Electrical Does EFI computer case need to grounded?

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New Member
Jan 3, 2021
Sun City, CA
Hi any help would be greatly appreciated. I purchased and installed the Ford racing EFI wiring harness on an 89 5.0 HO. Part # M-12071-A50. I've checked and rechecked then rechecked again all connections. I have battery voltage at all of the injectors but I get no pulse when cranking. To be sure everything was right I started at page one of the installation manual and went step by step again. Still no pulse but have battery voltage at the injectors. Engine fires and runs with ether then stalls. No fuel from the injectors. Does the case of the computer have to be grounded for fuel injectors to work?? One other issue is wiring kit comes with a amber dash, check engine light. Light only comes on dimly not bright. Can barely see it. Connector says about 5 volts at the light but light itself is marked with 12V. If you withe the light to a test 12v battery the light is brite. Any ideas are welcome. Thanks
Regarding your no start condition with your '55 Ford. I just installed a 302 in my '55 Ford. I have a no start condition. The fuel pump runs with the key on initially. It has over 40 pounds of pressure. Sprayed ether in the throttle body and it ran for 3 or 4 seconds. My failure codes were 15, 22, 67, 81, 82. I double checked all my wiring connections, etc. and it won't run. So since you have a similar situation and our codes are similar, I'm just wondering if there is something wrong with this wiring harness. I've done about 10 of these and the first 3 I did, I took an existing harness and deleted the wires I didn't need and had no problems. Because it was so time consuming, I decided to buy a ready made harness. I used several from Painless and 4 or 5 from Detail Zone (Ron Francis), but when I saw that Ford was making their own (actually made by Dunne Rite) and after your experience and my experience, I think I know why Dunne Rite appears to no longer be in business. I am now taking an existing harness and reworking it like I used to do to try to make the car run. I should know within a week if this does the job.
Gary Richards
Sun City, CA