10-13-2012, 01:59 PM
Officially Welcomed to the 'Fest
Location: Middle of a corn field
Join Date: May 2007
Mein Auto: E39 hamster w/ pin-wheel
Originally Posted by Max_VQ
Get an OBD2 scan tool or DIS and look at your fuel trims.
Don't guess and throw parts and money at the problem.
Originally Posted by doru
But I had good gas mileage with the old CCV & new CCV.
Then it started to slip away.
The mpg readings are consistent with the lower range I get.
I'm at 450 Km (280 miles) between fill-ups now....
No smoking, no white vapors nothing.
Tailpipe is clean as it gets, but looks like somehow I burn more fuel?
This summer, after I cleaned the TB & ICV, changed the spark plugs & vacuum hoses, the mpg improved suddenly.
Lasted only about a week, then it slipped abruptly (from the "normal" 10.8 - 11.2 l/100km to 13.2 l/100 Km).
I am stumped.
Yes, I have done similar to what you have done...
Replaced the CCV, cleaned the ICV, and throttle body, replace the rubber Intake Elbow, and various vacuum hoses...
Yet, the new CCV seemed to deteriorate faster than normal...
Very weird IMO, to say the least... LOL!
Lately, I have noticed more fuel fumes at start-up...
I am thinking/ GUESSING it has to do with:
1. The Secondary Air Pump,
2. Air Pump Valve that feed into the Secondary Air Pump, and
3. The Disa Valve, specifically with the deteriorated rubber frame-work around the Flapper Assembly...
I suspect a LOT of Carbon Build-Up in these areas causing the majority of the problems...
Best of LUCK...!
Let me know if I can help...!
Last edited by Jason5driver; 10-13-2012 at 02:02 PM.