The manual fan switch is almost a necessity here when sitting in traffic in temperatures over 100 degrees. Also, if your gonna race at the track they are good for keeping it cool while wailting in line. I'm just getting ready for my days at the track.

 

I don't really race my car.. I just want it to work right when I drive it.. I have been thinking of getting a manual fan switch though..

 

does it always heat up that much? if so, then, you prolly have a wrong temp t-stat. go to one ur supposed to have. oh, and also, make sure both ur fans work. oh, and one more thing...FLUSH your radiator.

 

First to start off, all stock Lt1 motors heat up to the last white mark before they cool thats the 224-226 degree mark. this is when the first fan kicks on. Keep the car cool with a 160 and a manual fan switch.

Next your real problem. This is the most typical problem found in the LT1 motors. Your optispark is bad! Im assuming you have a 93-94 car? For sum reason its hard to get these to pull a high or low resolution code.(bad opti) Its also typical for these optisparks to run fine cold then hesitate when warm.
Replace your optispark and call it a day.

 

if he said something about pulling off this post cat o2 so i dont think its a 93-94 more like a 96-97,

i had a slight hes. too i checked everything changed everything too...wires plugs filters, etc......

have you checked for burnt wires??doesnt sound like its that, but did you check really close?? i checked mine and they all looked fine...but i went further than that, jack your car up at night...get under it and check for arching...if you dont see anything, get a squirt bottle, and mix up a batch of salt water, salt is conductive with elec., but anyways...with a FINE MIST, mist the wires a little and if you see arcs, then maybe your wires are fried or not on all the way?, but i found this out through a friend and it helped me out.

BUT BY NO MEANS, DO NOT DOUCHE YOUR CAR DOWN JUST MIST IT, AND THERE SHOULD BE NO PROBLEMS

 

Did you do the coil too? Maybe u did, if not that'd be my prime suspect.

Go ahead, trade in your chebby, as long as your upgrading to a poncho (with a chebby motor )

 

sorry, have to disagree with you there...my 94 z28 never went to the last white line (except the time when my t-stat croaked). it had a stock t-stat.

 

mine is a 94z28.. my temps usually don't get up to the last white line unless im idling for a VERY long time.. and have driven around (stop and go) a whole lot before that.. its suppose to be a 160 thermostat though im not sure if they put the right one in.. it was the previous owner and they did all kinds of ****ty stuff to my car

 

I had some of the same simptoms, had the computer done by pcmforless....problem solved. Give them a try,it worked for me.

 

i change my o2s this weekend no help.
I changed my iat in the intake elbow, drove all day w/ motor above 220* and the surging & bad ilde didn't happen for the first time since I can remember.

Try it only $10.00 from Sam Taylor.

So far so good...

 

AHHHHH YEAH, thats what worked for me too. That pesky IAT sensor will get ya every time. HA HA Also, it wouldnt hurt to take off the TB and give it a good deep cleaning, and clean off your MAP, MAF, and IAC valve with some electric cleaner. That should about get it done for ya. Good Luck

 

If that IAT sensor fixes the hesitation im gonna have a heart attack.. 2 years and a 10 dollar part was all I needed.. its going to the shop on wednesday to get checked out/maintenanced anyways so ill make sure he changes that.. you guys will be gods if that fixes it

 

Yeah, I put in a new opti, trying to fix the hesitation and a little $10 part was the the main problem, my opti was getting weak though, so I guess it was now or just a ways down the road. I hope this fixes it for ya though, its nice to have the old Z back!!

 

Guys I have seen several posts where the IAT sensor was reading like 40 degrees colder and that made the cars hesitate and run like crap when the engine was warm/hot!!

I am the one who posted the effects of a Coolant Temp Sensor readings showing hotter than it is for example if the engine temp is 70 degree in the morning but the sensor tells the pcm the engine its at 122 degree... When engine cold in the mornin the freaking thing will turn and turn and barely start but then it will run fine after its wamed up...if the sensor is not linear with the engine temp it will do that when the engine its cold.


So change your IAT if you have a hot hesitation in your car and change your Coolant temp Sensor if its hard to start your engine when cold but then runs fine after it gets hot......

Thats what I gather from all the posts including mine.

Here is a chart for the Coolant Temp sensor

At 70*F the resistance should be 33 Kilo Ohms
At 80*F '' '' '' '' '' '' '' '' '' 25 Kilo Ohms
At 160*F 477 Ohms
at 180*F 333 Ohms
At 220*F 174 Ohms


hope that helps

Marvin

 

That is the temp when the fan comes on so obviously if your running a fan switch or not driving in traffic it will never heat up to the point where the computer turns the fan on.

Better yet the car is a 95+ change the cap and rotor on the opti, save yourself some money instead of buying a brand new one.