Starting problem

[tsyn]

Hi everyone,
Well, I thought I was an intrepid westy owner but this last debacle has me rather puzzled.
We have an 86 syncro which we use for an everyday vehicle. It has been fairly good to us and I have been able to fix, replace or modify just about everything that has gone wrong with this thing, and now it wont start.
So, of i went to the stickies and forums history etc.. and did everything tencentlife has been pounding into our heads.
Cranking, spark, fuel .....
The problem is, that it does crank over but there is no spark, no power to the FP relay, no power to the pump and no power to the ecu. I jumped the pump and it works so I am thinking that the only culprit left could be the ignition switch or a broken wire. I studied the bentley but I can't find how to test the ignition switch, plus, can it even be it when the engine is turning over?
Your collective wisdom is truly appreciated as always.
Cheers
Tony

[slc_syncro]

Tony,

Diagnosing the ignition switch is not too tough, but let me start by explaining the most common failure.

Vanagon (VW) ignition switches are oil filled to prevent arching across the contacts under the high load of cranking voltage. With age, the switch housing cracks and the oil leaks out allowing the contacts to arc. The arcing creates a carbon build up which effects the integrity of the contacts in the switch.

The trick in diagnosing a 'partial failure' is that it's hard to replicate the 'geometry' of the switch out the housing. The partial failure is that the power required to power the systems you describe is not sufficient or simply robbed due to resistance from the carbon buildup.

Often if you turn the switch to the 'on' position and wiggle it a bit, then crank, release (with a little wiggle again) your van will start. This has bailed me out of a couple of 'no starts' until I could replace the switch.

In my years of doing VW electrical I have seen this hundreds of times. I don't waste time testing the switch if it's very erratic or more than 5+ years old. You can remove it from the column and inspect it and if you see cracks (look close) or what appears to be internal discoloration, I would just replace it. The part should be available for $15~$20. I usually keep a spare in my glove box. It seems they love to fail on a hot day in the desert.

Since you car cranks you can add to your confidence level by running a jumper from the coil positive (black wire) to the terminal on the rear of the alternator, then crank it. It should start. If it does, I would just replace the switch. Be careful to connect your jumper wire to the coil first, then the alternator. That will avoid a spark at the coil which if it makes it to the coil negative (green wire) can theoretically damage the ignition computer.

As for actually testing the ignition switch, you need a test light or a VOM. I recommend a test light (get a good one) as a very useful addition to your tool kit. If you look at the back of the ignition switch (looking up the by the steering column) you should see 3 rather large wires. There may be more wire, but the larger ones are what you're interested in.

Assuming your battery is charge and you test light/VOM is properly grounded, the large red wire short have power with the ignition switch off. Red wires on VWs (original wiring) are always unswitched power from the battery.

Turn the key to the 'on' position and check the black wire. It should now have power. Black wires on VWs are always 'hot' when the key is on. This is the circuit that powers the ecu, coil, fuel pump relay, etc. If this doesn't light up then 'wiggle' it and see if if does. This is the wire that I suspect is casing your problem.

With the van in neutral and the the switch in the crank position the red wire with the black trace (I'm working from memory here so you might double check the wiring diagram) should light up. Since you van cranks, we know that this works. Perform this test again while checking the black wire. If the black wire looses power while cranking then this helps verify the faulty switch. It may dim a bit, but it should still light up in order to allow the coil to fire.

Hope this helps. I don't get on the site very often, so I may not be see any response. It's been a while since I've been on the site and I don't remember if I get mail notices.

Good luck.
Gene slc_syncro

[Christopher Schimke]

It's really easy to bypass the ignition switch.

Starting the engine without a key: Pull the plastic shroud that covers the steering column and remove the black plastic plug on the backside of the ignition switch. Now put a jumper between the large red wire and the solid black wire (a bent paper clip works great). Now place another jumper between the large red wire and the red/white wire. This is your starter wire. The engine should turn over at this point. When the engine starts, remove the big red to red/white jumper immediately. If you don't remove this jumper, the starter will continue to run just like holding the key in the start position.

So that eliminates the ignition switch from the equation. If the engine still won't start, check the smaller red wire on the starter itself for a good connection. Then trace this red wire to the alternator and check that connection.

From the alternator, this wire leads to terminal #21 that is inside the black box mounted on the left side forward wall of the engine compartment. You should have power at that terminal even with the ignition off.

From that point, the wiring makes a path to the double relay box that contains the fuel pump relay and the ECU relay. Check the red wire coming into the double relay box for power.

Without power to the double relay box, none of your described items will have power to them.
_________________
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[Vanagon Nut]

[tsyn]

Thanks for all your ideas. I just changed the switch, thinking it needed replaced anyhow and it was cracked and oily, a redish kind of oil. It wasn't at all hard to change it. If you don't have a puller, a hammer and a block of wood works great to take the switch housing of.
But, oh, to my horror, the van still didn't start. Frustration levels were approaching critical mass!
I finally chased it down to a broken connector at the alternator. I had checked it before but didn't see it. It was the connector for the red wire coming from the battery, easy fix, all is well.
Thanks
Tony