boosalmi

Ok, so I've done a bunch of searches for days and gotten some really great advise. I didn't know where to begin, so I took my Z (starts and runs for 1-2 seconds, then shuts off) to a local shop. They are at a dead end, thinking it is the ECU or the EFI Relay. But, they couldn't find the relay and want me to send in the ECU to be rebuilt $$$.
With your guys help, I found the EFI relay, but it didn't match the shops diagram. I downloaded the FSM and found that I do have the right relay and location. It is brown with no label and has 6 prongs.
Question #1. How do I test it to see if it is good? The shop said they couldn't without a diagram of the relay.

If the relay tests good or if I replace it and it doesn't fix the problem... I figured I would check the ECU.
Question #2. What ECU will work? Anyone from another N/A 280zx? I have found several on ebay 1980 N/A for an ok price, but none of them have my exact part number listed on my ECU.
Let me know if you guys need anymore info to help me... and thank you.
David

boosalmi

Oh, and to add... The shop said the reason they came to the ECU/EFI Relay was because the injectors have no pulse.

boosalmi

Well, I replaced the EFI relay and.... No dice. So I ordered a ECU off of ebay from an 80 280zx. Not the same A11-### ####, so I guess we'll see if it will work.

Lesnocker

Long as what it matches . . . . I know of three styles my 79 just had an egr system with two plug in square plugs on the thermostat housing. . . My 80 has an air injection system with a pipe and large valve going next to air cleaned has one plug in on thermostat bunch of vacume lines where the other plug was and has plug on head. My 81 has the same delete air injection and add 02 sensor. . . . Does yours have california emssion? Is it an 02 system? Egr? Air injection kinda would think that matters since what ever sensors you have the placement the wireing this all goes back to the brain box. . .

Lesnocker

What I got is from my 81 part nums are A 11 620 600 then ox28 this should work if you have the same style system as mine 80? Or make decent offer came out of a daily driver parts car. . . Its an 81 maybe Friday Ill plug it in see if it will run my 80. Then you know. . . Got my 79 ill check the nums the A11 don't mean **** I think maybe just a nissan code for a computer company. . . . Japan electronic control systems. now that funky black stamp ox 28 that's what your looking to match . . . Hope this helps

boosalmi

Ok. I don't know what exact sensors it has, its my first Z. But I was looking last night and I think the ecu in the car already is a replacement that isn't the right one. I'll try to explain with the following pics.


Someone wrote 80-Federal on the case in green marker... but that is the model ecu that is currently in the car.


So this is my harness, if you look into the harness some of the slots don't have metal in them. They are just empty. Which make sense being there are so many varibles. Notice, top right, #5&7 down on the left, etc.


Here is the ecu. Now, the right side of the ecu would plug into the left side of the harness because they have to face each other. Look at the pins on the right side, which should match where the metal is to connect to the harness. They don't match. The harness has metal conectors not being used by this ecu and the ecu has pins that basically plug into nothing.

My guess is this was a replacement ecu to begin with. So how do i find what ecu i need? I should get the ecu I bought off ebay for $59 on monday I think so I can check.
Does everyone's ecu mirror the harness exactly?

FricFrac

If you want you can do what a lot of shops do since it's not their money they are spending. They figure OK well the signal goes through the relay so replace that - it's cheaper. Didn't fix it - replace the ECU. That's just stupid and lazy. The way you should be checking it is get the FSM from xenonS130.com. Find out where your injectors get power from. Do you have +12V on one side of the injector? If so then you've got power there and you could manually turn the injector just by grounding the other side (and flooding the cylinder at the same time if there is fuel presure there.

All the cars are different so I looked up the '80 280ZX EF - Engine Fuel and on page EF-21 it shows you how the injectors run. The ECU in this case switches ground ON so one side of the injector has to have +12 volts to complete the circuit. On your car power goes from the battery +12 terminal through a fuseable link then through the EFI relay then through some current regulating resistors (so you don't fry the ECU since the older ones can't handle the current of a peak and hold or low impedance (resistance) injector) then to the injector itself. So here's how you check to see if you are getting +12 V. Activate the EFI relay (eg turn the ignition on). Do you get +12V to the injector? Yes then that side of the circuit is good. No then go back to the next bit - the resistors... etc, etc till you find the part that's not passing the +12 from the battery terminal. It's stupid easy if you think about it but like I said most mechanics can't be bothered to do any real (and basic) troubleshooting. If you get +12 to the injectors do the same thing to see if you get ground to the other side of the injector plug. Don't order parts till you know what's wrong is usually how I go about it...

boosalmi

I got the ECU I bought off ebay today! The guy didn't tell me it was from an automatic though. Well, I put it in and.... Success!! The car started and ran. It was missing and blowing a TON of black smoke out and running pretty rough, but it stayed running! It won't idle but with a tiny throttle it stays running. So, I went and got premium fuel and a good fuel system cleaner for it (it hasn't ran in 2 years). I put it in and started the car again. I propped the pedal to keep it running about about 2K RPM and let it warm up and burn up all the crud. I let it run about 20 minutes.
It started getting slightly better but not much.
I went a got plugs and wires for it. Installed them, and it runs better again, but its still missing and runs rough, and won't idle. It ran well enough to take it for a spin through my neighborhood.
Oh, and I replaced both battery terminals, to give it clean contacts.

Here are my questions.
It seems to me the car is missing, and running rich... it blows black smoke, its getting better but still does it alot. Can this be caused by this NEW ECU? Is the NEW ECU still my problem? Is that why it won't idle?

I'm basically asking... What now? I don't wanna throw money away obviously, so where would you guys start? Try to find ANOTHER ECU for a 5spd? Or start somewhere else?

To sum up:
I put a new 1980 280zx AUTO ECU in
Fuel system cleaner and fresh fuel
NGK plugs and New wires
New Terminals

The car runs rough, although you can still drive it roughly, won't idle, and blows black smoke.

Where do I start?

Thanks so much guys!

evandubya

The automatic ecu is fine in a 5-speed.

boosalmi

Thanks evandubya! That makes everything just a lil bit easier. Now on to my AFM rebuild!

boosalmi

I rebuilt my AFM or adjusted it anyways... and it still runs the same... but I did find something out-

After sealing the AFM back up, I replaced it on the car, then I had to make a phone call... When I got back, I fired the car up... No change. Still blowing black smoke, low idle and poor running/missing. Then I remembered I forgot to PLUG THE AFM IN!!! lol. So I shut it off, clean the connections and pluged it all in... The result? Nothing. Runs the same whether the AFM is plugged in or not.
So, do I need to replace the AFM? and if so anyone have one they wanna sell?? I check them on ebay and they are pretty pricey...

Twist

Your S130 problems sound a lot like the ones I had when I first resurrected my ZX for the road. The car wouldn't rev above 2000-2500 rpm and wouldn't idle about 400-500 rpm, if at all. Although I thought it was the EFI or a relay, I discovered that the problem was a faulty fuel pump. It was still active, but it wasn't giving out as much pressure as necessary. It might be something to look at and it's mounted outside of the gas tank.

I'm still learning as much as I can (I'm pretty new to being my own mechanic), but it might help.

boosalmi

I really appriciate the post Twist. The fuel pump is good, 30+lbs consistant. I'm thinking it is electrical... ie: CHTS, AFM, or something else I haven't come across during my 100's of nightly searches on here. lol.
The car runs now without fail... but it runs shitty. No problem hitting redline. When I drove it for the first time I ran it to 5200rpm.
I'm thinking timing or the AFM, like I posted before... Should I replace the AFM?

FricFrac

DId you go through the test procedure in the FSM for the AFM? If you can read the resistance that it tells you they should be then it's probably fine. Sounds like your connectors might have some issues.... Test the AFM from the AFM connector then hook the harness up and check it at the connector to the ECU and see if you get the same readings.

Also another item that causes a lot of issues - vacuum lines. Did you go through all those and make sure you don't have any vacuum leaks (eg oil cap test, etc)?