Replies to This Discussion

Permalink Reply by Kevin Lee on July 29, 2009 at 8:01pm

Sure I do Jake. that is the 5.2 L Magnum engine. Sounds like to me that you have a blown fuel pressure regulator. One, do you have a "Check Engine" light on? There are a few other possiblilties but would be helpful first if I knew if that light was on, and what codes you had. If you dont have a scan tool, Chrysler did make it easy to get codes out of it. Cycle the key from off to on 3 times in 5 seconds, leaving the key on after the third time. The cehck engine light will then flash you the codes. No matter what you will get at least one code. For example, this is the code you will get for sure. The light will flast 5 times, pause, then flast 5 times again. there will be a long pause between code flashes. that one I just described is code 55. That means end of message. If that is all you get that means there are not any codes stored. Anything else would be very helpful in diagnosing your problem

Permalink Reply by Jack R. Davis on July 30, 2009 at 3:30am

Kevin, that was a good refresher. I haven't had a Chrysler vehicle in at least 12 years, but I totally remember that feature now.

Permalink Reply by Jake on July 30, 2009 at 4:09pm

The engine light doesnt come on. Is then something esle? the truck was also sitting for two years before we bought, but we brouht it home put gas in it and put it on the charger the she fired right up.

Permalink Reply by THOMAS E EVERAGE JR. on July 31, 2009 at 9:18am

I WOULD TRY THE EGR SENSOR,RECENTLY HAD THAT ISSUE WITH A CHEVY MOTOR,UNPLUG AND SEE IF IT STILL DOES IT.

Permalink Reply by Jake on July 31, 2009 at 3:47pm

I'm 16, me and my dad have rebuilt about 8 engines, they where all older than '85. This is my first time workin on a newer engine without him. Could please tell me what it would look like or where it is please? Thanks for the help.

Permalink Reply by Aaron thomas on August 1, 2009 at 1:38pm

sounds like you have a problem with fuel pressure if i were you i would replace the fuel pressure regulator

Permalink Reply by Kevin Lee on August 1, 2009 at 2:45pm

Jake, one here has thought of a fuel pressure regulator like I had thought as well. Secondly, you do not have an EGR sensor to unplug, and that wouldnt have effected it anyway. It does have an EGR valve though, and if it is stuck open it will cause idle issues. Still do the key test though like I had said. That is an OBD1 setup, which means it wont keep the light on all the time, just when the PCM has seen the fault occur. It still could have a code in history. You want to cover basics first, before you start guessing. Code check is a valuable start, as that PCM is your friend, and will see things that you wont. Since the truck has sat for so long, there is no telling what could be clogged or gummed up, or sticking as well.

OK, basics. You said it put out white smoke and can smell unburnt fuel at idle, but would clear off idle. The white smoke is from that much excessive fuel in the exhaust, and the source of the unburnt fuel smell. That tells you that you are not experiencing a lean condition, like the before mentioned EGR valve will cause. So focus on the reasons why you have so much fuel. Two of us said a fuel pressure regulator. How to check it is to locate it on the fuel rail. It will look like a small can with a vacuum hose going to it, noramlly at one end, next to the return fuel line. Unhook the vacuum hose and see if you have gas running out of the hose. You might even cycle the key on to energize the fuel pump to see if fuel comes out of the vacuum port on the regulator. Still check for codes. If the regulator looks OK, there are a few other possibilities that it could be that the PCM might have recognized. The PCM determines how much fuel to deliver by sensor inputs. The basic inputs for that are manifold vacuum, or MAP sensor, engine temp, or ECT sensor, throttle position sensor, or TPS, and engine RPM. The oxygen sensor, or O2 sensor is for closed loop operation, or to help the PCM to create the proper air-fuel ratio for optimum running. Your truck cant get to closed loop operation yet as it is running too bad, so we wont worry about that sensor as of yet. The MAP, TPS, and ECT sensors or the ones that are a big possiblilty. The MAP sensor also gives the PCM barometric pressure, before the engine is started. If it is reading wrong, it could tell the PCM to deleiver that much fuel right away. The best candidate is the ECT sensor. IF this sensor goes open, it will tell the PCM that it is VERY COLD, as much as -41degrees F. That in turn will make the PCM go way too rich on fuel. This will most likely set a code, why you need to check. The TPS could be stuck in a position, making the PCM think the trottle is open more than what it is, making the PCM deliver too much fuel. IT is possible for a code too, as the PCM knows the voltage should be in a certain range at idle, but is not seeing that.

You can also have a stuck open injector as well, causing the excess fuel. One way to check that is to put a fuel pressure gauge on the service port. You will see a black cap on the rail, and that is the port. Intall the gauge, cycle the key on to get the fuel pressure up in the rail. After the pump runs, the pressure should settle in about 40 to 45 PSI. A bad regulator, or stuck injector will allow tthe fuel to run out, causing the pressure to keep dropping, maybe all the way to zero pressure.

Do your basic checks like I have said, and remembering you are getting too much fuel, and you will find the cause. Dont be unplugging things randomly, as you can create other codes and problems instead of finding the source of your trouble. Good luck Jake, and if you have any more questions, feel free to ask. And with any problem, you cannot describe enough fo what you are experiencing. Remember we are not there, so you are our eyes and ears. The more you can tell us, the better we can help.

Permalink Reply by Jake on August 3, 2009 at 6:00pm

I have got the codes from doing the "check engine light" thing, but i dont know how to decipher them. They are (I will be flashes and - will be Pauses) III-III-IIIIIII-IIII-IIIIII-IIIII-IIIII
3-3-7-4-6-5-5 (Number of Flashes)