the answer could very well be right in front of me, but I'm seeking help from those more experienced then me.

I have a 1995 Corvette Lt1 with a 6spd. The problem Is that after installing a BBK 58mm throttle body my cars idle rises as it warms up. When cold It starts up and gose to around 1200-1500 then settles at around 650-750 rpm quickly i consider this normal behavior .

Once the temp rises the rpm gradually increases. It never did this before the new throttle body. It gose to around 900-1k rpm. If I blip the gas or press and release it in anyway once it gose to around 900-1k rpm it will then constantly stay at around 1100rpm and will rest there.

I would like to keep my new throttle body as it makes the butt dyno happy , but if that is indeed a problem with aftermarket throttle body's then I will have to go back to stock in hopes it fixes it.

 

Welcome to the forum. When it warms up and goes in to closed loop, something isn't sending the right info to the ECM. I'd first check the temperature sensor. Any codes?

 

Welcome to the forums. If you swapped over the throttle position sensor, it should be set at.54 volts at idle and the air idle control is working correctly, which it sounds like it is. You could try a relearn procedure. I have not tried it myself where you start the engine and let idle for 3 minutes, turn the engine off and let it set for 1 minute. Then start the engine and let idle again for 3 minutes check engine light may come on, scan for codes and then clear. If idle speed is still off, drive car above 44 mph making several acceleration and deceleration cycles. if that doesn't work turn off engine and let it set for a minute then restart, that should reset the idle. Maybe.

 

No codes at the moment. Ran it all day yesterday and no codes/light. Unfortunately if it did start showing me a code i have 0 ways to pull the code. it has the obd2 connection but obd1 computer. With that said I can't find a scanner that will 100% work with my car.

a forum member from anouther page with a similar problem was also told it could be the temp sensor. So I'm thinking I should look into that.

As of right now plan is to go back to stock later today when I'm off work to see if problem persists. If it gose away I'll have to assume the throttle body is defective , or I simply am un able to learn how to make it work properly. I'm not exsactly the smartest person but this really doesn't seem like it should be this difficult especially because when its cold it still idles perfectly. I just wish it would have done this before the new throttle body because my automatic assumption is that's the problem when that's the only thing I changed before it acted like this.

It just feels like I took a car that ran perfectly and just had to go messing with stuff beyond my understanding. 🤦‍♂️🤷‍♂️🤦‍♂️but enough whining/rambling. I appreciate the advice and I'll look into the sensor if problem continues with old throttle body.

 

That's true the obd 1 was starting to change over at that time. (flashes codes) Temp sender maybe. weird timming for that. My son bought a bigger throttle for a 2000 6.0L pickup and it had compatibility problems, I didn't have time to figure it out at that time. Put the old one back on and ran fine. I will try again later. Electronics on these things can drive anyone nuts without the right tools. And there are issues sometimes with swapping parts back and forth.

 

I again appreciate the response 🙏💯 I'll report back if there are any or no changes after I put the stock throttle body back on.

 

Just to update, put stock throttle body back on and car instantly started to idle correctly at all temps. I believe my BBK unit had a defect from factory. The mechanical spring that closes/opens the valves wouldn't slide all the way back to reach the idle stopper. You could by hand force it back slightly and the idle would correct, also noticed the valves wanted to get stuck.

So my experience with a larger throttle body was kind of a bust so far. I mite get a wild hair and try a different brand or a new unit one day but for now I'm going to switch focus to things like headers and eventually cams/valves ect.

 

Sounds like you found the problem. Thanks for reporting back as it may help someone in the future.