Go Back   Jeep Garage - Jeep Forum > Jeep Technical Discussion > Troubleshooting/Problems Discussion

Join Jeep Garage Today
Reply
 
Thread Tools Display Modes
 
  #1  
Old 11-29-2010, 01:13 PM
06overland's Avatar
Member
My Jeep: 2006 5.7L WK
 
Join Date: Jun 2010
Location: Central New Jersey
Posts: 66
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 1678
06overland is on a distinguished road
High rev at start

Hey all,
I have a concern about how my jeep starts. As my name implies I have an 06 Overland with a 5.7 Hemi. When the truck starts, sometimes it revs up really high, over 2000rpm. What concerns me is the aweful noise it makes when it does this. I assume this is because there is no oil flow at this point. I use Mobile 1 5W20 with Mopar filters. Oil level is correct and change oil every 3k.

A few things I have tried are:

1) Starting with brake depressed, or released (maybe vacuum issue) = problem still exists

2) Turning key on but not starting right away (wait a few seconds for fuel pump to prime) = problem still exists

3) Crossing my fingers (hoping for good luck) = problem still exists.


I believe the truck revs high at start whether the motor is hot or cold, but I have only noticed the awefull noise when it is cold. I will take note of it and report back.

Has anyone else experienced the high rev, or awefull noise as startup (sounds like a whining rev).

I am a big believer in letting a car warm up before driving and this noise makes me nervouse. Any advice/suggestions would be greatly appreciated.

thanks!
__________________

__________________
Reply With Quote
  #2  
Old 11-29-2010, 01:16 PM
Chaoul1's Avatar
The Original

My Jeep: 2010 6.1L WK
 
Join Date: May 2009
Location: Fairfax, Virginia
Posts: 6,913
Thanks: 2
Thanked 25 Times in 25 Posts
Rep Power: 63437
Chaoul1 has a reputation beyond reputeChaoul1 has a reputation beyond reputeChaoul1 has a reputation beyond reputeChaoul1 has a reputation beyond reputeChaoul1 has a reputation beyond reputeChaoul1 has a reputation beyond reputeChaoul1 has a reputation beyond reputeChaoul1 has a reputation beyond reputeChaoul1 has a reputation beyond reputeChaoul1 has a reputation beyond reputeChaoul1 has a reputation beyond repute
Re: High rev at start

Does it hold its rev? How long does it rev for over 2k RPM?
__________________

__________________
-Paul-
2010 Jeep Grand Cherokee SRT8

PaulsProfessional Automotive Detailing

PPAD's Custom Headlights

Contact for both DetailingPPADscustomwork@yahoo.com
Reply With Quote
  #3  
Old 11-29-2010, 01:55 PM
06overland's Avatar
Member
My Jeep: 2006 5.7L WK
 
Join Date: Jun 2010
Location: Central New Jersey
Posts: 66
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 1678
06overland is on a distinguished road
Re: High rev at start

It takes about 1 second of cranking to start and seems like it cranks about 6 times. Usually it revs to about 1500 when it starts, but like I said before, sometimes it above 2k. The car quickly drops the idle down to around 800rpm.

I can hear the fuel pump turn on for a few seconds when I turn the key on before I start it. Is there an accumulator or pressure regulator that helps the car start? Too much fuel pressure?

I would say 50% of the starts rev high, and 10% of the starts make the awefull noise. And I have only heard the awefull noise if the car has sat for many hours and it cold. The high rev seams to be random and not affected by the temperature of the motor.

thanks!
__________________
Reply With Quote
  #4  
Old 11-29-2010, 03:44 PM
suzieque's Avatar
Senior Member
My Jeep: 2008 3.0L WK
 
Join Date: Jul 2009
Location: Canada
Posts: 1,224
Thanks: 0
Thanked 9 Times in 9 Posts
Rep Power: 3182
suzieque is a name known to all
Re: High rev at start

when you shut down and then start up later, do you turn off the interior fan including the defrost and air conditioning?
__________________
2008 WK "S" Limited bright metallic silver, 5 speed W5J400 transmission, June 18/2008 build, 213RE rear differential with 3.73 axle ratio, 245/60R18 Goodyear Fortera tires, NV245 transfer case, 3.0L CRD.
Reply With Quote
  #5  
Old 11-29-2010, 04:08 PM
06overland's Avatar
Member
My Jeep: 2006 5.7L WK
 
Join Date: Jun 2010
Location: Central New Jersey
Posts: 66
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 1678
06overland is on a distinguished road
Re: High rev at start

I do not always turn off the ac fan or defroster. I am assuming you ask because of the ac compressor adding a strain to the motor? I thought about this but do not see why it would make the motor rev so high at startup. I wouldn"t be surprised if the compressor clutch doesnt even activate for a few seconds after the car starts being computer controlled and all. The defroster, heated seats, and other large power draws all reset when the car is shut down so they are not on. I leave the key on for a few seconds before starting not only to let the fuel pump prime, but also to let the easy entry seat function move the seat forward.
I cannot think of any other large power drawings or strains on the motor due to accessories, and do not see why they would make it rev like this either.

Its almost like the starter is too powerful and whips the crank too fast but I highly doubt that is the case.

Does anyone know if this car has any features that specifically help it start? Perhaps a cold start injector or something like that?
Has anyone else experienced this high rev and dry/whining sound?

thanks for all of you suggestions so far!
__________________
Reply With Quote
  #6  
Old 12-06-2010, 02:26 PM
New Member
 
Join Date: Dec 2010
Posts: 1
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
jtleichtenberg is on a distinguished road
Re: High rev at start

Hello I am having the same problem with my 06' Jeep Grand Cherokee Limited with the 5.7 hemi. I started it yesterday and it revved way up and had the whine to it. I live in South Dakota, so when it's cold and the temp. outside is around 10 degrees or colder probably isn't the best on the motor to rev up right away. Just wondering as well if anyone knows of a solution.
__________________
Reply With Quote
  #7  
Old 12-07-2010, 11:31 AM
06overland's Avatar
Member
My Jeep: 2006 5.7L WK
 
Join Date: Jun 2010
Location: Central New Jersey
Posts: 66
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 1678
06overland is on a distinguished road
Re: High rev at start

My concern is that there is no oil flow yet and the valvetrain is probably not lubricated well.
Jtleichtenberg, does your motor only rev high when its cold out?
__________________
Reply With Quote
  #8  
Old 12-16-2010, 09:07 AM
06overland's Avatar
Member
My Jeep: 2006 5.7L WK
 
Join Date: Jun 2010
Location: Central New Jersey
Posts: 66
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 1678
06overland is on a distinguished road
Re: High rev at start

So this noise at start sounds like the engine is crying for its life!! Has anyone ever experienced this or know of a way to diagnose what it may be?
It's aweful...please help!
__________________
Reply With Quote
  #9  
Old 12-29-2010, 02:04 AM
Member
My Jeep: 2005 5.7L WK
 
Join Date: Dec 2010
Posts: 37
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 1466
252crew is on a distinguished road
Re: High rev at start

I have the same problem. I have a new to me, 2005 hemi wk with 80k. have had for only 3 months but had never had this problem till it got very cold. Then each morning i start the jeep up i get this strong sucking/ whistling noise very intense. kinda worries me. From my experience its only happing in cold weather under 35
__________________
Reply With Quote
  #10  
Old 12-29-2010, 02:04 AM
Member
My Jeep: 2005 5.7L WK
 
Join Date: Dec 2010
Posts: 37
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 1466
252crew is on a distinguished road
Re: High rev at start

Would love more info
__________________
Reply With Quote
  #11  
Old 12-29-2010, 09:42 AM
06overland's Avatar
Member
My Jeep: 2006 5.7L WK
 
Join Date: Jun 2010
Location: Central New Jersey
Posts: 66
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 1678
06overland is on a distinguished road
Re: High rev at start

I changed my oil last week and noticed that I used a Fram oil filter the last time I changed it because the mopar wasn't available. Since last week (mopar filter now) it hasn't done the high rev at all. It could be a coincidence but it has been very cold so it should have done it.

Is it possible that the filter doesn't let the oil pass to the valvetrain during the first few turns of the crank and the valves are dry when the engine finally fires up?

What oil filters do you guys use? The sound it makes sounds to me like dry valves...does anyone have any input on the oil system and how it reacts at startup?
__________________
Reply With Quote
  #12  
Old 12-29-2010, 12:34 PM
Chaoul1's Avatar
The Original

My Jeep: 2010 6.1L WK
 
Join Date: May 2009
Location: Fairfax, Virginia
Posts: 6,913
Thanks: 2
Thanked 25 Times in 25 Posts
Rep Power: 63437
Chaoul1 has a reputation beyond reputeChaoul1 has a reputation beyond reputeChaoul1 has a reputation beyond reputeChaoul1 has a reputation beyond reputeChaoul1 has a reputation beyond reputeChaoul1 has a reputation beyond reputeChaoul1 has a reputation beyond reputeChaoul1 has a reputation beyond reputeChaoul1 has a reputation beyond reputeChaoul1 has a reputation beyond reputeChaoul1 has a reputation beyond repute
Re: High rev at start

I use a Mobile 1 Oil Filter. I would also recommend a K&N Gold Oil Filter.
__________________

__________________
-Paul-
2010 Jeep Grand Cherokee SRT8

PaulsProfessional Automotive Detailing

PPAD's Custom Headlights

Contact for both DetailingPPADscustomwork@yahoo.com
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
My 2007 vortech jeep srt8 first start and a little rev. Vinnysrt8 Engine Performance/Superchargers/Turbos 20 04-10-2011 02:28 AM
How do I rev my engine from the engine bay? CherokeeOnToyos Engine Performance/Intake/Exhaust 6 10-02-2010 07:56 AM
Gibson exhaust start-up, idle, slight rev for anyone interested nick.jeff Grand Cherokee - WK 19 09-09-2010 10:17 PM
mario and chris jeep srt8 rev Vinnysrt8 Members Rides 5 10-23-2009 04:24 AM
Startup and Rev Video Robert Palmer Members Rides 30 08-04-2009 04:29 PM

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 09:00 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Copyright 2012 - JeepGarage.Org
The Jeep Grand Cherokee Owners Community

JeepGarage.org is in no way associated with or endorsed by Chrysler Group LLC.