Main Relay clicks constantly!

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Junior Member
Okay here is the problem i have... when i turn the key on the main relay clicks, cel, and red led on ecu all flash constantly at about half second intervals. Its what i beleive to be an 91 si, heres the deal the car is my sisters boyfriends and he just picked up someone elses "project" car. they had started with an hf that was damaged in the front pass corner and an si that was damaged in the rear. the previous owner had gutted the hf and basically cut the two in half and jigged and welded the two together using the si front end engine and trans. This is how we received the car. The previous owner said that it ran just fine before this work and it came with 2 cars worth of "extras". I reran the rear body harness (that had been wrapped up in where the gauge cluster would have been) gas lines and reinstalled gas tank, brake lines, and the car started with a little gas poured down the throttle but the dash out, and it came with 2 dashes, we took the best condition dash and went to install it, but it was the hf dash harness which was missing what appeared to be an important plug on top of the fuse panel (hacked off). found another harness with the correct plugs for the fuse panel area but it was missing every other plug again hacked off. so aquired a good 91 si dash harness installed it and now we have our crazy clicking no start no fuel pump issue. I already checked and cleaned the grounds, tested the main relay, tried a second main relay, tested for continuity between all the connections between the main relay to power, ground, fuel pump and ecu pins. I replaced the integrated control unit with a second one also. This is driving me insane! Any ideas? I am going to try to pick up another ecu in the next day or so incase thats the issue. Thanks.


New Member
sounds like the problem I just scratched off more hair with. my main relay would chatter along with cel and ecu led. Check for continuity from the black and green wire coming out of the main relay to ground it should be close to 0 ohms resistance. If you have a high ohm reading the small ground on the thermostat is bad.