bad fuel pressure regulator questions

[Blucifer99]

Hello stangnet.... new member here.. new to foxes too... i have a 1992 Lx , and i have a few questions about some stuff..
first question, will a bad or dieing fuel pressure regulator cause a car to surge or spudder while maintaining speed.. ive tested my fuel pressure and its showing 40 KOEO BUT one time i tested it and it only showed 10psi KOEO... and if i test with the vac line plugged into the fuel pressure reg its 28-30.. but with the vac line off and plugged its 43 all day long... and my fuel lines hold pressure for a long time.. so i kno its not a leaking or open injector.. also if i drive the car with the vac line plugged into the reg the car spudders while maintaining speed..and if i was to unplug the the regulator and plug it and then go for a drive the car does not spudder and has great power and drives normal.. and no theres no gas leaking from the top of the reg. Im thinking i might just buy a AFPR and set it at 38-40 and drive but not to sure about it.. so hopefully someone can help me out here before i either cause damage to my motor or do something i shouldnt... lol Thanks in advance and any advice is good advice in my books...

Btw The cars name is "Blucifer"

 

[90sickfox]

Fuel regulators are inexpensive....relatively speaking. That thing has probably been on the for a long time.... probably due for replacement.

Of the fuel injectors have never been replaced it may be a good idea to replace them, too. They pick up junk over the years.

 

[jrichker]

Check fuel pressure:
The local auto parts store may rent or loan a fuel pressure test gauge if you don't have one.
Disconnect the vacuum line from the fuel pressure regulator. Check it for evidence of fuel present in the line by removing it and blowing air through it. If you find fuel, the fuel pressure regulator has failed. Reinstall the line; leave the fuel pressure regulator end of the vacuum line disconnected. Then cap or plug the open end of the vacuum line and stow it out of the way.
Connect the fuel pressure test gauge to the Schrader port located just behind the alternator.
Turn the ignition switch on & start the engine. Observe the pressure: you should see 38-41 PSI at idle.
Turn the ignition off; reconnect the vacuum line to the fuel pressure regulator. Then disconnect the fuel pressure test gauge. Watch out for squirting gas when you do this.

Fuel pump pressure test
Disconnect the larger of the two fuel lines up by the Schrader valve. It is the return line and does not have the Schrader valve on it. Find a piece of rubber fuel hose and clamp it on the return line coming from the regulator. Stick a bolt in the other end of the hose and make sure that all your connections are tight and leak proof as possible. When this powers up, you don't want fuel squirting everywhere. Hook up the fuel pressure test gauge. Turn the ignition switch on and watch for leaks. You may want to use a helper inside the car to cut the switch off quickly if you have a leak. To trick the fuel pump into running, find the ECC test connector and jump the connector in the Upper RH corner to ground.

Caution!!! You have blocked the return line for the fuel pump! Pressure will rise very quickly past safe levels with a good pump
If the pressure goes up past 55 PSI, the pump is good and the fuel pressure regulator is bad. If the fuel pressure does not hit 55 PSI or more in a few seconds, the pump is bad or you have electrical problems.



Dump codes sticky

Look at the top of the 5.0 Tech forum where the sticky threads are posted. One of them is how to dump the computer codes. Codes may be present even if the CEL (Check Engine Light) isn’t on. You don’t need a code reader or scanner – all you need is a paper clip, or if your lady friend has a hair pin, that will do the job.
I highly suggest that you read it and follow the instructions to dump the codes. http://www.stangnet.com/mustang-forums/threads/how-to-pull-codes-from-eec4.889006/[/b]