Cadillac Owners Forum banner

1 - 8 of 8 Posts

·
Registered
2004 Deville
Joined
·
7 Posts
Discussion Starter #1
hello all

I have an 04 deville with 100k on it very clean and taken care of.
It has a knock at idle, ruled out pulleys and water pump. Almost sounds like spark knock. I dont know how to check, unplugged EGR no change in idle or sound. Any ideas

AL
 

·
Super Moderator
2010 DTS
Joined
·
87,415 Posts
Didn't I answer this once? :hmm: Coming from the drivers side? Listen close and see if it might be coming from the AIR pump check valve on the rear cam cover.
 

·
Registered
2004 Deville
Joined
·
7 Posts
Discussion Starter #5
it may be coming from there I unplugged it while running no change in anything what does it do?

Did the same to egr no change in anything are they just extra crap to break??

also noticed today as the knocking goes if I hold the hose from intake to master cylinder I can feel it pulsing in it with the sound????
 

·
Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
Joined
·
70,672 Posts
This is beginning to sound like a single cylinder miss or valve train problem.

Use the sticky post ^^^ "How to pull codes" to enter and display any Diagnostic Trouble Codes stored in the car's built in code reader/scanner. Write any codes down, noting whether each is Current or History. Return to the sticky and use the "obd2" instructioins to open a master Index box of code definitions - all codes are in the P, B, C, and U links. Write down all definitions and come back and post it all here.

You NEED either a real GM/Helm service manual (eBay or www.helminc.com) or a subscription to www.alldatadiy.com.

Descriptions such as "extra crap" and "big thing with the hose" don't really pinpoint the location or equipment.
 

·
Super Moderator
2010 DTS
Joined
·
87,415 Posts
it may be coming from there I unplugged it while running no change in anything what does it do?
It's a check valve to prevent exhaust gases from flowing into the AIR pump when it is not running. It only runs for 40 seconds or so after a cold start.

Sub, what I was thinking is that possibly that check valve failed and was fluttering. Does that sound like a possibility to you? Just kind of a shot in the dark as I have never heard of that and don't even know if it is possible.
 

·
Registered
2004 Deville
Joined
·
7 Posts
Discussion Starter #8
It does run rough on cold starts for about a minute then it calms down and runs smooth. I will keep looking into it.
As to sumariner409s comment, Einstien would call this the big thing on the back valve cover with the hose coming out LOL I dont know how else to describe it. I have been working on engines since I was 10 (35 years ago). It only got hard when they started putting a bunch of extra "crap" that doesnt do anything besides make you car run bad on them. I believe that was 1972 Before that engines were fun to play with. This is my first Cadi had lincolns and foreign before so just trying to figure these out. I have pulled codes awhile ago didnt find anything relative to the problem. Stupid stuff like cabin air cleaner. Will look again Thanks guys
 
1 - 8 of 8 Posts
Top