280z78

Hi just bought 280. Thing started right up. It was idling real low and would die automatically when gas applied. I took off black box on the computer intake under the hood and fingered it. The car now idles great after adjusting the air intake computer box thing under the hood. It needed more gas so I just loosened set bolt and tightened spring. Now, when gas is applied it still Boggs down. But if I feather the gas I can get it reving real nice up to 2k but drops back down to idle if pushed farther. If I floor the gas, the car slowly builds in rpm but falls in toms at about 2,500. Fuel pump sound good, no rough sounds. Replaced guild filter in between fuel tank and fuel pump. Checked to see if fuel pump was actually pushing a good amount of pressure by taking hose off of filter under good and it came out like faucet. Have not cleaned injectors. Also a lot of back fire in intake heard that was bad for air intake flap but don't know how to stop it. Also ticking noise coming from engine sounds like valves. Not sure tho
Thanks, Jon

Steve260Z74

1. The stock "filter" between the fuel pump and the tank is a check valve with a filter. It prevents pulse in the fuel pump.
2. Download a copy of the FSM and also the Fuel Injection Bible. The latter is available at XenonS130 - S130 Reference.
3. Get a good inline fuel pressure gauge and see what the fuel pressure is doing when you give it gas. Compare your readings to what is described in the FSM and Fuel Injection Bible. It could be a bad fuel pressure regulator.
4. Go through the other diagnostics in the FSM.

280z78

Update: after taking the info from the forum I replaced pump, regulator and main filter under hood. It helped it out but still was stalling pretty bad when gas was pressed. I descide to take a pressure gauge and put it on the fuel reg valve end of the fuel rail. So there was no way out for the fuel except through the injectors. Know the thing revs like a champ. Slow acceleration but still revs. So my question is why did adding a plug (pressure gauge) to the end of the fuel rail make the engine rev? The pressure fudge was an old one I had laying around so I'm not sure if it was reading right but It was 10psi.

280z78

Out new fuel reg in and new pump. Psi is at around 36. Replaced all filters. Pulled spark plugs and put in new ones. The last cylinder had oil on the spark plug. Not sure what that means but the car now revs but hits wall at 4k. Also when gas it pushed the car stalls but picks up. What is causing the intermediate stall and top end speed?
Any help would be awesome, thanks

Turksspeedwerks

If your gas is fine I'd check fire

280z78

If any one else has this problem this is what worked for me. Almost all z's have rust in fuel tank. My did and when I pulled fuel rail the injectors where packed full of them expect the front one and the last one. I took fuel rule rail out and spray carb cleaner everywhere and then hook neg side of injector on batter and while I was squirting carb cleaner I would click the injector to make sure "gas" was flowing. I hooked everything back up after cleaning injectors and the thing revs amazing.

lord of the z

Hopefully this is what's wrong with mine, sounds exactly wats wrong with mine except mine fluxuates with really high idle

lord of the z

Turns out it was the fuel pressure regulator

Steve260Z74

Thank you for the update. It's good for the archives of the board to get the resolution posted.