Only starts when i remove the oil cap?
#1
Only starts when i remove the oil cap?
My 2004 dodge ram 1500 ran perfect until one day I shut it off for twenty minutes at home then got back in to leave an it wouldn't start. A mechanic told me I'm better off selling it for part's! I didn't believe his word on that but he did replace my pvc valve because it never got replaced in a while, it caused oil to leak out the end of my exhaust pipe I don't know if that happens is it fixable or what. Please someone help me on this I love my truck an it's the only vehicle my wife an kids depend on so if someone can relay to my problem please help me out with this one.
#2
#3
5.7 hemi, it starts an runs a little sluggish when I remove the oil cap but dies soon as I put it back on like its a compression problem or something idk. It ran fine before this an there's still no knocks or any different sounds coming from the motor that has a little over 220 k on it. I really can't afford a motor swap right now do you really think the motor is shot or this problem is unfixable?
#5
5.7 hemi, it starts an runs a little sluggish when I remove the oil cap but dies soon as I put it back on like its a compression problem or something idk. It ran fine before this an there's still no knocks or any different sounds coming from the motor that has a little over 220 k on it. I really can't afford a motor swap right now do you really think the motor is shot or this problem is unfixable?
Take your oil dip stick out and see if theres any pressure on your finger, it should actually have a slight vacuum that wants to suck your finger if its a healthy engine, if it wants to push your finger off then you probably have a ring issue, though bad intake and exhaust valve seals can cause pressure to build in an engine.
Another thing that's a little more scientific than the dipstick test is to get a vacuum gauge (harbor freight sells them cheap) hook it to a vacuum port on your intake manifold and see what it reads, a Healthy Hemi is around 15-20 of vacuum with a steady needle on the vacuum gauge.
Last edited by JoshSlash87; 02-08-2016 at 05:55 PM.
#6
K I ordered a pressure gauge I'll get it first thing tomorrow, what's the best place to hook that up to? Do I need to shut off the ignition an pull all the plugs to the sparks an test it that way or just a vacuum line? Today I pulled the air filter an everything up to the throttle just to check an clean when I seen that a small amount of oil has left a stain on my filter an on the 04 ram's with the hemi is the throttle supposed to be a little less then a quarter of an inch open just curious because mine is. I just wanna thank you for taking the time to help me out with this seriously.
#7
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#8
K I ordered a pressure gauge I'll get it first thing tomorrow, what's the best place to hook that up to? Do I need to shut off the ignition an pull all the plugs to the sparks an test it that way or just a vacuum line? Today I pulled the air filter an everything up to the throttle just to check an clean when I seen that a small amount of oil has left a stain on my filter an on the 04 ram's with the hemi is the throttle supposed to be a little less then a quarter of an inch open just curious because mine is. I just wanna thank you for taking the time to help me out with this seriously.
Since the Hemi has 16 spark plugs (8 per side), just pull 4 plugs on each side (ONLY PULL ONE plug per cylinder, you need the 2nd plug to hold compression in for a accurate reading or it will bleed off and the gauge will read low if not zero compression). The purpose of pulling all the plugs on one side of the engine is so that you can rule out the possibility of a head gasket leak between cylinders and another cylinder holding the pressure in giving you a false reading of that cylinder holding its pressure, if you find a low reading between two or more adjoined cylinders putting plugs back in and running the test again can help you determine if its a head gasket leak and between what cylinders if the pressure improves with plugs removed.
As for the throttle body, it should reset itself every time the ignition is turned on, have a friend turn the ignition on and watch the butterfly open and shut to ensure normal operation. Also probably wouldn't hurt to clean the throttle body. It being open like in your pic should be normal.
On the hemi its a good idea to disconnect all coils from the harness before attempting a compression test so that the engine doesn't start during the test. Its also a good idea to get the engine up to normal operating temp if possible before doing the test, in your case just run it for as long as you can.
If a low compression reading is detected within 10% of the desired reading add an ounce of oil to the cylinder to see if that improves the reading.
#9