View Full Version : Check engine light!

12-26-2004, 04:27 PM
On my 04 cobra I have had a CAI, Throttle body, 2.8 Pulley and a predator tune for a few months now. Twice now the Check engine light comes on with code P0507: Idle air control system RPM higher than expected. I cleared it the first time and reflashed the computer, thinking maybe just a fluke. The code came back yesterday and am now concerned. At times the car will idle around 850(between 750-1000). Other than that the car runs awesome. Anyone have ideas? I checked for vacumm leaks etc. but couldn't find anything. Also I would like to become a member of this forum. I beleive there is a small fee. I would just like to show my appreciation for all the great info. Thanks again Guys!!:thumbsup:

12-26-2004, 05:31 PM
On my old T/B I was having the same problem.What kind of T/B do you have ?On my BilletflowI was getting to much air passing threw the blade and the T/B housing causing the check engine light to come on.. You may just have a defective T/B ..I have seen Billetflow and Accufab do this so you may just have to return it and get a new one..

12-26-2004, 08:04 PM
I have a accufab throttle body. How do you tell its bad? Should I try the stock one to see if it goes away?

12-26-2004, 08:12 PM
Yes, That is what I would do..

12-27-2004, 09:15 AM
when all else fails...go back to stock...im sure accufab/billetflow are aware that their products could be faulty...just let them now

12-27-2004, 09:35 AM

This is one aspect of buying after market parts that really upsets me. You pay a premium for these parts thinking that a company who solely markets their product "as the best" has gone above and beyond what the OEM manufacturer has done, only to realize their R&D is no where near as good as the OEM's. Case in point: I purchased a [company name withheld as to avoid further issues] TB thinking it would be tested on an '03 Cobra before I got it. Instead I had to "fix it" (read upgrade certain aspects of the part [stiffer spring/new gasket/sand down the butterfly valves so they closed properly, etc.) to make it work with my Cobra. Customer service? None existent and even when you do get a person via phone/email the burden is always on you to prove that you didn't install it incorrectly or damage the item in some way.

Now of course this isn't a blanket statement of the whole after market community, however, over the years I've had instances like the aforementioned which makes me realize that leaving a car stock may be sometimes be beneficial.

As for your issue, I can almost (I say almost because nothing is 100%) guarantee you that if you go back to the stock TB (which I did since I sold the "new" TB on eBay) it will solve your problem.

Good luck!

[gets off of soapbox]

12-27-2004, 11:40 PM
Accufab is now telling me that my Throttle Position Sensor could be out of adjustment. You can't adjust it!!.............. He says it might move a little but there is no true adjustment on it. Just a little warning before you go a purchase a $500 piece of crap, you might want to look into there tech support beforehand. On top of that I called Diablosport for some help. They told me to shut off the Oxygen sensors and that might solve the problem. If not I will need a custom tune at a price of $120. Didn't I pay $400 for this already. Always nice to see companys standing by there products!!:mad:

12-28-2004, 03:07 PM
It would be great just to bolt on parts and not have to worry about issues of faulty products. Also, when said vendors create new products, how was it tested? Too many products if tested at all are usually tested on an engine dyno which is far different than testing the product on a production vehicle since they use F.A.S.T. type equipment as compared to the actual ECU. In most cases, many mods that alter or change the air flow into the motor will require a tune to maintain proper air/fuel mix. A larger throttle body will definately change the volume of air flow for a standard tbs voltage curve. Most if not all programmers use the stock volumetric air flow curve provided by the stock TB. The MAF should compensate for the difference in providing the proper amount of fuel for the given air flow, however, if for any reason the meter gets pegged, all bets are off. The best solution would be to have the car custom tuned since not all motors behave the same with the identical parts. The aftermarket industry can and does provide some good products, how to make it work for your application can be a nightmare. Having the car dyno tuned may be a safer thing to do than expecting an aftermarket part to work on its own. The worse thing that could happen is you wind up with a very lean air/fuel mixture. There are so many parts out there and alot of research is needed to determine if that part is right for your vehicle or not as well as what is required to make it work properly. I was tempted to change the throttle body, but for now it will remain stock. Good luck with your mods! I hope you get the issues solved!

12-31-2004, 12:28 PM
Well I spoke with Dave B. from this forum and discussed possible fixes to my check engine light problem. I had an extra CAI (MAC Straight Shot) with a larger mass air tube. I think 95mm? not sure... but anyway after talking to Dave I decided to install it today. I drove her for about 15min with no check engine light!:bounce: I'll keep my fingers crossed. Thanks Guys for all your input and especially Dave. B for the info.:thumbsup: