What are symptoms of a bad fuel pressure relay?

I FIGURE THAT IT IS OPERATED BY THE EDC OF THE CAR.

i hope you do not have security device on the car, if you do there some security device that cut off the fuel supply and this could be your problem mostly, if the device is malfunctioning.

If your engine turns over, its not your starter, so im not going to include the location for now. If it turns over, but don't start up, then its either an igniton or fuel problem. First thing I would do is have the fuel pressure checked. If the pressure is ok, then move on to the igniton system. If you don't want to have the pressure checked, or if the pressure tests low, you will have to spend the money and buy a new fuel filter, and/or fuel pump relay, and/or fuel pump. Igniton system consists of the coil, ignition module, sparkplugs, plug wires, distrubter cap and rotor button (if your car has one, as some may not).

Have your codes read. Autozone does it for free. Only then will you have an idea of where to start looking.

Could have something to do with the security system. Read the info on this link. Might help you out with diagnosing, symptoms, and solutions. http://vatspasslockpasskeysecurityhelp.yolasite.com/

the relay. Try swapping the fuel pump relay with the wiper relay. These are in the engine compartment relay box. If this doesn't help, please get back to me.

The L67 GTP has a two speed fuel pump. There are two relays that control the fuel pump via the PCM module. The fuel pump relay and fuel pump hi-speed relay. Tied into the hi-speed relay is a fuel pump resistor that may go bad.

Symptoms vary but primarily the engine will start but die in a matter of seconds due to insufficient fuel pressure.

Here is an easy method to bypass the fuel pump resistor which puts the fuel pump in the high speed mode:



Keep in mind this is a temporary fix and your fuel pump will be running in hi-speed all the time, which can lead to premature failure - and another component you'll need to replace. You can purchase the resistor here.

Hope this helps!

-KC GTO Dad

Also check the vaccum hose from the fuel pressure regulator to the intake manifold, it is right on top, to the front right of the valve cover where the fuel lines attach to the fuel rail, there is a small vaccum hose that runs from the regulator to the intake manifold, I have a 93 grand cherokee limited w/ 4.0L 6cyl, it was hard to start at times, wouldnt start at times without starting fluid spray and had your symptoms at idle, running rough like it wanted to stall like it was out of gas, I had various opinions ranging from fuel pump was bad to the fuel filter to the fuel presure regulator, the fuel pump relay ,etc....after replacing the relay and having the same symptoms, some digging brought me to this vaccum hose, wich had a break in it, when it was replaced it allowed the regulator to have the correct fuel pressure output and solved all the afforementioned problems way cheaper than the suggested alternitives. good luck.

change the fuel filter if you have not already