Fuel pressure!

[DatsunZsRule]

Hello 78 280zcar,

So your having problems with loss of fuel pressure huh? I personally don't think the FPR. is the problem here. You stated that you went back to a stock one. Was it really a stock one??? or aftermarket?? If you used a new OEM Fuel Pressure Regulator then I highly doubt it would be faulty. Not that it can't happen I suppose but the chances on that are slim to none. Plus you said you tried 2 other ones and you still had the same problem??? Fuel Pressure Regulators very rarely go bad to begin with. It can happen but it's not common.

Your smart to go back with a stock one. Adjustable ones are nice if you have a Z thats modified that demands more fuel pressure. On a stock fuel injected 280Z it's suppose to have 36.3 @ idle and it's suppose to maintain this after you shut it down. since the L Jetronic system maintains 36.3 after shut down, it provides superior heat resistance and Vapor lock should not happen. Sounds like to me you have a very small fuel leak somewhere in the system. Very well could be one of the injectors. I'm sure it's not that big of a deal. Could just be something simple like worn out 0 rings. Take a look at those. they can wear out over time. Courtesy Nissan carries both the top and bottom 0 rings Top 0 rings are $10.62 for 6 and bottoms are the same for 6

Do you smell any fuel at all when you have it running?

Best of luck.

[78 280zcar]

Thanks for the reply. All the orings are new and all the fuel lines are new. I just did a 3000.00 rebuild on it, but I didnt change the injectors, except for one that had a crack on the tip of the injector(#5), so I got one from pick and pull. Since I have a JSK fuel rail, I am going to take it off with the injectors on it and build up the pressure and try to see which one leaks:paranoid: . I checked to see if there is gas in the oil just in case it was leaking passed the rings and it kinda smells like there is, but not bad, I hope that my bearings dont get screwed up. I am going to have to wait until after the holidays to work on it, too much money spent on presents and what not for christmas. And of course I am not going to drive it unless I put the aftermarket fuel pressure regulator back on, because that one doesnt hold pressure after the car is off and plus it ran a whole lot better with that one on. Thanks and merry christmas to ya all!

[DatsunZsRule]

Yep, It's an expensive time of year

Correct me if I'm wrong but didn't you have loss of pressure WITH the adjustable regulator to begin with??? I didn't know about your Aftermarket fuel rail. Maybe the adjustable one is better since your system isn't exactly Stock. either way correct the leak wherever it's coming from and reinstall the adjustable FPR since it works better with your set up. Should hopefully take care of it

[78 280zcar]

The adjustable regulator doesnt hold the pressure at all when you shut the car off it goes straight down to 0 psi. I am going to have to put that one back on until I get a new injector/s. Check out the price of these injectors, cheap

http://store.yahoo.com/dpstore/322a2311.html

[KDMatt]

The adjustable regulator doesnt hold the pressure at all when you shut the car off it goes straight down to 0 psi. I am going to have to put that one back on until I get a new injector/s. Check out the price of these injectors, cheap

http://store.yahoo.com/dpstore/322a2311.html

Holy crap, that's the cheapest I've seen rebuilt injectors! ... and do they actually refund you a $12 core charge after that too, or is that taken into account when they charge you $35.99?

I'll be curious to see what DZR has to say about 'em too, cuz they're mighty enticing, hmm...

[78 280zcar]

Yeah they refund the 12.00 after you send them back the old injector. Awesome price yeah

[TomoHawk]

Make sure you get FPRs that get you the right pressure for the vacuum applied. I don't think that just 'any' FPR would work, as they are set at different pressures.

Mine shows about 37 PSI when I shut off the engine. It takes a wile to 'bleed down', so that doesn't worry me. I'm concerned that I'm not really get a LOT of horsepower off t he line. It could be that the ol' engine (112k miles) just isn't up to smoking the wheels like most people think?

I wish I had the $$$ to rebuild the engine. I took a ride at an autoX in a 'stock' 280Z (slightly refreshed engine) that had me pinned into the seat (It was standard trans too, mine is auto trans).

[DatsunZsRule]

Factory rebuilt ones for $36.00 each?

My opinion- doesn't sound like a bad deal. They claim a lifetime replacement warranty so what the hell go for it. They sound like a good second choice if you can't afford to go with brand new ones.

You will probably have to install new 5/16 high pressure fuel hoses on them. I doubt they will come with those like new ones do.

since you have spent $3000.00 on the rebuild, I hope you would have new Plastic holders for the injectors as well.

[78 280zcar]

Got em, good looking out!