So aside from many different fluid leaks, and the sound of rattling coming from my engine which I have been told is my gas pinging. I am hearing what I can only describe as the sound of a small explosion coming from under the hood. Its not as loud as a backfire, but it definitely sounds like something is combusting where it shouldn’t be. its a '93 XLT V6. What could it be? how screwed am I?
Is the noise intermittent, or is it happening whenever the engine is running?
A cracked exhaust manifold will make the engine sound like it needs a muffler, except the noise comes from the engine compartment. But that noise will be more or less constant when the engine is running.
It’s comes in waves. not always constant. Also there will be a few of these muffled bangs after I turn off the engine.
Before you do anything else, I would suggest that you have the pinging remedied.
The fix could be anything from the need for new spark plugs, to cleaning a plugged-up EGR, or taking care of a cooling system that is running too hot, but the bottom line is that you are doing damage to the valves and pistons every time that you drive it while it is pinging.
And…who knows? Perhaps taking care of the pinging will remedy that intermittent explosion problem that is…“defiant”.
I had a 91 ranger that was having a similar problem. It was running incredibly rough and misfiring. It came down to a bad spark plug wire that wouldn’t stay seated and a clogged EGR like @VDCdriver said.
Was your Ranger also “defiant”, as the OP’s Ranger is alleged to be?
An exhaust leak prior to the muffler sometimes sounds like firecrackers going off under the car. That would be my first suspect.
If there’s a rattling coming from the engine, and you’re also hearing these explosions coming from under the hood, it could be that the timing chain is stretched which is causing the ignition/valve timing to be off. And an intake valve is being held open during the combustion process.
It’s a 1993 Ranger. Has the timing chain ever been replaced?
Timing is what I think it is. because it isn’t idling rough, it doesn’t feel like a missfire. and the noise is definitely (got it right this time) coming from under the hood and not by the muffler. It sounds like it is coming from the passengers feet area if I had to discribe it.
Pinging is a form of preignition wherein a second spot in a cylinder self-ignites just after the spark-induced ignition and the two wavefronts crash. Knocking just might also be preignition related, perhaps the cylinder is firing either due to bad valve or ignition timing, or even hot spots in the cylinder due to carbon buildup. Preignition can also happen due to a stuck EGR valve allowing the cylinder temps to spike and induce preignition. They can and do get carboned up over time.
Honestly, I don’t think yours is a simple “change this part” problem. I think you have t have the overall condition of the engine evaluated.
If you choose to go bit by bit, start by checking out the spark timing, the valve timing, and the EGR system. Pick up a manual at the parts store and begin the processes step by step.
NOTE: the knocking could also be a bearing knock, but we’ll assume it’s not for now. We don’t want to go there unless we have to.
Because of all the leaks that my engine has (water pump and oil being the big ones.) I have been debating if I just want to take it apart and clean it all up. replacing as many seals and parts at once as I can. Im not thinking of pulling out the whole engine just tearing it down and much as I can leaving it in. is that smart or am I getting in over my head?
And the knock doesn’t sound mechanical. it definitely sounds like some kind of combustion. I stuck my head under the hood as far as I could reach and didn’t see any physical damage to the engine so I am ruling out a crack or something along those lines. The most frustrating part is that when it happens I’m in the middle of the road or in traffic and can’t get out and open the hood to look.
It sounds like a tear down of the engine and cleaning everything up is the only way to really fix the pinging. I’ve had that problem for a while and have replace the spark plugs and it still comes back. It sounds as if something is rattling loose.
so is a tear down a good idea?
If you have already eliminated the possibilities of bad spark plugs and ignition timing that is advanced too far…Why would you tear down your engine prior to checking out the next most likely reasons for pinging, namely the EGR valve and the cooling system?
Yes, the problem could be carbon deposits in the combustion chambers, but I think that it would be much more logical to remove and clean the EGR valve as a first step, and to also check the actual operating temperature of the engine. If your cooling system is not operating properly, high operating temperatures could be causing the pinging.
This vehicle has an engine longitudinally mounted in a compartment large enough for a good sized V8. You might have to do some front end disassembly, like the fan shroud, but I don’t think you’ll have to pull the motor to do the work you need to do to get it running quiet.
You might even be able to drop the pan without pulling the motor, I don’t know on this vehicle, but I wouldn’t even mess with the gaskets until I determined the cause of the pinging and knocking.
I will definitely check the EGR valve first. The reason why I was considering a partial tear down of the engine (not taking it out completely) is due to the oil leak and coolant leak I have coming from somewhere. From what i can tell the coolant leak is coming from the water pump. looking at the front of my engine just bellow the pump, it always looks wet. so the tear down would for no other reason, to just clean the whole thing up. Im getting married in the spring and have nothing else if this car breaks down on me. so i feel like a tear down would help my confidence in knowing the engine. This was my first car after all. Had it since 2007 got it from the original owner its also on its 3rd transmission (technically only its second seeing as how the one that i replaced should have never been in there) but all this to say that I love this truck and want it to last me as long as it can.
It makes the sound after the engine is off? How soon after?
Does it ever make the sound at idle?
Exhaust leaks and spark knock (pinging) are likely ruled out.
It could be a loose heat shield.
yeah it usually will start making the sound about half way through my 20 minute drive home on city streets. ill be stopped in traffic and will hear it start up. and on the days that i hear it when i shut off the engine it will be only one or two more of the pops, almost as if something is decompressing. i know see how this could be a loose heat shield.
So it continues to pop as the motor spins down, and it does it stopped in trafic.
IMHO an EGR/ pinging are ruled out. It’s likely an exhaust leak. A crack in the manifold or a gasket breach that’s sensitive to temperature.
I don’t think the pinging is related to this problem. its just one thing on a list of meany. this is why i want to tear it down so I can see what all is going on. is it worth doing? Is damage like this something that would be more expensive to repair then its worth?
Not if the rest of the vehicle is in good shape and you’re doing the work yourself.
In truth, you probably won’t have to tear it down. 99% of the things we worry about don’t happen, and in this case you stand a good chance of getting it running right without having to tear it down.