Hi i have a 1995 camaro lt1 with heads intake and gm 847 cam, and was tuned by madz z28, the problem i am having is when i start my car and put it in reverse it idles down to like 500rpm and service engine comes on with code 33 map voltage high, but once its warmed up it works great, the question is is the sensor shot,or is this normal with a big Cam thanks Anthony

 

When the idle goes that low, the MAP is likely throwing the code, because of lower than expected vacuum. I would say the code is a result of engine operation-not the cause of a problem.

 

The code sets when MAP exceeds something like 68kPA at closed throttle. As Rob/Shoebox points out, that's probably an actual operating condition. Likely due to the cam, and the tune. It may be made worse by an IAC sensor that isn't reacting to the reduced RPM in reverse. The IAC should be able to put the idle back where it belongs. If it can't, the IAC isn't working correctly. Put a scanner on it and observe the MAP and the IAC counts.

 

hrmm i was wondering if anyone can tell me what is the difference with or without oil cooling if i were to buy a new iac thanks Anthony

 

Never have figured that one out.

 

lol so does it matter

 

IAC = Idle air control. http://shbox.com/1/iac3.jpg
Nothing to do with oil cooling in any way

 

Yea I don't understand here's a link to the iac valves I was looking at http://www.rockauto.com/catalog/x,ca...,parttype,6072

 

...but there are 2 different IACs based on whether it is optioned with an oil cooler or not.

Like I said, I don't know. Just order the one for how your car is equipped.

 

yea thanks for clearing that up shoebox, mine is not equipped with the cooler so im good to go, i appreciate the help, Anthony