82 Vanagon Diesel starting question

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greasy tom
Glow Plug
Posts: 3
Joined: Fri Oct 24, 2014 8:35 pm

82 Vanagon Diesel starting question

Post by greasy tom »

Hello,
New guy here. Thanks for having me on this forum.
I am posting to try to resolve a non-starting issue with my 1982 Vanagon with 1.9 NA diesel. After years of dependability and easy starting it decided to act up. It quit starting but cranks over well having a fresh battery. I checked for 12v at the fuel shutoff with key on and did have power there, however when my wife cranked the engine over, power to the shutoff stopped. I jumped power to the shutoff and the engine fired right up.
Question....... Why would the power coming from the glow plug relay cease when cranking the engine? Bad relay?
bscutt
Turbo Charger
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Joined: Mon Mar 10, 2003 4:49 pm
Location: Springfield, VA

Re: 82 Vanagon Diesel starting question

Post by bscutt »

this could be an ignition switch failure. When you crank the starter it basically cuts power to the regular circuits providing power to non-essential items. Most if not all of this is via the "X-relay" but I believe it's all controlled by contacts in the ignition switch. You would probably need a detailed schematic of that circuit to diagnose it. Not sure about the vanagon but changing out the ignition switch body requires some disassembly of the steering column, removing the steering wheel etc and may involve drilling out some tamper proof bolts.
You could "hot wire" your way around this by using a relay that is triggered off the starter wire and when activated provides power to the shutoff solenoid.

A basic headlight relay from your local auto parts store could be user. A relay has 4 or 5 terminals. Two of those terminals power the electromagnet inside the relay which causes the relay contacts to move. There is a diagram usually on the relay showing what looks like a coil. You would connect a wire from one of those (doesn't matter which) to the starter motor trigger wire (the small diameter wire going to the starter, usually connected via a slide on "spade" lug). The other side of the "coil" would be connected to chassis ground. For the contact connections (in other words the "switch" part of the relay) there would be terminals labeled "C" for common, "NC" for normally closed, and "NO" for normally open.
You would connect 12v from the battery (or also connect it to the starter Trigger wire) to the "C" terminal"and connect the "NO" terminal to the shutoff solenoid. So what would then happen when cranking is that power would turn on the relay and switch it on thus providing 12V to the starter solenoid only when cranking. When you stop cranking the relay would turn off (switch opens back up) and the regular power path would keep the solenoid turned on until you turn the key off.

This could also be a temporary fix until you find the root cause of the problem and fix it.
Bob

'06 Jetta TDI
'82 Rabbit 1.6NA
Honda, 99 GMC Suburban, '41 Chevy Coupe
greasy tom
Glow Plug
Posts: 3
Joined: Fri Oct 24, 2014 8:35 pm

Re: 82 Vanagon Diesel starting question

Post by greasy tom »

Thanks for the great ideas. I thought about running a wire from the starter trigger wire to the fuel shutoff but since there is power from the glow relay to the shutoff when key is in run position, I think it could feed back to the starter solenoid keeping it energized after the engine starts.
I've replaced the ignition switch twice in the last 80K miles, most recently two months ago. Could be the culprit....
Last night I ran wires to a switch by the driver's seat that let's me send power to the fuel shutoff while cranking. Works fine but I'd sure like to figure out what malfunctioned.
The solenoid idea may be a good solution if I can't figure it out.
Side note: This Vanagon has been running on straight recycled fryer oil for over 100,000 miles and loves it!
bscutt
Turbo Charger
Posts: 1720
Joined: Mon Mar 10, 2003 4:49 pm
Location: Springfield, VA

Re: 82 Vanagon Diesel starting question

Post by bscutt »

yes that's why you need the relay. otherwise your starter will keep running! I never messed around with a vanagon, only the old VW buses in the mid 60s Suspect the ignition switch may be the problem though.
Bob

'06 Jetta TDI
'82 Rabbit 1.6NA
Honda, 99 GMC Suburban, '41 Chevy Coupe
greasy tom
Glow Plug
Posts: 3
Joined: Fri Oct 24, 2014 8:35 pm

Re: 82 Vanagon Diesel starting question

Post by greasy tom »

I did the relay solution you explained. It works perfect. All is good now. Thank you......I don't have to park on hills anymore :-)
bscutt
Turbo Charger
Posts: 1720
Joined: Mon Mar 10, 2003 4:49 pm
Location: Springfield, VA

Re: 82 Vanagon Diesel starting question

Post by bscutt »

nice!
Bob

'06 Jetta TDI
'82 Rabbit 1.6NA
Honda, 99 GMC Suburban, '41 Chevy Coupe
Fatmobile
Global Moderator
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Joined: Wed Oct 30, 2002 10:28 pm
Location: north central Iowa

Re: 82 Vanagon Diesel starting question

Post by Fatmobile »

Good job finding the problem to begin with.
Most people check to see if the stop solenoid is getting power, but not while it's cranking.
'91 Golf gasser converted to a 12mm pump, M-TDI.
'84 1.6TD Rabbit with a VNT-15 turbo, still setup to run on vegetable oil.
'84 GTI with 1.7TD pistons and intercooled.
2003 TDI wagon
2000 TDI Jetta.
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