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Idles fine Falls on face when driving


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hey all i have had my 280zx for a couple months now and all of a suddin i have had problems with the fuel.(im guessing)

 

turns on and idles fine but once i get in gear and take off its hard to get it to 2000rpm.

 

checked the fuel pump pressure its as it should be replaced fuel filter and also replaced fuel pressure regulator but still no progress.

 

when i tap on the fuel rail it chippers up and runs fine and dandy or a short period of time then fall on its face again

 

the only thing i can think of is a new fuel rail (just because of the tapping and it running back to normal) unless some one has had this problem and knows whats going on i really need help guys

thanks Phil

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i am having i think the same problem right now on my 1975 280z coupe.....I never tried tapping the fuel rail. i had a fuel pressure guage hoocked up, and the fuel pressure dropped dramatically. it idles at 32 psi, but after the car warms up, and i rev it drops to 15-20 psi, and i thought it was the charging system so i replaced the alternator, and the external voltage regulator, but the same thing happens. so now it is either the afm, or the throttle position sensor. but if you figure it out before me could you tell me what needed to be fixed.

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google the phrase "techtips datsun" and go to Blue's techtips page. Find the EFI bible. Download it and read it through at LEAST twice, even all the diagnostic tests.

 

IIRC, the Bible says to check the AFM first. TPS wouldn't cause it to fall flat on its face; if the TPS was bad it would likely be open at all times, which is "cruise" mode (as opposed to "idle" or "WOT," the only other two positions the TPS can be in.) Cruise mode wouldn't fall flat on its face; it would run rich at idle and lack a little power (and possibly cause some detonation issues long-term) at WOT.

 

google xenons30. (or s130 if you have a Z) Find the FSM for your model year. Find the Engine Fuel section. (If you have a model year without a complete FSM, find an adjacent model year, they are virtually all the same from 75 thru 83.) Find the fuel pressure test section. Test fuel pressure at speed according to FSM directions.

 

 

I fix my car one procedure at a time. Until I have followed directions, I am fumbling about in the dark.

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  • 2 weeks later...

hey just got it back from the shop today turns out two of the fuel injectors werent working so they replaced them all in all after the different diagnostics parts and labor it cost me $270 could be more for you at a different shop i knew the mechanic and he really cut me a deal on the labor hope this helps

 

also how he knew which fuel injectors werent working for you do it your selfers this is just the summary he gave me could be more but if you know what your doing this may make since to you and if not get you on the right road

 

he checked the power to the injectors

 

2 cylinders werent firing properly so he swithced them with differnet injectrs the ones that were missing before started right and the onces he switched with those cylinders started missing

 

fairly easy if you know what your doing mut i myself have no idea what i doing when it comes to fuel injection lol

 

will be selling my car for around 1800 if any one interestd im in southwest missouri email me if you want mor details

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