Former VWDieselParts.com Forum

Here's a run-thru of the glowplug system with some pictures that may help:

http://www.vincewaldon.com/index.php?op ... &Itemid=28

There are a bunch of vane control threads in the FAQ here:

http://www.vwdiesel.net/forum/index.php?topic=16687.0

As a data point: in the MK3 chassis the glow plugs afterglow for 3 minutes routinely... same Bosch Duraterms everyone's using in their MK1s and MK2s. So I'm wondering what else is going on here... 'cause it really doesn't sound like you're abusing your plugs beyond their design limits. A couple of r...

Thanks for your expertise. Nah, dunno about that... just posting what I've learned while experimenting with my two Jettas (one gasser and one diesel) and my antique B&K oscilloscope. Perhaps I need to get a life. :roll: :) But doesn't the control system (high pressure relay) work off of the ave...

It's actually not a voltage thing but a frequency thing... rather than watching the frequency of the points on an gasser's ignition system on a diesel the oil pressure warning system watches the frequency of the W terminal. Using a AC voltmeter as a test it's kinda all or nothing... if you're gettin...

It's suspicious that this started as a result of you changing out your alternator... although of course sometimes stuff just happens. ;-) It could be that your new alternator has a defective/disconnected W terminal... if you have a multimeter with an AC range you can check.... you should see about 8...

Is your new alternator diesel-specific with the W-wire that drives the oil pressure warning system?

the switch is rated for 50A at 12VDC. We're good there. Yuppers... loads good. The 'hot start relay" is an old vw van trick you can search for on the internet.. here's one description with a pretty good wiring diagram that should help give you the general idea. http://www.type2.com/bartnik/rel...

but a few times I tried the push button switch (took a while to crank over) I was getting the bztbztbzt from the GP solenoid, Hard to tell just from the picture, but that pushbutton is probably only rated for a couple of amps, and I'd bet your solenoid is drawing at least twice that... meaning the ...

Yup, as folks who swap in a serpentine setup soon discover.

So it modifies the square wave duty cycle and the tach interprets this as RPM? Square wave frequency actually... the square wave is just a feed off of one of the stator windings before rectification by the diode bridge. http://i197.photobucket.com/albums/aa85/vwaldon/Wterm_1100RPM_distance_web.jpg

The alternator has a special connection (the W terminal) that feeds a speed-dependent square wave to the tach and oil pressure warning system, if equipped.

Also a good idea to lube the guide pins with hi-temp brake grease, refreshing the rubber sealing bushings as required. TRW makes a very inexpensive kit with new guide pins, lube, and sealing bushings that's a good way to freshen 'em up from scratch... I almost always uncover at least one rusted and/...

Check the 4th mounting bolt on your IP carefully... the one down low at the high-pressure end. It likes to wiggle loose and then the pump passes on the fact that it's now dancing the rumba directly to your right foot. BTDT.

IIRC VW says cracks between valves are perfectly acceptable as long as they are not wider than 0.5mm... half the thickness of an American dime and about the thickness of a thumbnail, as it turns out!