[Olddog]

After sitting idle for 5 years my '75 280 started and ran fine. After about 150 miles it starts, idles, and revs fine but bogs down when accelerating in gear.

If I get it rolling and immediately shift to 2nd, 3rd,& 4th it'll get up to 45mph. Under load about 1800 RPM is the limit.

I've flushed the fuel tank, replaced the filter, and cleaned the injectors.

Any suggestions?

 

[ZGimp]

Breathing problems

my friends dad just had this happen on his 280 after sitting 6 years... but his was a '78. does your have a catalytic converter? If it does have that checked to see if it collapsed. He spent a bunch of money at a shop replacing injectors and such, to find out that the engine couldn't get rid of it's exhaust, and would have only cost him like $100 (I think, not sure prices for those)

If your car doesn't have a cat. check for stuff in the intake, again it could just be having trouble breathing... mice nests could tend to do that Cause the higher you rev the engine the faster it wants to suck in and get rid of air/exhaust, and clogged plumbing will allow it enough at low rpm's but as you go up it will get/push out less and less air. it's like when you try to breath through a blanket, if you breath slow you can pull it trough, but fast you'lle just get dizzy... like your car is.

I would check those first before throwing parts at it like james did, it's alot cheaper and easier, but if neither of those turn true, and it seems to be running right (not excesively rich, lean, etc.) then post back.

Kris

 

[Olddog]

Re: Breathing problems

Kris,

Thanks for the ideas. I've got headers and no cat/conv but the exhaust still could be plugged.

The air filter is new.

The power shut off is instantaneous, like the fuel or ignition is cut off. But as soon as I depress the clutch it revs fine.

Dave

 

[Magic 280zx]

May need to undo the fuel lines and blow through them backwards. Also the input into the pump could be clogged with rust. If the pump is really loud then it probably isn't sucking gas some type of clog either in the tank or line to fuel pump. If it is spinning and sounds good probably a clog somewhere after the pump. There is a device after the pump that is suppose to even the flow of gas that could be cloged after sitting for so long with gas in it. I removed the tank and soaked in kerosean for a few days to help break down the rust in it.

 

[Olddog]

I'll check this out. There was rust and scale when I flushed the tank and it ran great after I replaced the fuel filter. Then, after 5 miles it was right back to sputtersville.

Dave

 

[RonZtoy]

Have you check to see if any moisture has gotten into the plug that goes into the side of the distributor. This happened to my 78 after I washed the engine. Unplugged it, dryed it out with a towel, plugged in and it did fine. I'm not sure what this plug is called-anyone?

 

[Olddog]

Don't have a plug on the distributor so I lifted the cap, no moisture at all.

Dave

 

[Olddog]

The pump is quiet and there seems to be plenty of fuel. I found the pressure regulator you mentioned and it is rusty inside (I've got it soaking in WD40) but no loose rust.

The engine revs fine as long as it's not under any load.Magic 280zx wrote: