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helpmymac Thu Apr 24, 2014 8:47 pm

Once again your tool has made my life a lot easier. While driving home one day my van started bucking and jerking like someone was toggling a switch. I barely made it home. Soon after my van refused to start at all. The starter cranked just fine but nothing from the engine.

At this point I did what most people do, pop the hood, or engine cover in this case, and stare mindlessly at the engine hoping the solution would just pop into my head, which, it kinda did. I remembered about a year before building your diagnostic tool. So I hooked it up and vroom, the engine purred to life! At that point I started disconnecting leads one at a time (with the fuse out of course).

First lead I removed was to the coil. Fired right up. Second was the lead to the ECU relay. Nothing. Cool! Hooked it back up and disconnected the lead to the fuel pump. Fired right up. So, I determined that the issue lies with the wiring related to the ECU.

After consulting the Bentley wiring diagram (ouch, my brain hurts) I determine what wires go where. First I check the hot lead (red wire, always hot) going to the relay. It's hot as it should be. Next I check the black lead that activates the relay when the key is turned on. Nothing. According to Bentley, this wire comes from the coil. I start probing the wire at several points. Nothing. I determined that the connection at the coil is hot (with key on) so it has to be the push-on connector itself. I break away the plastic shield from the connector and find it to be green and corroded. Not too surprising on an old Vanagon. I snip the old connector off and crimp on a new one. Vrooooom, the engine comes to life! Sweet!

Thanks again for your wonderful diagnostic tool Mark!

bdcain Sun May 11, 2014 11:34 am

The diodes are from Radio Shack, #276-1661 pack of 4.

whats the diode valu? if looking to source diodes from other than radio shack
cheers

thatvwbusguy Sun May 11, 2014 11:50 am

Radio Shack's website lists them as 6A, 50V Rectifier Diodes

bdcain Mon May 12, 2014 11:46 am

hey now cant source the diodes may have some in a week or 2
can i forgo the diode branch and try the 2 relay spades
and then use a direct fused feed to the coil by itself?with relays in

cybervette Sun Aug 10, 2014 9:10 pm

I can't tell from these posts which year Vanagons this tool will work on. I have a 1983 2.0 air cooled California model with electrical starting issues. The junction box in the rear corner is different and doesn't have the same locations to plug the connectors in. I assume power needs to be routed to the double relay? I not sure which terminals need to receive power for this to work. Can this tool be adapted to use on this 13 pin dual relay?

Mark Lewalski Thu Aug 21, 2014 7:30 pm

I was ready to make this wiring tool but did one last inspection...

Yep, waaaaaaaaay up under and on top of the frame, I found my fuel pump wires kind of... lets say... separated.

Seems that a hungry critter chose to chew on those two wires (and the evap canister outlet hose) just to make me work on the van.

A quick snip here, a quick snip there, a crimp or two, and I'm back in business.

But...

This thread led me in the right direction to find the problem.

So thanks again to the Samba and all it's posters.

Mark

Gunldesnapper Thu Mar 05, 2015 11:35 am

I am bumping this since this is the first i have heard of this tool. Ill be making one this weekend. You sir are brilliant.

hurricanejosh Mon Sep 07, 2015 9:46 am

does anyone know if this bypass would work with an aircooled 2.0, or what modifications would be required? it seems to be just the thing i need to complete my troubleshooting of non-firing fuel injectors.

tom-menke Sun Sep 20, 2015 6:15 pm

I'm trying to diagnose a no-start issue on my 1985 1.9 Digijet. After making this tool and heading out to the van to test it, I appear to not have an empty connection on my coil. All 3 are occupied by black wires. Will this test tool work for me?

crazyvwvanman Sun Sep 20, 2015 7:35 pm

You can buy a splitter to add another spade, see photo. Or you can unplug the largest of the black wires and plug the tool in instead while also using the 2 relay bypass leads.
Make sure any black wire you unplug can't touch metal and short out.



Mark

Canoli Sat Oct 31, 2015 2:40 pm

How did you attach the diodes to the wire?

Jaybird707 Wed May 18, 2016 5:22 pm

Might have to make this for my issue. This should be a sticky.

mad.macs Wed Jul 06, 2016 6:50 am

I think the Digi-Key equivalent part number for the Diodes is 6A05DICT-ND
I miss being able to drive to a Radio Shack. The nearest electronics supply store is an Hour away now.

http://www.digikey.com/scripts/DkSearch/dksus.dll?...5881316708

Paulbeard Sat Dec 16, 2017 1:21 pm

This kit and a laminated instruction sheet would be a great addition to the toolbox under the bench (or wherever you keep yours).

16CVs Sat Feb 03, 2018 8:08 pm

Mark's tool rocks. My 91 Westy is coming back out of a 9 year sleep. It was cranking and no start. I jumped the fuel pump and it buzzed, I tested the Halls sensor plug and there was no power and the Crankcase vent Line heater had no power either.
I pluggd the tool in and followed Mark's dirrections and it fired right up. After diagnosis, it is the Ground wire to the fuel pump relay has an open. I can't figure out exactly which one it is on the body behind the coil. I've cleaned them all and added a new wire from the body to the block which was totally corroded away.
If I jump the brown ground wire to the relay it starts right up, pull the jumper and it dies. This is the wire that also runs over to the Idle control relay. I've checked the wire for continuity against all of the ground wire and can not isolate it.
At this point I am tempted to just jump in to it and ground it. The Bentley says that it is at ground point 12. Can anyone ID which of the ground wire go to the Fuel Pump Relay? I have other things to do and it starts right up, but I'd love to solve this mystery.

Alan Brase Sat Feb 03, 2018 9:54 pm

My 87 had almost exactly the same problem: One of the connectors going into the bottom of the relay the wire was almost completely corroded off.
You know you can release the terminals individually from the relay socket?
Seems like it was a brown wire, maybe with a white stripe?
I found mine with a test light connected to ground. When the ground terminal tests hot, something is wrong.After looking at it closely I could see the corrosion. I think all I did was open the terminal up and strip the wire and solder it on.
30 years of salty road driving finally caused a failure.

16CVs Sun Feb 04, 2018 11:49 am

All of my connections at the relays are sound. As I look at it I think I may replace the ground loops at the body.
To get it running I am using a jumper insid the breakout box clipped onto the stub of the ground wire and clipped to chassis ground.
I checked it with an OHM meter and was getting mixed signals and realize that it goes to the idle control relay and it was stealing ground through the box. I am now going to disconnect the Idle Control Relay and I think I'll find my open.

Stacy

Alan Brase Sun Feb 04, 2018 12:16 pm

Sounds like you're on the right track! What I meant to stress was that if you have a bad connection, it does not need to be totally open for it to cause problems. I'd guess as little as 4 volts lost across a connection may cause the relay to not function.
So a test light may not be as good as a digital device for troubleshooting. The light may not indicate at 4 volts but the digital meter certainly would.
In my case the terminal was still firmly crimped, but the conductors were green at the end of the insulation.
Incidentally, that same car is now failing to start again. Maybe I take my own advice and look at every wire connect exposed to road salt?

joebus Wed Feb 07, 2018 6:50 am

Hi,
Let me also jump in here, have a similar issue with my van, bought recently (2 weeks ago) and was told by previous owner it overheated, tried starting it but discovered no FP sound, fixed that, when cranking, discovered water running out from above pushrod tubes (Welsh plug rusted a hole in it), pulled the tops to sort that, but before that, tried cranking it, it sort of started, but does not run and dies immediately! I am closing the engine tomorrow, where can I start looking for solution with this short background? Really eager to get it running in order to diagnose other issues.
Thanks, any advice will be valued!
Cheers

Alan Brase Wed Feb 07, 2018 10:27 am

joebus wrote: Hi,
Let me also jump in here, have a similar issue with my van, bought recently (2 weeks ago) and was told by previous owner it overheated, tried starting it but discovered no FP sound, fixed that, when cranking, discovered water running out from above pushrod tubes (Welsh plug rusted a hole in it), pulled the tops to sort that, but before that, tried cranking it, it sort of started, but does not run and dies immediately! I am closing the engine tomorrow, where can I start looking for solution with this short background? Really eager to get it running in order to diagnose other issues.
Thanks, any advice will be valued!
Cheers
This is a 2.1? Precious few 2.1 wasserboxers in Namibia, I think!
Al



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