3rd Gen Ram Tech2002-2008 Rams: This section is for TECHNICAL discussions only, that involve the 2002 through 2008 Rams Rams. For any non-tech discussions, please direct your attention to the "General discussion/NON-tech" sub sections.
Need help - Slow starts, misfire codes on 2004 5.7 hemi
I need some help troubleshooting multi cylinder misfire alarms and slow starts on a 2004 Ram 1500, 5.7 hemi, 44,000. Here are some details: Historically, truck cranks for a few seconds before firing up (typicaly between 2 - 5 seconds), changed to platinum plugs at 30,000. Misfire codes have been intermitent, multicylinder and sometime individual cylinders. The eng light appears to come in immediately after the engine fires up after a slow start. I have observed no rough idle or rough engine performance at highway speeds and MPG is as expected 15.5 for short trip driving and 21 or slightly higher for continuous highway driving. I ran 4 cans of Seaform through the fuel system to ensure it was clean with no apparent affect. Dealer cleaned engine carbon with a spray cleaner and updated flash menory which did not resolve problem. I am thinking the misfiring is during the slow starts. Any help to focus my troubleshooting in the right would be appreciated.
This ad is not displayed to registered and logged-in members. Register your free account today and become a member on Dodge Forums!
The current DTC code is 0300 Random multiple cylinder misfires detected. I have gotten this code several times in the past along with misfire codes for a few specific cylinders. A defective cam or crank positioning sensor was something I had thought about. Also, I had thought about the fuel pressure bleeding down with the engine shutdown.
It turns out my problem was a leaking fuel injector. I purchased a fuel pressure gauge and noticed that when I turned the ignition from ON to OFF, the fuel pressure would drop fairly quickly. I then knew either an injector was leaking or the pressure was bleeding back through the fuel pump/check valve. I figured out a way to determine If the problem was a leaking injector. After priming the system to operating pressure which is 60 PSI for this vehicle, I quickly bled down the pressure using the pressure gauge bleed valve. This allowed the pressure to bleed down before fuel had a chance to leak through a leaking injector. I found that when I quickly bled off the pressure and waited a few hours, the engine would immediately start as it should - it was obviously not flooded. Knowing that the problem was a leaking injector, I purchased a new injector and obtained instructions for injector replacement. After removing the injector & plug wires, I removed the left side 4 injectors together without having to remove the fuel line. With the injectors out of the intake, I pressurized the fuel rail by turning the ignition to ON - and immediately noticed one injector started dripping fuel. I replaced the leaking injector and my truck now starts as it should and there are no misfire alarms.
I can say I put back in mine what cane out and those were coppers. At 1.76 each times 16, I felt good about it. I drive the **** out of my truck and never any hesitation issues, stumbling or skipping at high RPMs. I cant see why i would pay more to get nothing more.