QuestionQUESTION: ...I have a f150, 302 I am getting slight amounts of oil in no# 3 and 4 plugs. I was told valve seals. I get a popping sound when accelerating and lack of power. Have you ever heard of a popping sound. When i change the seals do i have to be concerned with any specs? other then torquing the lifters down? My concern is could this possibly be something simple such as seals or should i be concerned about replacing the head. It has a full tune up, including timing. I have never heard popping when accelerating its almost like it were carbeurated and backfiring....any thought or ideas would be great.....thanks for your time
ANSWER: Brian, the popping sound is kinda strange. The first thing I think of when I hear that is that your ignition coil is going bad. When you say that you also have a lack of power, does that mean that it takes a hard "nose dive?" Oil on the plugs definitely suggests valve stem seals. It can be an easy job to do as long as you don't remove anything old and replace it with new ones (other than the seals). As far as specs go, the only thing you would need to do is like you said, adjust the lift. That is nothing more than tightening your rocker arms while the vehicle is running. Remember not to tighten down the rocker arms before you start the vehicle, or you will likely bend them. Give them an initial tightening to where they will not shake off the push rod, but they move around a slight amount. They should not be absolutely tightened, I cannot say that enough, until the vehicle has started. Then, just tighten them down until the lifter quits knocking. 302's tend to oil very well, so will probably get splashed. Also, if you want to put off changing the seals, you could always just bump up to a hotter plug, and that might help with burning off the oil during startup. Now, to give you the best advice I can about the popping, I would need to know a little more about the truck; year model, what happens when the popping sound begins, does it happen during start up, or does it happen after the truck warms up for a while. Also, does it happen at high rpms, low rpms, or any all ranges of rpms. I will say that a really bad valve stem leak will cause a popping sound. It happens because of lowered compression due to the oil being in the cylinder. And yes, it will sound like a carbureted vehicle. Give me a little more information about the popping and I might be able to narrow it down for you. I hope I have helped you,
Jason
p.s. I doubt it is the head. You would have (much)bigger problems if the head was bad.
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QUESTION: This is a 91 f150, efi 302, replaced motor with crate motor last year..bottom has 20,000 miles on it....the popping occurs when truck is under load starting out say 20 to 25 mph and when accelerating to pass on highway,,it will pop a few times then go away...i thought maybe distributor? just guessing....i get no engine lights, had scanned came up with egr vacuum solenoid, replaced still the same....had timing redone at shop...still the same...the engine starts fine and idles a little rough...thought maybe because of slight oil in the no 4 plug...did a full tune up, o2 sensor....since im not getting a light i havent replaced throttle position or any other sensors....thought maybe computer chip might not be compatible with motor i installed just another guess...im at a loss here...
AnswerBrian, changing the engine can cause issues with the computer. If the dealer, or a good mechanic did the work, no problem. As long as you swapped apples for apples, the computer should not be a problem. The EGR solenoid does present a problem. Have you had the truck checked to make sure that the code has erased? The solenoid will cause the truck to run lean, which could (possibly) cause some popping. Also, if a bad solenoid will eventually clog the Cat Converter, which could cause some popping. To be honest, it really sounds like you have a bad ignition coil. Sometimes a coil will "limp" along causing you to diagnose the vehicle incorrectly. Trust me, I have done it before. You can have the coil checked at AutoZone, if you can find someone who knows what they are doing. (Good Luck) Or you can check it yourself with a multi-meter. I don't have the resistance tolerances on me, but you can call AutoZone and get them, if you can find someone who knows what they are doing. All you will need to check the coil is a multi-meter and possibly a paperclip. Since the truck has not all together quit, then I would suggest that you check the coil after you have run electricity for a while. Basically, check it while it is hot. If the resistance is extremely close to the tolerances, replace it. If you don't mind throwing a little money at the truck, just go buy one. I hope this helps and keep me informed. Good luck, Jason
