Fuel Pressure questions on a 2000 Mercury Mountaineer

[Hetchman]

Greetings all! My wife and I recently purchased a 2000 Mercury Mountaineer from a local dealership. It has the 5.0L V8 engine in it. As with all used car purchases I took it to a local mechanic to run diagnostics on it. Besides that, it was starting hard about 25% of the time. I'm going to preface the rest of this post by saying I know very little about cars. I can change a tire and put oil in, but that's about it.

Diagnostics revealed that the fuel pressure regulator was bad. I called the local parts store (a carquest) and they told me that part didn't exist for my vehicle. I find that odd, since the diagnostics told me that's what I needed.

Here's where I get into the crux of the problem. The mechanic has a good local reputation, half the town uses his services. I believe him when he says it's the regulator. But I can't find an "official" ford regulator for my car. If I buy one of those "universal" regulators, 1)Will it fit?? and 2)Will it work?

Also, I've got a buddy who is going to help me put it in. He needs to know what the pressure is supposed to be at. I've searched google multiple times and I've searched these forums multiple times as well. I have yet to get a satisfactory answer from either. The closest I could find is someone on the forums said a 2000 explorer is supposed to be between 55 and 70 PSI. I'm not sure if that's the same engine as my car or not, I don't know anything about cars.

The universal regulator I'm looking at is a blackworks racing brand universal fuel regulator. It says it can handle 20-80 PSI adjustments. Here's the link for you more car savvy folks: http://www.andysautosport.com/mercu...egulators/blackworks_racing/bwrc00000116.html

Any help would be much appreciated. Other than starting hard, it runs like a champ and I'm really enjoying it.

 

[koda2000]

the 2000 model does not have a fuel pressure regulator on the fuel rail. when you first turn the key to the ON position, you should always hear the fuel pump run for about 2 seconds. then it will stop. this primes the fuel system until you start the engine. once the engine is started the fuel pump runs continuously. there's a pressure regulator, which is part of the fuel pump assembly. it dumps excess fuel right back into the tank.

my 2000 Mountaineer V8 had starting problems when the weather got cold. it would not prime unless you turned the key from ON to OFF multiple times. at 180K i figured it was most likely a worn out fuel pump. i installed a new pump, filter sock and fuel filter. i also replaced the fuel hoses in the tank. i haven't had any problems with starting since. if you're concerned about the pressure regulator in the tank, you can replace the entire fuel pump assembly instead of just the fuel pump. the new assembly includes the regulator, pump and fuel level sender.

forget about the universal fuel pressure regulator.

 

[snoranger]

You have a "returnless" fuel system. The truck does have a regulator... It's built into the fuel pump assembly in the tank. The pressure should be somewhere around 70psi. ( I don't recall the exact pressure off the top of my head.)

 

[koda2000]

You have a "returnless" fuel system. The truck does have a regulator... It's built into the fuel pump assembly in the tank. The pressure should be somewhere around 70psi. ( I don't recall the exact pressure off the top of my head.)

i think it's supposed to be something like 67 PSI.

 

[Hetchman]

Thank you so much for your prompt responses. I called up my buddy and he's going to go over my fuel system with a fine tooth comb for leaks as I've smelled gas before before/during/after driving. Not a really strong smell and no puddles, but gas all the same. If it's not a simple leak, we're going to go ahead and get the pump assembly thing as that does indeed include the regulator.

Does the brand of said parts matter??? Carquest carries Delphi (275 bucks ouch), spectra (215 dollars) and Carquest brand by Airtex (240 dollars). I've also seen parts online as low at 100 bucks, but I'm wary of a deal too good to be true. IE: crappy parts I'll have to replace again soon. Any thoughts on the best brand?? I'm leaning towards the carquest one so far. It's local, I've bought parts from them before and had no problems, and the owner is a friend of mine.

 

[koda2000]

i put an Airtex pump in mine. some may tell you they don't last, but i'm happy with it so far. Bosch is supposed to be a quality pump. i'd suggest you just buy what you're comfortable with. once you get a part number, i'd check Amazon and Auto Parts Warehouse for the best price with free shipping and make sure the filter sock is included (usually is with the assembly). also, make sure your mechanic puts in a new fuel filter.

the gas smell you're experiencing may have to do with the evaporation system. this is part of the emissions system and includes many possible vapor leak points, however the fix is usually fairly simple and inexpensive once found.

 

[jremington59]

Have your friend do a fuel pressure test at the rail and see if you're in the 60 pound vicinity. Are you showing any codes?

 

[koda2000]

yeah, you may have some codes. check to make sure the CEL light works during the bulb-check (key ON). sometimes dealers will clear codes and it can take a while for them to reappear. i would expect a code or two if you have a leak in the evap system because it's part of the emissions and that's what sets the CEL.

 

[2000StreetRod]

what's that on the fuel rail?

Depending on the year of vehicle there can be three different items mounted on your fuel rail with a vacuum hose connection.

For Explorers/Mountaineers thru 1998 with the return fuel system a fuel pressure regulator is mounted on the fuel rail. It adjusts the fuel pressure according to engine vacuum (load) and returns excess fuel to the fuel tank via a separate fuel line.

For Explorers/Mountaineers from 1999 thru 2003 with the returnless fuel system (fuel pressure regulator mounted in fuel tank) a fuel pressure damper is mounted on the fuel rail. It smooths the pulses from the intank fuel pressure regulator.

For Explorers/Mountaineers from 2004 with the returnless fuel system a fuel pressure/temperature sensor is mounted on the fuel rail. It allows the PCM to monitor the fuel pressure and temperature at the fuel rail and control the fuel pressure.

All of the above devices utilize a diaphragm that can rupture with age. When that happens there are consequences: the fuel pressure rapidly drops when the fuel pump isn't running; and fuel is leaked into the intake manifold resulting in a rich mixture when the engine is running (vacuum present).

The check valve in the fuel pump assembly is fairly reliable and if functioning properly will hold pressure for many hours. My fuel pressure only drops from 67 psi to 30 psi in eight hours. If there is a rapid drop in fuel pressure I would test the rail mounted device first. It is easier to access and test, and less expensive to replace.