Knock box wiring testing help

[treed2@u.washington.edu (T. Reed)]

> My car just suddenly kicks like I've got a 50,000 pound AC compressor,
> then it won't rev past 4k.  Sometimes, it kicks back to life and is fine
> for a few minutes.  Occasionally, it's dead as a dog off the line (feels
> like starting in 4th gear), then explodes to life at 3000 rpm.
> The coil is the next component I'm looking at, as it's the only thing
> not new or swapped in the ignition.  (Knock sensor is the second one,
> brand new)
> The local VW mechanic replaced my distrib and rotor and timed the
> motor.  It was sluggish when I brought it to them (17+ second 1/4 mile),
> but ran normal.  Should I be wary of the job they did?  If the distrib
> cap is loose, I wouldn't be able to turn it by hand, right?
> How about the rotor?  How do I check that (visually) for problems?
> Thanks!

Okay, here is what I would check:

1. cam <-> crank timing. it sounds stupid, but if your car is running
crappy I'd really look in to it. I know from experience. Your car will
still drive with as many as 2-3 teeth off on the timing belt. This will
screw up your ignition timing, too, since the distributor is driven off
the exhaust cam. My car was actually fast as shit when this happened, but
only around redline :)

2. the coil is definitely a possibility. I would take the cheap route and
swap it with a known good from a local lister befwore buying a new one,
though. Any CIS-E coil should work so an '88-ish Golf/Jetta 16v would have
the necessary equipment if you can't find rocco peeps in your area.

3. pull the distrbutor cap and make sure you have all bosch components.
Check the distributor itself, the cap, and the rotor. you don't want any
aftermarket crap.. if you have said crap, get a bosch replacement asap

4. make sure you have the correct distributor cap for your distributor. As
my brother will tell you an 8v cap will fit on a 16v distributor.. your
car will just run shitty.

5. make sure the distributor is installed in the correct pair of bolt
holes. There are two sets and thus at least two ways it can be installed.
The plug for the hall sender should be facing towards the radiator.

6. check plug wire order. 1-3-4-2 COUNTER-clockwise, IIRC. the left hand
side of the motor as you're standing in front of the engine bay looking
towards the back of the car is where the #1 cylinder is. It counts up from
there as you go right.

7. make sure both metal finger-clamps are holding the distributor
cap on when you re-install it.

8. check that you have a good ground wire between the intake manifold and
the coil, and a good ground between the chassis and the
engine/transmission/starter, and a good ground from the battery to the
chassis or motor.

9. make sure your plug wires are in good shape. spray some water on them
and listen for arcing or a change in the idle.

10. try a different ICU. This is that little computer on a heatsink that
has a 7 pin connector. Apparently these go bad once in a blue moon..

11. pull back the boot of the connector for the hall sender and make sure
that the wires aren't frayed or shorting or soaked with oil.

12. check that you have no vacuum leaks and there is a good vacuum line
hooked to the knock sensor computer (the one with the yellow cap on the
side)

13. try swapping your knock sensor computer with someone. i've seen
several for sale for $25 in the past month in various places (eBay,
vortex, here, etc)

14. verify that your distributor isn't somehow 180 degrees off. find true
tdc using the screwdriver or wooden dowel down #1 spark plug hole method,
and verify your crank/cam sprockets are properly timed in the process, as
well as your flywheel timing mark. Then pull off your dist cap and check
that the rotor is pointing roughly at the cut/notch in the edge of the
metal backing plate on the distributor.

15. measure the resistances of your spark plug wires including the one
from the coil to the distributor cap and check against bentley specs.

Try all that stuff, then come back to the list if your car still doesn't
run right :)

HTH

-Toby