Key On cycling and hard starting
Installed Go EFI 4 600hp kit on a blue print 383 this winter on a customers 78 corvette. Got dialed in pretty well and gave back to customer. After a couple hundred miles he called to report crank / no start condition. I picked up car, started diagnosing, and found very little voltage drop at power feed wire (yellow) when measuring at fuse. Back probed white wire at 4 pin connector and found under 8 volts and connector faulty as the lock tab was not holding the connectors together properly. Replaced the connector with a higher quality Deutsch connector and now have over 11 volts at white wire and yellow wire during cranking. However the problem still persists. When you simply turn the ignition switch to "run", the fitech cycles on and off repeatedly up to a dozen times before settling down. During this time, the screen flashes and shows very low voltage if it shows anything. I have already eliminated the installation wiring as an issue and run wires directly from yellow and white to battery positive and another jumper from battery negative directly to throttle body mounting stud. Again, this cycling is evident at key on without even cranking. Voltage drop is not the issue in this circumstance. I removed front cover to trace power wire hoping to find a loose connection but all are potted. Verified ground wire bolt is tight under front cover.
I am awaiting response from Fitech and wondering if anyone has encountered this failure before?
Thank you for any assistance!
Derek
Fitech wanted the unit sent to them for inspection / repairs. My customer was able to get Summit to send a replacement to reduce vehicle down time (and tying up my bay). I installed the new unit and loaded my tune. Key on and started right up. Turn key to run position, fuel pump cycles, injectors prime pulse, and pump shuts down. No more issues. I suspect there is an interruption of the main battery feed wire where it is potted in the ECU as removing the fuse from the yellow wire makes no difference. Fitech prohibits cutting into the harness so I did not want to hear about voiding the warranty. Hopefully this one lasts a little longer for the customer. Just wanted to give feedback so it may help someone in the future.
DerekO
Just seen this after I posted a new topic.
My 30004 is now having the exact same issues as you describe. Worked good for a while last summer but now doing this.
Unfortunately its off warranty and its looking like this may not be easily fixable as I agree its probably in the ECU like you say. Also may explain my random O2 fuel trim faults I had for a while too. Not sure what is the most feasible thing to do at this point. I see you can buy replacement ECU's now for about 1/3 the price of a new unit. I guess that may be better than a whole replacement if your injectors and body are still fine.
Mine is doing the exact same thing right now and throwing a bunch of codes. Looks like I need to call Fi Tech tomorrow.