Have 2005 Dodge ram 1500 4.7L have had numerous problems with misfire numerous times p0301-#1
then Had constant on p0303-#3-found cam follower fell off-had to replace followers on #3 also found #3 lifter was seized replaced because was in there also replaced all valve springs
was good for a bit but then misfire on #1 again cleared good for a bit then p0305-misfire #5 now-checked found plug black-has all new plugs less than 1500km ago, all other plugs look okay-switched coil and plug to opposite side-#6-still miss at #5. checked fuel balance-was bad on #5-suspected problem in fuel-plugged -pulled fuel rail off and cleaned and replaced #5 injector-put all back together still miss at #5
note: also has had to fill coolant in rad a few times no leak found externally, no sign of coolant in oil or coming out exhaust, this time when #5 started to misfire drove for a bit then noticed temp started to rise turned off and checked coolant rad was almost empty-no signs of coolant at all???
Is the engine misfiring all the time?
How many miles on the vehicle?
With a scan tool, erase all data trouble codes and road test the truck to see if any codes come back.
When you checked the fuel pressure and found that injector was bad you said you removed the injector and cleaned it. Do the fuel pressure drop test on the bad injector again; the fact that the plug was black indicates excessive fuel in that cylinder possibly from the injector leaking or being stuck open.
Vacuum leaks can cause a misfire or rough running engine which can set a code. A restricted air induction system, exhaust system and also internal engine component failures.
Pressure test the cooling system and see if you have any pressure drop, if you do and you don't see any leak, remove all the spark plugs and crank the engine over and look for any antifreeze squirting out of any spark plug holes. This will confirm an internal mechanical failure. If this doesn't happen you can take the truck to a reputable repair shop they can use an emission gas analyzer to check if the radiator has any exhaust emissions in it. This can confirm if there is any internal mechanical failure like a head gasket, cracked head or block. If you loose coolant and there is no sign of it on the ground and you can't tell if it's coming out of the tail pipe then this should be investigated.
the truck has 165000km on it. right now the misfire is constant-we clear and start truck misfire comes right back and truck is obviously missing badly now.
most immediate concern is the misfire then I will check for reason for coolant loss
I have checked all plugs and they are all nice and clean as they should be except #5 that was very black
Gotta do the basics beginning with being sure which cylinder is not firing. Without a scan tool, you can do this by unplugging each injector one at a time. The one that has no affect on engine RPM, is the cylinder which is not firing.
Then remove that ignition coil at that cylinder and test for a strong spark. If it's good, confirm injector pulse to that injector (on and off voltage and ground). Still good, you need an injector tester and a fuel pressure gauge to pulse the injector and view correct pressure drop.
Still good, do a compression test on that cylinder.
We have a scan tool and have done test of each injector-pulse all was good-also did replace #5 injector with new made no difference
checked compression good 150
confirmed good spark
only problem at #5 for sure
We just pulled valve cover and found #5 follower has fallen off!
We had this problem with this truck before had #3 follower fall off and damage camshaft-we have replaced all valve springs and #3 lifter as was seized. This time #5 follower seems like #5 lifter may be seized-any common issues with lifters on these???
No technical service bulletins, but the 4.7-liter has had some valvetrain issues.
There are several things that could cause the followers to fall off, due to excessive clearance.
- Low oil pressure or contaminated oil.
- Sludge or debris possibly restricting oil delivery to the lifters (adjusters)
- Defective adjusters
- Worn cam, followers, or adjusters
- Weak or broken valve springs
- Excessive carbon build up on the valve stems preventing full valve return to valve seat
Seems like bad adjusters may be the most common ailment, but the best way to go after confirming no sludge and good pressure, would be pulling both heads and have them completely done-over at a qualified machine shop, along with replacement of cams, springs, followers, adjusters, etc. as needed.
If you're in there already, you might want to give it one more shot by replacing all the adjusters on that bank.
Still a problem, pull the heads and send them out -- like you maybe should have done in the first place.