Well I just bought my first Z car, a 1976 280Z. The car was non-running when I bought it. I was told the battery dead shorted to the firewall and would never start again after that. I have the FSM and read the EFI Bible and have done test after test. The first major problem I found was the ecu wasn't seeing ground. I added a ground wire from the battery to the chassis and then put the ecu ground on the same chassis point. Once I did that the cold start injector would work and give about a second or two of run time. I can pulse the injectors with the ignition on by applying ground to each injector's respective ecu wire. I can get a few seconds of run time that way. I have continuity from pin 1 to to the coil negative and all power and ground terminals tested fine at the ecu. The EFI Bible basically said replace ECU. I opened up the ECU and everything looks perfect. The only other thing I read was that tach has to be connected with a 2.2K Ohm resistor inline in order for the ecu to fire the injectors. At this point I'm stumped besides just trying another ECU. If anyone know anything else to test let me know.

 

Do NOT connect the injectors straight to ground, even to pulse them. They are designed to have a dropping resistor in the circuit. When I measured the voltage drop across an injector in a working system, it was only about a 2 VDC drop, not 12 VDC. Have you located the dropping resistor, yet?

 

Steve i pulsed the injectors with ground from the ECU connector with the ignition on. In doing so you are using the dropping resistor on the positive side of the injector as designed and verifying that it is still functional as well as the power relay assembly too.

 

Okay, I just wanted to make sure you weren't going to fry your injectors. I hate saying it, but it sounds like you did something to your ECU. There is a guy over at Classiczcars.com that had been tinkering around with making a replacement ECU. His screen name is SuperLen. You may want to check on his progress.

 

Fixed the car tonight. It was the ECU after all. I bought the car in non running condition, and the previous owner said he dead shorted the battery on the firewall. I assuming this fried the ECU as there was also no ground connection at the ECU when I test it.

 

Hey, at least you can get an ECU still.