I put new throttle body in and had dealership relearn and the idle is still high. was idling normally (around 800 rpm) but i noticed i wasnt getting the best gas milage. So i removed throttle body and cleaned with throttle body cleaner and cleaned maf sensor with the sensor cleaner. Once i put back in my car was idling up to 2500-2700rpms. I bought new throttle body and installed. I then took to GM dealership and had them relearn my idle. My idle is still high.... Dealership thinks i need new MAF sensor.. Any ideas? Before all this my car ran fine other then the bad gas mileage but it idled normal. So once i removed throttle body to clean its been messed up ever since. Please give me a solution.
What is the make model and year of your car? What is the engine displacement?
Testimonial: "2006 Chevy Cobalt SS 2.4"
Ok I'm a dumass. I see the information now. The cobalt ss is a supercharged 2.0 4 cylinder right? Since these supply a pretty constant push the MAF is your best direction to follow.
2.4 L LE5 Ecotec engine
Hmm ok 2.4 durn no supercharger. Well shoot so it can be a vacuum leak. It is common for technicians to use brake cleaner and spray around the suspected leak areas while the engine is running and listen for the change in the engine rpm or quality. This can cause a fire so be really careful if you try this. The only problem with this is the engines generally aren't running at such a high idke. It's like your egr valve is partially stuck open.
Ya i dont know why they call it a SS.. lol. When i cleaned the old throttle body the rpms were around 2500-2700rpms when i put back in. So i took to mechanic to relearn and he said it wont go down and ill need a new throttle body.. So i bought a one and once i installed it i noticed the rpms were down a little to 2200-2500rpms. I cranked my heat all the way up and put my defrosters on and the rpms went down to 1500-1800rpms. But once i turned my heat off the rpms shot back up to 2500rpm. I dont know if that means anything ha
The dealership did say the MAF sensor kept showing up even after they cleared all codes. I didnt know if air leaks or any other reason could cause that code to show
×
In theory once the desired idle speed is programmed into the management system, in the absence of such faults as air leaks, sticking idle air control valve and suchlike it should be impossible for the idle speed to be much different from the programmed value because the ECU should continue closing down the amount of air bypassing the throttle butterfly until the idle is around the correct value.
I think you need to go back to basics and double-check the work to ensure everything is as it should be. In the absence of mechanical faults and ignoring the possibility of electronic problems a high idle must be caused by too much air entering the engine, either because the idle air control valve is not closing properly or because the throttle butterfly is not closing fully.
It is worth noting air can enter the intake through leaky diaphragms, split vacuum hoses or faulty pcv systems. It is also worth checking the egr valve if fitted.
Testimonial: "The dealership thinks i need to replace the MAF sensor. They said the MAF sensor kept popping up even after they cleared all codes. Couldn't a leaky hose or anything like you said cause the MAF sensor code to keep popping up? I just don't want to put more money in something that wont resolve the issue. What is the proper way to check for an air leak? I've heard ppl spraying brake cleaner while engine is running.."
Reading the code should really be just the first step in diagnosis and other equipment should be used to verify what the code reader finds before any money is spent.
Air leaks can be tested for by spraying something volatile around but I suggest listening through a length of hose before taking the risk as well as blanking off vacuum hoses and suchlike. The basic setting of the throttle butterfly could be important too.
Alright im gonna go back thru and check to make sure everything is as it should be and for air leaks. Thanks for the help and ill let you know what i find out
×
1,142 views
Usually answered in minutes!
×