of power to keep everything as it should be.

Working on the Foci we used to disconnect the neg terminal just to reset the ECU to factory specs. As years and months go by the ECU learns the temps and how you use the car and it will change settings. By disconnecting it you automaticly rest everythign back to factory specs. Think of it as the brain. It can learn small things that change the way it performs.

[Speed3girl]

Geez.....i guess I will see what happens with this tank of gas....and go from there. I have about 105 miles on my car and it is not to 1/2 tank yet. So we will see. :(

[the7comeback7ki]

+1 for resetting ECU