New owner of '77 280z from Upstate SC

[Driver_X]

Here's my story getting my 77 back on the road. 

 

http://petrolicious.com/here-s-why-i-fell-in-love-with-the-datsun-280z

 

Most of running issues were electronic in nature.  All the rubber bits were so shot, and every connection full of corrosion, it just made sense to start all over with new connections instead of trying to restore old ones. 

Good luck with your project. 

 

 

[siteunseen]

Mine stumble a bit when the oil cap is removed. Also there is a small bundle of wire inside the original valve cover hose, a trap of some sort? It may need to be removed and cleaned.

[black gold man]

Its called a flame arrestor. The org hose has grounding property's

[the_tool_man]

This is taking longer than I thought. I didn't get much time to work on it this weekend, due to some issues that came up.  But tonight, I went through the temperature sensor circuit.  I drained the coolant and removed the sensor.  It checked out, reading 3.5 kOhms in my ~55 degree shop.  I could even get the resistance to drop by holding the end with my fingers, as you would expect.  I cleaned the bullet connectors in the harness over the intake, and checked continuity in the harness where I could.  Once I did that, the resistance at the ECU plug read correctly.  I was very hopeful that I'd solved it.

I refilled the coolant.  I pulled the spark plugs.  They were completely covered in carbon, from running rich I think.  I cleaned and reinstalled them.  The connector on the bottom of the AFM wouldn't stay plugged in (I think it's broken).  So I used a couple of crossed loops of wire ties to hold it.  I hooked up everything, crossed my fingers and turned the key.

No difference.

At idle, it stumbles and dies after a few seconds.  I can rev it to 2000rpm, and it'll run, badly.

The search continues.  Next session I'll try the cold start valve and clean all the other connectors I can get to, etc.

My next opportunity to work on it won't be for a couple of days.  That's a good thing, as I'm so discouraged, I don't want to look at the car right now.

I did get the car titled and insured today.  That's something, I guess.

[Zed Head]

7 minutes ago, the_tool_man said:

At idle, it stumbles and dies after a few seconds.  I can rev it to 2000rpm, and it'll run, badly.

The search continues.  Next session I'll try the cold start valve and clean all the other connectors I can get to, etc.

There are a lot of different parts on the EFI system.  Try to break them down in to their individual systems.  Each system needs to work right so the next system can do its job.  I think that you've mixed the running rich problem up with the fuel pump power problem.  These engines will almost always idle just fine forever if the fuel pump is supplying fuel.  Consider jamming the fuel pump power contact switch or hot-wiring the pump while you do the other tuning.

And the cold start valve is almost never the problem.  It's there and it could leak, but it would have to leak a lot to cause major fuel enrichment.

[siteunseen]

Try a new fuel filter in the engine bay, passenger's side behind the radiator.  If it's been sitting you need one anyway.  There about $10. 

[the_tool_man]

I'm going to put in a new fuel filter and a fuel pressure gauge.  If nothing else, this will rule out fuel supply issues.  The engine revs fine.  The plugs are sooty (see pic), indicating running rich.  So I doubt it's a fuel supply issue.  But it doesn't hurt to check.  Like I said.  It'll be a couple of days before I can get to it.

[siteunseen]

Too me that looks like your rich running problem. Those plugs aren't able to burn the fuel. Imho

[gwri8]

Not exactly the same problem you are having but When I brought my Z home (actually drove it) I knew it had problems with fuel delivery. Would idle kind of OK, would run not so OK. I made it anyway. Had a long list of priorities on the car and tried new fuel filters and simple stuff trying to get lucky but never could define the problem exactly because I was working on several different things at one time.  Finally came to the conclusion that I needed to just remove the entire EFI system, clean and inspect it and replace the Fuel Injectors. It was old enough and I knew eventually I was going to do that anyway.  Turned out the the PO never did any of that stuff and Fuel Injectors were the main problem. 3 were different from the other 3.  In fact the #1,2 and 3 injectors were rusted in place, probably why they were different. I felt like a surgeon trying to remove the rusted bolts. Dremel tool, pliers and my special language got involved.

My point is, Run a good FI cleaner in it and Consider taking a day and just going through the entire EFI system and refreshing it, replacing all the fuel hoses and vac lines. It's not hard to wind up chasing your tail when working on an old EFI system. Eliminate the variables and simple stuff that is going to need replacing anyway. 

[charliekwin]

I've only been at it with my Z for a bit under a year and don't feel remotely qualified to be giving out advice like some of the more knowledge people around here, so I'll just offer up my own experience.

Mine ran when I got it, but was very rich. I ran through all the usual suspects and fixed obvious problems: coolant temp sensor, a missing thermostat, etc. hoping to find a magic bullet and never did. Eventually I made my way through all the checks in the EFI Bible. They aren't tough, just a bit tedious and require some contortions, but uncovered a couple of problems I hadn't found on my own. Once those were fixed, I passed smog easily.

Guess that's just my long-winded way of saying to not get too frustrated. The troubleshooting resources available will get you there eventually.

[Zed Head]

1 hour ago, the_tool_man said:

I'm going to put in a new fuel filter and a fuel pressure gauge.  If nothing else, this will rule out fuel supply issues.  The engine revs fine.  The plugs are sooty (see pic), indicating running rich.  So I doubt it's a fuel supply issue. 

The other hard part of solving problems is describing what you're seeing.  I said "fuel pump power" but you're writing about fuel supply.  You're looking at very rich conditions but talking about lack of fuel from a clogged filter.  Often, just trying to describe the problem will make you think of something more to look at.

If the engine will rev you might try just cranking up the idle speed to keep it running.  It's the big screw head on top of the throttle body.  You can turn it by hand.  Get fuel flowing and let things loosen up.

The TVS (aka TPS) has a full throttle position that can get stuck and cause excess fuel.  The test is described in the Guide and the FSM, Engine Fuel chapter.  By the time you're done testing you'll be an expert on basic fuel injection principles.

[the_tool_man]

26 minutes ago, gwri8 said:

...Had a long list of priorities on the car and tried new fuel filters and simple stuff trying to get lucky but never could define the problem exactly because I was working on several different things at one time...

If I'm brutally honest with myself, this statement describes where I've been with the car since I bought it.  I've been assuming it would be one or two easy things to fix, and I'd be driving it.  That's what's frustrated me.  I just need to get past that and be methodical.