My 92 Z28 is stock with the exception of replacement fuel injectors and fuel pump around 150 miles ago and general maintenance and tune up pieces. I only drive it about once a month for twenty miles or so. I want to use it as my daily driver now and am having some strange starting issues.

Here is what it is doing:
~Starts fine the first time you start it for the day.
~Takes 5 to 10 seconds to start it if it sits in the sun after driving it and letting it sit. Stumbles a bit before it starts to idle normal.
~After it's started it runs great.

So far I have replaced the fuel filter, cleaned and tested the fuel overpressure valve on the tank, tried different fuel, checked everywhere for vacuum leaks.

Any ideas are greatly appreciated.

 

I don't know, but I am surely interested. My 92z28 is doing the same thing. I have even replaced plugs, cap, rotor, etc and it continues to do it.

 

If we don't figure it out on the forum I am going to try a few more things. If this doesn't work its going to a local shop. Will let you know what happens.

 

Sounds good thanks! I also changed the coil and map sensor and nothing helped.

 

Did you change the coolant temperature sensor?

 

no, I haven't tried changing that or any other sensors.

 

I'm going to change mine today to see if it has corroded and is sending a false signal when warm. Will let you know how it goes.

 

Coolant sensor didn't solve the issue. I have noticed something strange. Originally when it was cool outside the car started fine. After sitting in the sun for the day it's was hard to start.

The weather changed here and we are now averaging over 110 deg. Now the car is always hard to start.

If the fuel pressure was bleeding off the temperature should not make a difference in the starting. On vacation next week and will take the car to the shop for more diagnosis when I get back. I will share the info when it's done.

 

Please do. I have now torn mine down and am in the process of rebuilding it. Contemplating on replacing every sensor on the motor so I know everything is good, but that is going to be some $$.

 

Try seafoaming your car. It should be done about every 10,000 miles anyway...
http://www.ls1tech.com/forums/genera...-your-car.html