79Daytona

Say I got a question I'm working on my 92 Z28 Camaro 5.7 TPI I'm working on an issue that may or may not be a fuel pressure regulator problem but I saw a video on youtube of a guy testing a fuel pressure regulator by capping or pinching the return line and then priming the pump and if the fuel pressure reads high and stay there than the fuel pressure regulator is bad. I was wondering if that could be true.

W.E.G.

You should post a link to the video if you want opinion on the video.

PaulyC

Yes, if you pinch the return line it will essentially dead head the pump. It is actually in the GM troubleshooting guide.

79Daytona

Ok here's the link.

79Daytona

So if it dose hold high pressure when deadheading the return line that means the fuel pressure regulator is bad. And what should it read if its good.

W.E.G.

Static pressure with pump on should be 35-45.

Return line pinched should boost to 55-75.

Defective regulator can leak fuel out the vacuum nipple or out the return line.

W.E.G.

System holding high pressure when return line is pinched is not indicative of defective regulator.

W.E.G.

The job of the regulator is to release excess pressure on fuel rail by allowing fuel to return to tank.

Regulator is DOWNSTREAM from fuel rail. I suspect your question was asked with the incorrect assumption that regulator was upstream from fuel rail.

79Daytona

Cool thanks for the info.

79Daytona

Say I am going to replace all the old fuel injector because of all the rusty trash that ran through them from the old rusty gas tank . So I was wondering is there a fuel injector that you guys might recommend I use I've seen a lot of cheap one on sale on ebay but I don't want to use any cheap crappy ones .

Tuned Performance

iTrader: (92)

Southbay08 has 22#hrs for a good price.
https://www.southbayfuelinjectors.co...ctors-bosch-d3

https://www.southbayfuelinjectors.co...tors-1986-1992

79Daytona

Thanks for the info that's just what I need and the price is good to. Thanks again.

79Daytona

Hey I got another question I just installed a new fuel pressure regulator with a adjustable housing which I got from SouthBay . When I prime the pump it reads about 46 psi and I think that's a little high but it won't go any lower I've try to adjusted it and that's as low as I can get and also it drops pressure to about 20 psi . I was wondering would a bad injector cause that drop in pressure i'm planning on replacing the injectors .

Tuned Performance

iTrader: (92)

How long are you waiting for the pressure to drop .
Your prime psi is normal. What was the need for the afpr?

79Daytona

The pressure drops to about 20 psi in about 10 or so seconds after it primes up. The reason I got the new fuel pressure regulator and housing was I thought the fuel pressure was a little low it would prime up to about 42 and then drop and when running it would hover around 35.

Tuned Performance

iTrader: (92)

You have a leak some where, check valve in the pump, pulsator in front of the pump or injectors.

79Daytona

That's what I'm thinking , I installed a new gas tank and sending unit as well as a new fuel pump but who to say with parts you buy today . Sorry for asking a dumb question but how do you check the valve in the pump. Also I got a feeling it maybe one of the injectors because the car has like 3 stock injectors and 5 after market ones but I don't know how long they ran the car with the rusty gas tank that was on it .

Tuned Performance

iTrader: (92)

The only way I know how to test the injectors is do several leak downs with pump prime.
Then pull the plugs looking for wet plugs. No way to test the pump check valve.
If you do end up replacing the pump throw away the pulsator it’s a known area for leaks. It’s job is to help isolate the pump noise from the fuel hardline.

79Daytona

Yeah I was thinking of pulling the plugs to check them . Well anyways thanks for the help I owe you one.

79Daytona

The pulsator sorry to ask whats that .