Hard starting
Thread Starter
Cruising
Joined: Jun 2009
Posts: 10
Likes: 0
Hard starting
I am rebuilding a 1986 corvette that was used for a parts car. When trying to start, it just turns over and does not want to start but when you go back to run postion, it tries to start. It appears that in start, it's not getting power to the injectors, I can finally get it started. Than it runs rough till it warms up, than it's OK. Any help with this problem would be very much appreciated.
Thank you, Don S.
Thank you, Don S.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
You need to verify what is missing that prevents normal starts during cranking. Get a noid light (parts store), or make one with an LED (light emitting diode) in series with a 680 ohm 1/4 or more watt resistor (Radio Shack sells both). Put the light on an unplugged injector plug (homemade light must be connected with the correct polarity, so you have to try it both ways) and see if it pulses during cranking. If so, then use a timing light to check for spark and spark at the right time. Next, put a fuel pressure gauge on the shrader valve at the end of the right fuel rail. You should get 35 to 42 psi and with the ignition off, the pressure should hold up for 1/2 hr or longer. Rapid pressure loss indicates leaky injectors or defective check valve in the fuel pressure regulator. Engines need spark and spark at the right time, fuel and air and in the correct ratio and compression to start and run.
Injector pulses missing during cranking but not missing in run, indicates a defective ignition switch. The ign sw has three contacts that supply power to different parts of the car.
Injector pulses missing during cranking but not missing in run, indicates a defective ignition switch. The ign sw has three contacts that supply power to different parts of the car.
