Hey Guys, A friend and I just installed my BBK/Edelbrock 52MM TB on my 1991 Z28 5.7 L98. Well..the installation went very well..not hard at all. When I started the car...the idle was WAY to high...is it because of maybe the TPS? When I bought the TB....I removed the TPS so I could sand down and polish the TB. Is the TPS causing the engine to idle VERY high? ALSO....my Check Engine Light came on....does this all make sense? I took of the 52MM TB and out my old 48MM TB back on.....and it's fine...so...does the TPS just need to be adjusted?

 

Look on the main page for Tech Central, and then find "setting minimum air".

You might just get by with closing the TB's down some, but best to start from scratch with a different Throttle Body.

I don't think the TPS is the issue, unless the voltage is really off...but set min air first

 

If you haven't reset the idle, IAC and TPS, you could have all sorts of idle issues. Take Mike's suggestion and follow the procedure in the tech article.

 

u used a new TB gasket right

 

Yep, brand new 52MM TB gasket...

 

As soon as I have some time....I will try to set the TPS up....also..I never thought about reinitializing the ECM....installing a 52MM TB seems like it would upset it a little....wonder if any of the other guys with 52MM TB's have had any problems like this? Little more air...seems like it would throw everything off a little anyways....or maybe I'm just crazy?

 

You are using a larger TB on your system. Your TPS, etc is set for the 48mm, and when you go to a 52, it's flowing more air at the 48mm setting, making your idle very high. You will have to adjust it to get the idle correct. Not a big problem, just needs some tinkering.

 

Great news.....me and a buddie of mine adjusted the TPS sensor..and the car runs fantastic.....the whole time...it was the TPS.....just wanted to let everyone know.