chaseincats

Is there a way to test the ecu to see what the issue is? Do you mean the big 'transistor ignition module' box in the passenger footwell?

Really strange thing happened today. I was sitting at a stoplight idling and the car suddenly died. The car runs so smoothly that I didn't even know it was off until I looked at the gauge and saw the e-brake light on. I turned the key and it fired right back up like nothing happened and drove home another 20 miles without issue. This is probably electrical/spark related since if it was fuel the car would have stumbled before it shut off I'd assume. I popped the hood when I got back to see if anything was loose then checked under the dist cap to see if the pickup coil was chewed up at all and everything looks perfect. Any ideas where to start?

I was curious about that. It's surprising to see how much current the defogger actually pulls from the system.

This is awesome! Did all cars come with glovebox and cigarette lighter lamps? I don't believe mine has either.

This will be invaluable for the community. Weird that the voltage regulator would have a fuse.

I wasn't aware there were spare fuse holders. I usually just kept fuses loose in my center console.

I replaced all the fuses probably back in 2017. So while its not decades old, it has been cooking in there for a while.

Thanks Capt. So I replaced the fuse - lets see how long it lasts.

I was looking in BE but didn't see a list just a bunch of wiring diagrams to follow. It's weird that the turn signals would be affected by this because while the hazard switch doesnt work due to the fuse, the turn signals do...

Question for you guys, is there a master fuse list for the s30s? I found the below image that lists which fuses cover which electrical aspects of the car but only for a 280zx (below image). My voltmeter fuse blew while driving today which apparently shares that circuit with the hazard switch, so I was curious if there was a list like the below for a 1978 280z that would list where else I should look for the short.

Gotcha. You are a wealth of information per usual. In this case I think I'll just stick with my warm feet lol

It definitely isn't the vacuum system since nothing changes when I pull the vacuum pod that controls the heater doors all the way shut. When the heater is engaged that pod is what pulls the doors open.

Ah, I didn't think about that. Yes, the small amount of air coming out of the heater vents is indeed heater hot. I'm assuming replacing that valve is a messy and possibly dash-out repair?

Quick question - the "mode door"'s foam I'm sure is on its way out because with the car on vent or AC, a small amt of heat comes through the heater vent on the bottom. I tried pulling on the vacuum pod that opens/shuts it and it's all the way down. Any idea how big (or small) a pain it is to re-foam the mode door (sometimes called the blend door)? Is this doable without taking the dash out?

Haha sounds good. I just went to check and this is my ECU's version label like we were talking about:

Oh gotcha, that makes sense. I'll give that a shot next time but this literally happens every few months so it may be a while before I'm able to test that theory.

Interesting theories, I'll try and answer them in order! - I haven't opened the ecu before but there is a number on the side which should denote which it is - I can grab that tonight - I haven't tried this but am a bit confused. If the starter doesn't crank and the engine isn't running, how would the a/f ratio be readable? Sidenote: I forgot to mention earlier that before I shut it off last time when I returned to the garage, I popped the hood and unplugged the TPS to see if it leaned itself out further as it should. It indeed did go leaner at idle but noticeably less of a change than if it was not in a lean-boot mode. We're talking going from mid 14s to upper 14s instead of low 14s to 16. Not sure if that data point is useful or not but I figured it couldn't hurt bringing it up! -chase

Yep. The only thing not stock about it is the tuning we all worked through on this thread.

Lean boot is a fantastic way of describing this. Yeah it literally will run lean for the duration of that boot. I ran it like that for my entire trip then when I got in the garage I shut it off and immediately turned it back on and it dropped back down into the 14s.

Will do. Why do you think a restart solves it though?

Yesterday was pretty hot actually - mid 90s.

Here's an interesting observation. Every so often (a handful of times since finishing this project) I've noticed the car running more lean than usual (in the 16s instead of 14s). Any idea why that would be? All the contacts are clean and literally the only thing I do to fix this is shut the car off and just restart it - then the computer behaves properly. This has literally happened maybe 2-3 times since I was able to read the engine's a/f ratio with the gauge and is a non-issue since a restart fixes it but I am curious. Reminds me of "The IT Crowd"'s famous line, "have you tried turning it off and on again?"

Interesting, I very well might give that a shot. Thanks for all the info.

Interesting. My question then is, since the hole is pretty tiny, am I losing vacuum advance movement on my distributor since the EGR is now taking some of that vacuum or is there enough vacuum for everybody?

Definitely - a fire extinguisher was one of the first things I bought when I got the car years ago haha