f1d094

I took a bunch of photos of the ECU for inspection and parts hunting

Hi all. Longtime listener. First-Time caller. My question to to community, in short: If you have a rock-solid 280z with the stock EFI, what happens if you "Tap Control Unit" while running? Anything? What if you knock it "a bit harder"? I have a '78 280z that will very random-ish-ly very occasional-ish-ly simply turn off as though I had removed the key. After 10-20 mins of sitting, it fires right up and runs like a train...until it randomly turns off again, leaving me in some scary circumstances. Sometimes it fires up immediately like nothing happened. I have been trying to diagnose the issue for quite a while. After the last episode, I've decided she's never leaving the garage again until this is sorted. While testing in the garage I randomly closed the car door and it immediately shut off. I thought it was a coincidence. Later, when I opened the door, it shut off...but then started immediately. I found a couple posts online of similar examples: https://old.reddit.com/r/Datsun/comments/1f38p25/280z_shut_the_door_car_shuts_off_bad_ecu/ https://old.reddit.com/r/Datsun/comments/1iu2huj/280z_random_stalling_issue/ I have since checked every ground, pulled the drop resistors, cleaned/de-oxed all the connections and made sure they were tight. Just for good measure I swapped-in my spare ECU. I thought that had fixed it...I've been running it for an hour-per-lunch for the past 4 days, opening and slamming the door every 5mins, without issue. I was beginning to think I was good, until today. After about 20 mins of running I opened/closed the door and...stumble stumble stumble...running on 3 cyls...stumble. I gave the ECU a kick, and Poof. Back to normal. Kicked it again...sumble stumble...kick again...stumble...OFF. Won't start. Wait 10 mins. Starts immediately, runs like a train. In the reference book "ELECTRONIC Fuel Injection - 280Z Electronic Fuel Injection Theory Troubleshooting" on page 39 it also has a small reference under "Engine Misfires - HC Reading Too High" it says "5. Tap Control Unit While Driving To See If This Aggravates Or Alleviates The Problem. If So, Try Another ECU." So...have both my ECUs aged-out and need rebuilt? Or is "kicking the ECU" always going to result in some stumbling while 'something' re-sorts itself, even on a "known-good" ECU? I found a thread of a similar-but-different issue where a fix was successful: https://www.zcar.com/threads/efi-harness-continuity-voltage-problem.311536/page-2 And a quick-comment-on-the side by @zedhead that "In my case, I replaced the transistors and that fixed it. " (shot him a DM) My follow-along questions would be about rebuilding and where to get parts...Trying to find a rebuilt unit seems like a non-starter. I spoke to David at MSA today about timelines, because "The rebuilder is locating a qualified Bosch-experienced technician"...for about 3 years now. I'd be entirely happy to rebuild it myself and document the process...but I have no idea where to find components. Arrow and Mouser came up empty. Someone mentioned I should ping @Captain Obvious, which is what brought me here. Would love to hear everyone's thoughts.