76' 280z Starts then stalls

[lady24d]

update: Tested all tests in the EF section. pin 6 to 8 .2 with no sound on my meter, 7 to 8 .4 no sound, 8 to 9 .2 no sound, 10 to 20 .1 sound, 13 to ground .5 no sound, 20 to ground .2 no sound, 34 to ground .2 no sound, 5 to ground (sound), 16 to ground (sound), 34 to ground (sound) pin 1 to ground 11.4 volts (battery is getting a little low) pin 10 to ground 11.4v, pin 14, 15, 30, 31, 32, and 33 to ground 11.4 volts, also - ingnition coil to pin 1 has sound/continuity. With all that I am thinking my ecu is the culprit, I am going to take it out and look at it to see if it can be repaired, I read this http://www.classiczcars.com/forums/showthread.php?37534-76-no-start-problem&highlight=fuel+injectors and seems to be pretty similar so I am thinking maybe a new ecu is in order.

[FastWoman]

I bought a spare for $20 off of eBay. I guess that was a pretty lucky find. Here's one for $100, but you might try offering $50:

http://www.ebay.com/itm/ECU-used-1975-1977-280Z-/120756404307?pt=Motors_Car_Truck_Parts_Accessories&fits=Model%3A280Z%7CYear%3A1976&vxp=mtr&hash=item1c1da48053

If you're patient, you might find one cheaper.

I don't know all the pin numbers from memory, but I'm presuming you're saying everything checks. Just the same, I'll offer the following thoughts:

If you have these essential elements...

+12 and ground to the ECU

Spark

Continuity from the coil to #1 of the ECU

A +12 reading on each of the injector wires (measured at ECU plug)

Healthy connections for all of the above

A marginally working ECU

... then you should get at least a base pulse to the injectors.

Be certain to check the connections to and from the drop resistor assembly, located beneath the brake master cylinder. Current to the injectors passes through that assembly.

[lady24d]

Well I got the used ecu today and no luck so back to the drawing board. Going to recheck the wires and such if I can't solve the issue the bottom side of the motor will be going into the 240z and the rest of the car will be parted out or sold as a parts car. This car needs to move out of the parking lot soon. Any other tips would be great

[lady24d]

just went out and tested pins 14 15 30 31 32 and 33 which run to all 6 injectors, grounded the pins with key in the on pos. and got injector clicks on 14 31 32 33 but not on 15 and 30 which is cylinder 1 and 5, now I tested cylinders 4 5 and 6 injectors for power at injector plug and they all have 11.8v. 1 2 and 3 I have not pulled the inj. plugs on yet to test but did a test at the ecu and all injectors have power going to them. so with the no clicks on 15 and 30 pin would this indicate both relays are faulty? Would this short out all injectors.... on a side note I have the injector out on cyl. 6 (yet still hooked up) which is one that clicked when grounded. when I turn the engine over this injector does not spray fuel so its like all 6 are shorted out

[lady24d]

I looked once more and it seems that when I ground pin 31 the injector on 6 clicks and sprays fuel so that's def a good sign now I just don't understand what's going on here, thinking it could simply be the relay switch

[Zed Head]

I can't decipher your train-of-thought-dump-to-paper writing of your results and don't want to open an FSM to try and figure out what you're reporting, but you must have power to the injectors if they spray fuel when you ground the pins at the ECU. You said that you had continuity from Pin 1 at the ECU to the negative side of the coil (I think). If this is the case, and you want to test the whole circuit and the ECU, then take a jumper wire and connect it to the negative terminal of the coil, leaving the other end free but not touching anything. Turn the key on (listen for the fuel pump to be sure that you have fuel), and tap the end of the coil negative jumper to ground quickly. Every third tap, the injectors should click. If they do, that means the circuit is correct and complete and the ECU is seeing the negative side of the coil.

If they don't, and you have Pin 1 connected to coil negative, then you might be missing the resistor in the tachometer wire. Or your tachometer is disconnected. The ECU needs that wire and resistor to work right.

[lady24d]

sorry about that but I have no idea what I did but it finally started and ran for a couple minutes then stumbled and stalled. I pulled the tach out and everything was hooked up so I am assuming there was a loose connection somewhere. but now she wont even start and I am assuming the cold start wont dump fuel in cause its not cold so either the mysterious connection is loose again or I have no spark but I'm calling it a night. Thanks for the heads up on the tach that might just be where the problem is.

[justinyee]

Just want to say that i've been having the same issue inconsistently. I haven't deep dived into finding out the solution, but what temporarily gets me back on the road is simply restarting a several times. The car would cruise just fine, then all of a sudden pressing the accelerator will make the car hesitate, rpms drop, and eventually stall. I'd sit by side of the road restarting, engine idles, and rpms slowly drop and engine stalls. Just today i just let the engine idle, and it dropped to 500rpms, but didn't stall out. I let it run there for a couple of mins. then turned it off, and restarted. This next restart fired up to 1000rpms, and all was fine.

Just wanted to note my experience, and say i'll also be following the thread.

[justinyee]

Lady24d, have you seen this thread?

http://www.classiczcars.com/forums/showthread.php?37846-76-280z-starts-but-dies-after-30-seconds

Baki280z had solved their issue with the Air Flow Meter (AFM). It's a good read.

Sounds more like my issue, so i'm going to start my tests there and i'll note back my results.

[lady24d]

mmmm thats interesting well I got it to start again today by messing with the tach, Fired up and got to move it on its own so I know at least reverse and 1st gear works couldn't move far since I am pumping out of a gas can. Well I noticed a lot of coolant coming out under the intake manifold, the gas tank is severely clogged and has 3 rust holes, so since my whole idea with this car was to get it running with as little money as possible and sell it. I have hit my limit that I am willing to spend on it trying to get it running so I could sell it. I will now be parting this car out, the body on this car is pretty rough so I am gonna salvage all I can, I'll keep the bottom side of the motor to use on the 240z, Keep your eyes peeled for some parts on the classifieds.

[grantf]

You may make more money buy parting it out but a z will be lost forever. It's you're car but it would be a shame.:disappoin

[lady24d]

Yes I know its a shame to part out yet I would much rather part it out to make another z get up and running or give it something that was missing or damaged I would never just throw this into a junk yard to rot