Author Topic: Idle doesnt change when the oil dipstick or cap is removed what does this point to? (Read 3012 times)

JoeDellio · « **on:** August 27, 2009, 11:42:28 PM »

Trying to diagnose some codes. I found that when I removed my dipstick nothing at all changes, I can just hear oil gurgling a little.

When I pull the oil filler cap the idle doesnt really change at all, actually gets a little better for a short period of time. I was thinking I had a vacuum leak somewhere, but after replacing all intake gaskets and vacuum hoses, and hose inspections I am not sure. CCV is new.

nicknikolovski · « **Reply #1 on:** August 28, 2009, 08:17:50 AM »

What are the fault codes and what is the problem?

Why do you believe that the idle should change when removing the dipstick or the oil cap?

JoeDellio · « **Reply #2 on:** August 28, 2009, 12:25:05 PM »

Because the M42 is a sealed pressure system I do believe. Taking off the cap or dipstick should be like introducing a huge vacuum leak.

I just dont understand what it means if it doesnt. My codes are 1215,1222,1223,1224,and 1226.

enildeR · « **Reply #3 on:** August 28, 2009, 03:12:00 PM »

heh posted in your other thread, and just saw this one.

FWIW, I never noticed an idle speed change whenever I popped my oil fill cap.

3bvert · « **Reply #4 on:** August 28, 2009, 03:20:44 PM »

cant help with codes, mine changes idle too
I would guess you have a vacum leak someplace
do you still have all the throttle body heater crap. most likely leak
get rid of and bypass
use the search to see how

JoeDellio · « **Reply #5 on:** August 29, 2009, 10:47:36 AM »

checked engine with vacuum gauge, no leaks. TB heater has long been bypassed, my problem was my ProFormance chip. My car showed a vacuum leak when I pulled off the cap, it just seemed like it was blowing out.

roundel318 · « **Reply #6 on:** August 30, 2009, 08:43:28 AM »

sounds like a monster vac leak, as others have said, sorry I can't tell you where.