1976 Datsun 280Z wont stay running

[joshotto94]

ok so i have been posting lots of questions on here thank you to all for all the information. I have got the car to turn over and start but she will only stay running for about 10 seconds sounds fine when its running. Then it shuts off when you try to give it the gas anyone with any pointers or info on a possible fix please help thank you JOSH

[I'm BLUE]

When you say it will run for about 10-seconds and sounds fine ... will it continue to run/idle if you do not push the gas pedal ?

 

Have you replaced all of your vacuum/breather lines under the hood ? (very common for 280z/zx Bosch EFI systems).

(Just cutting off the ends of a hose that was cracked and using it isn't good enough for a long-term fix ... should only be a very temporarily fix !! ....  unless low funds than do what you have to do)

 

The air intake boot between the AFM and Throttle body is known to crack/leak , but you have to really look for problem by peeling it back after taking it off for a look.

Make sure you have your TPS adjusted correctly.

Make sure your coolant temperature sensor connector is in good shape (I've seen the harness connector short on one 280zx .. not a big deal at all)

Check your fuel pressure to verify you're getting some. ( with a helper you can disconnect the feed line , and direct it into a bucket/gas can carefully... then turn on the ignition switch to verify the fuel pump is running ).

 

On occasion the fuel relay will go out on both the 280z and 280zx's , but wouldn't worry about that and doesn't initially sound like you have that issue.

 

 

Take a picture of the engine bay and throw it up if you're up to it.

 

 

Here is the factory service manual ----> http://www.xenons30.com/reference.html

It will tell you all you want to know and more with mostly a multi-meter , and a few other items.

[joshotto94]

when I push the gas car shuts down or bogs out will try to post picture tonight thanks for the info

[Driftease]

check your airflow meter if it is stuck the fuel pump will prime but will not stay on as it is turned on by the meter

[Slowpoke]

How old is the fuel in there? Has the car been sitting for any long amount of time? Have you checked the fuel tank for rust, checked the fuel filter, or fuel pressure? My guess is some rust or crud is stuck in your fuel system, is lowering your fuel pressure and causing your car to stall. Download the FSM, get your hands dirty and go check the basics; spark, fuel, and air.

[joshotto94]

fuel pump has been removed bench tested, lines have been blown out all the way to the fuel filter everything has been re installed pump is pumping fuel all the way from the back to the front and through the filter again.  pumped fuel into a cup and the pump is pumping plenty of fuel. drained fuel tank befre I even started the project so there is fresh fuel in there. Checked spark yesterday also car is getting spark. pulled air flow meter today air flow meter tested out to be correct according to all the test in the book.

[Slowpoke]

Well, your eliminating potential possibilities. That's good.  I would check vacuum and then compression next.

[Driftease]

Inspect computer grounds on the intake manifold as well

[joshotto94]

Does anyone think it might have to do with the Throttle position sensor. I was doing some test in the workshop manuel and cant seem to get the throttle position sensor to pass the test

[Driftease]

A failed tps will cause drivability issues, normally it won't cause engine to die. First you need to determine what stops when it dies put on a spark tester and run it til it dies watch it closly to see if the spark stops before rpm goes down or after. If spark stops before rpm drops off then trace back starting at the coil then igniter and wiring and lastly ecu. If the spark slows as the engine comes to a stop then you need to look at the fuel system the first thing to try on that is to install a pressure gauge in the high side fuel line (before reg after filter) check if pressure is dropping off before or after engine dies. If it drops off before engine dies it is a supply problem (pump filter and lines) if after it will be on the injector side. If it is an injector problem their wiring must be inspected, test them with a lite to see if it stops blinking before or after it dies. If it stops before it dies it may be a faulty resistor pack for the injectors, bad wiring or bad ecm. If it slows blinking with rpm the the injectors are clogged or you are injecting water, Phase separation can cause large amounts of water in the tank that can still smell like gas but does not burn.

 

Back to the tps I believe yours will be a switch type, not potentiometer. The switch type tells the computer that you are intending to idle or intending to accelerate and selects proper enrichments for either of the two possibilities. if it is bad you will want to replace it but is not likely to cause your problem. Hope this helps sorry if it is confusing i'm not known for my ability to type.  

[Driftease]

I'm also assuming you did what blue said to do. I didn't want to repeat what he said but that stuff shoud be inspected / done too.