Diagnose This: Episode 1

[scirocco at vintagewatercooleds.com (Eric S)]

On this episode of Diagnose This we bring to you one sluggish VW Fox.

Patient details:

1990 VW Fox Wagon
1.6 liter, Heron Head 8v, 9.5:1 compression
Stock CIS-E
Stock Exhaust
Iginition timing at 8 degrees
Cam timing advanced 1 tooth, this rasied our compression to 160 psi a cyl!

Symptoms:

1. Slow to rev even just idling and bliping the throttle
2. Super slow, can barley maintain 80 mph, making maybe 60-70 hp on the
butt dyno
3. Runs excellent, idle smooth, a soft miss when under load, more of a
surging really
4. Plugs show proper mixture, O2 system not having to do any adjustments,
and confirmed its operating correctly (ground the O2 wire, it idles up,
then loads up and starts to falter, give it 12vs it dies, no change in
idle speed with O2 unhooked or hooked)
5. Car just feels like it can't breath, similar to how the previous 1.8
acted, but now much more pronounced with the 1.6

Possible causes (feel free to add on here and "vote" for your diagnosis):

1. Cam timing? I am already 1 tooth advanced, this got me to the proper
comression

2. Cat clogged? This could explain why I hated the 1.8 so much, and the
sluggishness to rev

3. Intake/Injection issues?  Fox intake is one of the best flowing from
what I have heard?  Its all the stock Fox CIS-E stuff, just with the
shrouds knocked off the injectors.   Cannot check DPR current (don't have
the harness).


-- 
Eric
www.vintagewatercooleds.com

1979 Dasher Coupe 2.0 8v
1981 Scirocco S (TDI swap project)
1990 Corrado TDI
1990 Fox Wagon 1.6 Heron Head 8v
1991 Cabriolet (2.0 crossflow 8v project)