Hey all, this is my first post on this board, and I am buying an 87 Iroc Z28 from my mechanic (who's only had the car 2 weeks). He took the car to the track on Sunday and made it less than half way down the track when the Check Engine light came on. Not wanting to hurt the car since I'm buying it (pick it up on Wed 2-20) he shut it down. It has done it to him a couple of times. It only comes on when it's a fullthrottle for a few seconds (like a drag race). Thanx for the help
Wes-87 Iroc Z28

 

your buying it from your mechanic and he didnt tell you what may cause it to come on? id replace oxygen sensor

 

Or the TPS, but I figured I'd ask here first. Also, my mechanic is doin a complete tune up tomarrow: new wires, plugs, dist. cap, new belts, hoses, oil change, tranny fluid change, etc.
Wes

 

If he's a mechanic of any worth, one would think he could check the codes & figure it out himself. I'd be worried about a mechanic that doesn't know how to retrieve code from a GM car.(personal opinion).

99% of the time, when the check engine light comes on it's a sensor failure/problem & is non-fatal to the engine.

(edit,, you'd think I'd learn how to spell/type one of these days too so I wouldn't have to edit post )

edit edit, just a side note, anything over (I believe) ¾ throttle, the ECM goes into WOT (wide open throttle) mode & comes out of closed loop which makes it disregard the o2 sensor so, that would not be the cause of the light during a race. 87 would be MAF and it may be getting 'false air' (air comming in behing the MAF sensor).

Something else did not match what the ECM expected to see, pulling the codes would confirm which sensor caused the problem.

 

As we were giving it a tune up he realized that the knock sensor wasn't hooked up. So it's off to the parts store to get a new one, along with hood struts, and new radiator cap among other things. Thanx for all your help.
Wes 87 Iroc