weird rattling noise after start up - JeepForum.com
 
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post #1 of 8 Old 12-20-2008, 07:22 PM Thread Starter
blacky_j
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weird rattling noise after start up

hey guys, i'm getting this weird rattling noise whenever i first turn on the jeep. (not sure if it does it when its warmed up).

all i know is i start her up, and she starts making this weird rattling noises (like someone's taking a can filled with metal shards and shaking it), it goes away after i drive for like half a minute or so.

i happened after i changed my TPS, after like the second start later in the day.

i'm worried that maybe some of the grommit stuff fell inside when i was taking it off? but i'm pretty sure nothing fell inside from what i remember.

things that i've done recently to it:

cleaned the throttle body with deep creep/tooth brush, replaced IAC, TPS, and the rear PCV hose grommit, elbow, and tube that goes by the throttle body.

any suggestions?

also my oil pressure stays at 40 most of the time? could it be a bad Oil pressure sending unit, i did some reasearch on that and i heard that sometimes even getting a new one you can still get some bad readings, so i'm going to get one from the dealer.


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post #2 of 8 Old 12-21-2008, 06:02 AM
tjwalker
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Have a buddy start the vehicle while you use a mechanics stethoscope to help you to "isolate" where this noise might be coming from. The stethoscope is invaluable in this process. There are lots of things to suspect under the hood.

Does your oil pressure come up "immediately" upon startup? It's possible that you have a cranky lifter that takes a while to quiet down when started.

As for your consistent oil pressure reading of 40, I'd suspect the oil pressure sending unit. An extremely common failure on the Jeep 4.0 I've had best luck with factory senders there....

99 Cherokee, 4.0 AW4, NP242
Past Jeeps: 49 Willys, 81 Scrambler, 88 Comanche
Without "data", all you have is an opinion!
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post #3 of 8 Old 12-21-2008, 06:30 AM
mtl4life
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Common rattling noise on an XJ is the catalytic converter. The "honeycomb" can break up or break away from the housing and rattle like no tomorrow. In some cases the rattle will stop when the engine warms up because it will expand and tighten up a little. Check the converter.

- 1995 Cherokee SE 4X4
- 2004 Grand Cherokee Laredo 4X4
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post #4 of 8 Old 01-01-2009, 05:45 PM Thread Starter
blacky_j
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Quote:
Originally Posted by mtl4life View Post
Common rattling noise on an XJ is the catalytic converter. The "honeycomb" can break up or break away from the housing and rattle like no tomorrow. In some cases the rattle will stop when the engine warms up because it will expand and tighten up a little. Check the converter.
i don't think it is, because i bought a new one not too long ago, i got a mangnaflow high flow cat.

the rattling happens for like 5 seconds then goes away. but only on cold start up. (from what i hear)

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post #5 of 8 Old 01-01-2009, 06:16 PM
xjfever
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Sounds like a lifter to me also. Mine do it sometimes, esp. when the heep hasn't been drove in a couple of days.

  1. '95 XJ country edition, 4" coils/3/4" spacers, HD leafs with extra main added in, Ironman adjustable control arms, rough country shackles, aussie locker, JK rubicon shocks, 35" mudder's, soft 8's, cobra cb
  2. Sold'99 WJ limited, 4.7L, 3" IRO lift. Bilstein shocks, JK rubicon wheels, 255/70/17's, carolina driveshaft, IRO adjustable control arms, IRO adjustable A-arm
  3. Sold '00 TJ, 4" lift, rusty's adjustable control arms, skyjacker shocks, rock krawler adj. trac-bar,rugged ridge SYE and RE driveshaft, soft 8's, 35" mud king xt's,XJ HP D30 w/aussie locker, 4:88 yukon gears, hella 500's, rock crusher diff covers
4. 04 Dodge ram 1500 quadcab, yes, it has a hemi.
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post #6 of 8 Old 01-01-2009, 08:31 PM Thread Starter
blacky_j
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whats a lifter?

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post #7 of 8 Old 01-02-2009, 09:24 AM
440_Magnum
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Quote:
Originally Posted by blacky_j View Post
whats a lifter?
http://en.wikipedia.org/wiki/Hydraulic_lifters
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post #8 of 8 Old 01-02-2009, 10:12 AM
mk34
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Mine does the same thing. Though my rattling sounds like its coming from somewhere in the dash. And then it goes away after 5-10 minutes.
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