help! son's 92 cherokee knocking

10ga · 02-19-2006, 09:18 PM

my son's 92 cherokee 4.0 has been running rough and now has a knocking sound in the top end of the engine. not the normal jeep tapping sound but more of a knocking. the oil has always been kept changed and full, i check it about evey week myself. it only has 139k on it and i know the 4.0 will normally last a long time. any ideas what it might be? and help would be appreciated.

97Xj_Sport · 02-19-2006, 09:23 PM

I don't have any idea right now what it could be but if you take it to autozone they'll read your jeep's codes for free and that will tell you if anything is wrong with it. I just did tonight and it turns out that I have a malfunction in the electrical circuit for the transmission range sensor. Don't mean to Hijack your thread but does anyone know if the problem in my transmission is that urgent to fix (it still runs strong right now) and if it is how much should it be to be fixed? Again sorry for Hijacking.

XJ4oh · 02-19-2006, 09:29 PM

How hard does he drive it..? If he nails it with those miles and all it could be something in the valve train... Lifters are more of a tap or a tick, but it could be a loose or worn rocker arm or something. Is it related to RPM's or is it just at idle? If its just at idle, it could be loose flexplate bolts. Best way to figure it out is to know if its RPM related or not. Could be a ton of things.. Lifters, rocker arms, valves, rod knock, flexplate bolts... And are you positive its coming from the top end?

Mine started ticking at around 130k miles, im now at 153k and it hasnt gotten any worse. Same with a slight knocking.

ChaoticBastard · 02-19-2006, 09:32 PM

Quote:

Originally Posted by 97Xj_Sport

I don't have any idea right now what it could be but if you take it to autozone they'll read your jeep's codes for free and that will tell you if anything is wrong with it. I just did tonight and it turns out that I have a malfunction in the electrical circuit for the transmission range sensor. Don't mean to Hijack your thread but does anyone know if the problem in my transmission is that urgent to fix (it still runs strong right now) and if it is how much should it be to be fixed? Again sorry for Hijacking.

They cant check the codes on a 92 its OBD1 you will have to take it to a garage that has an OBD Codereader.Knocking if it is constant when you rev it up and when its coming down its probably a rod.If it is a come and go tap it can be a collapsed lifter etc.Very hard to diagnose without hearing it myself

hmmhoyhoy · 02-19-2006, 09:38 PM

I have heard lifters making a knocking sound aswell as a whistle and a tick so it could very well be your lifters

97Xj_Sport · 02-19-2006, 09:42 PM

Quote:

Originally Posted by ChaoticBastard

They cant check the codes on a 92 its OBD1 you will have to take it to a garage that has an OBD Codereader.Knocking if it is constant when you rev it up and when its coming down its probably a rod.If it is a come and go tap it can be a collapsed lifter etc.Very hard to diagnose without hearing it myself

Yeah your right, I didn't take notice to the year.

97Xj_Sport · 02-19-2006, 09:44 PM

Quote:

Originally Posted by ChaoticBastard

They cant check the codes on a 92 its OBD1 you will have to take it to a garage that has an OBD Codereader.Knocking if it is constant when you rev it up and when its coming down its probably a rod.If it is a come and go tap it can be a collapsed lifter etc.Very hard to diagnose without hearing it myself

yeah your right, I didn't notice the year.

XJAce · 02-20-2006, 03:21 PM

Take the Jeep for a drive and let it get to normal operating temperature and get going to about 55 or so and let off the gas all the way, if you hear a knock then its probably a rod ready to let go. I had a 96' Explorer 4.0L V-6 with a 5-speed and 4-wheel drive that had this problem. I would go to shift and as soon as i dumped the clutch it would knock for a second and go away or if i kept the RPM's constant at about 2500 in about 2nd gear it would be a continuous knock. It started when the Explorer had about 182,000 on it and i used to shift every 4000rpm and redline was 6000. Used to blow donuts in the school parking lot and have it revved up to 5000 for a few minutes and it still was the same till the end for it came at about 190,000 miles and a snowwy day with crappy State plow drivers and a telephone pole later. Still runs good, just doesn't move......

Billabong1416 · 02-20-2006, 03:31 PM

Quote:

Originally Posted by 97Xj_Sport

I don't have any idea right now what it could be but if you take it to autozone they'll read your jeep's codes for free.

None of the autozones do this in my area, so call before you drive there. although they will let you rent the tool for a mere $200.

Sorry I'm no help to you, just didn't want anyone to drive to idiotzone only to waste their gas.

XJ4oh · 02-20-2006, 03:45 PM

Quote:

Originally Posted by XJAce

I had a 96' Explorer 4.0L V-6 with a 5-speed and 4-wheel drive that had this problem..

The pushrod 4.0 Fords tend to knock too, ive noticed. Not the SOHC ones though. We had a pushrod 4.0 in one of our older Explorers.. knocked from VERY low miles untill about 120k when my brother got it. He drives THE PISS out of that thing, downshifting every 2 seconds to at least 3500-4k, usually runs it up to 3k+ just for normal acceleration, so on.. But we have taken many a trips in it, and even after he started beating the crap of it, it hasnt gotten any worse. The oil pump also siezed up in it once, that didnt kill it either.

91xjgawes · 02-20-2006, 03:47 PM

mine has a main bearing noise when i crank it up, and every once in a while while idling i can hear the lifters ticking, and sometimes thery havea sorta knowking sound.. but it is the lifters, aftyer it get to normal temp, the higher the rpms, i get a noise, have no clue what it is, when i let off the gas nothing happens, sounds normal drives wonderful, has plenty of power, and has done this for 15,000 miles, i really have no worries, seems like its find, most folks say "its's a jeep thing"

LEAD_NOT_FOLLOW · 02-20-2006, 03:54 PM

We need a little more info to help. Saying "it knocks" dosn't really do much for trying to help.

Does it do it only when cold? Does it do it at idel or higher RPM's? When running go pop the hood and try to see if the sound is coming from the top end or the bottom end. What weight oil are you running? Why is it not idleing correctly?

10ga · 02-20-2006, 03:58 PM

this morning i took it down to the jeep doctor in jefferson city and had him to look at it. he tried to listen to it outside but couldn't hear exactly where it was coming from. he said to leave it and he would pull it inside and check it out, but said it didn't sound too good. he called me in a couple hours and said " it's fixed", the torque converter bolts were loose. man was i happy to hear that

he said when he first herd it, he thought it was bad. i was preparing my son for a rebuild, thank God that wasn't it. the guy we took it to had been servicing it since it came out of warranty and he said it should be good for another 100,000 miles if my son took good care of it. he said he only got about 1 out of every 200 with the converter bolts loose, but that was the 2nd one this week. i would have never guessed that was the problem, thanks for the help anyways.

drmiller31 · 02-20-2006, 05:08 PM

my 1990 xj is at 266,000 miles on original 4.0 and transmission. its been knocking as long as i can remember

still runs great, the only real engine work i have replaced is an alternater at 240,000 something miles and routine maintenance. great engines!

02-19-2006, 09:23 PM	#2
97Xj_Sport Registered User Join Date: Aug 2005 Location: Republic of Texas Posts: 296 Profile Gallery Classifieds My Jeeps	I don't have any idea right now what it could be but if you take it to autozone they'll read your jeep's codes for free and that will tell you if anything is wrong with it. I just did tonight and it turns out that I have a malfunction in the electrical circuit for the transmission range sensor. Don't mean to Hijack your thread but does anyone know if the problem in my transmission is that urgent to fix (it still runs strong right now) and if it is how much should it be to be fixed? Again sorry for Hijacking. __________________ 97 XJ 2 door sport- 3" Rusty's lift, 31" MTR's

02-20-2006, 03:47 PM	#11
91xjgawes Registered User Join Date: Jan 2006 Location: augusta, georgia Posts: 1,071 Profile Gallery Classifieds My Jeeps	mine has a main bearing noise when i crank it up, and every once in a while while idling i can hear the lifters ticking, and sometimes thery havea sorta knowking sound.. but it is the lifters, aftyer it get to normal temp, the higher the rpms, i get a noise, have no clue what it is, when i let off the gas nothing happens, sounds normal drives wonderful, has plenty of power, and has done this for 15,000 miles, i really have no worries, seems like its find, most folks say "its's a jeep thing" __________________ blue jeep club member 174 2001 xj- 2 inch bb moabs 1998 zj 5.2- 245/75's moabs

02-20-2006, 03:58 PM	#13
10ga Registered User Join Date: Jul 2005 Posts: 6 Profile Gallery Classifieds My Jeeps	it's fixed this morning i took it down to the jeep doctor in jefferson city and had him to look at it. he tried to listen to it outside but couldn't hear exactly where it was coming from. he said to leave it and he would pull it inside and check it out, but said it didn't sound too good. he called me in a couple hours and said " it's fixed", the torque converter bolts were loose. man was i happy to hear that he said when he first herd it, he thought it was bad. i was preparing my son for a rebuild, thank God that wasn't it. the guy we took it to had been servicing it since it came out of warranty and he said it should be good for another 100,000 miles if my son took good care of it. he said he only got about 1 out of every 200 with the converter bolts loose, but that was the 2nd one this week. i would have never guessed that was the problem, thanks for the help anyways.

02-20-2006, 03:21 PM	#8
XJAce Registered User Join Date: Jan 2006 Posts: 76 Profile Gallery Classifieds My Jeeps	Take the Jeep for a drive and let it get to normal operating temperature and get going to about 55 or so and let off the gas all the way, if you hear a knock then its probably a rod ready to let go. I had a 96' Explorer 4.0L V-6 with a 5-speed and 4-wheel drive that had this problem. I would go to shift and as soon as i dumped the clutch it would knock for a second and go away or if i kept the RPM's constant at about 2500 in about 2nd gear it would be a continuous knock. It started when the Explorer had about 182,000 on it and i used to shift every 4000rpm and redline was 6000. Used to blow donuts in the school parking lot and have it revved up to 5000 for a few minutes and it still was the same till the end for it came at about 190,000 miles and a snowwy day with crappy State plow drivers and a telephone pole later. Still runs good, just doesn't move......