Blinkerfluid22

After some more diagnosis i found constant a 12v to the injectors even on the ground side. At some point the previous owner wired in new injector connectors, could it be the wiring has just gone bad? Could it be the ECU?

the AFM plug is plugged in but the connector clip is broken, so I doubt it has the best connection. The ground for the AFM is this black wire shown, right? Its supossed to be attached to the AFM under that mounting bracket and is grounded to the bracket correct? I did drive around 2-3 times without it grounded, could that have fried the AFM?

Well after rebuilding the head after dropping a valve the car was up an running again. One night a few weeks ago I had let the car warm up and was backing out of my garage when it just stalled out and i haven't been able to get it to restart. When I try to start it the starter just cranks and once in a while there is a loud bang from the tail pipe. I have confirmed spark to all plugs, fuel pressure is around 40psi while cranking, cylinders have compression (thank God) and the battery is fully charged. One odd thing I noticed was that the plugs were dry after trying to start the engine. Shouldn't they be covered in fuel if the injectors are firing? What should I focus my attention on next? The car is a 76 280z, with 63k miles and only about 60 miles since the rebuild. I also replaced the AFM with a remanned version at the time of the head rebuild.

Well i finally got to the bottom of it. The oil spray bar for the cam clogged causing everything to overheat. This eventually cause a valve to drop in cylinder 1 and ruined the cam. Looks like i have a fun an expensive road ahead with a new cam, head rebuild and new rockers.

Sorry i havent replied in a while, i have been traveling. I was able to take measurements at the ECU connector and everything seemed ok, so i went and did a compression test. Here are the results: 1- *DEAD* 0 2- 195 3- 180 4- 210 5- 205 6- 210 So where do i go from here? Obviously something happened to cylinder 1, but what about the readings in 2-3? Could the zero compression be valve related or something worse?

found this picture showing alll the switches/sensors on the thermo housing. The broken one pictured above is shown in the bottom right of this picture. It looks like the temp switch not sensor. Could this be the issue or should i move onto the ecu connector?

here are some pics of said sensor i also checked the plugs, they are getting spark put when i pulled them they seemed to be fouled and smelled of fuel

So as I'm checking the various connections I noticed the hose from the fpr to the manifold wasnt connected, so reconnected it but it still wont start. The car turns over and a series of pops come from the exhaust but the car still wont idle long, maybe 3 seconds before it stalls. the idle is very low as well, 500rpm or so. Checked the coolant temp sensor and see that one of the connectors is sheared off. The blue/green on is still connected though. Where is the sheared off connector supposed to go to? I couldn't find a loose connector.

thanks zed, i will add these connectors to my list as well as the linkage

Thanks for the link FW, i will replace the filter and blow some air through the rail.

Yes, I checked the air filter, it looked new. I didnt replace the fuel filter up front, but I tested to see if it was blocked and fuel came shooting through exit side so i presume its good.

I have a 10 day temp registration to get the vin verified, so any help is welcomed.

Thanks for the advice Chas, I have updated the OP

Today I replaced a leaky fuel pump and installed an inline fuel filter pre-pump. I got the car back together and drove to the gas station. During this drive the car hesitated a lot from 2000-3000 rpms. After filling up the car was much better and reved more freely, but the throttle seemed to stay open on deceleration while stopping. After the car warmed up I reved to about 5500 and then something happened. The car started stumbling and would shut off unless I gave it throttle, it also sounded like it wasn't running on 6 cylinders. Now the car cranks and begins to fire but it doesn't start. There are just a few pops from the exhaust, which are only sustained for 2-3 seconds, rpms are very low during this as well around 500rpm. I thought maybe the new fuel pump dislodged something in the fuel line that maybe clogged the filter. So I unplugged the line from the fuel filter and cranked the car, and it shot out fuel, so no blockage. Any suggestions here? What should I focus on next? Plugs?injectors?afm? The car is a 76 280z, I just picked this up last weekend so I'm trying to work out the kinks. The guy i bought if from said it had an aftermarket cam, but no specific information about which one. Other than that the motor appears to be stock with the exception of a 6-1 header.