1999 Dodge Ram Engine running rough and dying

Tiny
VINCARTHUR
  • MEMBER
  • 1999 DODGE RAM
  • V8
  • 2WD
  • AUTOMATIC
  • 189,000 MILES
My dodge sudenly stopped after giving no indication of a problem. After I got it home, I checked all sensors and ran a diagnostic with a scan tool--nothing! I checked timing, spark, and fuel pressure all OK. After changing plugs, they were fouled with black soot, the motor ran good for a moment and then died. I removed some fuel from at injector fuel rail and noticed that it looked yellowish. It looks alot like old fuel that you see in a lawn mower thats been sitting for several years. I have never experianced bad gas before and am not sure if it is. I filled up at the station and drove almost half a tank out before my engine quit. Could this be bad fuel or something else?
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Wednesday, October 21st, 2009 AT 11:34 PM

5 Replies

Tiny
JACOBANDNICKOLAS
  • EXPERT
Does the fuel have a strange odor to it?
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Thursday, October 22nd, 2009 AT 10:10 AM
Tiny
VINCARTHUR
  • MEMBER
After rechecking the fuel, It looks like it may be ok. The yellow color was coming from contamination in the hoes I was using. One thing I have noticed is the fuel pressure bounces around erratically, between 35-50 psi, when the motor is turning over and also when it finally does idol for a little while. I am thinking it may be the fuel pressure regulator or maybe EGR valve--not real sure.
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Friday, October 23rd, 2009 AT 3:14 PM
Tiny
JACOBANDNICKOLAS
  • EXPERT
When you checked the pressure, did you disconnect the regulator to see what happened? If so, how did the pressure react? Based on what you are saying, it does sound like a bad regulator.

Here is a HOW TO for checking fuel pressure and the regulator. Try it and let me know what you find with the regulator.

http://www.2carpros.com/how_to/how_to_check_fuel_pressure.htm

Let me know what you find.
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Friday, October 23rd, 2009 AT 8:57 PM
Tiny
VINCARTHUR
  • MEMBER
I watched the video on testing the regulator but the regulator on this vehicle is a "returnless" fuel system, according to the Hanes manual. The regulator is mounted on top of the fuel pump sending unit at the tank. I am not sure how to test this one. Another tid-bit of info, yesterday when I finally got the engine to run, roughly however, my engine suddenly smoothed out and idled correctly, I was able to give a little throttle without stalling the motor out; during this time I watched my pressure gauge and noticed that it was holding a steady pressure and not bouncing around. This only lasted for about 60 seconds and then went back to rough idle and pressure gauge bouncing around erratically.
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Saturday, October 24th, 2009 AT 12:46 AM
Tiny
JACOBANDNICKOLAS
  • EXPERT
I'm sorry!!! you are correct. THis has the regulator mounted at the top of the fuel tank. It's a combination filter and pressure regulator. The regulator is a mechanical device not controlled by the PCM or engine vacuum. It's calibrated to maintain a pressure a pressure of about 49 psi at the fuel injectors. The unit contains a diaphragm, calibrated springs and a return valve.

Chances are that is the problem. Here are the directions to replace it:

REMOVAL & INSTALLATION

Disconnect the negative battery cable.
Remove the fuel tank filler cap.
Properly relieve the fuel system pressure.
Raise and safely support the vehicle.
Remove the fuel tank assembly.
The fuel pressure filter/regulator assembly is located on the top of the fuel pump assembly. It is not necessary to remove the fuel pump to remove the pressure filter/regulator assembly. Matchmark the direction the hose fitting points. Unit must be reinstalled pointing in the same direction.
Twist the filter/regulator assembly out of its grommet on the fuel pump.
Remove the snap ring that retains the convoluted tube to the filter/regulator. Slide the tube down the plastic fuel tube to access the fuel tube clamp.
Gently cut the old fuel tube clamp off, taking care NOT to damage the fuel tube or drop the clamp inside the tank.
Remove the fuel tube from the filter/regulator assembly by gently pulling downward.
Remove the filter/regulator assembly from the fuel pump module.

To install:

Install a new clamp over the plastic fuel tube.
Install the filter/regulator assembly to the fuel tube. Rotate the filter/regulator until it is pointed to line up with the matchmark previously made.
Tighten the clamp to fuel line using Hose Clamp Pliers C-4124 or equivalent.
Slide the convoluted plastic tube up to the bottom of the filter/regulator and install the snap ring.
Press the filter/regulator assembly into the rubber grommet making sure it is pointed in the 10 o'clock position.
Install the fuel tank.
Lower the vehicle.
Connect the negative battery cable.
Install the fuel filler cap.

Here is a picture of the regulator:


http://www.2carpros.com/forum/automotive_pictures/249084_pressure_regulator_1.jpg



According to what I have read, the regulator isn't serviceable. The pump should be regulated to aprox 49 PSI. If it is more than that, chances are the regulator is bad and the pump is good. If it is droping below that, both should be replaced.

Let me know what you find. If I recall, you were droping into the 30PSI range. If you remove the tank, replace both with the filter too.

Joe

LEt me know if this helps.
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Saturday, October 24th, 2009 AT 11:34 AM

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