Mysterious Knocking sound ?

[dolphans1]

This post is a continuation of my "dropping the fuel tank" and changing out my fuel sending unit.

Up to this point the SUV never knocked. When I replaced the tank to its original state I added 2 gallons of gas and the car started after 2 cranks and there were no knocks.

I filled the entire tank up with gas, cranked the car and it was making a mild knocking noise. My mind was going, oh,oh, what the hell is that. I imagined my fuel pump going crazy and bursting into flames, OK back to reality.

But I am concerned about the fuel pump as I read in the book that poor fuel pressure in line could cause engine knocking.

Am I going nuts or what? Could this really be happening? Fix one problem and create another one?

Any suggestions?

d-1

 

[dolphans1]

Well just like that the knock went away. I waited 24 hours before I started the car. Like someone just said, if it beats you up, walk away from it and come back when you're ready. Well I went out and started it and it ran perfect, no knocks. I am wondering if it was the gas I purchased or if when I washed the tank with water, some water may have gotten inside the tank or since I literally ran the tank dry of any gas (by mistake), it may have created some intermittent vapor lock in the fuel line. I thought I had at least 20 miles of gas (1 gallon) left based on the travel odometer.

If it starts again I will let you guys know, to those that are interested, of course. My big fear was I had a faulty fuel pump or some debry may have been sucked up the line. I did not want to drop the tank all over again. It's a pain in the you know what. It would be no big deal if you had a car lift and you could stand up underneath it.

Note: the old fuel sending unit and pump has a little fabric rectangular filter at the end of it that catches any sand or debry that may inadvertnly get into your tank. I was surprised to see how clean it was. Also a person told me that deals with cars, its best to never let your tank go too low, as the fuel acts as a lubricant to the fuel sending Unit. My therory was your car gets better gas mileage as the tank emptys, because 20 gallons of fuel, give or take weighs a lot.

d-1

This post is a continuation of my "dropping the fuel tank" and changing out my fuel sending unit.

Up to this point the SUV never knocked. When I replaced the tank to its original state I added 2 gallons of gas and the car started after 2 cranks and there were no knocks.

I filled the entire tank up with gas, cranked the car and it was making a mild knocking noise. My mind was going, oh,oh, what the hell is that. I imagined my fuel pump going crazy and bursting into flames, OK back to reality.

But I am concerned about the fuel pump as I read in the book that poor fuel pressure in line could cause engine knocking.

Am I going nuts or what? Could this really be happening? Fix one problem and create another one?

Any suggestions?

d-1

 

[dolphans1]

Well that noise has returned. It sounds more like one of those toy lawn mowers a kid pushes when he pretends he's cutting the grass. It's like a rattling around when you press the accelerator down. When it first did it I thought it might have been something I did not tighten down with the fuel tank or the fuel pump itself, but that doesn't make any sense. The car drives smooth and does not get hot, nor missess, but it appears to only do it when the car is warmed up, than when it is cold. Could it be the catalytic converter? It seems to be coming from around that area, but I don't know.

I drove the SUV to work with the A/C on and it started to do it after I drove 20+ miles and I made a stop. On the way back from work I drove the car with A/C off and windows down and it didn't to it.

Any guess as to what it might be?

d-1

Well just like that the knock went away. I waited 24 hours before I started the car. Like someone just said, if it beats you up, walk away from it and come back when you're ready. Well I went out and started it and it ran perfect, no knocks. I am wondering if it was the gas I purchased or if when I washed the tank with water, some water may have gotten inside the tank or since I literally ran the tank dry of any gas (by mistake), it may have created some intermittent vapor lock in the fuel line. I thought I had at least 20 miles of gas (1 gallon) left based on the travel odometer.

If it starts again I will let you guys know, to those that are interested, of course. My big fear was I had a faulty fuel pump or some debry may have been sucked up the line. I did not want to drop the tank all over again. It's a pain in the you know what. It would be no big deal if you had a car lift and you could stand up underneath it.

Note: the old fuel sending unit and pump has a little fabric rectangular filter at the end of it that catches any sand or debry that may inadvertnly get into your tank. I was surprised to see how clean it was. Also a person told me that deals with cars, its best to never let your tank go too low, as the fuel acts as a lubricant to the fuel sending Unit. My therory was your car gets better gas mileage as the tank emptys, because 20 gallons of fuel, give or take weighs a lot.

d-1

 

[Creager]

Knocking like pinging from the engine? Some describe it as 'marbles in the engine'

Detonation is the best explaination i can give without hearing it.

if thats the case, not much you can do for it. 89 octane (still going to ping under really heavy load in 4th and 5th gear) or a chip can be programed stop it all togeather i believe?...

 

[dolphans1]

It sounds almost like metal clanging together but it doesn't do it all the time. It didn't start doing it till I changed out the fuel pump and sending unit because my fuel gage was not working. I can't imagine it would be related, it doesn't make any sense. I know what pinging is from bad fuel and I have searched the other posts for similar sounds and the scary part is not many of them found any solutions.

d-1

Knocking like pinging from the engine? Some describe it as 'marbles in the engine'

Detonation is the best explaination i can give without hearing it.

if thats the case, not much you can do for it. 89 octane (still going to ping under really heavy load in 4th and 5th gear) or a chip can be programed stop it all togeather i believe?...

 

[Creager]

maybe something isnt tightened down right? check all the straps and whatnot holding the tank and skid plate. Something just isnt fastened down

 

[dolphans1]

I drove the car today without the A/C running and it never did it. I wonder if it could be the A/C Compressor? I know everything underneath the fuel tank is tightend correctly, it's just that I jumped to that conclusion. This Explorer is a gem and in above average mechanical condition. (my opinion of course) But my point is it's not abused in any way shape or form.

I will try and isolate the problem and report back, but if anyone else had the same problem please let me know.

d-1

maybe something isnt tightened down right? check all the straps and whatnot holding the tank and skid plate. Something just isnt fastened down

 

[dolphans1]

Figured out what that noise was, anyone care to guess? It was my flywheel, it was cracked in the center and was out of round.....will write more specifically as to what actually happened later.

d-1

 

[Creager]

thats crazy, and hey its pretty close to the gas tank aswell.

 

[dolphans1]

The top center hub of flywheel was cracked severely and would cause a loud knocking noise, but it was intermittent. It became so off center that my starter would not enage the flywheel and I assumed the starter was the problem. Well I replaced the starter with a new one and it engaged but made clanking noise. Well the knock grew louder and I turned the SUV off and tried to start it and the starter would not engage the flywheel.

If the fly wheel is off center, imagine how unbalanced it would be, as it is turning those high RPMS.

The fuel tanks is not that close, but since I changed the fuel sending unit I assumed the pump was vapor locking and causing the knock.

I read online that Ford flywheels had a defective/problem with flywheels cracking where it attaches to the crankshaft adapter/spacer.

I saved it and should take a picture to show you guys. The teeth still looked great, but the flywheel was out of round, because of the large crack at the center where the bolts attach.

d-1

thats crazy, and hey its pretty close to the gas tank aswell.

 

[BrooklynBay]

I'm surprised that your cracked flywheel, and spacer didn't cause your front seal on the transmission to leak, or the front pump gears to break. Did you notice any leaks in that area from the rear main seal, or front pump seal?

 

[dolphans1]

The Explorer never had any leaks, but 2 months after changing the flywheel the transmission rear seal close to the drive shaft started to leak.

The flywheel knock was only intermittent and it confused me.


d-1

I'm surprised that your cracked flywheel, and spacer didn't cause your front seal on the transmission to leak, or the front pump gears to break. Did you notice any leaks in that area from the rear main seal, or front pump seal?

 

[rikguy]

I had to replace my flywheel about 5 months ago when it broke and left me stranded. Now, I've been having a clanking noise for the past 2 weeks and today my mechanic told me that it was the flywheel again. What would cause it to crack again so soon?!

 

[BrooklynBay]

They probably used the powdered iron OEM part. The Sonnax part is made out of billet steel, and is a little thicker. Check the link in my signature for more information about that part.

 

[BrooklynBay]

Here is the link just in case you had any problems finding it: http://www.transmissionspecialty.com/parts/parts/56000-CS6.htm

 

[BrooklynBay]

Here is a picture of it:

 

[dolphans1]

I agree with Brooklyn Bay, it was probably the OEM spacer that they either did not replace to begin with. Usually this part is what cracks and needs to be replaced as well. When my flywheel was cracked, I thought it was just the flywheel, but the spacer was also cracked and back to the parts store we had to go, its always something as the saying goes. I agree with you, it should not have cracked that soon, even if the part was an OEM part and it was 5 months old and not a used part. Let us know what you find out.......

d-1

They probably used the powdered iron OEM part. The Sonnax part is made out of billet steel, and is a little thicker. Check the link in my signature for more information about that part.

 

[rikguy]

The mechanic can't get to changing out the flywheel until Monday. How hard of a job is this to do yourself? I know that you'd have to drop down the tranny, do you have to remove it entirely?

 

[BrooklynBay]

You have to remove the transmission, part of the exhaust, the starter, the hydraulic lines, and the electrical connections. If you have 4X4, then the transfer case has to come out too.

 

[dolphans1]

It's a you know what (pain in the---) if you do it yourself. I'd take it back to the shop that worked on it before, it has to have at least a 1 year warranty. Call all the different tranny shops in your area. You'll be surprised how low some might charge you just to drop and and change it for you, if you supply the parts.

Let's us know that outcome.....

d-1