Quick, but scarry knock... - Ford Explorer Ranger Enthusiasts "Serious Explorations"®

Bmwz389 · 05-28-2007, 08:48 PM

Ok, so I finally got rid of my pinging about a week ago. Everything has been running great since then, aside from the notorious pushrod tick and squeaking front right side (still working on it). I was driving the other day to a friends gradutation when I was in the parking lot. I quickly hit the gas and removed my foot to move forward, and out of nowhere you hear a very loud knock that goes away as soon as you let go of the gas. It's instant, and inconsistent. It's happened twice and I'm not sure what's causing it.

I have a 92 XLT (4.0 V6) 2WD

Things I've changed recently:

Spark plugs
Spark wires
SeaFoam treatment (Gas)
SeaFoam treatment (Oil)
Seafoam treatment (Induction)
Cleaned IAC
Cleaned MAFS
Upper Intake manifold and valve cover gaskets

Could this be from the FPR? I've been meaning to check my fuel pressure, but I laid off because I think I solved my rough idle/sputter problem with the MAFS.

What could it be?

Thanks guys,

- Brandon

Bmwz389 · 05-29-2007, 04:46 PM

bump

*manaen* · 05-29-2007, 06:32 PM

what is your definition of very loud?

your FPR would not cause a nock that is that loud, and if it is going the injectors would be tapping all the time and you would have a rich condition. can you reproduce the sound? does it sound metallic in nature? If you tweaked the throttle in gear maybe one of your engine mounts is gone and the fan was rapping on the shroud from motor torque, look for signs of wear. Other than that it could be things like timing chain, lifter, or worse case bearings, but since the nock goes away it doesn't sound like bearing.

we would need a lot more info to figure anything out here...

**Turdle** · 05-29-2007, 06:46 PM

A knock which is loud under load, and goes away when coasting is usually a slapping piston, or a rod bearing

Bmwz389 · 05-29-2007, 08:39 PM

You know those movies where one character has a really beat up car and before it dies on them it knocks? That's the sound, only instant and it doesn't kill the motor. I hope it's nothing serious. Which is why I so stubbornly want it to be the FPR, because they are cheap to replace. I have a very laggy throttle response. I can pull my foot off the pedal, then it accelerates. I've been chasing it for a month, finally trying to solve it. I just tweaked my TPS and checked my throttle cable slack (there's none). I'm about to order my KKM, now that I have steady money because I just graduated high school. I have tinkering money =), I'm splitting it half and half between Clara (X) and the 87 Monte. I want to get rid of major problems before I add parts. I find it that it's more safe to do that lol.

It's loud enough to hear inside the passenger compartment with the driver's side window down. I'm just glad it's not consistent...

Hope that helps...

*manaen* · 05-30-2007, 10:30 AM

The more information you give, makes this problem sound worse. Start with a compression test on each cylinder. I think that will tell the whole story, sorry to say but it sounds like your in for a rebuild/replacement.

the good news is, with an OHV motor they can be found almost anywhere, and are excellent motors if well maintained. you should be able to find a good low mileage motor for under 1000 in a salvage yard.

Sorry dude, I just recently had to replace my motor as well so I know where you are right now. It's never fun. The good news is with the spare motor in hand and the right tools by your self it is only a 16 hour task. and if you have a good shop with great tools (and friends) it is only an 8 hour task. And when you are finished you will have a great truck again. It will just take a few weeks to recover from the bank account hemorrhage.

*manaen* · 05-30-2007, 10:36 AM

Quote:

Originally Posted by jtsmith

A knock which is loud under load, and goes away when coasting is usually a slapping piston, or a rod bearing

that's very interesting, I guess whenever I had a motor go in the past it was all out becuase all my bearing problems were a constant rap they got louder with revs but were always there. All I know is that I don't want to hear that sound for another 150K miles at least

or I'll be forced to -

Bmwz389 · 05-30-2007, 01:14 PM

Yeah, that's all I need is putting another 1000 into Clara again. I barely know in depth mechanics, only basics and a little deeper (Thanks to this site

). Isn't there a good diary I saw somewhere on the forum and compression testing? And I know I'd have to get a tester from an auto parts store right?

Bmwz389 · 05-30-2007, 01:27 PM

So do you suggest I not get my intake then? If I'm going to have to replace a motor, I'm not going to waste money on an intake that will get a dead motor nowhere.

Besides the fatal option, what else could it be, if anything?

Thanks again guys!

- Brandon

98blk5.0 · 05-30-2007, 01:32 PM

id compression test it before you spend money that may be needed on you new motor

Bmwz389 · 05-30-2007, 08:12 PM

Ok so I found out I can rent a Compression Tester for $50 and get my deposit back after I return the tester.

So....Now I need to know HOW to do a compression test....I've never done one and I don't wanna go blindly into it.

So, can anyone tell me how...or point me to a link that shows me how to do it?

Thanks again for all your help so far!

-Brandon

**Turdle** · 05-30-2007, 08:15 PM

Quote:

Originally Posted by Bmwz389

Ok so I found out I can rent a Compression Tester for $50 and get my deposit back after I return the tester.

So....Now I need to know HOW to do a compression test....I've never done one and I don't wanna go blindly into it.

So, can anyone tell me how...or point me to a link that shows me how to do it?

Thanks again for all your help so far!

-Brandon

It will screw into a spark plug hole-you then crank engine a few revs and check reading on the gauge

First, warm engine. Then remove all spark plugs. Check each cylinder in order, and write down the reading. A cold engine may give false low compression readings.

Bmwz389 · 05-30-2007, 08:22 PM

This wont hurt the engine? I'm assuming I just crank it over with all the spark plugs removed? How long do I crank the engine? Sorry if I'm being difficult, but I wanna do this right the first time =)

**Turdle** · 05-30-2007, 08:25 PM

you will see the gauge jump as the cylinder compresses--

3-4 good jumps should do it--

this will not hurt a thing. I would remove the fuel pump relay first though--

Bmwz389 · 05-30-2007, 08:30 PM

So that way I'm not feeding my fuel rails, wasting gas and flooding the engine? That would make sense. So will it hold the final reading that I'll want after it jumps?

Bmwz389 · 05-30-2007, 08:35 PM

I just did a quick Google search and I found a link here

http://www.aa1car.com/library/compression.htm

Does this sound right?

It doesn't mention the Fuel pump relay, but it does mention disabling the Coil pack, which I have no idea how to do.

**Turdle** · 05-30-2007, 08:40 PM

Quote:

Originally Posted by Bmwz389

I just did a quick Google search and I found a link here

http://www.aa1car.com/library/compression.htm

Does this sound right?

It doesn't mention the Fuel pump relay, but it does mention disabling the Coil pack, which I have no idea how to do.

just unplug it.
And yes the gauge will hold the reading. There should be a pressure release knob to release it.

Bmwz389 · 05-30-2007, 08:46 PM

Quote:

Originally Posted by jtsmith

just unplug it.
And yes the gauge will hold the reading. There should be a pressure release knob to release it.

Ah, now I REALLY look like an idiot hehe.

So how long would this roughly take?

**Turdle** · 05-30-2007, 08:57 PM

probably 1 hour.
Grab a six pack and invite a friend over to help. It is handy to have a tool grabber and key turner--

Bmwz389 · 05-30-2007, 09:04 PM

haha yeah so I hear. If I can't pull a friend into it I have a flew tool graber and I could always manually start it by crossing two positive wires from the starter =)

I have a good 17 or so beers left downstairs from graduation night. Might bust those out.

So all sounds good?

Still kinda scared, but it's something I need to do to chase the problem. Hopefully everything will turn out fine!

Thanks again guys!

- Brandon

05-28-2007, 08:48 PM	#1
Bmwz389 Wannabe Elite Explorer Iowa 1992 XLT Join Date: Mar 2005 Posts: 281 Vehicle Specs	Quick, but scarry knock... Ok, so I finally got rid of my pinging about a week ago. Everything has been running great since then, aside from the notorious pushrod tick and squeaking front right side (still working on it). I was driving the other day to a friends gradutation when I was in the parking lot. I quickly hit the gas and removed my foot to move forward, and out of nowhere you hear a very loud knock that goes away as soon as you let go of the gas. It's instant, and inconsistent. It's happened twice and I'm not sure what's causing it. I have a 92 XLT (4.0 V6) 2WD Things I've changed recently: Spark plugs Spark wires SeaFoam treatment (Gas) SeaFoam treatment (Oil) Seafoam treatment (Induction) Cleaned IAC Cleaned MAFS Upper Intake manifold and valve cover gaskets Could this be from the FPR? I've been meaning to check my fuel pressure, but I laid off because I think I solved my rough idle/sputter problem with the MAFS. What could it be? Thanks guys, - Brandon __________________ 1992 Explorer XLT with a sweet front end, and a badass sound system...

05-29-2007, 04:46 PM	#2
Bmwz389 Wannabe Elite Explorer Iowa 1992 XLT Join Date: Mar 2005 Posts: 281 Vehicle Specs	bump __________________ 1992 Explorer XLT with a sweet front end, and a badass sound system...

05-29-2007, 06:46 PM	#4
Turdle Topless in winter Humboldt, KS 1998 Mountaineer MX4 O/R Join Date: Jun 2003 Posts: 17,417 Vehicle Specs	A knock which is loud under load, and goes away when coasting is usually a slapping piston, or a rod bearing __________________ "I set my standards low, so I am not easily disappointed" 98 MX4 OFF ROADFOR SALE 93 with sky light Explorerforum license frames here

05-29-2007, 08:39 PM	#5
Bmwz389 Wannabe Elite Explorer Iowa 1992 XLT Join Date: Mar 2005 Posts: 281 Vehicle Specs	You know those movies where one character has a really beat up car and before it dies on them it knocks? That's the sound, only instant and it doesn't kill the motor. I hope it's nothing serious. Which is why I so stubbornly want it to be the FPR, because they are cheap to replace. I have a very laggy throttle response. I can pull my foot off the pedal, then it accelerates. I've been chasing it for a month, finally trying to solve it. I just tweaked my TPS and checked my throttle cable slack (there's none). I'm about to order my KKM, now that I have steady money because I just graduated high school. I have tinkering money =), I'm splitting it half and half between Clara (X) and the 87 Monte. I want to get rid of major problems before I add parts. I find it that it's more safe to do that lol. It's loud enough to hear inside the passenger compartment with the driver's side window down. I'm just glad it's not consistent... Hope that helps... __________________ 1992 Explorer XLT with a sweet front end, and a badass sound system...

05-30-2007, 01:14 PM	#8
Bmwz389 Wannabe Elite Explorer Iowa 1992 XLT Join Date: Mar 2005 Posts: 281 Vehicle Specs	Yeah, that's all I need is putting another 1000 into Clara again. I barely know in depth mechanics, only basics and a little deeper (Thanks to this site ). Isn't there a good diary I saw somewhere on the forum and compression testing? And I know I'd have to get a tester from an auto parts store right? __________________ 1992 Explorer XLT with a sweet front end, and a badass sound system...

05-29-2007, 06:32 PM	#3
manaen Elite Bow Hunter Clear Spring, MD 2001 Mountaineer Join Date: Feb 2007 Posts: 2,546 Vehicle Specs	what is your definition of very loud? your FPR would not cause a nock that is that loud, and if it is going the injectors would be tapping all the time and you would have a rich condition. can you reproduce the sound? does it sound metallic in nature? If you tweaked the throttle in gear maybe one of your engine mounts is gone and the fan was rapping on the shroud from motor torque, look for signs of wear. Other than that it could be things like timing chain, lifter, or worse case bearings, but since the nock goes away it doesn't sound like bearing. we would need a lot more info to figure anything out here...

05-30-2007, 10:30 AM	#6
manaen Elite Bow Hunter Clear Spring, MD 2001 Mountaineer Join Date: Feb 2007 Posts: 2,546 Vehicle Specs	The more information you give, makes this problem sound worse. Start with a compression test on each cylinder. I think that will tell the whole story, sorry to say but it sounds like your in for a rebuild/replacement. the good news is, with an OHV motor they can be found almost anywhere, and are excellent motors if well maintained. you should be able to find a good low mileage motor for under 1000 in a salvage yard. Sorry dude, I just recently had to replace my motor as well so I know where you are right now. It's never fun. The good news is with the spare motor in hand and the right tools by your self it is only a 16 hour task. and if you have a good shop with great tools (and friends) it is only an 8 hour task. And when you are finished you will have a great truck again. It will just take a few weeks to recover from the bank account hemorrhage.

05-30-2007, 01:27 PM	#9
Bmwz389 Wannabe Elite Explorer Iowa 1992 XLT Join Date: Mar 2005 Posts: 281 Vehicle Specs	So do you suggest I not get my intake then? If I'm going to have to replace a motor, I'm not going to waste money on an intake that will get a dead motor nowhere. Besides the fatal option, what else could it be, if anything? Thanks again guys! - Brandon __________________ 1992 Explorer XLT with a sweet front end, and a badass sound system...

05-30-2007, 01:32 PM	#10
98blk5.0 Wannabe Elite Explorer AZ Join Date: Apr 2007 Posts: 80 Vehicle Specs	id compression test it before you spend money that may be needed on you new motor

05-30-2007, 08:12 PM	#11
Bmwz389 Wannabe Elite Explorer Iowa 1992 XLT Join Date: Mar 2005 Posts: 281 Vehicle Specs	Ok so I found out I can rent a Compression Tester for $50 and get my deposit back after I return the tester. So....Now I need to know HOW to do a compression test....I've never done one and I don't wanna go blindly into it. So, can anyone tell me how...or point me to a link that shows me how to do it? Thanks again for all your help so far! -Brandon __________________ 1992 Explorer XLT with a sweet front end, and a badass sound system...

05-30-2007, 08:22 PM	#13
Bmwz389 Wannabe Elite Explorer Iowa 1992 XLT Join Date: Mar 2005 Posts: 281 Vehicle Specs	This wont hurt the engine? I'm assuming I just crank it over with all the spark plugs removed? How long do I crank the engine? Sorry if I'm being difficult, but I wanna do this right the first time =) __________________ 1992 Explorer XLT with a sweet front end, and a badass sound system...

05-30-2007, 08:25 PM	#14
Turdle Topless in winter Humboldt, KS 1998 Mountaineer MX4 O/R Join Date: Jun 2003 Posts: 17,417 Vehicle Specs	you will see the gauge jump as the cylinder compresses-- 3-4 good jumps should do it-- this will not hurt a thing. I would remove the fuel pump relay first though-- __________________ "I set my standards low, so I am not easily disappointed" 98 MX4 OFF ROADFOR SALE 93 with sky light Explorerforum license frames here

05-30-2007, 08:30 PM	#15
Bmwz389 Wannabe Elite Explorer Iowa 1992 XLT Join Date: Mar 2005 Posts: 281 Vehicle Specs	So that way I'm not feeding my fuel rails, wasting gas and flooding the engine? That would make sense. So will it hold the final reading that I'll want after it jumps? __________________ 1992 Explorer XLT with a sweet front end, and a badass sound system...

05-30-2007, 08:35 PM	#16
Bmwz389 Wannabe Elite Explorer Iowa 1992 XLT Join Date: Mar 2005 Posts: 281 Vehicle Specs	I just did a quick Google search and I found a link here http://www.aa1car.com/library/compression.htm Does this sound right? It doesn't mention the Fuel pump relay, but it does mention disabling the Coil pack, which I have no idea how to do. __________________ 1992 Explorer XLT with a sweet front end, and a badass sound system...

05-30-2007, 08:57 PM	#19
Turdle Topless in winter Humboldt, KS 1998 Mountaineer MX4 O/R Join Date: Jun 2003 Posts: 17,417 Vehicle Specs	probably 1 hour. Grab a six pack and invite a friend over to help. It is handy to have a tool grabber and key turner-- __________________ "I set my standards low, so I am not easily disappointed" 98 MX4 OFF ROADFOR SALE 93 with sky light Explorerforum license frames here

05-30-2007, 09:04 PM	#20
Bmwz389 Wannabe Elite Explorer Iowa 1992 XLT Join Date: Mar 2005 Posts: 281 Vehicle Specs	haha yeah so I hear. If I can't pull a friend into it I have a flew tool graber and I could always manually start it by crossing two positive wires from the starter =) I have a good 17 or so beers left downstairs from graduation night. Might bust those out. So all sounds good? Still kinda scared, but it's something I need to do to chase the problem. Hopefully everything will turn out fine! Thanks again guys! - Brandon __________________ 1992 Explorer XLT with a sweet front end, and a badass sound system...