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Subject:Poor fuel consumption 81 aircooled- aux air reg bad?
From:Adam Puzerewski
Date:Sun, 30 Dec 2001 15:24:36 -0500

Volks,
I am having a wierd problem.  As of late, the fuel consumption of my freshly rebuild engine is falling. i am getting 12.5 mpg..........

I know my valves are at zero lash.........

Here are the strange symptoms.  Crappy cold idle, sorta rough.  around 400-700 rpm, and turning the idle screw has no effect.  Once it warms up, it holds 1000 rpm or so no prob.  These latest things happenned after I adjusted the valves to zero a month or so ago.  Prior to that, no probs...........so, one would think well, adjust them back?   Well, I reply what is the reason?  They are at zero already and what could be the advantage to that.

Prior to this latest valve adj, I had the CO set to 2 % drove about 1800 miles over thanksgiving, the whole while averaging about 16.5 mpg.

So, I go to type2.com ;library and go thru the fuel injection troubleshooting.

Test pressure regulator, and it is in line.35 psi or so at idle, and when you give it throttle, drops to 30 or so.  In the ballpark for the crappy gauge i own.

Checked resistance at the temp sensor on cylinder 3 and it was in line after warming up at 67 ohms.  I replaced the thermo-time switch, and same result.   

Looked at the injectors for leaks, and not happenning................left the fuel pressure gauge on for an hour and it stayed steady.

Timing is set at 7.5 btdc at 1000 rpm..............spot on.............

I am thinking MUST be auxillary air regulator..................any thoughts?

Adam P

81 Vanagon westy ( The Brick)
70 SingleCab "Whitey"
74 Beetle "ol yeller"
73 Transporter (STILL at paint shop)

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